Seminar Report On Air Insulated and Gas Insulated Substation
Seminar Report On Air Insulated and Gas Insulated Substation
Seminar Report On Air Insulated and Gas Insulated Substation
A
Seminar Report
Submitted in Partial Fulfillment of the Requirements for the Degree
Of
Bachelor of Technology
In
Electrical Engineering
Submitted By:
Pathik Patel
(13BEE079)
Page 1
ACKNOWLEDGEMENT
It is our proud privilege and duty to acknowledge the kind of help and guidance received from
several people in preparation of this report. It would not have been possible to prepare this report
in this form without their valuable help, cooperation and guidance.
First and foremost, our sincere gratitude to our guide, Prof. C. R.Mehta, Department of
Electrical Engineering, Institute of Technology, Nirma University for guiding us in
investigations for this seminar. Our numerous discussions with his were extremely helpful.
We express our sincere gratitude to Prof. Sarika S Kanojia, Department of Electrical
Engineering, Institute of Technology, Nirma University for her valuable suggestions and
guidance throughout the period of this seminar.
The seminar on Air Insulated and Gas Insulated Substation was very helpful to us in giving
the necessary background information and inspiration in choosing this topic for the seminar. Our
sincere thanks to Prof. Gaurang Buch and Prof. Sukanta Sahoo Seminar Coordinator for
having supported the work related to this project.
Last but not least, our classmates who made valuable comment suggestions on this proposal
which gave us an inspiration to improve our work. We thank all the people for their help directly
and indirectly to complete our work.
Special Thanks to Microsoft Office 2007.
Place: Ahmedabad
Raj
Patel
Pathik Patel
Page 2
ABSTRACT
Reliable and economical power transmission and distribution are key functions for the future
electric power supply. Air insulated Substation requires more space and more danger to faults.
So, Gas insulated switchgear is used in industrial areas to fulfill high-energy demands by space
saving design with a minimum of cost. Only SF6 insulated switchgear is able to fulfill these
requirements. SF6 switchgear installed in Canada in a 550 kV substation with 100 kA as the
highest breaking capacity ever achieved in one of the steps of development since then.
Consistent research and development and innovative energy led to the third generation of
nowadays compact and overall optimized switchgear. The advantages of gas-insulated
switchgear are its compact design and the modular system. The standardized modular structure is
made to match the various customers specifications and allows to realize almost all substation
configurations in compliance to them.
Page 3
LIST OF FIGURES
1) Fig.1.1 (A) Air Insulated Substation
2) Fig.1.1 (B) Gas Insulated Substation
3) Fig.1.2 (A) Pole Mounted Substation
4) Fig.1.2 (B) Traction Substation
5) Fig. 1.3 ELECTRICAL DISTRIBUTION NETWORK
6) Fig. 2.1.4 Protective Relays
7) Fig. 2.1.6 (a) Pin Type Insulator
8) Fig. 2.1.6 (b) Suspension Disc Insulator
9) Fig. 2.1.6 (c) Strain type Insulator
10)Fig. 2.1.7 Lightning Arrestor
Page 4
NOMENCLATURE/ABBREVIATIONS
Page 5
TABLE OF CONTENTS
ACKNOWLEDGEMENT
ABSTRACT
LIST OF FIGURES
(2)
(3)
(4)
NOMENCLATURE/ABBREVIATIONS
TABLE OF CONTENTS
(5)
(6)
CHAPTER 1: INTRODUCTION
(8)
(13)
(18)
(21)
REFERENCES
(22)
Page 6
Page 7
CHAPTER 1: INTRODUCTION
What is a Substation??
A Substation is a part of an electrical generation, transmission, and distribution system.
Substations transform voltage from high to low, or the reverse, or perform any of several
other important functions.
Between the generating station and consumer, electric power may flow through several
substations at different voltage levels.
Globally economy and population continues to grow, results, rise in electrical power
requirements. For this purpose, substation equipment has to be made more efficient and reliable
to cope up with increase in demand, specially adapting current power distribution and
transmission system.
Air insulated Substation:An electric power substation that has the busbars and equipment terminations generally open to a
ir and utilizes insulation properties ofambient air for insulation to ground.
Gas insulated Substation: A Gas insulated substation (GIS) is a high voltage substation in which the major
structures are contained in a sealed environment with sulfur hexafluoride gas as the
insulating medium.
All the equipments are placed inside SF6 modules filled with SF6 gas.
GIS technology originated in Japan, where there was a need to develop technology to
make substations as compact as possible.
Gas Insulated Substations are high voltage Substations that are compact, requiring little
maintenance when compared to air-insulated conventional Substations.
Page 8
Page 9
Pole mounted substation are mainly distribution substation constructed on two pole
Traction Substation:-
Page 10
Page 11
Page 12
2.1
The major equipments and accessories that may be used in substation:-1. Bus bar,
2. Circuit Breakers,
3. Isolators,
4. Protective Relays,
5. Transformers,
6. Insulators,
7. Lightning Arrester,
8. Current Transformers,
9. Potential Transformer,
10. Control room.
2.1.1 Bus Bar: The bus is a line in which the incoming feeders come into and get into the instruments for
further step up or step down.
