Digsilent Powerfactory: Integrated Power System Analysis Software

DIgSILENT PowerFactory
Integrated Power System Analysis Software

Generation * Transmission * Distribution * Industrial
Product Information
September 2002
DIgSILENT GmbH
Germany
Table of Contents
1. Introduction
2. What Makes PowerFactory Unique
3. General Concept
4. Modes of Operation
5. Data Management
6. The Graphical Editor
7. Documentation
8. Load Flow Analysis
9. Optimal Power Flow
10. Fault Analysis
11. Protection Functions
12. Harmonics
13. System Dynamics and EMT Simulation
14. Transient Motor Starting
15. Low-Voltage Network Analysis
16. Distribution Network Optimization
17. IEC Cable Sizing
18. Reliability Analysis
19. Production Planning
20. DIgSILENT Programming Language (DPL)
21. Software Installation Options
22. Compatibility to other Software Systems
23. DIgSILENT PowerFactory Connectivity
24. DIgSILENT Support and Training
25. DIgSILENT Consulting
1. Introduction
The development of DIgSILENT (DIgital SImuLator for Electrical NeTwork) software began
in 1976, and utilized the talent of many experienced power system engineers and software
developers directly involved with the planning, operation and maintenance of power systems.
Since the inception of DIgSILENT, the program has grown to incorporate a vast array of
analysis features that are required to plan, operate and maintain any aspect of the power
system.
The new DIgSILENT PowerFactory software is an integrated power system analysis tool
that combines reliable and flexible system modeling capabilities, with state-of-the-art solution
algorithms and a unique database management concept. The PowerFactory concept was
initiated in 1993 when the decision was made to re-engineer the already successful
DIgSILENT Version 10.31 with improved solution algorithms and advanced software
technology incorporating an object-oriented database. PowerFactory is setting new
standards in functional integration, by incorporating a feature that can best be described as
“Active Documentation”. This flexible feature allows the user to create detailed power
system models in a single database, allowing model functionality to be easily extended to
specify a wide range of steady state, time domain, frequency domain and stochastic system
characteristics, for all analysis requirements.
PowerFactory incorporates an impressive and continuously growing list of simulation

functionality including:
Load Flow and Fault Analysis of complete AC/DC network representation, and allows
meshed and mixed 1-,2-, and 3-phase AC and/or DC networks to be modeled.
Low Voltage Network Analysis
Distribution Network Optimization
IEC Cable Sizing
Dynamic Simulation
EMT Simulation
Eigenvalue Analysis
System Identification
Protection Analysis:
Harmonic Analysis
Reliability Analysis
Voltage Stability Analysis
Contingency Analysis
Power Electronic Device Modeling
Grounding
A/D Interfacing
Interface for SCADA/GIS/NIS
Compatibility with other software systems such as PSS/E & PSS/U
Multi-User Database and User Accounting
Advanced Tools: Optimal Power Flow and Production Planning
PowerFactory - the new generation power system analysis software was first released in
1997 providing the required product stability to guarantee efficiency in your daily application.
DIgSILENT PowerFactory 5
2. What Makes PowerFactory Unique
There are many commercial packages available that can address most power system analysis
problems. However, these packages differ considerably in their integration, result validity and
computational efficiency. This is due to a variety of approaches employed to incorporate the
following software requirements:
General software package design.

Data structures and redundancy.
Precise object definition.
Mathematical formulation.
Solution techniques.
Programming and maintainability.
Man-machine communication structures, techniques and compatibility.
Versatility.
Functional interaction.
DIgSILENT PowerFactory succeeds in amalgamating the requirements in each of these

areas, to combine sophisticated database techniques, for the efficient organization of system
data and projects, with a flexible system modeling capability and state-of-the-art solution
algorithms. The combination of these features in one fully Windows 95/98/NT/2000/XP
compatible package offers the user a high degree of flexibility, and a capability to analyze any
aspect of the power system, both, efficiently and accurately.
DIgSILENT PowerFactory is the leading product with respect to integrated modeling

capabilities and solution algorithms. It provides all required models and techniques of modern
power systems.
6 DIgSILENT PowerFactory
3. General Concept
DIgSILENT PowerFactory comes with a number of advanced features introducing highest

flexibility and providing best possible user support and quality assurance mechanisms.
Functional Integration
DIgSILENT PowerFactory software is implemented as a single executable program,

and is fully Windows 95/98/NT/2000/XP compatible. The programming method
employed allows for a fast 'walk around' the execution environment, and eliminates
the need to reload modules and update or transfer results between different program
applications. As an example, the power flow, fault analysis, and harmonic load flow
analysis tools can be executed sequentially without resetting the program, enabling
additional software modules and engines or reading external data files. Total
integration is our key concept for fast and reliable development of future generations
of the PowerFactory software.
Vertically Integrated
A special feature of the DIgSILENT PowerFactory software is the unique vertically

integrated model concept. This allows models to be shared for all analysis functions
and more importantly, for categories of analysis, such as “Generation”,
“Transmission”, “Distribution” and “Industrial”. No longer are separate software
engines required to analyze separate aspects of the power system, as DIgSILENT
PowerFactory can accommodate everything within one integrated frame and one
integrated database.
Database Integration
DIgSILENT PowerFactory provides optimal organization of data and definitions

required performing any type of calculation, memorization of settings or software
operation options. There is no need in tedious organization of several files for defining
the various analysis aspects. The PowerFactory database environment fully
integrates all data required for defining cases, scenarios, single-line graphics, outputs,
run conditions, calculation options, graphics, user-defined models, etc. There is no
need any more to keep and organize hundreds of files on hard disc.
• Single Database Concepts: all data for standard and advanced functions are
organized in a single, integrated database. This is applied also for graphics,
system stages, study case definitions, outputs, run conditions, calculation options,
fault sequences, monitoring messages as well as user-defined models.
• Multi-User Operation: support of multi-user database server operation with the

definition of accesses rights, user accounting and data sharing.
System Stage Management: in DIgSILENT PowerFactory, project and study

case development is a unique application of the object-oriented software principle.
Standard software packages often require the user to create a large number of similar
saved cases, with multiple nested directories for large complex networks and studies.
However, DIgSILENT PowerFactory has taken a totally new approach, and
introduced a structure that is both easy to use while avoiding redundancy for System
Stages and Study Cases.
4. Modes of Operation
Windowing Operation
DIgSILENT PowerFactory performs within a fully graphical windowing

environment, allowing the application of the most modern and intuitive man-machine
communication techniques. It follows the latest Windows standards, including tree-list
boxes, integrated browsers, tab-pagers, tab-bars, and docking windows, etc. In order
to be independent of specific manufacturers, proprietary libraries such as MFC are not
used.
Separate windows are available for output display, single line graphics and substation
drawings, data base editing and calculation functions. Additionally, multiple windows
in each window class may be open simultaneously to show for example different
aspects of the same substation graphic, or to highlight different hierarchies in a
network single line graphic.
Full Interactive Mode
The most basic (but nevertheless quite powerful) DIgSILENT PowerFactory mode
of operation can be found in the interactive command line. All activities executed by
the user are entered automatically in a special command Activity Window. This
window can be viewed at any stage, and be used for entering command sequences.
The interactive mode can be combined with the DIgSILENT Script Language DPL
providing a powerful tool for implementing user-defined procedures and batch mode
operation.
Engine Mode
DIgSILENT PowerFactory may be operated as a background process in situations

where it is integrated into GIS/NIS or SCADA systems or linked with other simulation
tools such as SIMULINK, ASPENTECH’s process simulation tool or other software
systems requiring interaction with network analysis procedures. The engine mode also
features parallel processing with other PowerFactory processes. The “Engine Mode”
capability permits the remote control of all PowerFactory functions.
5. Data Management
DIgSILENT PowerFactory comes with a new and innovative philosophy of storing system
data, system stage definitions, case data and runtime parameter. Instead of requesting the
user to edit, organize and maintain hundreds of files thereby keeping most information fully
redundant, PowerFactory features a powerful data manager that serves as a window to the
built-in relational database.
Introducing Intelligent Data Structures
In order to minimize data redundancy, object data is split into Type and Element Data so that
the same set of data can be used many times via type references. For most network objects
such as cables, motors or relays, comprehensive libraries are provided allowing user access and
maintenance on various levels.
Characteristics defined as vectors or matrices can be applied to perform parametric studies with
discrete or continues scales. The application of characteristics allows keeping a perfect
overview on data that change from case to case, such as loads, generation, set points or
transformer tap position, without having the need to create and organize additional and
separate cases.
System Stages and Study Cases are defined on the basis of easy-to-use mechanisms for
incremental information handling which creates and maintains base cases, alternatives,
expansion stages and operational scenarios. The maintenance of these variants will
automatically update or delete extensions of subsequent stages. In addition, full support is
given to the comparison of appropriate variants or alternatives.
The generation and editing of cases is not done by an additional 'Job-File Editor' but, instead,
is included in the program itself, utilizing modern windowing techniques for all data entry and
maintenance. Consequently, any modification of system data and structures is done within the
program’s memory and on the database level at the same time. This technique allows the
fastest possible program handling, since typical calculation sessions do not require the time
consuming and tedious standard procedures like “editing - file saving”, “ program restart -
update of data, etc”.
Libraries
The user is free to define and organize his own integrated libraries for all kind of data, grids,
output definitions, forms, user-written models, frames, fault sequences, DPL scripts, etc.
Special importance is given for equipment types such as transformers, cables, generators,
motors, conductors, tower configurations, controllers, relays or any other object support by the
PowerFactory software.
PowerFactory is supporting Global Libraries and User Libraries with respective access and
modification rights. Libraries can be imported and exported to many other software systems
such as MS-EXCEL.
System Stage Management
In general, any network structure is organized around Grid Definitions such as the transmission
systems, the distribution networks, industrial complexes, composite models or neighboring
systems. Here, the user is free to organize all data according to his individual requirements.
Configuration changes within each Grid Definition are defined as System Stages – sometimes
also called “Variants”. They are represented in a tree structure when there are hierarchies and
dependencies. Within each project, any number of System Stages may be created to represent
any number of study alternatives to the base case networks. All data - equipment data,
structural data and graphical information - is added or subtracted via the “incremental objects”
of System Stages. This, fully non-redundant organization principle provides basic quality
assurance mechanisms which are required to keep base cases and any subsequent alternatives
consistent.
To further reduce data redundancy

