1. 1
A
presentation
ON
RRVPNL, 132 KV GSS (GIS) OLD POWER HOUSE
JODHPUR (RAJ.)
submitted in partial fulfilment
for the award of the Degree of
BACHELOR OF TECHNOLOGY
(Rajasthan Technical University, Kota)
IN
Department of Electrical Engineering
Submitted To : Submitted By:
Mr. Vikas Bhalla Harish kumar
Assistant Professor EnrolmentNo.:
12ECTEE019

2. GAS INSULATED SUBSTATION
BY:
HARISH KUMAR
ELECTRICAL
ENGINEERING
1510-15
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6. CONTENTS:
Substation
Conventional substations (AIS)
Limitations of AIS
The need for GIS
Introduction to GIS
Properties of SF6
GIS assembly
Advantages of GIS
Design features
Drawbacks
SF6 – Environmental concerns
SF6 /N2 mixtures
Future trends in GIS
Conclusion.
6

7. SUBSTATION:
• An assembly of apparatus installed to control
transmission and distribution of electric power.
A : P R I M A R Y P O W E R L I N E S ' S I D E B : S E C O N D A R Y P O W E R L I N E S ' S I D E
1 . P R I M A R Y P O W E R L I N E S 2 . G R O U N D W I R E 3 . O V E R H E A D L I N E S 4 . T R A N S F O R M E R
F O R M E A S U R E M E N T O F E L E C T R I C V O L T A G E 5 . D I S C O N N E C T S W I T C H 6 . C I R C U I T
B R E A K E R 7 . C U R R E N T T R A N S F O R M E R 8 . L I G H T N I N G A R R E S T E R 9 . M A I N
T R A N S F O R M E R 1 0 . C O N T R O L B U I L D I N G 1 1 . S E C U R I T Y F E N C E 1 2 . S E C O N D A R Y P O W E R
L I N E S
7

8. AIR INSULATED SUBSTATION(AIS):
Air used as a dielectric.
Normally used for outdoor substations.
In very few cases used for indoor substations.
Easy to expand (in case that space is not an
issue)
Excellent overview, simple handling and easy
access.
8

9. LIMITATIONS OF AIS:
Large dimensions due to statutory clearances and
poor dielectric strength of air.
Insulation deterioration with ambient conditions and
susceptibility to pollutants.
Wastage of space.
Life of steel structures degrades.
Seismic instability.
Large planning & execution time.
Regular maintenance of the substation required.
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INTRODUCTION TO GAS INSULATED
SUBSTATION
What is GIS?
 A gas insulated substation is an electrical substation in which the major
structures are contained in a sealed environment with sulfur
hexafluoride gas (SF6) as the insulating medium.
Where and why Gas Insulated Substations
are used ?
 Gas Insulated Substations are used where there is space for providing
the substation is expensive in large cities and towns. In normal
substation the clearances between the phase to phase and phase to
ground is very large. Due to this, large space is required for the normal
or Air Insulated Substation (AIS).
 But the dielectric strength of SF6 gas is higher compared to the air, the
clearances required for phase to phase and phase to ground for all
equipments are quite lower. Hence, the overall size of each equipment
and the complete substation is reduced to about 10% of the
conventional air insulated substation

11. THE NEED FOR G.I.S:
Non availability of sufficient space.
Difficult climatic and seismic conditions at site.
Urban site (high rise building).
High altitudes.
Limitations of AIS.
11

12. GAS INSULATED SUBSTATION:
Introduction:
Compact, multi-component assembly.
Enclosed in a ground metallic housing.
Sulphur Hexaflouride (SF6) gas – the primary
insulating medium.
(SF6) gas- superior dielectric properties used at
moderate pressure for phase to phase and phase to
ground insulation
Preferred for voltage ratings of 72.5 kV, 145 kV, 300 kV
and 420 kV and above.
Various equipments like Circuit Breakers, Bus-Bars,
Isolators, Load Break Switches, Current
Transformers, Voltage Transformers, Earthing
Switches, etc. housed in metal enclosed modules
filled with SF6 gas.
12

13. PROPERTIES OF SF6:
• N O N - TO X I C , V E RY S TA B L E
C H E M I C A L LY.
• M A N - M A D E .
• L I F E T I M E – V E RY L O N G ( 8 0 0 TO
3 2 0 0 Y E A R S ! ) .
• I N S U L AT I N G P R O P E RT I E S 3 - T I M E S
T H AT O F A I R .
• C O L O R L E S S & H E AV I E R T H A N A I R .
• A L M O S T WAT E R I N S O L U B L E .
• N O N I N F L A M M A B L E .
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14. 14
Kalisindh Thermal Power

