Sccada
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ACKNOWLEDGEMENT
DECLARATION
ABBREVIATIONS
INTRODUCTION TO HIL
TECHNICAL SPECIFICATION
SCADA
INTELLIGENT LOAD MANAGEMENT SYSTEM
SCADA’S FUNCTION
SCADA AT RENUKOOT AND RENUSAGAR (AN OVERVIEW)
HIGHLIGHT OF ILMS
INPUT/ OUTPUT DETAILS
OPERATIONAL DRIVERS FOR ILMS
FUNCTIONALITIES OF ILMS
LOAD SHEDDING SCENARIO
LOAD SHEDDING (THE TYPES)
WHY LOAD SHEDDING?
BASIC POWER BALANCE CALCULATION FOR LOAD SHEDDING
LOAD SHEDDING ALARMS
GOVERNOR CONTROL
IMPORTANT TERMS USED IN AGC CONTROL
HINDALCO AGC CONTROL
AUTOMATIC LOAD CONTROL
AUTOMATIC VOLTAGE CONTROL
OPERATION AT DIFFERENT MODES
CONTROLLER AC 800M HARDWARE
BASIC COMPONENTS IN CONTROL PANEL
CONTROLLER AC 800M HARDWARE
TYPICAL SINGLE LINE DIAGRAM
SECURITY ISSUES
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ABBREVIATIONS
DI : Digital Input
AI : Analog Input
DO : Digital Output
AO : Analog Output
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INTRODUCTION TO
To evacuate electrical power from Renusagar power to Hindalco, Renukoot. There are 10
132kv transmission lines between Renusagar and Renukoot. Further, there is a wide spread
Electrical network for power distribution at 11kv, 6.6kv and 3.3kv at Renukoot. The
Hindalco power network is also connected with northern grid at 132kv sub-station of Rihand
Hydel Power Plant and UPPCL.
Coal based power plant is situated at Renusagar, 35km away from Renukoot. The power
plant consists of 10 no.s Turbo Generators over six control locations named as CL-1, CL-
2, CL-3, CL-4, CL-5 and CL-6.
The plant started its operation in 1966-1967 with the commissioning of two units of 67.5MW
each. Since the Renupower goes subsequent expansion. The present capacity of plant is
760MW with 10 turbo- generators and 11 boilers (1 spare).
The centre has developed learning culture in the organization. It is first training centre of its
kind recognized by “ Central Electrical Authority, Ministry of Energy and Govt. Of India”.
The centre is equipped with the latest training aid and facility for theoretical, practical and
on job training like lecture hall, model rooms, library, laboratory, workshops and well
trained faculties to provide technical and managerial training.
In India, 71% of the total power generated comes from thermal power stations. In general
thermal power plants burn fuel and use the resultant heat to raise the steam temperature
which drives the turbo-generators.
Raw materials for the thermal power plant are coal, air, high speed diesel and water. The coal
is brought to power station by the trucks, from the coal mines to the Coal Handling Plant
(CHP). From CHP, the coal is being carried by conveyer belts to the coal bunkers where it is
fed to pulverizing mill, which grind it as fine as face powder. Finally, powdered coal mixed
with preheated air is then blown into furnace by primary air fan. The resulted ash is also fine
powder. Some of it bind together to form lumps, which fall into ash plants pits at bottom of
the furnace. Most of the ash, still in particle form, is carried out of boiler to the Electrostatic
Precipitator (ESP) as dust where it is trapped by electrodes charged with high velocity
electricity. The dust is conveyed by water to disposal area and while the clean gases pass
through ID fans to discharge up through the chimney.
Meanwhile, the heat released from the coal is absorbed by the water which gets converted
into steam. The steam in superheated is further passed through the turbines where it is
discharged through the nozzle on the turbine blades. Energy of steam striking these blades
makes the turbine to rotate. Coupled to end of turbine is the rotor of the generator, a large
cylindrical magnet, so when the turbine rotates, the rotor turns with it. The stator has heavy
coils of copper wire in slots. The electricity is produced by the rotating the rotating magnetic
field created by rotation of exciter motor. The
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electricity produced by stator winding is transmitted to transformer which steps up the
voltage to 132kv so that it can be transmitted to long distance efficiently with low losses
over the power lines of grid. The steam which has given up its heat energy, is changed back
to water in condenser so that it is ready for recirculation. The boiler feed water must be
demineralised, an absolutely pure so as to avoid any damage to tube that feeds the turbine.