within DIgSILENT PowerFactory,
object data is split into type and
element data. This means for
example, that a section of “cable”
from say node A to node B in a
network, requires a certain data type
(e.g. NACBA), and element data
specific to that section, e.g. length,
reduction factor, etc. This database
strategy has the advantage that any
updated type information will be
automatically incorporated into all
System Stages employing that type.
Study Case Management
Study Cases are used to define and activate certain functions and parametric alternatives of
System Stages. They allow to define which grid variants, network interconnection options or
system expansion stages are activated. Additionally, they are used to initialize certain sets of
calculation commands such as:
• Command options
• Trigger settings
• Simulation events
• Graphical desktop
definitions
• Display options
• System Stages
The Study Cases also save all

data necessary for reproducing
previously obtained results on
basis of a single mouse-click.
Basic Quality Assurance Principle - No Data Redundancy
One benefit of this data structure is that large power companies have only a single database
with a single set of data to manage. In case of a change in network data, updating the
database only requires the database administrator to make one change and all System Stages
of all applications of all network simulations are updated automatically. This feature improves
quality assurance and is an attractive feature to many power companies.
6. The Graphical Editor
Interactive Graphics
DIgSILENT PowerFactory also provides a fully integrated graphical editing environment,

which enables the user to:
Draw and modify electrical grids for integrated network and area diagrams, classic single
line and substation configuration diagrams, with a configurable multi-layer network viewing
and plotting capability;
Multi-Layer-Techniques: view and operate several windows with different layers and
grid sections simultaneously. Utilize several graphical representations of the same system
at the same time;
Auxiliary graphics are best used to further document your drawings via text boxes or
sketches;
Utilize a comprehensive “drag and drop” power system element library containing
transformers, generators, HVDC systems, etc., which the user is free to expand to include
new elements for both devices and types;
Define substation diagrams that generate the graphical representation of basic HV and MV
substation types automatically according to the ABB handbook, namely for:
- 1-, 2- and 3-busbar systems with and without transfer buses

- U-Bars
- Ring main schemes
- 1 1/2 breaker schemes
Automatically modify library-generated substations according to user specific requirements;

Reflect any editing activity on the graphical level immediately in the case definition;
Network Coloring: define different colors and line widths to represent voltage levels,
voltage bands, areas, grids, isolated voltage levels, or other user-defined criteria;
Define single or multiple breaker and disconnectors in cubicles and hence in the station
graphic;
Update, adjust and compare single line diagrams and case definitions to guarantee that
graphical versions of grids are consistent;
Initiate calculation events directly within the graphical environment, including circuit
breaker switching, fault implementation and other data changes;
Results Display: Display calculation results immediately in result boxes within the single
line diagram. All program variables and signals can be displayed according to the most
flexible user definition for various object categories and levels;
Access equipment editing menus in the single line diagram by cursor selecting the
appropriate element, region or composite model;
Zoom-in or zoom-out of area networks or composite model graphics;
Show a mixed representation of detailed substation and single line graphics;
Display any calculation result, object parameter or additional user text at any location
according to user definable settings;
Elements in object browsers can automatically be searched and marked in graphics for
visual identification
Block Diagrams for User Written Models
DIgSILENT PowerFactory features the most user-friendly, flexible and powerful definition of
user written models within a fully graphical environment. The integrated graphical editor
provides the needed flexibility to implement the most complex models also supporting unlimited
model nested. Connectivity checks are permanently active ensuring proper “wiring” of all frame
signals and model connections.
7. Documentation
DIgSILENT PowerFactory provides various methods and options to document input and
output data, report and print calculation results and to generate graphical documents.
Text Output
Following the classical approach, text pages can be generated to report on entered equipment
data, summarize calculations results, print detailed reports on load flows and short circuit
results, document harmonic analysis results, provide lists on relay characteristics and relay
settings, or summarize on DSL models. All reports can be printed in graphical format on
standard printers in various formats.
Text output is based on forms with flexible definitions according to user needs. At any time,
user may change reporting language, layout and variables. Standard outputs are pre-defined in
A5 size format.
There are a number of different methods to select objects for which an output shall be
generated. Based on a pre-defined or user-definable “Selection” various filters may be stored
and applied accordingly. Filter definition is provided via Data Manager Selection, Object
Manager Selection or directly on the level of the single line graphics.
Spread - sheet Output
Both, Data Manager as well as the Object Manager feature a direct link with the Windows
Clipboard allowing to directly transfer any variable into other application programs. As special
Flexible Page definition is supported which makes it possible to report and display any variable
such as input parameter, calculation result, DSL signal or DPL script variable.
Virtual Instruments
DIgSILENT PowerFactory applies the concept of Virtual Instruments (VI) as a tool for
displaying any calculated result or variable. These results may be in the form of bar graphs,
plotted curves, or even tables of values, with all display representations completely user-
definable. VIs are used to display protection curves, harmonics analysis results or to view
electrical variables from any location in the network single line diagram, and any model variable
during RMS and EMT simulations. Many VIs provide additional build-in functionality such curve
labeling and measuring, scaling, curve fitting, filtering and digitizer functions.
Graphical Documentation
In general, any printing or plotting device supported by the Windows Print Manager can be
used to produce high quality graphical documents from within the program. Graphical
interchange with other software systems via the Windows Meta File (WMF) and Bit Map
exchange is available with high precision coordinates. In addition, format conversion from WMF
to other formats like DXF is available via internal program format conversion routines.
8. Load Flow Analysis
Within the Load Flow analysis environment, the accurate representation of a variety of network
configurations and power system components is possible. Any combination of meshed 1-, 2-,
and 3-phase AC and/or DC systems can be represented and solved simultaneously, from HV
transmission systems, down to residential and industrial loads at the LV voltage levels. The
Load Flow tool accurately represents unbalanced loads, generation, grids with variable neutral
potentials, HVDC systems, DC loads, adjustable speed drives, SVS, and FACTS devices, etc., for
all AC and DC voltage levels.
DIgSILENT PowerFactory also incorporates an enhanced non-decoupled Newton-Raphson

solution technique, with current or power mismatch iteration, and typical round-off errors below
1 kVA for all buses. The superior stability and convergence of the implemented algorithms is
making other traditional load flow methods such as Current Iteration obsolete. Several iteration
levels are guaranteeing convergence under all conditions. If for example the Load Flow is
tending towards divergence, due to unrealistic constraints, the solution algorithm will analyze
the constraints and modify them automatically.
DIgSILENT PowerFactory is introducing a new, intuitive and easy-to-use modeling

technique fully avoiding the definition of bus types such as SL, PV, PQ, PI, AS or any other
definition often required to model special devices. PowerFactory simply provides such control
mechanisms and devices characteristics which are found in reality.
More Load Flow Analysis Features
Supports device characteristics, such as loads with voltage dependency and

asynchronous machines with saturation and slip dependency, etc.
Practical station control features with various local and remote control modes for
voltage regulation and reactive power generation. Reactive power is automatically
adjusted to ensure that generator output remains within its capability chart.
Comprehensive area/network power exchange control features using Secondary
COntrollers (SCO) with flexible participation factors.
Transformer OLTC able to control local or remote bus voltages, reactive power flows
as well as voltage-drop compensation (LDC) within distribution systems.
Devices controllers for shunts, double-fed asynchronous machines and other power
electronics elements such as PWM converters, inverters, rectifiers or integrated FACTS
devices.
Local and remote control mechanism for SVS systems. Automatic and continuous
control of the TCR and TSC switching is performed within component ratings to hold
voltage at a given value.
Correct representation of transformer vector groups and phase displacement.
Shunts can be modeled to consist of a combination of series and/or parallel connected
capacitors, reactors and resistors. Shunts can be connected to busbars and feeders or
to the remote end of cables and lines. Filters may consist of any number of shunt
combinations. Automatic shunts switching can be included in the automatic voltage
regulation.
Full support of any parameter characteristic and scale to allow parametric studies or
easy definition of loading scenarios or load profiles.
Contingency Analysis
The new DIgSILENT PowerFactory Contingency Analysis functions have been designed to
offer a high degree of flexibility. There are now three different ways that contingency analyses
can be carried out:
By analyzing a single contingency. This is achieved by selecting one or more objects

for simultaneous outage, and running a load flow case to analyze the outage.
By creating one or more contingencies, each of which may define one or more objects
to be taken out of service simultaneously. Load flows are then run to analyze all
outage combinations.
By running a DPL script that specifies certain contingencies, which are then analyzed
sequentially.
A detailed report of each contingency case for each option is available after the analysis has
been completed.
Further Special Functions
Analysis of system control conditions

Calculation of dV/dQ sensitivities.
Parameter scaling for the determination of voltage stability curves (V-P) and transfer
limits (Voltage Stability Analysis)
Determination of “Power at Risk”
Automatic Outage Simulation (n-1), including detailed reports for user-defined voltage
limits and equipment overloading
Support of DPL scripts e.g. to perform load balancing, determination of penalty factors
or any other parameter required.
Load Flow Results
Display of any variable within the single line and station diagram according to a most
flexible VI definitions;
Fully flexible filter mechanisms to display objects in colored mode;
Detailed analysis reporting, which can list overloaded system elements, unacceptable
bus-voltages, islanded system areas, out of service components, voltage-levels, area
summaries, and many other documentation features;
Detailed text output with pre-defined or user-defined filters and levels;
Support of the Flexible Page with free variable definition and DPL interactivity;
Result export to other software system such as MS-EXCEL
Radial Feeder Analysis
DIgSILENT PowerFactory provides a number of special functions that make LV analysis

more transparent and adopted to practical constraints.
Feeder Plots
Using the most innovative “Feeder plot” a

special, high level graphical display feature
(Virtual Instrument, VI) is provided to
increase transparency in grid loading and
voltage profile analysis across several
voltage levels. Full interactivity is given to
access via the VI all relevant data and
structures.
Feeder Load Scaling
Feeder load scaling is a feature that allows to automatically adjust the individual bus loads to
match a given total feeder load. An option is available to decide which loads of a feeder will
participate in the scaling procedure.
9. Optimal Power Flow
The DIgSILENT PowerFactory Optimal Power Flow (OPF) serves as the ideal complement to
the existing load flow functions. Whereas the standard load flow calculates branch flows and
bus bar voltages based on specified “set points” (active/reactive power generation, generator
voltage, transformer tap positions, etc.) the OPF also calculates the “best possible” values for
“higher level set points” considering a user specified objective function and a number of
constraints. In this way, the OPF adds intelligence and consequently improves efficiency and
throughput of power system studies significantly. The OPF avoids the tedious and manual
search for a “best possible solution” via several, iterative runs requiring a number of manual
modifications, which quite often are leading to un-comparable solutions when performing
various load flow sequences to arrive at certain conditions as defined by various load flow
scenarios. From practically any starting point, within a couple of fast iterations, the OPF will
assure a globally optimal and reproducible solution, satisfying the defined system limits while
minimizing the applied cost functions.
From point of view of software application, the OPF is just an enhanced function of the
standard load flow, being fully integrated, powerful and easy-to-use. The OPF is simply
accessed via an extra page of the load flow option definitions.
The OPF supports a number of new applications typically found in today’s less-regulated power
markets such as:
Scheduling of Ancillary Services for reactive power and active power