15. GIS ASSEMBLY:
ESSENTIAL PARTS OF GIS:
1. Bus bar
2. Circuit Breaker
3. Disconnector (line or bus)
4. Earthing switch (line or bus)
5. Current transformer (feeder / bus)
6. Voltage transformer (feeder/ bus)
7. Feeder Disconnector
8. Feeder Earthing switch
9. Lightning / Surge Arrester
10. Cable termination
11. Control Panel.
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16. 16
BUS BAR
 When a number of lines operating at the same voltage have to
directly connect electrically bus bar are used as the common
electrical component.
 There are following bus at the 132 gss:-
• 132 kv main bus bar
• 132 kv auxiliary bus bar
ISOLATOR
 Isolator is used to break the circuit under off-load
where as on-load circuit breaking is done by circuit
breaker
 Isolators are classified as:-
• Off load isolator
• On load isolator

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18. 18
CIRCUIT BREAKER
An automatic switch that stops the flow of
electric current in a suddenly overloaded
or otherwise abnormally stressed electric
circuit.
Types of circuit breaker:-
• Vaccum circuit breaker
• SF6 Circuit breaker
• Air blast circuit breaker
• Oil circuit breaker

19. 19
CIRCUIT BREAKER OPERATION
MECHANISM

20. 20
INSULATOR
Barrier insulator: The GIS is sectionalized into
individual gas compartments by means of gas-
tight barrier insulators. By this, the impact of
extension or internal faults on the overall
installation is reduced to a minimum, and control,
supervision and maintenance are greatly eased.
All flange connections are sealed by means of
age-resistant O-rings. Due to the gas tight design
of the insulators no leakage between
components can occur.
Support insulator: Support insulators are used
to mechanically support the conductors. They
mainly used for long SF6 bus duct connection.

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23. CURRENT TRANSFORMER
Current transformer is used for measurement
of alternating electric current.
The objective of C.T. is :-
Reduce the scale of the metering scale.
Insulated the measuring instrument from
voltage.
• Used for protective system
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25. POTENTIAL TRANSFORMER
Potential transformer is used for step down the
line voltage.
PT is connected in prallel with line.
Secondary voltage of the PT is generally 110v.
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CAPACITOR
VOLTAGE
TRANSFORMER
 A capacitor voltage transformer
consists of a Capacitor Voltage
Divider (CVD) and an inductive
Intermediate Voltage Transformer
(IVT).
 The rated voltage of the complete
capacitor voltage transformer
determines the ratio at the capacitor
voltage divider.
 It is more convenient to make an
Inductive voltage transformer for
lower voltage levels and let the CVD
take care of the high voltage.

27. LIGHTENING ARRESTER
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LIGTHNING ARRESTOR
Lightening arrester is used to protect the power station
sub station and transmission line against the voltage
wave reaching there.
It is also known as surge diverter which is connected
between line and earth to divert the incoming high
voltage to earth.
 It is the first equipment in a substation.
Generally arresters are connected in parallel with the
equipment to be protected, typically between phase and
earth for three phase installations.

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30. GIS ASSEMBLY:
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Supervisory Control And Data Acquisition
(SCADA)
 Supervisory Control and Data Acquisition (SCADA) offers the
ease of monitoring of sensors placed at distances, from one central
location.
 SCADA systems are used to monitor and control a plant or equipment
in industries such as telecommunications, water and waste control,
energy, oil and gas refining and transportation.
 A SCADA system gathers information, such as where a leak on a
pipeline has occurred, transfers the information back to a central site,
alerting the home station that the leak has occurred, carrying out
necessary analysis and control, such as determining if the leak is
critical, and displaying the information in a logical and organized
fashion.
 SCADA systems can be relatively simple, such as one that monitors
environmental conditions of a small office building, or incredibly
complex, such as a system that monitors all the activity in a nuclear
power plant or the activity of a municipal water system.
 SCADA systems were first used in the 1960s.

32. SCADA CONTROL ROOM
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33. LARGE SCADA DISPLAY
33

34. ADVANTAGES :
Occupies very less space (1/10th) compared to
ordinary substations.
Hence, most preferred where area for substation
is small (eg: Cities)
Most reliable compared to Air Insulated
Substations.
Number of outages due to the fault is less
Maintenance Free.
Can be assembled at workshop and modules can
be commissioned in the plant easily.
Pollution free
Explosion proof & fire proof installation
Increased safety
Easy operation & long life 34

35. DESIGN CHALLENGES:
1 . S A F E T Y :
• O P T I M I Z I N G O P E R AT I N G E L E C T R I C A L
S T R E S S E S T O S A F E L E V E L S B Y B E T T E R
I N T E R E L E C T R O D E S PA C I N G .
• I N C R E A S I N G T H E G A S V O L U M E A N D T H E
T H E R M A L I N E R T I A O F T H E S Y S T E M T O
E N H A N C E C O O L I N G A N D R E T A I N
I N S U L AT I O N S T R E N G T H .
2 . H I G H R E L I A B I L I T Y :
• S U P E R I O R C O N T A C T S Y S T E M S F O R
C I R C U I T B R E A K E R S A N D
D I S C O N N E C T O R S .
• M U LT I - C O N T A C T A N D F R I C T I O N F R E E
S U R F A C E S I N C O R P O R AT E D F O R L O N G
O P E R AT I N G C Y C L E S .
• R U G G E D , T I M E P R O V E N O P E R AT I N G
D R I V E S U S E D .
35