Coal is supplied to 1200MT & 1500MT capacity bunkers at Jhingurdah loading station
by NCL conveyers. Coal is transported through mono-cable (300TPH) & bicable
(250TPH) ropeway to Renusagar through UP and MP forest areas.
At unloading station the coal is fed to 250TPH & 300 TPH capacity crushers. The crushed
coal travels trough conveyers. Vibrating screens are sent to different bunkers with the help
of tripper. The coal from bunker is fed to boiler mills/pulverisers through coal feeders. This
pulverised coal of size 74 microns is sent to the furnace through coal pipes and coal bunkers.
Primary air from PA fan aids to transport the coal into four corners of furnace at different
elevations.
BOILERS
There are total eleven boilers. These boilers are “ Top supported, Bi- drum, Radiant type,
Natural circulation, Tangential tilting firing system with pulverised coal firing.” Each
having capacity of 275- 320t/hr. Boilers are run with 83-85% efficiency.
STEAM TURBINE
Ten numbers impulse reaction type turbines with five extraction points with regenerative
feed water heating cycle and two pass surface type condensers are in each unit.
Raw water is taken from Rihand lake and it is send to demineralisation plant. After
demineralisation process, water is fed to boilers for producing steam. The saturated steam in
upper drum is separated with help of drum internals and then superheated to 510deg Celsius
in superheaters.
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The superheated steam is lead to rotor, which in turn transmits torque to generators and
power is generated. Extracted steam is sent into heaters where it exchanges heat. The drip
from the heaters flow into the condensers in a cascading process. The non soluble gases are
vented to the atmosphere through de-aerator.
Ash handling system consists of bottom ash system, fly ash system and electrostatic
precipitator (ESP). Around 15-20% ash is taken out through bottom ash system and through
fly ash system. The whole system consists of pumps, hydro ejectors, hydro vectors, clinker
grinder etc. Apart from furnace bottom, the ash is removed from economiser, air pre-heater
and electronic precipitator hoppers. All the 11 boilers are provided with ESP. The
efficiency of ESP is about 99%.
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3Typical diagram of a coal-fired thermal power station
1. Cooling tower 10. Steam Control valve 19. Superheater
2. Cooling water pump 11. High pressure steam turbine 20. Forced draught (draft) fan
3. transmission line (3-phase) 12. Deaerator 21. Reheater
4. Step-up transformer (3-phase) 13. Feedwater heater 22. Combustion air intake
5. Electrical generator (3-phase) 14. Coal conveyor 23. Economiser
6. Low pressure steam turbine 15. Coal hopper 24. Air preheater
7. Condensate pump 16. Coal pulverizer 25. Precipitator
8. Surface condenser 17. Boiler steam drum 26. Induced draught (draft) fan
9. Intermediate pressure steam
18. Bottom ash hopper 27. Flue gas stack
turbine
ELECTRICITY GENERATION
Steam turbine coupled generators run at 3000rpm and delivers 10.5kv (#3 to #10) and 13.8kv
(#1 & #2) at generator terminals. The power generated at 10.5kv and 13.8kv is stepped up to
132kv with the help of generator transformer and send to HINDALCO through 10
transmission lines for its pot lines. Approximately 10% of the generated power is used for
auxiliary equipments at Renusagar.
All the 11 boilers and 10 turbines are connected with common feed water header and steam
header. The advantage of connecting them with common feeder is that in case of failure of
any boiler. The particular turbine may be connected with other boiler and availability of the
unit is 100% assured.
