1. Rajasthan Rajya Vidyut Prasaran Nigam
220Kv Grid Substation
(Kunda Ki Dhani, Kukas, Jaipur)
Submitted by
Palak Gupta
Submitted to
Department of Electrical and Electronics Engineering
Birla Institute of Technology, Mesra
2. Rajasthan Rajya Vidyut Prasaran Nigam Limited
RVPN is a company of Rajasthan State Electricity Board(RSEB) established by the government of
Rajasthan.
Aim Of RVPN is to provide reliable transmission service to customers.
RVPN provides a pathway for power within the whole of Rajasthan. It owns, builds, maintains, and
operates the high voltage electric transmission system that helps to keep the lights on, businesses
running and communities strong.
3. Introduction
• The present-day electrical power system is A.C. i.e., electric power is
generated, transmitted, and distributed in the form of alternating
current. The electric power is produced at the power stations which are
located at favourable places, generally quite away from the consumers. It
is delivered to the consumers through a large network of transmission
and distribution.
• Along the transmission lines, secondary substations are created where
voltage is further stepped down to sub-transmission and primary
distribution voltage.
• A substation is an assembly of apparatus, which transforms the
characteristics of electrical energy from one form to another say from
one voltage level to another level. Hence a substation is an intermediate
link between the generating station and the consumer.
• For economic transmission the voltage should be high, so it is necessary
to step up the generated voltage for transmission and step down the
transmitted voltage for distribution. For this substations are installed.
The normal voltages for transmission are 400kv, 220kv,132kv, and for
distribution 33kv,11kv, etc.
4. 220 kv GSS, Kunda ki Dhani ,Jaipur
The 220 KV GSS is situated in KUNDA ki Dhani, Jaipur. In the GSS single main and auxillary scheme is used. There are
total three incoming feeder and many outgoing feeders which are mentioned in the next section.
The GSS step down the voltage level from 220KV to 132 KV and 132 KV to 33 KV or 11 KV in different manner.
There are three bus bar arrangement, main bus bar used at a time and auxillary bus bar are connected through bus
coupler. In case of main bus or other equipment are out of order or other maintenance purpose than supply should be
given through auxiliary bus bar without interruption in supply.
6. BUS BARS
Bus bars are a common electrical component through which a large number of feeders operating at some
voltage have to be connected.
Electrical Busbar consists of the number of lines electrically, which are operating at the same voltage and
frequencies. Generally, copper or aluminum conducting material is used in the construction of bus bars.
Bus bars are arranged in different configurations, any particular arrangement of the bus bar is to achieve
adequate operating flexibility, sufficient reliability, and minimum cost.
7. ISOLATORS
It isolates the device from live line when there is a maintenance.
It operates when there is no load.
It is also used to change bus bar line from main to reserve and vice versa.
8. Circuit Breaker
A circuit breaker is an automatically operated
electrical switch designed to protect an
electrical circuit from damage caused by
overload or short circuit. Its basic function is
to detect a fault condition and interrupt
current flow.
A circuit breaker can be reset (either
manually or automatically) to resume normal
operation, unlike fuse(which operates once).
Today, two most popular circuit breakers are
used in substation which are: Vacuum Circuit
Breaker and SF6.
9. Lightning Arrestor
A lightning arrester is a device used on electrical power systems to protect the insulation on the system
from the damaging effect of lightning.
When a lightning surge or switching surge travels down the power system to the arrester, the current from
the surge is diverted around the protected insulation in most cases to earth.
A lightning arrestor has two terminals viz a high voltage terminal and ground terminal .
10. INSULATOR
The electrical insulator is a device
that provides the required insulation
between the line conductor and
earth. Due to this insulation,
leakage current can’t flow from the
line conductor to earth.
Insulator has very high resistivity
(offers very high resistance). Due to
this high resistance, electrical
current does not flow from one
point to another.
11. RELAY
In a power system it is inevitable that immediately or later some failure does occur
somewhere in the system. When a failure occurs on any part of the system, it must be
quickly detected and disconnected from the system. Rapid disconnection of faulted
apparatus limits the amount of damage to it and prevents the effects of fault from
spreading into the system.
For high voltage circuits relays are employed to serve the desired function of automatic
protective gear. The relays detect the fault and supply the information to the circuit
breaker. The electrical quantities which may change under fault condition are voltage,
frequency, current, phase angle.
12. WAVE TRAP
Line trap also is known as Wave trap.
A Line trap (high frequency stopper) is a maintenance free inductor , mounted inline on high
voltage Ac transmission power lines to prevent the transmission of high frequency(40kHz to
100 kHz) carrier signals of line communication to unwanted destinations.