36. GIS FAILURE STATISTICS:
57.30%
18.10%
12.40%
12.30%
INSULATION FAILURE
MECHANICAL
TROUBLE
GAS LEAK
OTHERS
36

37. MAIN DRAWBACKS:
• H I G H C O S T C O M PA R E D T O
C O N V E N T I O N A L S U B S TAT I O N ( A I S ) .
• E X C E S S I V E D A M A G E I N C A S E O F
I N T E R N A L FA U LT.
• D I A G N O S I S O F I N T E R N A L FA U LT A N D
R E C T I F Y I N G TA K E S V E R Y L O N G T I M E
( H I G H O U TA G E T I M E ) .
• S F 6 G A S P R E S S U R E M U S T B E
M O N I T O R E D I N E A C H C O M PA R T M E N T.
• R E D U C T I O N I N T H E P R E S S U R E O F
T H E S F 6 G A S I N A N Y
M O D U L E R E S U LT S I N F L A S H
O V E R A N D FA U LT S .
• S F 6 C A U S E S O Z O N E D E P L E T I O N A N D
G L O B A L WA R M I N G .
37

38. SF6 – ENVIRONMENTAL CONCERNS:
• C U R R E N T LY, 8 0 % U S E D B Y
E L E C T R I C A L P O W E R I N D U S T RY.
• O T H E R U S E S – M I C R O -
E L E C T R O N I C S ; A L & M G
P R O D U C T I O N .
• 7 0 0 0 M E T R I C TO N S / Y R I N 1 9 9 3 .
• R E A C H E D 1 0 , 0 0 0 M E T R I C TO N S / Y R
B Y 2 0 1 0 .
• T W O A R E A S O F H E A LT H A N D
E N V I R O N M E N TA L I M PA C T:
I . T H R O U G H I T S N O R M A L U S E I N A
W O R K P L A C E – A R C I N G
B Y P R O D U C T S .
I I . G L O B A L E N V I R O N M E N TA L I M PA C T 38

39. SF6/N2 MIXTURES FOR GIS?
• S F 6 G A S – S P E C I F I C A L LY M E N T I O N E D
I N K Y O T O P R O T O C O L .
• S M A L L Q U A N T I T I E S O F S F 6 I N N 2 C A N
I M P R O V E D I E L E C T R I C S T R E N G T H
D R A S T I C A L LY.
• A L L O F T H E D I E L E C T R I C S T R E N G T H
O F S F 6 , N E A R LY, C A N B E A C H I E V E D
B Y A D D I N G L E S S T H A N 2 0 % S F 6 I N T O
N 2 .
• S F 6 / N 2 M I X T U R E S L E S S
S U S C E P T I B L E T O E F F E C T S O F F I E L D
N O N U N I F O R M I T Y T H A N P U R E S F 6 .
• T H U S M I T I G AT I N G T H E E F F E C T S O F
PA R T I C L E S A N D S U R FA C E
P R O T R U S I O N S .
39

40. FUTURE TRENDS:
• C O M PA C T D E S I G N O F S W I T C H
G E A R B Y U S I N G T H R E E P H A S E
M O D U L E S .
• U S E O F VA C U U M C I R C U I T B R E A K E R
C E L L S I N T H E M E D I U M H I G H
V O LTA G E G I S .
• O P T I M I Z AT I O N O F G I S D E S I G N TO
A L L O W E A S I E R M A I N T E N A N C E .
• D E V E L O P M E N T O F D C G I S F O R
I N C O R P O R AT I N G I N TO E X PA N D I N G
N AT I O N A L / I N T E R N AT I O N A L H V D C
S Y S T E M S .
• S E A R C H F O R R E P L A C E M E N T
G A S E S F O R S F 6 . 40

41. CONCLUSION:
• G I S – N E C E S S A R Y F O R E X T R A H V &
U LT R A H V
• S O M E I M P O R TA N T A R E A S T O B E
S T U D I E D I N C L U D E :
• M O R E C O N S E R VAT I V E D E S I G N .
• I M P R O V E D G A S H A N D L I N G .
• D E C O M P O S I T I O N P R O D U C T
M A N A G E M E N T T E C H N I Q U E S .
• A C H I E V I N G & M A I N TA I N I N G H I G H
L E V E L S O F AVA I L A B I L I T Y R E Q U I R E –
M O R E I N T E G R AT E D A P P R O A C H T O
Q U A L I T Y C O N T R O L B Y B O T H U S E R S
A N D M A N U FA C T U R E S .
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