Various Incoming and outgoing circuits are connected to Bus Bars.
There may be double line in the bus so that if any fault occurs in the one the other can
still have the current and the supply will not stop.
The Cross Section of the bus bar is to be decided as follows :
1) It should be able to carry the current without any heating so that maximum temperature
doesnt exceed 700C.
2) The current capacity generally adopted as 200 amp/mm2.
3) Corona must not be formed at normal operating voltage. To prevent corona hollow bus
bar is also used.
4) Mechanical force current I2 1/ Spacing between two conductors
Page 13
Circuit breaker is used for switching during normal and abnormal conditions.
It is used to interrupt short circuit currents and connected in series with circuit.
There are many types of circuit breakers.
1) Air blast circuit breaker
2) Oil circuit breaker
3) SF-6 circuit breaker
2.1.3 Isolators
Mainly Used when repairing and maintenance of substation has to be carried out.
Operated on No load as circuit breakers are used for On Load.
Employed to give protection to the equipments against abnormal conditions and faults in
the power system.
Isolates the faulty element from the system with the help of circuit breakers.
Page 14
2.1.5 Transformers:
There are three transformers in the incoming feeders so that the three lines are step down
at the same time.
At the generation, it will be step-up transformer and at the distribution end, there will be
step-down transformer.
Transformer tanks up to 25 MVA capacity are generally oil filled.
And those of higher capacity are transported with N2 gas filled in transformer tank to
avoid the ingress of moisture.
2.1.6 Insulators:
There
are
of
insulator used
as overhead
insulator likewise
1. Pin
2. Suspension
3. Strain Insulator
Insulator
Insulator
Page 15
Lightening arrestors are the instrument that are used in the incoming feeders so that to
prevent the high voltage entering the main station.
This is done by MOV Disk which is fast acting electronic switch.
If some lightening occurs the arrestors pull the lightening and ground it to the earth.
In any substation the main important is of protection which is firstly done by these
lightening arrestors.
Page 16
A current transformers step down the current and this is used for metering purpose.
The relays which detects abnormal conditions by monitoring system currents which
supplied from the outputs of CTs.
Page 17
3.2 Advantages of GIS:A GIS has many advantages over a conventional substation, including a space saving and
flexible design, less field construction work resulting in quicker installation time, reduced
maintenance, higher reliability and safety, and excellent seismic withstand characteristics.
Aesthetics of GIS are far superior to that of a conventional substation, due to its substantially
smaller size. A GIS can even be installed in a building, if desired. When all of these advantages
are taken into consideration, a GIS is a cost effective alternative to a conventional substation that
offers many benefits to the end user.
Special Features
Enhanced insulating properties and reduced long-term operational costs by means of sealed
metal enclosure filled with SF6 gas.
Reliability
Extensive experience in designing optimum phase and feeder spacing dimensions according to
site conditions enable compact dimensions that reduce space requirements to less than 20%
of conventional air insulated substations.
Compact Design
Ensured
personal
safety
by
earthed
enclosure,
numerous
interlocks and lockout devices. Increased stability during earthquakes with a low center of
gravity.
Maintenance
Page 18
Page 19
c) Normally this type of substations are indoor type and requires separate building. Each
and every component of substation is exposed to air and pollution.
e) When fault occurs internally, the outage period will be very long. The damage effect will
also be severe.
Page 20
Compact design of switchgear by using three phase switchgear in the same enclosure.
Use of Vacuum circuit breaker cells in the medium high voltage GIS and fewer breaks
per pole in high voltage circuit breakers.
Optimization of GIS design to allow easier maintenance by reducing access points.
Smart GIS Integration of Electronic CTs and PTs.
Another important problem facing the industry is to develop strategies to effectively use
older equipment. Even today, spare parts are not easily available for the older design of GIS.
A completely satisfactory solution for the management of spare parts is yet to be found. A
compromise solution will be a reasonable and rational stocking of spare parts by both the
utilities and manufacturers. Also, a solution has to be found for fitting the new switchgear
into old installations with minimum readjustment work.
Page 21
REFERENCES
1) http://www.prnewswire.com/news-releases/global-gas-insulated-switchgear-gis-transmission-distribution-manufacturing--processing-infrastructure--transportation-and-power-generationmarket---trends-and-forecasts-to-2019-789339884.html
2) ELECTRICAL POWER SYSTEMS: Concept, Theory and Practice, By SUBIR RAY
3) http://www.cea.nic.in/reports/regulation/grid_standards_reg.pdf
4) http://www.spml.co.in/mediaroom/2014/Electrical-Monitor-April-2014.pdf
5) Comparison of Gas Insulated Substation over Air Insulated Substation by M.Bilal Latif,
Department of Electrical Engineering, Superior University, Lahore, Pakistan.
6) GAS INSULATED SUBSTATIONS BY M.S.NAIDU.
Page 22