Development of system reference scenarios
Transfer capability analysis
Determination of voltage stability limits
Implicit Penalty Function consideration
Comparative reliability analysis studies
Supported Objective Functions:
• Minimize system losses

• Minimize fuel costs (based on non-
linear fuel cost functions for each
generator)
• Maximize profit (considering fuel
costs and load tariffs)
• Minimize area exchange flows.
Above listed objective functions are solved

under the consideration of a number of
possible constraints to which the final
solution must comply with are:
• Branch flow limits (loading)

• Bus bar voltage limits
• Generator reactive power and stator current limits
• Generator active power and reserve limits
• Transformer tap changer limits
• Adjustable shunt limits
Because the OPF can also dispatch the active power of generators considering reserve limits
and the fuel cost minimization which is based on non-linear fuel cost functions, the
PowerFactory OPF is at the same time very advanced Economic Dispatch function.
10. Fault Analysis
DIgSILENT PowerFactory features three-phase network fault calculation functionality based

on international standards as well as the most accurate DIgSILENT General Fault Analysis
(GFA) method.
In general the following features and options are supported for all implemented fault analysis
methods:
Includes calculation of all three symmetrical components as well as phase quantities.

User definable fault impedance
Calculation of short circuit quantities at a specific, selected busbar or along a defined
section of line/cable, including all branch contributions and busbar voltages.
Provision of specially designed graphs and diagrams including all quantities typically
required by the protection engineer.
Thermal overloads highlighted on the single line graphic for busbars and cables, with all
equipment overloads available in a summary text report.
A complete power flow output, including branch currents and busbar fault voltages, can be
displayed for all branches and nodes, or selected busbar subsets.
Calculation of Thevenin impedances as seen from the faulty node.
Calculation of apparent phase impedances (magnitude and angle) at any location along a
transmission line/cable or busbar, for all branches, selected subsets, or 1,2 or 3 nodes
from the faulted node.
IEC 909 and VDE 102/103 Fault Calculation
For the world-wide most frequently used standard for component design, PowerFactory
provides a strict and complete implementation of the IEC 909 and VDE 102/103 fault
calculation standard according to the latest published versions.
Calculation of the initial symmetrical peak current Ik" and short circuit power Sk", peak
short circuit current Ip, symmetrical short-circuit breaking current Ib, and thermal
equivalent current Ith (IEC 60909-0 2001). Both minimum and maximum short circuit
currents can also be calculated based on network voltage c-factors.
Support of all fault types (balanced and unbalanced)
Automatic grid type identification
Calculation of Ik with selectable “Decaying Aperiodic Component”
Selectable method for calculating the Peak-Short Circuit Current in meshed networks
User definable fault impedance, conductor temperature and c-voltage factor.
Fault calculation can include or exclude motor contribution to the fault current.
Provision of specially designed graphs and diagrams required by the protection engineer
for protection coordination and design.
IEEE 141/ANSI e 37.5 Fault Calculation
PowerFactory provides a strict and complete implementation of the IEEE 141/ANSI e37.5 fault
calculation standard according to the latest published version. Special features are:
Transformer tap positions can be included in the fault current calculation.

User defined fault impedance and pre-fault voltage can be included in the fault current
calculation.
DIgSILENT General Fault Analysis (GFA)
Especially for protection coordination purposes or for analyzing observed system contingencies,
the DIgSILENT PowerFactory General Fault Analysis (GFA) is providing the required
algorithms and precision for determining the “real” short circuit currents without considering
the typical simplifications or assumptions typically applied for norm based fault analysis. The
General Fault Analysis (GFA) is based on an unconstrained sub-transient power flow, and takes
into account all specified network devices with their full representation and pre-faulted load
conditions. The general fault analysis tool is based on a complete 3-phase system
representation (a-b-c phase coordinates). The analysis of multiple fault conditions is one of the
most important features of the GFA.
Additional features are summarized below:
Calculation of any asymmetrical, single or multiple fault conditions with or without fault
impedance, including single and double phase line interruptions.
The initial response of many other “event” like motor starting, generator tripping, shunt
switching, load shedding, etc., may be analyzed (stability module required).
Fault Analysis Results
Various reports may be produced, including detailed reporting on all short circuit levels for
all faults, or alternatively, a specific report for one fault type. Special protection reports can
also be generated to include impedance, current and voltage information.
Display of any variable within the single line and station diagram according to a most
flexible VI definitions.
Fully flexible filter mechanisms to display objects in colored mode
Detailed analysis reporting, which can list overloaded system elements, unacceptable fault
currents, islanded system areas, out of service components, voltage-levels, area
summaries, and many other documentation features.
Detailed text output with pre-defined or user-defined filters and levels.
Support of the Flexible Page with free variable definition and DPL interactivity.
Result export to other software system such as MS-EXCEL
11. Protection Functions
The DIgSILENT PowerFactory protection analysis tool is an extension of the basic functional
model library, containing additional devices like CTs, VTs, relays, fuses and more complex
protection schemes including user-defined modeling capabilities. Additionally, there are
specially designed interactive VIs (Virtual Instruments) for displaying system quantities and
more importantly for modifying protection settings in the graphical environment. This last
feature is especially useful, as coordinated settings between different protection schemes can
be modified via the cursor in the graphical environment, which then updates the settings both
in the database and simulation environment.
All protective devices are also fully functional under steady state as well as transient conditions,
allowing device response assessment under all possible simulation modes, including load flow,
fault analysis, RMS and EMT.
Protection Model Library and Functionality
The DIgSILENT PowerFactory protection

analysis tool contains a comprehensive
protective device model library and includes:
Time overcurrent relays for 1 phase, 3

phase, ground and negative sequence time
over-currents. Additionally, the relay
characteristics can incorporate the following
standards and solution methods:
• IEC 255-3
• ANSI/IEEE
• ANSI/IEEE squared
• ABB/Westinghouse CO (Mdar)
• Linear approximation
• Hermite-spline approximation
• Analytical expressions vi build-in formula editor and analyzer
Instantaneous overcurrent relays for 1 phase, 3 phase, ground and negative sequence
time over-currents.
Directional relays for overcurrent, power, ground current, and any combination of time and
instantaneous overcurrent relays. Additionally, voltage and current polarization is used for
the detection of negative and zero
sequence components.
Distance relays for phase, ground, and
zone distance protection. Provision is
available for incorporating overcurrent and
under-impedance starting.
Different characteristics for distance relays
steps including:
• MHO
• Polygonal
• Tomatoes
• Lens
• Circle
• R/X Blinder
• Offset characteristic
Voltage relays for undervoltage, instantaneous voltage, voltage balance and unbalance.
Additional devices include Breaker fail, Motor protection, Generator, and Out-of-step relays.
Apart from the standard circuit breakers the model library contains Low voltage circuit
breakers and Fuses
Additional to these protection functions and relays DIgSILENT PowerFactory provides

further devices and characteristics for more detailed protection system modeling, such as:
Current and Voltage transformers that include saturation effects

Conductor, cable damage curves, cable overload curves and inrush peak current modeling
Transformer damage curves (ANSI/IEEE Standard C57.109 – 1985) and inrush peak
current modeling
Motor starting curves, cold and hot stall, in-rush peak current modeling, and any user
defined curves
All protection device models are implemented within the composite model frame environment.
This allows the user to easily design and implement their own models, by utilizing the graphical
user interface for constructing block diagrams (see also stability section).
Protection Co-ordination
The co-ordination of overcurrent-time protection is done graphically on basis of the current-

time diagram. Relays settings are modified using Drag & Drop for moving the characteristics.
Short-circuit currents, calculated with the short circuit command, are shown in the diagram as a
vertical line. In addition the corresponding tripping times of the relays are displayed. Co-
ordination between relays at different voltage level is also available. Therefore currents are
automatically based on the leading voltage level, which can be selected by the user.
For distance protection co-ordination two powerful graphical features are integrated. The R-X
diagram for displaying the tripping area of distance relays and the line impedances. Several
relays can be visualized in the same R-X diagram. This might be useful for comparison of two
relays that are located at both ends of the same line. The relay characteristics with the
connecting line will be shown in the same R-X diagram. After short-circuit calculations the
measured impedances are visualized with a marker in the shape of a small arrow or cross.
From the location of the marker the user can see the tripped zone and its time of the relay. For
dynamic simulation, measured impedances of the relays can be displayed online. Therefore it's
possible to detect problems graphically like a power swing.
The time-distance diagram is used for checking the selectivity between relays along a co-
ordination path. The relays of a co-ordination path can be displayed in diagrams for forward,
reverse or for both directions. Consequently, it is very easy to check the selectivity of the relays
along a co-ordination path. Two different methods for calculation of the tripping curves are
provided. These are the kilometric and the short circuit method.
Kilometric method: the reach of the zones is calculated by cutting the given positive sequence
impedance of the lines with the impedance characteristic of the relays.
Short circuit method: this is the main method for checking the selectivity. Along the co-
ordination path short-circuits (user-defined fault type) are calculated. The tripping times for the
time-distance curve are determined using the calculated impedances. The starting signal of a
relay is considered, too.
As special feature blocking signals or POTT (Permissive over-reach transfer tripping) PUTT
(Permissive under-reach transfer tripping) are also taken into account. In addition to tripping
curves of distance relays the curves of overcurrent relays can be displayed and co-ordinated in
the same diagram using the short circuit method.
Both, the kilometric and the short circuit method consider breaker opening times in the
calculation of tripping times. As an option the breaker opening time can be ignored.
Protection diagrams
Relay settings are modified very easily be clicking twice on the characteristics/curves. The
settings dialog for the clicked zone pops up and the parameters can be modified. After
confirmation of the changes with the OK button the dialog is closed and the
characteristics/curves are adapted to the new settings immediately. The most important
settings and commands in protection diagrams can be accessed easily using the context-
sensitivity menu.
DIgSILENT
0.60
[s]
0.48
0.36
0.24
0.12
0.00
0.0 21.0 42.0 63.1 84.1 [pri.Ohm] 105.
HV-UT2 SS-D3 SS-D2 SS-D1 HV-Infeed
HV-UT2 SS-D3 SS-D2 SS-D1 HV-Infeed
105. [pri.Ohm] 84.1 63.1 42.0 21.0 0.0