A step-up transmission receives electric power from a nearby generating station and uses a
large power transformer to increase the voltage for transmission to different locations. A
transmission bus is used to distribute electric power to one or more transmission lines. There
can also be a tap on the incoming power feed from the generation plant to provide electric
power , to operate equipment and the generation plant.
Substations have circuit breakers that are used to switch generation and transmission circuits
in and out of service as needed or for emergencies requiring shut down of power to a circuit
or redirection of power.
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The specific voltage leaving a step-up transmission substations are determined by the
customer needs of utility supplying power and to the requirement of any connection to the
regional grid.
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TECHNICAL SPECIFICATION
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SCADA
(Supervisory control and data Acquisition)
In other words we can say that SCADA is a centralized control system which is used to
those field processes which has multiple function.
When the dimension of process becomes very large hundreds or even thousands of
kilometers from one end to other’s one can appreciate the benefits of SCADA offers in terms
of reducing the cost of routine visits to monitor facility operation.
A SCADA system allows an operator to make set points changes on distant process
controllers to open or close values or switches to monitor alarms and to gather
measurement information from a location central to a widely distributed process such as
an oil or gas field , pipeline system or hydroelectric generating complex.
SCADA’S FUNCTION
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Basic Overview of SCADA
Control Room
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Renukoot Network Configuration
Fast Network (VIP)
Redundant Plant
Network OPGW
Redundant
Servers from
Renusa
gar
Redundant Control
Network
CC
R
Co-
CR-1, Load Gen
C shedding
R-2&3,
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Renusagar Network Configuration
Fast Network (VIP)
Redundant Plant
Network OPG
Redundant W
Servers
To
Renuk
Redundant Control
Network oot
PQ GS/LS
Controller Controller
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HIGHLIGHT OF INTELLIGENT LOAD MANAGEMENT SYSTEM
INPUT/OUTPUT DETAILS
2. Digital Inputs for Pot lines (Tap position, L/R position, Protection...
8. Digital Inputs for all Generator CB (Breaker ON/OFF status, Lock out)
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OPERATIONAL DRIVERS FOR ILMS
Critical loads
Limited plant generation Load
} Load/Generator
Shedding
throw
FUNCTIONALITIES OF ILMS
1. Load Shedding
2. Active Power Control (Frequency control)
3. Reactive Power Control (Voltage Control)
4. Import Control
5. Export Control
6. Generator Control
7. Pot line Control
8. MD Control
9. Supervision, Control and Data Acquisition (SCADA)
10. Circuit breaker Control
11. On Load Tap Changer (OLTC) Control
12. Overloading – Transmission line, Tie line & Bus bar
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LOAD SHEDDING SCENARIO
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BASIC POWER BALANCE CALCULATION FOR LOAD SHEDDING
1. Network islanded
2. Generator tripped
3. Bus coupler tripped (contingency change)
4. Import high limit violated
5. Import high limit for fast action violated
6. Load shedding blocked
7. Error in priority entry
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Operator Input Loadbusbar Priority/Load Table
Generation Data
Maximization of Contingency
Active power measurement & determination
Generated power
Maximum Power Contingency
on Turbine max.
Priority/Load Table
Circuitbreaker status building
Power Balance
Calculation
I/O error detection Calculate shed
priority
Fast LS Data presentation
Detection of CB Trigger for FLS
change
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GOVERNOR CONTROL
1. Capability curve
2. The various modes and data related to the generators are presented on the MMI in
the form of capability curves. Limits, such as the rotor and stator heating, minimum
and maximum excitation etc. are considered while preparing this diagram.
3. The calculation of the various control margins for MW and MVAr are based
upon this capability diagram.
4. Participation factor
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HINDALCO AGC CONTROL
e. If the calculated frequency is greater than dead band then the difference will
be distributed among the available generator by considering its participation
factor
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3. Transmission line/Busbar overloading control
1. HINDALCO has to maintain an import which shall not greater than operator
settable limit(40Mw instantaneous)
2. When total load exceeds this limit ,the deference in set point (grid limit)
and grid mw is calculated
3. Identifies available loads in the network
4. Difference is distributed among the loads in that network by considering its
participation factor
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5. calculated automatic set points send to individual Potline control which in
turn generates lower pulses or lower setpoint.
