BVM Engineering College

V.V. Nagar, Gujarat, India

Subject: Electronic Design Laboratory (3EE31)

Report on project titled Smart Fault Detection in Overhead Transmission Line,

displayed & demonstrated during the Project Expo-2023 held by Electrical
Department on 8th April 2023. Prepared by Krunal Prajapati (20EE060) under
Professor Swapnil Arya.

Professor’s Sign:
Introduction
Electrical energy, after being produced at generating stations (TPS, HPS, NPS, etc.) is
transmitted to the consumers for utilization. This is due to the fact that generating stations are
usually situated away from the load centers. The network that transmits and delivers power from
the producers to the consumers is called the transmission system. This energy can be transmitted
in AC or DC form. Traditionally, AC has been used for years now, but HVDC (High Voltage
DC) is rapidly gaining popularity.

Faults In Electric Power System

A fault in an electric power system can be defined as, any abnormal condition of the system that
involves the electrical failure of the equipment, such as, transformers, generators, busbars, etc.

The fault inception also involves in insulation failures and conducting path failures which results
short circuit and open circuit of conductors.

Under normal or safe operating conditions, the electric equipment in a power system network
operate at normal voltage and current ratings. Once the fault takes place in a circuit or device,
voltage and current values deviates from their nominal ranges.

The faults in power system causes over current, under voltage, unbalance of the phases, reversed
power and high voltage surges. This results in the interruption of the normal operation of the
network, failure of equipment, electrical fires, etc.

Types Of Faults
Two broad classifications of faults are:
 Symmetrical faults
 Unsymmetrical faults

Symmetrical Faults

Symmetrical faults also known as three phase fault or balanced fault can be defined as the
simultaneous short circuit across all the three phases.
This type of fault occurs infrequently, for example, when a mechanical excavator cuts quickly
through a whole cable, or when a line, which has been made safe for maintenance by clamping
all the three phases to earth is accidentally made alive or when due to slow fault clearance, an
earth fault spreads across to the other two phases.

Symmetrical faults can be further classified as:

a) L-L-L Fault (triple line fault)
b) L-L-L-g Fault (triple line to ground fault)
Unsymmetrical Faults
Unsymmetrical faults also known as unbalanced faults can be classified as below:
a) L-g Fault (line to ground fault)
b) L-L Fault (line to line fault)
c) L-L-g Fault (double line to ground Fault)

Single line to Ground (L-g) Fault

A short circuit between any one of the phase conductors and earth is called a single line to
ground fault. It may be due to the failure of the insulation between a phase conductor and the
earth, or due to phase conductor breaking and falling to the ground.

Line to line (L-L) Fault

A short circuit between any two phases is called a line to line or phase-to-phase fault

Double line to Ground (L-L-g) Fault

A short circuit between any two phases and the earth is called a double line to ground or a two-
phase to ground fault.

Effects Of Faults

 Heavy short circuit current may cause damage to equipment or any other element of the
system due to overheating and high mechanical forces set up due to heavy current.
 Arcs associated with short circuits may cause fire hazards. Such fires, resulting from
arcing, may destroy the faulty element of the system. There is also a possibility of the
fire spreading to other parts of the system if the fault is not isolated quickly.
 There may be reduction in the supply voltage of the healthy feeders, resulting in the loss
of industrial loads.
 Short circuits may cause the unbalancing of supply voltages and currents, thereby
heating rotating machines.

Current Situation
At distribution side whenever fault occurs, the relative circuit breaker will trip & then the
maintenance team will go for patrolling to identify the fault location, which is very time-
consuming process. Because of this system reliability will decreases, and revenue losses also
increases.
To increase system reliability, to decrease outage time & to decrease revenue losses we need to
identify fault location as soon as possible.
To locate the fault as soon as possible we are going to use “Fault Passage Indicator (FPI)

Fault Passage Indicator (FPI)

An Overhead Line Fault Passage Indicator detects and indicates faults that occur in an electrical
distribution network. It monitors the system 24×7 for fault occurrence and reduces downtime
time by quickly identifying the fault location. A Fault Passage Indicator is installed under live
conditions with the help of a hot stick and an adapter.

How does a Fault Passage Indicator work?

One Fault Passage Indicator is usually clipped onto each phase of the circuit allowing the utility
or Operation & Maintenance firm to monitor current and faults in each phase. By placing the
FPI’s at regular intervals along the line, the device can identify faults in the downstream section
from its point of installation by monitoring the electromagnetic field surrounding the conductor

During the fault condition, the magnetic field around the conductor increases rapidly as a high
current will flow through that path for a fraction of time (di/dt) & then suddenly breaks to zero as
circuit breaker trips, this condition is sensed by the FPI & gives the alarm physically on-site &
remotely to SCADA centre.