0.00
0.12
0.24
0.36
I=2279.374 pri.A
I=2276.817
DIgSILENT
1000.0
0.48
[s]
0.60
x-Axis: Reactance Cub_2\Rel-U1 Cub_2\Rel-L2-1 Cub_3\R1-Dist
Cub_1\R22-D1 Cub_2\R3-Mho-1 Cub_1\R4-Mho-2 [s]
Cub_2\R5-Mho-4
Cub_1\R6-Mho-5 Cub_2\R7-Mho-6 Cub_2\R8-Dist
Max. 3-phase Short-Circuit TD-Path I Date: 7/19/2002 Transformer Damage Curve

DIgSILENT Annex: /2
10.000
1.078 s Relay I Curve

Fuse Curve
Motor Starting Curve
0.130 s
0.100
Relay II Curve
DIgSILENT
[pri.Ohm] R3-Mho-1
0.001
Zl A 101.311 pri.Ohm -0.9 deg
20.00 kV 1.0000 10.000 100.00 1000.0 10000. [pri.A] 100000.
Zl B 10.522 pri.Ohm 81.25 deg
Zl C 100.634 pri.Ohm
0.40 kV 167.12100.000
deg 1000.0 10000. 100000. 1.00E+6
120. Faulttype: BC
Tripping Time: 0.09
110.00 kVs 1.0000 10.0000 100.000 1000.0 10000.
110. Zone:1 Cub_2\Rel-U1 Motor 1
Ph-Ph 1: 0.09 s T-110/20 Cub_2\Rel-L2-1
Zone:2 Cub_2\Fuse
100. Ph-Ph 2: 0.19 s
Zone:3
90.0 Ph-Ph 3: 0.29 s
Zone:4
80.0
Ph-Ph 4: 0.44 s
R1-Dist
70.0
Zl A 110.057 pri.Ohm 16.91 deg
Zl B 44.355 pri.Ohm 82.75 deg
Zl C 109.521 pri.Ohm 149.23 deg
60.0 Faulttype: BC
Tripping Time: 0.17 s
50.0 Zone2
ZPHPH2: 0.17 s
Zone3
40.0 ZPHPH3: 0.37 s
30.0
20.0
10.0
-50.0 -40.0 -30.0 -20.0 -10.0.. 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100. 110. 120. 130. 140. 150. 160. 170. 180. 190. [pri.Ohm]
-10.0..
-20.0
-30.0
Cub_3\R1-Dist
Cub_2\R3-Mho-1
Max. 2-phase Short-Circuit R-X Diagram Date: 7/19/2002

DIgSILENT Annex: /3
12. Harmonics
The harmonic analysis functionality is ideal for applications in Transmission, Distribution and
Industrial networks for filter design, ripple control signal simulation or for the determination of
network natural resonance frequencies.
For analyzing the impact of harmonics in power systems, DIgSILENT PowerFactory provides
two basic harmonic analysis functions.
Harmonic Load Flow
The DIgSILENT PowerFactory harmonic load flow features the calculation of harmonic
voltage and current distributions based on defined harmonic sources and grid characteristics. It
allows the modeling of any user-defined harmonic voltage or current source, both in magnitude
and phase including inter-harmonics. The harmonic sources can be located at any busbar in the
power system and may be implemented within any network topology. Most power electronic
devices carry their harmonic characteristics already and need not to be defined by the user.
3-phase harmonic voltage and current distribution allowing an unbalanced harmonic load
flows to be carried out.
Harmonic current sources can be associated to every load, to any SVC (TCR injection) and
to any rectifier or inverter. Harmonic voltage sources can be modeled using the AC voltage
source model or the PWM AC/DC converter model. The build-in rectifier models inject the
spectrum of ideal 6-ulse rectifiers if no other definition has been made.
DIgSILENT PowerFactory supports any type of characteristic harmonic, un-

characteristic harmonic (even harmonics etc.) and non-integer (inter-) harmonics. Also
unbalanced harmonic sources (e.g. single-phase rectifiers) are fully supported. The
analysis of inter-harmonics or unbalanced harmonic sources is based on a complete abc-
phase network model.
Transformer phase shifts are completely represented why 12 pulse rectifiers can be
modeled correctly using 6-pulse rectifiers and transformers with the necessary vector
groups.
DIgSILENT PowerFactory calculates all symmetrical and asymmetrical harmonic indices

for currents and voltages, including harmonic current indices and harmonic losses, such as:
- HD and THD
- IT product
- Harmonic losses
- Active and reactive power at any frequency
- Total active and reactive power, displacement and power factor
- RMS quantities
- Unbalance factors
Results can be represented:
- In the single line diagram (preferably total harmonic indices)

- As histograms (Frequency domain)
- As waveform (Transformation into the time domain)
- As profile (e.g. THD versus bus bars)
Frequency dependent representation of network elements such as lines, cables, two and
three-winding transformers, machines, loads, filter banks etc. for considering skin effects.
Frequency Scan
The frequency scan performs a continuous analysis in the frequency domain. The most
common application is the calculation of self- and mutual network impedances for identifying
the resonance points of the network.
All impedances are calculated simultaneously in the same run. Since DIgSILENT
PowerFactory uses a variable step size algorithm, the calculation time of frequency scans
is very low while the resolution around resonance points remains very high (typically 0.1
Hz).
DIgSILENT PowerFactory also supports series voltage sources with which it is possible
to identify possible series resonance points of the network (important for subsynchronous
resonance studies).
Frequency scans can either be performed with the positive-sequence network model (very
fast) or the complete three-phase abc-network model.
Calculation of self- and mutual network impedances
Calculation of voltage amplification factors
Impedance plots may be realized in either Bode, Nyquist or magnitude/phase forms.
Support of flexible, user-defined libraries for voltage and current sources as well as for
indices
Network Modeling
Skin effect is considered by associating frequency characteristics to line or transformer

resistances and inductances. These characteristics can either be specified by setting the
parameters of a polynomial expression or by entering the characteristic point by point using
tables. DIgSILENT PowerFactory uses cubic splines or hermite polynoms for appropriate
interpolation.
Lines are modeled either by approximate PI sections or the fully accurate distributed
parameter line model that should always be used for long lines or high frequency
applications. Skin effect can be included in both line models.
Filters can either be specified by so-called “Layout” parameters or by “Design”
parameters. “Layout” parameters are typically the rated reactive power, the resonance
frequency and the quality factor. Design Parameter are the actual values of R, L, and C.
Ripple Control Signals
DIgSILENT PowerFactory provides full support for analyzing and dimensioning ripple control
systems. Series and parallel coupling of ripple control systems can be modeled including all
necessary filter elements.
The level of the ripple control signal in the entire network is calculated and reported in the
single line diagram, output window or the browser.
Dimensioning of Filters
DIgSILENT PowerFactory features a special, easy-to-use function for the dimensioning of all
kind of filters. All relevant voltages across all components are calculated and available in the
“Filter Sizing” report.
13. System Dynamics and EMT Simulation
DIgSILENT PowerFactory provides a basic simulation kernel, which, together with a

comprehensive model library and a graphical, user-definable modeling system (DIgSILENT
Simulation Language (DSL)), provides an extremely flexible and powerful platform for solving
power system dynamic problems. Any combination of meshed 1-, 2-, and 3-phase AC and/or
DC systems can be represented and solved simultaneously, from HV transmission systems,
down to residential and industrial loads at the LV distribution levels. It includes transient
analysis problems concerning short-, mid- and long-term dynamics, with adaptive step-sizes
ranging from milliseconds to minutes.
DIgSILENT PowerFactory features integrated analysis of classical stability problems using

the RMS simulation mode as well as electromagnetic transients via EMT simulation. In other
words, PowerFactory incorporates solution techniques making additional EMT software
obsolete. This approach has many advantages over the classical application of two separate
software systems such as:
No duplication of data entry and case definitions

User defined models need to be setup only once
Absolutely compatible modeling features for RMS and EMT
Easy cross-check of RMS results via EMT simulations
No additional investments in other software and training
DIgSILENT PowerFactory is the leading software in power system dynamics. It’s modeling
flexibility and precision, it’s numerical robustness and performance and especially it’s
comprehensive model library is providing everything required to implement all kind of dynamic
studies in the most efficient and economic way.
System Dynamics (Stability, RMS)
At DIgSILENT, it is a principle policy to provide the most accurate simulation models

and up-to-date solution algorithms, to enable analysis of the complete range of power
system dynamic phenomena. On basis on fast and reliable adaptive step-size
algorithms, the simulation kernel features excellent precision when solving short-, mid-
and long-term stability aspects.
Mid-Term Stability
Short-Term Stability Long-Term Stability
Excitation Limiting
Induction Motor Dynamics
System Operator
Capacitor Switching
Line/Transf Overloading
Prime Mover Control
LTC Transf
Generator/ Excitation Dynamics
Generator Inertial Dynamics