6. AGC action automatically stops when import become within the grid
limit(40Mw)
Objectives are
a. Maintain system power factor within the limits when grid connected
b. Maintain system voltage(132kV) when HINDALCO electrical
network gets islanded
c. Perform the control operation within the capability of generators and
shift the operation to OLTC for maintaining voltage/pf
HINDALCO has to maintain pf between 0.93 when exporting and 0.97 while importing.
control action performed by AVR is as follows
During following conditions automatic shifting of generator control to OLTC take places
a. Generator reactive power reaches its maximum (reactive margin A=0) then
operation shifted to GT OLTC and performs OLTC TAP lower.
b. Generator reactive power reaches its minimum (reactive margin B=0) then
operation shifted to GT OLTC and performs OLTC TAP Raise.
Individual generator are facilitated with lower and raise button for controlling reactive
power
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Margin between priorities – 0MW
b. If freq. > 49Hz & Import < 30MW
Only ALC slow action (Pot line load regulation)
c. Freq. > 49Hz & Import >30MW
Load shedding command to pot lines as per priority. Margin between
priorities – 15MW
OLTC OPERATION
If voltage reach Min. in all units or Max. in all units then OLTC operate command
is enabled.
Qmax max
Qmin min
7MVARH
Qmin is 5MVARH in all units (except #5) & still surplus reactive power is going to grid then
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SCADA generate an alarm to trip capacitor bank at HIL, Renukoot.
ISLANDING CONDITION
To charge a tripped pot line, HIL will generate request to R.P.D. and
R.P.D. will give permission to change the same. LOADING
MODE LM: f=50.5 + 0.5 Hz
In loading mode pot line can be changed at >50.7 Hz and at less than 50 Hz SCADA will
block the loading signal.
-Press soft key at the time of synchronization before closing Renukoot end breaker and
after closing of Rihand end breaker the soft key is depressed.
65MW –
40MW –
MIN.
MAX.
During switching/ charging operation O/L calculation will start after 3 sec timer.
ISLANDING MODE
MIN.
>50.5Hz
MAX.
MAX. LIMIT
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Bus Bar #2 895 Amp.
3. IN ISLANDING CONDITION
a. If frequency < 49Hz (1st stage)
Load shedding command to Pot line tripping for priority st
1 .
b. If frequency < 48.5Hz (2nd stage)
Load shedding command to Pot line tripping for priority nd
2 .
If generator tripping occurred and frequency greater than 49Hz with power
deficit of less than 30MW Only ALC slow action
c. If generator tripping occurred and frequency more than 49Hz with
power deficit of more than 30MW.
Load shedding command for pot line tripping up to required priority
to maintain power balance margin between priorities 15MW.
d. If generator tripping occurred and frequency less than 49Hz
If generator terminal voltage VT is less than 9kv & difference of any two phase is greater
TERMINAL VOLTAGE
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UNIT #3,4&5 (Min.) 10.4KV – 11.0KV (Max.)
OLTC Control
Import/Export control
of Mvar/PF
Q-Lead Q-Lag
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CENTRALIZED COMPUTER SYSTEM CONCEPT
Input P
Peripherals R
O
CPU C
E
S
Memory S
I
/
Output O
Peripherals
© Copyright yearABB - 3 -
All input, output and control functions are done through the
ONE redundant central computer.
AC 800M
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b. Local and remote I/O possibilities
c. Built in redundant Ethernet
d. Built in RS232
e. Integrated ABB drives on optical ModuleBus possibility
f. Hot swap of I/O modules
g. Optional communication modules
i. PROFIBUS-DP & DP/V1(line redundant)
ii. Foundation Fieldbus – H1
iii. RS232C
iv. MaserBus 300
v. Support INSUM
vi. Support S100 I/O
h. Marine certified
I/O
CPU
CI 861
1. PM 864 RTU
2. S800 IO
Modules 3. TB 840
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4. TB 825
5. CI 861
6. Communication Cables
a. OFC
b. TCP/IP
7. Networking Switches
8. Transducers
9. BPS – Bulk Power Supply
10. DOU – Diode Oring Unit
11. Thermostat & Space Heater
12. Cubical Fluorescent Lamp
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The hardware units that form the AC 800M Controller are:
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How does it look in real life?