In the case of a non-communicable type, the FPI will give alarm physically on-site by blinking
the RED Ultra bright LED & in the case of a communicable type the FPI gives alarm physically
on-site as well as send the data to the SCADA centre through DCU over GSM/GPRS.
The illustration below provides a basic topology of a communicable system.
Advantages
The main aim of an Overhead Line Fault Passage Indicator is to reduce the physical efforts
needed to identify the faults & that occur in distribution networks. There is a significant
reduction in the time, effort and manpower required for identifying faults Communication.

In recent times, however, the use of communications has widely spread to distribution grids. This
opens the door to diverse communication channels and protocols, where there is no actual
consensus between DNOs. Some of the channels that have been in use for communicative FPIs
are radio-frequency, mobile communications (2G, 3G), fiber optics, WAN, power line carrier,
LAN, CAN, Ethernet RJ-45 port (typically), RS485, GSM (e.g. by means of SMS notifications)
or via a Remote Terminal Unit (RTU). Concerning the protocols, some examples are the IEC
60870-104, IEC 60870-101 (power line carrier, low bandwidth), Telnet, SSH, HTTP (Web UI),
Modbus, CAN or DLMS/COSEM. 34

Moreover, with communications, the state of the FPIs can be monitored via SCADA interfaces,
which implies knowing the faulted section immediately at the control center. This allows the
crew to be sent directly to the switch to be maneuvered. This has led to a great reduction of the
ENS, which often justifies the cost of adopting communicative FPIs.
In general terms, the use of communications has been a major step in FPIs and improvement of
their functionalities. Despite the obvious advantages, the use of communications and remote
indication do not replace the visual indications, still useful in case of communication non-
operation, thus becoming a back-up indication.

Simulation Of FPI
The equipment used in the simulation are discussed below.
 Alternator (AC voltage source)
 Load bulb
 Resisters
 ACS712ELCTR-30A-T Hall effect sensor
 Arduino Uno
 LED
 Virtual terminal

The hall effect sensor is connected in with this circuit so it can measure the current and give the
output to the Arduino uno. Here we have used two power sources of +5V DC to give power
supply to the hall effect sensor and to the Arduino uno. LED is connected for the fault indication.

Arduino Uno senses the current value from the hall effect senser continuously, so whenever we
are creating the fault, current flow of the line will be increases. So, we have to program Arduino
as per our need. Arduino programming is given in figure. Now in fault condition the current
exceeds the threshold value, which we have programmed the Arduino then Arduino will give
indication by turning on the LED. LED is giving the indication of high current flow from the line
(or Fault in the line). Once the LED turns on, we have to turn off it by reset button which is
given at the pin A1 of Arduino, so if we creating the transient fault it will glow & we have to
reset it by button given at pin A1.

Applications:
1. Fault detection and location: FPIs continuously monitor the electrical distribution
network and detect faults in real-time. By placing the FPIs at regular intervals along the
line, the device can identify faults in the downstream section from its point of installation
by monitoring the electromagnetic field surrounding the conductor. This reduces the
downtime caused by the fault and helps in quickly identifying the fault location, allowing
maintenance crews to quickly repair the fault.
2. Reduction in maintenance costs: The FPI system helps reduce the costs associated with
maintenance of electrical distribution networks by identifying faults in real-time,
reducing the need for manual inspections and repairs. This leads to a significant reduction
in the time, effort and manpower required for identifying faults.
3. Remote monitoring and control: The FPI system can be equipped with communication
capabilities that allow it to send real-time data to a central control system. This enables
remote monitoring and control of the electrical distribution network, allowing operators
to quickly respond to faults and other issues.
 4. Integration with SCADA systems: FPIs can be integrated with Supervisory Control and
Data Acquisition (SCADA) systems, providing real-time monitoring and control of the
electrical distribution network. This enables operators to quickly identify faults and other
issues, and take appropriate action to resolve them.
5. Improved safety: The FPI system can improve safety for maintenance crews by providing
early warning of faults and reducing the need for manual inspections. This helps prevent
accidents and injuries associated with maintenance activities on electrical distribution
networks.

Conclusion
In this project, we have seen the simulation and the results of the simulation of the FPI. From this
we can say that the FPI gives the fault indication by glowing the LED. So, if we have mounted
this in the system, we can get the fault location between operating and non operating FPIs. By
this we can reduce the fault detection time.