SVC
1
0.1 10
1 100
10 1000
100 10000
1000 100000
10000
Time in seconds
Time frames for power system stability studies
The dynamic simulation tools available to the user in DIgSILENT PowerFactory
incorporate the following features:
Calculation of initial conditions is carried out prior to the dynamic simulation, and
is based on a solved load flow and other conditions such as power plant settings.
Network representation and algorithm options are selected, with the following
system representations available:
• positive sequence only - the classical RMS representation for simulation

studies
• steady state a-b-c RMS representation, allowing any kind of asymmetrical
fault;
Highly accurate and adaptive integration technique for solving the AC and DC
network load flow and dynamic model equations. This is combined with a non-
linear electromechanical model representation to enable a high degree of solution
accuracy, algorithmic stability and time range validity;
Models for both solid and salient pole generators down to the sub-transient
reactance and time constant level, with enhanced saturation effects, and Canay
reactance incorporated;
A sophisticated model for asynchronous machines that includes primary and

secondary leakage reactance saturation, rotor resistance slip-dependency, and an
additional single/double cage asynchronous machine with parameter
identification;
DC motor models, ASD systems (Adjustable Speed Drives), double-fed induction

machine, PWM converter and other power electronic elements such as softstarter,
inverter and rectifier;
General load models where load inertia, bus voltage and frequency dependence
is represented. A special lumped load model to accurately represent feeders
containing a high percentage of motors in the load. The capability of modeling
motor stall effects is included, and was developed on the basis of comprehensive
system tests.
The user can interrupt the simulation at any time, either manually or by
scheduled interrupt time or automatically via interrupt conditions. When the
simulation is interrupted, most DIgSILENT commands such as displaying or
printing power flow results, checking the bus voltages, calculating eigenvalues or
analyzing the controller status, etc. can be activated.
By activating predefined fault types, or by accessing and modifying DIgSILENT

variables any type of fault can be realized. Typical faults are:
line, transformer, feeder load and generator tripping

starting/tripping of synchronous and asynchronous machines
load shedding and shunt switching
application and clearing of faults at substations or along lines
change of controller set-points; controller failure
synchronization of isolated areas
injection of signals generated by a DSL device.
The user can interrupt the simulation at any time, either manually or by
scheduled interrupt time or automatically via interrupt conditions. When the
simulation is interrupted, most DIgSILENT commands such as displaying or
printing power flow results, checking the bus voltages, calculating eigenvalues or
analyzing the controller status, etc. can be activated.
Any DIgSILENT variable, or any quantity identified in the transmission network

or dynamic models, may be selected for simulation observation or for later
plotting within x/t or x/y diagrams or any other VI provided. In addition to these
variables, the DSL algebraic expression interpreter and logical expression
evaluator which can calculate any user defined quantity. Plotting files may be re-
tained for re-plotting in comparison with subsequent runs
Simulation monitoring window log of all simulation event procedures, which allows
a detailed analysis of manually entered or automatically initiated events.
Long-term Stability
In many cases stability calculations must be run for long periods thus taking effects of
slower control systems such as boiler control, network exchange control or
transformer tap-changer control into account. Other applications are varying loads or
applications of wind power where the impact of wind speed fluctuations must be
analyzed. In such cases, short-term and mid-term dynamics have already reached
steady state but slower transients are still being observed.
Long-term stability simulations require therefore adaptive step-size algorithms that

allow an automatic variation of step-sizes within the range of milliseconds and several
minutes without any decrease of precision or even manipulation of transient behavior.
DIgSILENT PowerFactory features a highly accurate long-term simulation

algorithm with precise, event-controlled integration step-size adoption.
RMS Simulation with a-b-c Phase Representation
The a-b-c phase, steady state component representation of the power system, allows
the fundamental frequency analysis of any asymmetrical fault combination, including
single and double phase line interruptions. This representation is valid for
electromechanical transients and 1, 2, and 3-phase systems with or without
asymmetrical pre-loading. This system representation mode fully avoids tedious hand-
calculations of equivalent fault impedance. It also allows for accessing any a-b-c phase
quantity for plotting or precise modeling purposes (e.g. protection devices).
EMT Simulation
DIgSILENT PowerFactory also provides an EMT simulation kernel for solving power
system transient problems such as switching over-voltages, ferro-resonance effects or
sub-synchronous resonance problems. In the EMT simulation environment, the
network model and associated devices are not represented as constant steady state
impedances, but by the differential equations that govern their behavior. For
transmission and distribution network lines and cables, the transient PI models as well
as distributed parameter models are provided. Additional standard built-in models
include:
Transmission lines (according to tower layout), distribution network lines and

cables
Passive RLC branches, filters and sources
2 and 3 winding transformers for 1, 2 or 3 phase systems, including saturation
effects
VT, CT and PT models
Series capacitor, MOV’s and bypass switches
HVDC valve groups (6 and 12 pulse Graetz bridge configurations) and other
FACTS devices such as SVC’s, UPFC’s and TCSC’s
Circuit breaker models
Special numerical integration methods have been implemented in DIgSILENT

PowerFactory in order to avoid numerical oscillations caused by switching devices
and other non-linear characteristics. The calculation of initial conditions is carried out
prior to the EMT simulation, and is based on a solved load flow (symmetrical or
asymmetrical).
The DIgSILENT Modeling Flexibility
DIgSILENT PowerFactory features an unmet flexibility for implementing user

specific modeling needs. The basic flexibility level is realized via graphical object wiring
diagrams – called Model Frames. They allow for a comfortable configuration of
functional block relations using object signal connections. Any existing PowerFactory
object can be plugged into such a “slot”. Frames can be lumped and nested to any
degree of complexity. Hundreds of objects such as power system equipment (e.g.
busbars, generators, lines, transformers, motors), relays, relay components, CTs, VTs,
measurement files, FFT devices, real time clock, RMS signal transducer, parameter
identifiers, controllers, power plant control components, A/D converter, RPC links,
result files or display objects are at the user’s disposal. In cases where additional
functions are required, such functions can be build using the DSL language.
The most critical and decisive factor for producing reliable steady state and transient
calculation results is the accuracy and completeness of the applied system model
representation. Methods for solving this task especially for stability analysis purposes,
range from the traditional way of using software which allows interfacing of user-
defined models at the FORTRAN level - typically via connection lists (e.g. PSS/E)- to
the block-oriented approach which is based on the provision of predefined basic block
macros, connected at the case definition level (e.g. NETOMAC, NEPLAN). In addition,
most modern commercially available general purpose simulation tools can only be
used for flexible and not specific system representation (e.g. SIMULINK). In most
cases the above mentioned approaches do not cover the special characteristics of
electrical power systems adequately requiring iterative solution techniques to be able
to determine the initial AC/DC load flows and to solve nonlinear grid characteristics
during the simulation process.
The DIgSILENT Simulation Language – DSL
Although DIgSILENT PowerFactory contains a comprehensive model library and

powerful built-in functions, there are many cases in which the user may want to
implement additional control options and calculation functionality. For these reasons,
the DIgSILENT Simulation Language (DSL) was developed.
DSL allows the creation of any kind of static or dynamic multi-input/multi-output

model. Typical applications are:
• Voltage controller and excitation systems

• Power system stabilizers (PSS)
• Primary and secondary controllers
• Prime mover units
• Motor driven machines
• FACTS controllers
• any type of protection device, such as: distance relays, undervoltage
relays, over-current relays, load-shedding relays, unit trip devices,
electronic motor starting devices (EMR).
• any comprehensive calculation procedure required in the control
environment
• Supervisory control devices
To provide a flexible modeling and simulation tool that forms part of an integrated
steady state analysis and stability program, a control system based simulation
language was developed. The following main features of the DIgSILENT Simulation
Language (DSL) are considered to be most relevant:
The DSL simulation tool falls into the category of Continuous System Simulation
Languages (CSSL) including a complete mathematical description of (time-)
continuous linear and nonlinear systems. The DSL is dedicated to common control
and logic diagrams leading to a non-procedural language as the sequence of
elements could be chosen arbitrarily. In sum, a DSL model is directly convertible
into a graphical block diagram representation.
Provision of a flexible definition of macros, which can be: algebraic equations,

basic control elements like PID, PTn or even complete physical subsystems such
as HVDC valve groups or excitation systems. In addition, various intrinsic
functions like "select, lim, limits, lapprox, picdrop”, as wells as “interrupt
procedures” are included.
Provision of various formal procedures for error detection and testing purposes,
e.g. algebraic loop detection, reporting of unused and undefined variables and
missing initial conditions.
Automatic calculation of initial conditions is supported – an important feature

especially when complex, nonlinear equations must be solved iteratively.
DSL models are interfaced on all DIgSILENT level functions such as load flow,
fault analysis, stability analysis, protection coordination and harmonic analysis,
etc. Therefore multi-level modeling is given for the different steady state
descriptions and transient time domains (short/mid-term, long-term and
electromagnetic).
DSL models can be generated directly on the graphical level by drawing the
“block diagram”. Any “block” may contain another DSL model, a macro or any
sequence of DSL syntax. The DSL-editor will then generate the DSL description
automatically and will also provide direct model testing functions such as
eigenvalue analysis or step-response tests.
DSL Implementation
The DSL is a semi-independent module that is appropriately linked to the program
kernel via the graphical interface - Model Frames (FMs). A FM is drawn in form of a
block diagram that defines the “wiring” of the different functions required. The blocks
can be understood as “slots” which are used to “plug-in” the appropriate models. The
definition of frames is completely flexible featuring e.g. the definition of relay frames,
plant frames or any other functions.
Signal input and output channels: Any variable defined within the kernel
(actually more than 5000) or a DSL model can be accessed in a read-and-write
mode.
Interrupts: Conditions derived by DSL models can cause interrupts to be sent to

the program kernel where they are then scheduled within the event queue.
Output and Monitoring: Conditions may trigger an output to be displayed on

simulation monitor and stored in the simulation log file.
Advanced Features
DSL models feature the direct interaction with external processes such as DAQ
interfaces, SIMULINK modules or other software systems.
Procedures written in C++ code can be directly linked via appropriate interface
mechanisms.
The numerical integration of DSL models, interrupt scheduling and input-output

signal processing is handled automatically by the program kernel. In addition, if
the output of a DSL model is an electric current that is added to the appropriate
total bus current - which is the case if a load or generator model is created - all
Jacobean elements necessary for static analysis like load flow and for the iterative
simulation procedures will be calculated automatically.
Interpreter versus C++ Code