CPU 1 - Upper
CEX Link
Redundancy Link
RCU Cable
© Copyright year ABB - 26 -
CPU 2 - Lower
PROFIBUS-DP/V1 Cable
Redundancy Link
Cable
© Copyright year ABB - 30 -
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Control IT
I/O systems
Redundant Connection of I/O via Module bus (Local I/O)
Control IT
Optical
Modulebus
© Copyright year ABB - 7 -
TB840
Control
S800 I/OIT
I/O systems
Overview Redundancy
Features
Redundant FCI
Redundant ModuleBus
Bumpless switch-over
Redundancy principles
Bumpless switch-over at lowest possible system level
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Typical Single Line Diagram:
36
SECURITY ISSUES
The move from proprietary technologies to more standardized and open solutions together
with the increased no. of connections between SCADA systems and office networks and the
internet has made them more vulnerable to attacks. Consequently, the security of SCADA
based systems has come into question as they are increasingly seen as extremely vulnerable
to cyber-warfare/cyber- terrorism attacks.
The lack of concern about security and authentication in the design, deployment and
operation of existing SCADA networks
The mistaken belief that SCADA systems have the benefit of security through
obscurity through the use of specialised protocols and proprietary interfaces
The mistaken belief that SCADA networks are secure because they are
purportedly physically secured
The mistaken belief that SCADA networks are secure because they are supposedly
disconnected from the internet.
SCADA systems are used to control and monitor physical processes, examples of which are
transmission of electricity, transportation of gas and oil in pipelines, water distribution,
traffic lights, and other systems used as the basis of modern society. The security of these
SCADA systems is important because compromise or destruction of these systems would
impact multiple areas of society far removed from the original compromise. For example, a
blackout caused by a compromised electrical SCADA system would cause financial losses
to all the customers that received electricity from that source. How security will affect
legacy SCADA and new deployments remains to be seen.
There are two distinct threats to a modern SCADA system. First is the threat of unauthorised
access to the control software, whether it be human access or changes induced intentionally
or accidentally by virus infections and other software threats residing on the control host
machine. Second is the threat of packet access to the network segments hosting SCADA
devices. In many cases, there is rudimentary or no security on the actual packet control
protocol, so anyone who can send packets to the SCADA device can control it. In many cases
SCADA users assume that a VPN is sufficient protection and are unaware that physical
access to SCADA related network jacks and switches provides the ability to totally bypass all
security on the control those SCADA networks. These kinds of physical access attacks bypass
firewall and VPN security and are best addressed by
endpoint-to-endpoint authentication and authorization such as are commonly provided in the
non-SCADA world by in-device SSL or other cryptographic techniques.
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Many vendors of SCADA and control products have begun to address these risks in a basic
sense by developing lines of specialised industrial firewall and VPN solutions for TCP/IP
based SCADA networks. Additionally, application white listing solutions are being
implemented because of their ability to prevent malware and unauthorized application
changes without the performance impacts of traditional antivirus scans. Also, the ISA
Security Compliance Institute (ISCI) is emerging to formalise SCADA security testing
starting as soon as 2009. ISCI is conceptually similar to private testing and certification that
has been performed by vendors since 2007.
Eventually, standards being defined by ISA99 WG4 will supersede the initial industry consortia
efforts, but probably not before 2011.
The increased interest in SCADA vulnerabilities has resulted in vulnerability researchers
discovering vulnerabilities in commercial SCADA software and more general offensive
SCADA techniques presented to the general security community. In electric and gas utility
SCADA systems, the vulnerability of the large installed base of wired and wireless serial
communication links is addressed in some cases by applying bump-in-the-wire devices that
employ authentication and Advanced Encryption Standard encryption rather than replacing
all existing nodes.
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