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1. A REPORT
on
undertaken at
400 KV SUBSTATION-PTCUL, RISHIKESH
submitted in partial fulfillment of the degree
of
BACHELOR OF TECHNOLOGY
in
ELECTRICAL ENGINEERING
by
Priya Saini
Department of Electrical Engineering

2. Power Map of Uttarakhand

3. Single Line Diagram (SLD)
of Existing Transmission Network of PTCUL

4. Single Line Diagram (SLD) of 400 kV Substation,
Rishikesh

5. Transformers
Step-Up Transformers
Step-Down Transformers
Generating Transformer
Inter Connecting Transformers
Power Transformers

6. Parts of Transformer
Main Tank
Core
Winding
Insulation
Transformer Oil
Terminals Bushing
Breather
Tap Changer
Radiators & Fans
Cooling Tubes
Buchholz Relay
Conservator
Temperature Gauge
Pressure Relief Device

7. Transformer Protection
• Pressure Release Value (PRV)
• Oil Surge Relay (OSR)
• Over Flux Protection
• Over Voltage Protection
• Under Voltage Protection
• Under Frequency Protection
• Directional Earth Fault Relay
• Over Heating Protection
• Over Current Relay
• Differential Relay
• Buchholz Relay
.
.
.
.

8. Instruments Transformers
• Current Transformers (CT)
– A current transformer is a type of transformer that is used to measure the
AC current. It produce an alternating current in its secondary sufficiently
reduce in magnitude (step-down) which is proportional to AC current in its
primary.
• Capacitive Voltage Transformer (CVT):
– A Capacitive Voltage Transformer (CVT) is a transformer used in power
systems to step down extra high voltage signals and provide a low voltage
signal for metering or operating a protective relay.
• Potential Transformer (PT)
– The main use of this transformer is to measure voltage through the bus.
There are two main parts in it-measurement and protection. A potential
transformer (or voltage transformer) is connected with its primary in the
power line. The secondary provides for the instruments and relays a voltage
which is a known fraction of the line voltage.

9. Instruments Transformers
Current Transformer (CT) Capacitive Voltage Transformer
(CVT)

10. Isolator (Disconnector)
Line Isolator (LI)
A 3-phase isolator connected at the line side is known as line isolator. A
line isolator is an off-load switch that connects the line breaker and the
bus. It is placed between circuit breaker and current transformer.
Bus Isolator (BI)
A 3-phase isolator is connected at the bus side is known as bus isolator.
There is no difference in construction and working between line and bus
isolator. Bus Side isolator is connected directly in between the main bus.
A bus isolator is an off load switch that connects the line breaker and
the bus. It sits between circuit breaker and the bus.
Transfer Isolator (TI)
In case of some maintenance work on any of the circuit breaker or
isolator an auxiliary circuit breaker is used (known as bus coupler) a
transfer isolator is used to transfer the supply to the auxiliary bus so
that the bus coupler can be used in place of other circuit breaker. It is
also known as tandem isolator.

11. Lightening Arrestor (Surge Arrestor)
• A protective device which conducts the high voltage surge on the power system
to ground.
• Protection against any overvoltage caused due to lightning surges.
• It is first device in the substation connected in parallel to main line (between
the ground & the line conductor.)
• LA diverts the abnormal high voltage to the ground without affecting the
continuity of supply.
• In an extra-high voltage AC system, the surge diverter is used to protect the
generators, transformers, bus bars, lines, circuit breakers etc.

12. Line Trap (Wave Trap)
– Line Trap/Wave Trap (High Frequency Stopper) - parallel resonant
circuit, mounted in-line (in series) on HV transmission lines to
prevent the transmission of high frequency (40 kHz to 1000 kHz)
carrier signals of power line communication to unwanted
destinations.
– Line trap is a device that imposes high impedance for high frequency
signals and low impedance for low frequency signals thus passing
only low frequency signals.
– A frequency message signal is being transmitted along with the
power line for the purpose of communication and protection knows
as carrier protection.

13. Line Trap (Wave Trap)

14. DC Supply System (Battery System)
Battery System consist of battery set (banks / panels) for the operation of relay and
controlling panels as they all requires D.C. supply for their operation.
• Battery Set (Battery Bank)
 Battery Bank has two groups of batteries one of 220 V DC & one of 48 V DC.
 Batteries connected in series so that they add up to 220 V DC or 48 V DC.
 Nickel-Cadmium (Ni-Cd) batteries which are rechargeable .
 Sulphuric acid is used as an electrolyte and it is mixed with dilute water.
 Each battery has the same ratings as below: Voltage 2 Volts, 400 Ah
• Battery Charger
 Battery charger is used for the charging of batteries.
 Battery Charger is an AC to DC convertor.
 Two battery chargers are used for 220 V DC out of which one is used as backup.

15. DC Supply System (Battery System)

16. Relays &its Types: The function of a protective relay is to detect and locate
a fault and issue a command to the circuit breaker to disconnect the
faulty element. It is a device which senses the abnormal conditions on
the power system.
(a) Mechanical Relays: These types of relays use mechanical parts
for its operation. Due to mechanical parts
these relays are slower in operation.
(b) Numerical Relays: These relays are microprocessor based relay
which allow them to operate accurately
within no time.
-Over Current and Earth Fault Relays
• Directional Over Current and Earth Fault Relay
• Non- Directional Over Current and Earth Fault Relay
-Differential Relay
-Distance Relay
Protection System: Relays and its Types

17. Metering and Monitoring
• Ammeter
• Voltmeter
• Energy Meter
• Watt Meter
• VAr meter
• Temperature Indicator
• Alarms and Annunciator Panel
• Fire Alarm Annunciator

18. Fire and Fire Extinguishers
S.
No.
Class of
Fire
Description
1 Class A
Fires
Fires in ordinary combustible material such as wood, cloth,
paper, rubber and many plastics.
2 Class B
Fires
Fires in flammable liquids, combustible liquids, petroleum
greases, tars, oils, oil based paints, solvents, lacquers, alcohols
and flammable gases.
3 Class C
Fires
Fire that involves energized electrical equipment
4 Class D
Fires
Fire in combustible metals such as magnesium, titanium,
zirconium, sodium, lithium and potassium.
5 Class E
Fires
Fire in cooking appliances that involve combustible cooking
media (vegetable or animal oils and fats).

19. Fire and Fire Extinguishers
Fire Protection System
 High Velocity Water Spray (HVWS) System (for 400 kV Substation)
 Hydrant System
 Nitrogen Injection Fire Protection System (NIFPS)
Types of Fire Extinguishers
 Carbon Di-Oxide (CO2) Fire Extinguisher : For use on Class B and Class C fires.
 AFFF Foam Type Fire Extinguishers: For use on both Class A and Class B fires
 Dry Powder Type Fire Extinguishers: For use on Class D fires

20. Fire and Fire Extinguishers
Types of Fire Extinguishers
 Carbon Di-Oxide Fire Extinguisher : For use on Class B and Class C fires.
 AFFF Foam Type Fire Extinguishers: For use on both Class A & Class B fires
 Dry Powder Type Fire Extinguishers: For use on Class D fires