DSL model definitions are included in the DSL model library using their native
language. This method can be compared to procedures used in conventional
programming (e.g C, Pascal or FORTRAN). The main difference however, is that DSL
does not require any compiling or linking procedures as DSL works like an interpreter,
building up an RPN list (Reverse Polish Notation) which is then processed
automatically during runtime. Although DSL model interpretation is slightly slower than
a compiled code in terms of execution times, the process of model development and
testing is significantly faster than code compiling which requires linking and program
reloading.
In order to cut down the DSL model execution times, an optimised DSL to C++ cross-
compiler is also available, featuring the generation of dynamic link libraries (DLL)
which is automatically loaded during program start-up, respective run time
initialisation or directly re-loaded during program execution. With this option the user
can implement self defined models on all calculation levels including network branch
and bus elements with its maximum possible execution speed.
Parameter Identification
Built-in system identification and general optimization procedures provide an easy and
accurate method to perform model parameter identification on the basis of system
tests and field measurements. The PowerFactory identification tool is applicable for
parameter estimation of multi-input multi-output (MIMO) systems, which are
described by any type of nonlinear DSL model. The identification procedure itself is
fully integrated in the graphical frame definition and block diagram level and also
features parameter estimation of integrated models which forms part of a power
system model such as loads or generators.
The provided optimization procedures are highly generic and can also be
used for optimally tuning parameter such as PSS settings according to
defined model response functions.
Eigenvalue Analysis
The DIgSILENT PowerFactory modal analysis tool features small signal analysis of
a dynamic multi-machine system. System representation is identical to the time
domain model. It covers all network components such as generators, motors, loads,
SVS, FACTS, or any other component used for the system representation including
also controllers and power plant models.
The calculation of eigenvalues and eigenvectors is an extremely powerful tool, e.g. for
low-frequency oscillatory stability studies, PSS tuning, determination of
interconnection options and basic parameter, and is a natural complement to the time
domain simulation environment. It also allows for the computation of modal
sensitivities with respect to generator or power plant controllers, load characteristics,
reactive compensation or any other dynamically modeled equipment.
Eigenvalue analysis is with DIgSILENT PowerFactory performed in an easy, well-

defined, and almost automatic procedure. The calculation steps are described as
follows:
Based on a converged and adjusted power flow, the modal analysis starts with
the calculation of the systems initial conditions; alternatively any interrupted
status of a time domain simulation could be used as initial condition.
The system A-matrix is constructed automatically for the complete system

(including generators, general loads, predefined system plant and controller
models as well as DSL-devices). Therefore the overall system representation of
the homogeneous form is:
dx/dt = A x
System and model linearization - incl. user defined models - is performed by

iterative procedures. Limiting devices are disabled automatically. The
representation of the network model is equivalent to the simulation model,
allowing a direct comparison between time domain simulations and modal
analysis results.
System order reduction is automatically performed for zero rows and columns.
This may occur, if a time constant or a gain has been set to zero.
All eigenvalues are calculated and listed in their appropriate order. Based on the
calculated eigenvalues and eigenvectors, the normalized participation matrix for
the system oscillation is computed and the oscillation vectors for all modes are
displayed graphically.
DIgSILENT PowerFactory can deal with multiple eigenvalues and eigenvectors

which is an important feature when identical units are operated in parallel.
Depending on the program version, the resultant system A-matrix may have an order
of up to 2500 and more - and hence may describe more than 250 machines modeled
in detail and thus resulting in a correct damping pattern. If a system with a higher
order is being analyzed, the application of the DIgSILENT selective eigenvalue
analysis is recommended.
14. Transient Motor Starting
The motor starting function makes use of the PowerFactory stability module by providing a pre-
configured shortcut for easy-to-use motor starting analysis. The motor starting is initiated by
just selecting the respective motors within the single line diagram and initiating the motor
starting calculation via the appropriate mouse-click. A complete symmetrical or asymmetrical
AC/DC load flow will be computed prior to the motor starting event, Pre-selected and pre-
configured Virtual Instruments (VIs) are automatically created and scaled.
Consideration of complex motor models with build-in parameter estimation fully covering
high precision modeling effects. A comprehensive library of low voltage, medium voltage
and high voltage motors is provided;
Typical motors supported are: single- and double cage asynchronous machines, squirrel
and slip-ring motors, double-fed induction machine, synchronous motors;
Access of model library for of build-in motor driven machine characteristics with flexible
user-modeling support;
Support of various starting methods such as direct start, star-delta starting, variable rotor
resistor, thyristor softstarter, transformer softstarter, variable speed drives, etc.; start
from any rotational speed;
Full representation of generators with exciter/AVR model support on basis of build-in

models (e.g. IEEE models) as well as user-defined models via the DSL approach;
consideration of protection devices such as under-voltage protection, over-current
protection our automatic restarting relays (EMR) or transformer OLTC;
Compared to the more complex dynamic simulation approach, Transient Motor Starting
simulation is performed by assuming constant grid frequency (prime mover dynamics are not
considered). Consequently, in cases where grid frequency varies significantly, the Dynamic
Simulation Functions must be used.
15. Low-Voltage Network Analysis
DIgSILENT PowerFactory integrates enhanced features especially designed for analyzing

low voltage networks. These functions enable the user to:
Define loads in terms of number of customers connected to a line;

Consider load diversity;
Perform a load flow analysis that considers load diversity for calculating maximum voltage
drops and maximum branch current
Perform an automatic cable re-enforcement
Voltage drop and cable loading analysis
View feeder plots and perform feeder load scaling
Low voltage analysis of complex meshed systems is a standard feature with DIgSILENT
PowerFactory. Neutral current caused by unbalanced single-phase loading and load diversity
to various sources are statistically calculated to represent a realistic network.
Stochastic Load Modeling
On the basis of defined “Customer Units” the user may specify a number of customers
connected to a line. When performing a load flow, the load per unit customer is defined either
by:
• Power per customer unit

• Power factor
• Coincidence factor for an infinite number of loads (“simultaneity factor”)
In addition, the user may select between two methods for considering the stochastic nature of
loads, such as:
• Stochastically evaluation
• Maximum current estimation
The first method is the more theoretical approach that can also be applied to meshed network
topologies. The “Maximum current estimation” only applies stochastic rules for estimating
maximum branch flows. Based on the
maximum current flow branch element,
maximum voltage drops are calculated
and added along the feeder. However,
this method has its limitations in case
of meshed LV networks.
Upon successful execution of the load

flow, maximum currents (Imax),
maximum voltage drops (dumax) and
minimum voltages (umin, Umin) are
displayed in every branch element and
at every bus bar.
The usual variables for currents and

voltages represent here average values
of voltages and currents.
Losses are calculated based on
average values, max. circuit loading is
calculated using maximum currents.
Cable Reinforcement
The cable reinforcement procedure

determines the most cost-effective option
for upgrading overloaded cables. Based on
specific cable costs and voltage drop
limitations, the corresponding cable is
automatically selected and a respective
report is issued.
16. Distribution Network Optimization
DIgSILENT PowerFactory incorporates features to assist the user in distribution network

optimization, and comprises of the following options:
Optimal capacitor placement optimizing investment costs and losses

Open tie optimization optimizing losses, supply reliability or any other user-defined function
Cable reinforcement optimization (see also “LV Network Analysis Functions)
The user is also able to write is own DPL scripts for other user-defined optimization functions.
Alternatively, DIgSILENT could prepare such scripts upon request.
Optimal Capacitor Placement (OCP)
The DIgSILENT PowerFactory Optimal Capacitor Placement determines the optimal

locations, types and sizes of capacitors to be installed in radial distribution networks. Using
“Gradient Search” or “Tabu Search”
methods, a cost function considering
losses, cost of losses, capacitor
installation costs, various load
profiles, operational voltage limits
and available capacitor types and
costs is minimized over a period
defined by feeder load profiles.
The result of the optimization

procedure is a set of locations where
capacitors should be installed, which
type of capacitor(s) should be
installed at each site, and whether or
not a switched capacitor is
suggested. Proposed capacitors are
selected from a user defined
capacitor library.
Tie Open Point Optimization (TOPO)
The DIgSILENT PowerFactory Tie Open

Point command will minimize the losses in
the network by changing the network
topology, while preserving voltage and
loading limits. The command is implemented
as a DPL-script, which can be used as-is, or
which can be adjusted to specific needs. The
heuristic method used by the script is
applicable to radial distribution networks.
• No parts of the system will be isolated

• No meshed structures will be introduced
• Any switch can be marked as an
"optional open tie" and only user-
defined optional Open Ties will be
opened/closed.
The default script uses a penalty function which optimizes losses when voltage and loading are
in range. This penalty function can be easily adjusted to include specific loading limits for
network components, short-circuit power limits, transformer tap limits, or any other condition.
Further features:
• New system topology can be accepted/rejected
• Topology changes are made visible in single line graphics
• All changes in switch positions, system losses and penalty functions are reported.
17. IEC Cable Sizing
The DIgSILENT PowerFactory cable reinforcement procedure determines the most cost-
effective option for upgrading overloaded cables. Based on specific cable costs and voltage
drop limitations, the corresponding cable is automatically selected and a respective report is
issued. The automatic cable sizing procedure is performed in accordance with the IEC 364
Standard.
18. Reliability Analysis
Reliability calculations are essential for the evaluation and comparison of electrical power
systems in terms of both design and operation. Although non-stochastic contingency analyses
(for example (n-1)) are able to highlight obviously unacceptable operational events, they
cannot rank these events in terms of either frequency or duration. The DIgSILENT
PowerFactory Reliability analysis tool incorporates standard reliability assessment features
together with sophisticated modeling techniques that enable all forms of reliability assessment
to be carried out.
Failure model definition is achieved by defining mean yearly failure frequency and repair
duration data. For lines and cables, this data is entered in per length terms. Detailed models
are available for generators that enable derated states to be represented, with maintenance
and common mode models also available.
Loads can be grouped into load areas, each of which is described by load forecast and growth
curves. Load models are additionally available for hard-to-predict industrial situations, and each
can be assigned its own interruption cost, from either the money/customer/interruption,
money/kW/interruption or money/interruption functions.
All failure and load models can be represented either by the Markov method, where simple
mean repair durations are modeled, or by the sophisticated Weibull-Markov method, where
repair duration variance is additionally modeled. The Weibull-Markov model also has the unique
property that annual interruption cost indices such as load and process (industrial) interruption
costs can be calculated both analytically and quickly. Consequently, the DIgSILENT
PowerFactory reliability analysis tool enables the comparison and justification of alternative
investment proposals on a financial basis.
Finally, the results of all reliability assessments can be presented in text format, as user defined
graphs, or within the single-line graphics environment. DIgSILENT PowerFactory offers both
generation pool adequacy analysis ("Level I") as well as network adequacy analysis ("Level II"
and "III"). The network reliability analysis can be carried out on the basis of a simple
connectivity check (primarily meant for distribution networks) or on the basis of AC loadflow
calculations (for bulk power system analysis).
Generation Pool Adequacy Analysis
Generation pool adequacy analysis compares the total available generating capacity with the
load demand, regarding:
Generator forced and planned outages (failures and maintenance);