What it does is trapping the high frequency communication signals sent on the tine from the
remote substation and diverting them to the telecom/teleportation panel in the substation
control room (through coupling capacitor and LMU).This is relevant in Power Line Carrier
Communication (PLCC) systems for communication among various substations without
dependence on the telecom company network.
13. Transformers
Transformer is a static machine, which transforms the potential of alternating current at
same frequency. It means the transformer transforms the low voltage into high voltage &
high voltage to low voltage at same frequency. It works on the principle of static induction
principle.
When the energy is transformed into a higher voltage, the transformer is called step up
transformer but in case of other is known as step down transformer.
14. POWER TRANSFORMER
The Power transformer is one type of transformer that is
used to transmit electrical energy in any component of the
electronic or electrical circuit between the distribution
primary circuits and the generator. These transformers are
utilized in distribution networks to interface step down and
step up voltages. The usual form of power transformer is
fluid immersed, and the life cycle of these instruments is
approximately 30 years. Power transformers can be divided
into three types according to the ranges. They are large
power transformers, medium power transformers, and small
power transformers.
The range of large power transformers can be from 100MVA
and beyond
The range of medium power transformers can be from -
100MVA
The range of low power transformers can be from 500-
7500kVA
15. CURRENT TRANSFORMER
There are 3 sets of the current transformers
installed at the sub-station. Each set have three
current transformers. Like any other
transformer, a current transformer has a
primary winding, a magnetic core, and a
secondary winding. The alternating current
flowing in the primary produces a magnetic
field in the core, which then induces a current
in the secondary winding circuit.
. A primary objective of current transformer
design is to ensure that the primary and
secondary circuits are efficiently coupled so
that the secondary current bears an accurate
relationship to the primary current.
16. Potential Transformer
Potential transformers are instrument
transformers.
They have a large number of primary turns and a
few number of secondary turns. It is used to
control the large value of voltage.
These are used for the metering purposes. The
potential transformer works along the same
principle of other transformers.
It converts voltages from high to low. It will take
the thousands of volts behind power transmission
systems and step the voltage down to something
that meters can handle. These transformers work
for single and three phase systems, and are
attached at a point where it is convenient to
measure the voltage.
Potential Transformer is designed for monitoring
single-phase and three-phase power line voltages
in power metering applications.
17. CAPACITIVE VOLTAGE
TRANSFORMER
A capacitor voltage transformer (CVT), or
capacitance coupled voltage transformer
(CCVT) is a transformer used in power
systems to step down extra high voltage
signals and provide a low voltage signal,
for measurement or to operate a
protective relay.
In its most basic form the device consists
of three parts: two capacitors across
which the transmission line signal is split,
an inductive element to tune the device
to the line frequency, and a transformer
to isolate and further step down the
voltage for the instrumentation or
protective relay.
18. TRANSFORMER OIL
TESTING
Oil testing of transformer is how blood testing to human beings. Transformer oil testing is a proven and best-
known loss prevention technique that should be part of any maintenance program of an organization. It not
only acts as an early warning system but also helps us to understand the inner health of the transformer
without disrupting its operation.
Transformer oil testing when done on a regular time interval allows the maintenance department to identify
priorities, plan work assignments and gives enough time to arrange outside vendors for transformer servicing or
maybe order necessary parts and materials.
19. FEW OIL TESTING TECHNIQUES
Visual Examination: One of the first test which is generally conducted
in lab is visual examination which is done by passing a beam of light
through it to determine transparency and identify foreign matters.
Dielectric Breakdown Voltage (BDV Test)-With this test, the
dielectric strength of the insulating oil is tested or on other words we
measure the voltage at which the oil fails electrically which is a good
indication of the amount of oil containment or moisture present inside the
oil. This test is conducted by placing oil sample between two electrodes
and voltage is applied gradually till the time electrodes have enough
potential and starts to conduct through the oil and that’s what we call as
the breakdown voltage of the oil.
Flash Point or Fire Point- This test is used to check the volatility of
the oil. It is the minimum temperature at which the heated oil starts to give
out sufficient vapor to form flammable moisture with the air. The
international standard used for this test is ASTM D92
.
21. CONCLUSION
We think that our training was successful and we
think that the 220KV sub-station at RVPN, KUNDA
KI DHANI ,KUKAS, JAIPUR is an excellent training
centre for inquisitive emerging electrical engineers
to learn about the transmission and distribution of
high voltage electricity and all other protective
devices. In the training session we came to know
about the fundamentals of power system which
may be quite useful for our fore coming studies.
The three wings of the electrical system viz
generation, transmission, and distribution are
connected to each other that to very perfectly.