Generator derated states (partial outage);
Stochastic load behavior
With this technique, sequential (Monte Carlo) analysis is used. The purpose of the generation
pool adequacy analysis is to identify the generator ability to fulfill load demand in the case of
an infinitely strong transmission and/or distribution system. Results from this analysis include:
Loss of Load Expectancy (LOLE, hr/yr)

Loss of Energy Expectancy (LOEE, MWh/yr)
Loss of Load Duration (LOLD, hr/occ.)
Loss of Load Frequency (LOLF, occ./yr)
Expected Energy Not Supplied (EENS, MW)
Typical generating capacity and reserve curves
Network Reliability Analysis
Distribution and bulk power network analysis are both carried out by the "Network Reliability"
analysis function. This comprises of the assessment of interruption statistics for individual loads
and busbars in distribution, sub-transmission and transmission systems. There are basically two
approaches that can be taken:
For a classical bulk power ("Level II")

analysis, it is assumed that post-fault
overloads may occur. A full AC load
flow, incorporating basic generator re-
dispatch and automatic tap changing, is
used to analyze post-fault system
conditions. Additional load transfer
and/or load shedding may then be
simulated.
For a classical distribution ("Level III")

analysis, it is assumed that
contingencies will not lead to
component overloading in the system.
This can only be assumed in distribution
systems. Without the overload analysis
and alleviation functions incorporated,
the analysis time can be considerably reduced.
The network reliability assessment considers:
forced outages and subsequent repair of all primary network equipment

generator dispatch and realistic load curves
basic protection lay-out
load priorities
For both bulk power and distribution system analyses, a realistic Failure Effect Analysis (FEA) is
performed for all analyzed single and multiple contingencies. The FEA simulates both the
automatic and manual reactions to faults of installed protection and of the system operators
during each reliability assessment. The FEA can be checked and fine-tuned in an interactive
way to exactly match the real system and operator reactions.
The FEA comprises:
Automatic fault clearance by protective devices

Automatic or manual fault isolation
Automatic or manual power restoration by network reconfiguration
Overload alleviation by optimized load transfer and load shedding, using both load
priorities and load shedding properties.
Network reliability assessment can be executed for any contingency level (i.e. single order
contingencies and 2 or more overlapping failures), for specific types or failure selections, and
station configurations. A special "FEA mode" (Failure Effect Analysis) is also available which
indicates all actions performed by the FEA functions for specific contingencies. The "FEA mode"
was added to further increase calculation transparency, as it allows a detailed checking of the
network reconfiguration activities during each assessment.
The following indices are calculated by the “Network Reliability” analysis assessment:
For loads:
Average Interruption Duration (AID, hr)

Load Point Interruption Time (LPIT, customers*hr/yr)
Load Point Interruption Frequency (LPIF, customers/yr)
Load Point Energy Not Supplied (LPENS, MWh/yr)
Load Point Expected Interruption Costs (LPEIC, M$/yr)
Average Customer Interruption Frequency (ACIF, 1/yr)
Average Customer Interruption Time (ACIT, hr/yr)
The ACIF and ACIT are ‘per customer’ indices, while the LPIT, LPIF, LPENS and LPEIC are
summations for the number of customers at the aggregated load model.
For busbars:
Average Interruption Duration (AID, hr)

Yearly Interruption Frequency (LPIF, 1/yr)
Yearly Interruption Time (LPIT, hr/yr)
19. Production Planning
DIgSILENT PowerFactory can be utilized for production planning, through determination of

optimal unit commitment and economic dispatch for both hydro and thermal generation
systems. This is performed on the basis of integrated load and unit availability scales. The basic
characteristics of this analysis option are:
For Thermal units/plants:

Unit availability incorporating minimum and maximum run conditions, and power output
limitations
Maximum and minimum energy production during a planning period
Minimum plant up and down times
Power output gradients
Prohibited operating zones
Imposed power output
For Hydro units/plants:

Unit availability incorporating minimum and maximum run conditions, and power output
limitations
Minimum and maximum reservoir levels
Prohibited unit loading points
Maximum and minimum discharge during a planning period and imposed water discharge
for irrigation purposes
Water transit times for coupled reservoirs
Imposed power output
General
Network control and reserve requirements (active power)
Reliability levels and reserve policies
Power exchange limitations, costs, tariffs, etc.
Special characteristics are available for the determination and consideration of spinning reserve
requirements, such as:
Active power control margins.

Spinning reserve requirements that consider the individual transient spinning reserve
release characteristics.
Reactive (optional) and active power requirements including control capability margins and
operational restrictions (e.g. reactive power required for large motor starting, reserve for
covering units trips, separation of areas).
20. DIgSILENT Programming Language (DPL)
The DPL-Programming Language, offers a flexible interface for automating tasks in the
DIgSILENT PowerFactory program. The DPL scripting language adds a new dimension to
the PowerFactory software by allowing the creation of new calculation functions. Typical
examples of such functions are
• Transfer capability analysis

• Automatic protection coordination
• Specific voltage stability analysis
• Contingency - network impedance
analysis
• Parametric sweep calculations
• Penalty factor analysis
The DPL Object Oriented script language is

intuitive and easy to learn. The basic set of
commands includes:
• flow commands like "if-then-else",

"do-while"
• Input, output and reporting routines
• Mathematical expressions
• Execution of PowerFactory commands
• PowerFactory object procedure calls and DPL subroutine calls
The strength of the DPL scripting language can be characterized by the following keywords:
Easy Development
The small basic syntax allows for the quick creation of simple commands to automate tasks.
Tasks like renaming objects, executing specific search and replace commands, post-processing
calculation results and creating specific reports are just some examples.
Transparency
All parameters of all objects in the network models are accessible. DPL can be used to query
the whole database and to process all user-input and result parameters without restrictions.
Standardizing Commands
The DPL language can be used to create new 'standardized' DPL commands that can be used
over and over again. DPL commands allow for the definitions of input parameters and can be
started for specific selections of objects. Proven DPL commands can be safely stored in DPL
command libraries and be used from there without the risk of damaging the scripts.
Control
DPL commands can configure and execute all PowerFactory commands. This includes the
load flow and short-circuits calculation commands, but also the commands for transient
simulation, harmonic analysis, reliability assessment, etc. New objects can be created in the
database, and existing objects can be copied, deleted and edited. New reports can be defined
and written to the output window, new graphs can be created and existing graphs can be
adjusted to a user-defined selection or the current calculation results.
Modularity
A DPL command may contain other DPL commands which will then act as subroutines. This
allows for the testing of subroutines as independent commands. Existing commands can be
combined to quickly create more complex commands.
21. Software Installation Option
In addition to the classical, stand-alone single-user databases, multi-user database servers are
optionally available. These enable different project teams to have partial or full access to
project databases via user accounting and project access rules. In DIgSILENT PowerFactory
three distinct configurations are available:
Local Installation: Both, the program and database are installed locally on each computer.
Typical local installation
Network installation on a File Server: With this configuration the program resides externally
on a file server but utilizes the local machine CPU for program operation. The database for
each user also resides on each local machine or at any other location in the network.
Typical network installation on a file server
Network installation on an Application Server: In this instance, the program and database
both reside on an application server, with program execution and database updates
occurring over the network. Access and operation of the PowerFactory software is made
via Clients from each user terminal.
Typical network installation on a Server / Client environment
22. Compatibility to other Software Systems
Under certain circumstances, data compatibility with other software system is required. There
are several reasons that could make such data transfer required:
• Users who have been using another power system analysis software have decided to
migrate to the more powerful and complete DIgSILENT PowerFactory tool.
• Users who need to consider the neighboring systems which are still being analyzed with
another software
• Data exchange with SCADA systems often require different formats, traditionally used and
widely applied.
DIgSILENT PowerFactory comes with a feature that enables conversion of a variety of other
formats. This is achieved using the DOLE syntax (DIgSILENT Object Level Exchange), which is
essentially a flexible object-oriented ASCII interfaces with external database structures.
Therefore, conversions are typically implemented via “OtherToDOLE” processors. As DOLE is
supporting system data, graphic information as well as execution commands, import functions
are in most cases generating compatible structures. The conversion process itself is performing
a detailed and in-depth check of data and structures according to stringent data quality criteria.
Foreign file input via DOLE is supported for several versions of the following software systems:
NETCAL, NEPS, PSS/E, PSS/U, Adept, NEPLAN and DVG.
As the DOLE input format is very generic, it can also be used to implement any user-defined
conversion routine for other third party software incl. SCADA and GIS interfacing.
23. DIgSILENT PowerFactory Connectivity
DIgSILENT PowerFactory has the ability to interface directly with a number of external
programs and hardware structures, such as GIS (Graphical Information Systems) and SCADA
(Supervisory Control And Data Acquisition) systems. Additionally, A/D interfacing capability with
the PowerFactory Monitor monitoring system is also possible.
The DIgSILENT PowerFactory DOLE software was developed in part to allow data
conversion from programs, but also to meet the increasing demand for interfacing with GIS and
SCADA systems. The DOLE structure is quite simple and allows users to custom design their
own interface protocols, which enables compatibility with any number of SCADA and GIS
systems.
SCADA Interface
Interfacing with SCADA gives direct access to dynamic and/or static SCADA data, allowing both
real time system analysis and incident analysis from previous snapshots. As DIgSILENT
PowerFactory integrates topology processing already, interfacing can be made on a point to
point relation using foreign database keys.
GIS Interface
DOLE can also be interfaced with any existing Graphical Information Systems (GIS). For this
purpose DIgSILENT PowerFactory provides the user with an auxiliary EXCEL file that
permits data conversion from the GIS to DOLE formats. Figure 10.1 illustrates a typical GIS to
DOLE data conversion program.
Engine Mode
DIgSILENT PowerFactory may be operated as a background process in situations where it is

integrated into GIS or SCADA systems. This capability also permits the remote control of
PowerFactory via the GIS or SCADA system directly, in what is called “Engine Mode”. The
basic advantages of this approach are summarized as follows:
Engine Mode is an in-built feature available in all DIgSILENT PowerFactory package

configurations, at no extra cost.
All PowerFactory functionality is available in Engine Mode.
Simple integration with the GIS or SCADA system.
PowerFactory software upgrades will not require complex re-integration procedures on
the source code level.
The PowerFactory MMI can be activated for data maintenance, operation and display
purposes at any time in Engine Mode.
A/D Interface Capability
The DIgSILENT PowerFactory A/D interface with the PowerFactory Monitor monitoring
system, is the latest development in integrated operation supervision, fault recording and test
analysis evaluation. This is achieved via the generic model frame and VI (Virtual Instrument)
environments, and may be utilized to:
Implement analog inputs with for up to 5 kHz per channel

Perform signal normalization and correction
Calculate RMS values and phasor quantities
Realize soft-transducers for active power, reactive power, frequency, speed, frequency
spectrum, system oscillation analysis and many other quantities
Determine trigger conditions for fault recording
Perform permanent monitoring
Detect system oscillations
Analyze and supervise connection conditions
Direct interchange of signals with the model identification blocks.
24. DIgSILENT Support and Training
Training
DIgSILENT does not offer regularly scheduled training courses for the PowerFactory
software; however special theoretical and application training is available, according to user
requirements and timetables. Our training specialists can cover the complete range of power
system analysis topics and DIgSILENT PowerFactory application training, including:
Data organization and case management

Steady state analysis (power flow and short circuit analysis)
Protection coordination
Harmonic power flow
All aspects of stability calculations
Enhanced system modeling for power plants, loads, generators, protection devices and
controllers
Special training programs are available upon request, and may be carried out at the
Gomaringen office or any user-specified location. All training courses may be optionally
conducted in German, English or Spanish.
Maintenance
Fixed term software maintenance contracts are available for both 12 and 24-month periods.
Additionally, these contracts may be structured with automatic extensions to the existing fixed
term periods. All optional maintenance contract costs are available upon request to
DIgSILENT.
25. DIgSILENT Consulting
DIgSILENT also offers a wide range of engineering services that can supplement your in-
house expertise, specializing in the less common areas of power system engineering and
analysis.
Operation Optimization
DIgSILENT has a broad knowledge of operation optimization, as well as trouble shooting

experience in many areas of power system dynamics and control, such as,
Spinning reserve optimization

Optimal load-shedding concepts
Network control and primary control
Optimal PSS tuning and damping analysis
Performance monitoring and fault analysis
Implementation of system tests and identification (prime movers, AVRs etc.)
Determination of simulation models
Load measurements and parameter estimation
Analysis and SSR and ferro-resonance problem solving
Earthing and transient over-voltage studies
Load forecasting
Unit commitment and economic dispatch
Optimal power flow
Reliability assessment
Industrial Application
DIgSILENT has a long tradition and extensive experience in industrial system planning
and optimization. The DIgSILENT PowerFactory software provides us with a high
degree of solution accuracy and flexibility for studies of industrial power systems, and the
following services are offered:
Power quality analysis (harmonics, voltage sags, operational characteristics)

System transient analysis (motor start-up, primary control, voltage control, over-
voltages)
ASD and LCI applications
Protection coordination
Reliability and security studies
System tests and measurements
Operational optimization
Design review and system specification
System Planning
DIgSILENT offers a wide range of specialized engineering services relating to system

planning and market liberalization, such as;
Master plans
Feasibility studies
Conceptual design reports
Unbundling and privatization
Power purchase agreements (PPA)
Power wheeling
BOT/BOO schemes for power plants, transmission and distribution networks
Grid code development
Connection conditions and characteristics
Generation, Transmission and Distribution Planning
Technical economic evaluations
Proposed HVDC and FACTS installation analysis
Stability and reliability
Protection concepts and setting optimization
System Tests
DIgSILENT also offers specialized expertise in the performance of system tests, test
evaluations and plant modeling, such as;
Analysis of system characteristics

Secondary control performance analysis and optimization
Determination of primary control parameter and spinning reserve capabilities
Analysis of AVR and excitation control dynamics
Definition and tuning of PSS parameters
Over-voltage, SSR and ferro-resonance studies
Load measurements and parameter estimation
Analysis of system oscillations
System model development
Analysis of plant measurements and system identification
DSL model development
Model testing and verification
Connection characteristics
Evaluation of primary and secondary response characteristics
Determination of harmonic penetration

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DIgSILENT PowerFactory

Integrated Power System Analysis Software

PowerFactory incorporates an impressive and continuously growing list of simulation

 General software package design.

DIgSILENT PowerFactory succeeds in amalgamating the requirements in each of these

DIgSILENT PowerFactory is the leading product with respect to integrated modeling

DIgSILENT PowerFactory comes with a number of advanced features introducing highest

DIgSILENT PowerFactory software is implemented as a single executable program,

A special feature of the DIgSILENT PowerFactory software is the unique vertically

DIgSILENT PowerFactory provides optimal organization of data and definitions

• Multi-User Operation: support of multi-user database server operation with the

System Stage Management: in DIgSILENT PowerFactory, project and study

DIgSILENT PowerFactory performs within a fully graphical windowing

Full Interactive Mode

DIgSILENT PowerFactory may be operated as a background process in situations

Introducing Intelligent Data Structures

System Stage Management

To further reduce data redundancy

Study Case Management

The Study Cases also save all

Basic Quality Assurance Principle - No Data Redundancy

DIgSILENT PowerFactory also provides a fully integrated graphical editing environment,

- 1-, 2- and 3-busbar systems with and without transfer buses

 Automatically modify library-generated substations according to user specific requirements;

Block Diagrams for User Written Models

Spread - sheet Output

DIgSILENT PowerFactory also incorporates an enhanced non-decoupled Newton-Raphson

DIgSILENT PowerFactory is introducing a new, intuitive and easy-to-use modeling

 Supports device characteristics, such as loads with voltage dependency and

 By analyzing a single contingency. This is achieved by selecting one or more objects

Further Special Functions

 Analysis of system control conditions

Radial Feeder Analysis

DIgSILENT PowerFactory provides a number of special functions that make LV analysis

Using the most innovative “Feeder plot” a

Feeder Load Scaling

 Scheduling of Ancillary Services for reactive power and active power

Supported Objective Functions:

• Minimize system losses

Above listed objective functions are solved

• Branch flow limits (loading)

DIgSILENT PowerFactory features three-phase network fault calculation functionality based

 Includes calculation of all three symmetrical components as well as phase quantities.

IEC 909 and VDE 102/103 Fault Calculation

IEEE 141/ANSI e 37.5 Fault Calculation

 Transformer tap positions can be included in the fault current calculation.

Additional features are summarized below:

Fault Analysis Results

Protection Model Library and Functionality

The DIgSILENT PowerFactory protection

 Time overcurrent relays for 1 phase, 3

Additional to these protection functions and relays DIgSILENT PowerFactory provides

 Current and Voltage transformers that include saturation effects

The co-ordination of overcurrent-time protection is done graphically on basis of the current-

HV-UT2 SS-D3 SS-D2 SS-D1 HV-Infeed

105. [pri.Ohm] 84.1 63.1 42.0 21.0 0.0

Max. 3-phase Short-Circuit TD-Path I Date: 7/19/2002 Transformer Damage Curve

1.078 s Relay I Curve

Max. 2-phase Short-Circuit R-X Diagram Date: 7/19/2002

General software package design.

Automatically modify library-generated substations according to user specific requirements;

Supports device characteristics, such as loads with voltage dependency and

By analyzing a single contingency. This is achieved by selecting one or more objects

Analysis of system control conditions

Scheduling of Ancillary Services for reactive power and active power

Includes calculation of all three symmetrical components as well as phase quantities.

Transformer tap positions can be included in the fault current calculation.

Time overcurrent relays for 1 phase, 3

Current and Voltage transformers that include saturation effects

DIgSILENT PowerFactory supports any type of characteristic harmonic, un-

DIgSILENT PowerFactory calculates all symmetrical and asymmetrical harmonic indices

Calculation of self- and mutual network impedances

Calculation of voltage amplification factors

Impedance plots may be realized in either Bode, Nyquist or magnitude/phase forms.

No duplication of data entry and case definitions

A sophisticated model for asynchronous machines that includes primary and

DC motor models, ASD systems (Adjustable Speed Drives), double-fed induction

By activating predefined fault types, or by accessing and modifying DIgSILENT

line, transformer, feeder load and generator tripping

Any DIgSILENT variable, or any quantity identified in the transmission network

Transmission lines (according to tower layout), distribution network lines and

Provision of a flexible definition of macros, which can be: algebraic equations,

Automatic calculation of initial conditions is supported – an important feature

Interrupts: Conditions derived by DSL models can cause interrupts to be sent to

Output and Monitoring: Conditions may trigger an output to be displayed on

The numerical integration of DSL models, interrupt scheduling and input-output

The system A-matrix is constructed automatically for the complete system

System and model linearization - incl. user defined models - is performed by

Full representation of generators with exciter/AVR model support on basis of build-in

Define loads in terms of number of customers connected to a line;

Optimal capacitor placement optimizing investment costs and losses

Generator forced and planned outages (failures and maintenance);

Loss of Load Expectancy (LOLE, hr/yr)

For a classical bulk power ("Level II")

For a classical distribution ("Level III")

forced outages and subsequent repair of all primary network equipment

Automatic fault clearance by protective devices

Average Interruption Duration (AID, hr)

Average Interruption Duration (AID, hr)