Indus Institute of Engineering & Technology Kinana, Jind – 126102
ELECTRICAL ENGG. DEPARTMENT
PROJAECT REPORT ON:- 400/220kv SUBSTATION
(INDIAN OIL CORPORATION LIMITED)
SUBMITTED BY:- SUBMITTED TO:-
ANIL KUMAR MS.RICHA GOUR
(5608181) (HEAD OF DEPARTMENT)
ACKNOWLEDGEMENT:-
I am extremely thankful & indebted to the numerous IOCL Engineers, who provided vital information about the functioning of their respective departments thus helping me to gain an overall idea about the working of organization. I am highly thankful for the support & guidance of each of them. I am highly indebted to my project guide, Mr.SubhashRakshit, Ms. Aditi Sharma for giving me his valuable time and helping me to grasp the various concepts of switchyard equipments and their control instruments and their testing. Last but not the least, I would like to thank my parents & all my fellow trainees who have been a constant source of encouragement & inspiration during my studies & have always provided me support in every walk of life.
We are very grateful to Shri Rajeder Singh. He has introduced us to the control room. He helped us to gain knowledge about the operation system of various lines, transformer and their applied equipments for Six weeks
Contents:-
· What is an Electrical Substation?
· Introduction: about substation
· Overview of substation
· Single line digram of substation
· Brief description
· Power transformer
· Transmission towers and structures
· Isolators
· Circuit breaker
· Lightning arrestor
· Current transformer
· Potential transformer
· Capacitor voltage transformer
· Arching horns
· Underground cables
· Wave trap
· Protective relays
· Shunt reactor for bus voltage
· Capacitor bank
· Clearance at glance
· Other definitions
· Communication in the substation
· Specification and rating
Electrical Substation :-
“Electric Power is generated in Power Stations and transmitted to various cities and towns. During transmissions, there are power (energy) loss and the whole subject of Transmission and Distribution...
An electrical substation is a subsidiary station of an electricity generation, transmission and distribution system where voltage is transformed from high to low or the reverse using transformers. Electric power may flow through several substations between generating plant and consumer, and may be changed in voltage in several steps.
The word substation comes from the days before the distribution system became a grid. The first substations were connected to only one power station where the generator was housed, and were subsidiaries of that power station.
Elements of a substation:-
Substations generally have switching, protection and control equipment and one or more transformers. In a large substation, circuit breakers are used to interrupt any short-circuits or overload currents that may occur on the network.
Smaller distribution stations may use reclosecircuit breakers or fuses for protection of distribution circuits.
Substations do not usually have generators, although a power plant may have a substation nearby. Other devices such as powerfactor correction capacitors and voltage regulators may also be located at a substation.
Substations may be on the surface in fenced enclosures, underground, or located in specialpurposebuildings.
High-rise buildings may have several indoor substations. Indoor substations are usually found in urban areas to reduce the noise from the transformers, for reasons of appearance, or to protect switchgear from extreme climate or pollution conditions.
Where a substation has a metallic fence, it must be properly grounded (UK: earthed) to protect people from high voltages that may occur during a fault in the network. Earth faults at a substationcan cause a ground potential rise.
Currents flowing in the Earth's surface during a fault can causemetal objects to have a significantly different voltage than the ground under a person's feet; this touch potential presents a hazard of electrocution.
Transmission substation:-
A transmission substation connects two or more transmission lines. The simplest case is where all transmission lines have the same voltage. In such cases, the substation contains high-voltage switches that allow lines to be connected or isolated for fault clearance or maintenance.
A transmission station may have transformers to convert between two transmission voltages, voltagecontrol devices such as capacitors, reactors or static VAr compensator and equipment such as phase shifting transformers to control power flow between two adjacent power systems.
Transmission substations can range from simple to complex. A small "switching station" may be little more than a bus plus some circuit breakers. The largest transmission substations can cover a large area (several acres/hectares) with multiple voltage levels, many circuit breakers and a large amount of protection and control equipment (voltage and current transformers, relays and SCADA systems).
Distribution substation:
A distribution substation in Scarbor-ough, Ontario, Canada disguised as a house, complete with a driveway, front walk and a mown lawn and shrubs in the front yard. A warning notice can be clearly seen on the "front door".
A distribution substation transfers power from the transmission system to the distribution system of an area. It is uneconomical to directly connect electricity consumers to the high-voltage main transmission network, unless they use large amounts of power, so the distribution station reduces voltage to a value suitable for local distribution.
The input for a distribution substation is typically at least two transmission or sub transmission lines. Input voltage may be, for example, 115 kV, or whatever is common in the area. Distribution voltages are typically medium voltage, between 2.4 and 33 Kvdepending on the size of the area served and the practices of the local utility.
Introduction: about substation:-
400 kvrefinary substation is one important substation of IOCL. It is one of the largest power grids in the state of HARYANA and the north India. It is situated at National
Highway-1 Panipat. The construction of this substation completed during 1990-95 by
IOC(INDIAN OIL CORPORATION) .The area of this substation is about 500 acre.
The whole substation is divided in four parts:
1. 132kv switchyard
2. 400/220kv switchyard
3. 765kv switchyard
For 400kv &220kv switchyard a common control room is used and for 132kv switchyard
A separate control room used. IOCL, an Indian Multinational with manufacturing bases in 8 countries, have signed the contract on 5th March’2010 with Indian Oil Corporation Ltd for construction of 765/400 kV Substation at refinery, in Panipat. The value of contract is Rs 302 Corers .
A 765/400 kV substation is the highest grade system voltage for transmission in India. IOCL is first state utility to enter into 765 kV area.
The scope of the project includes Design, Engineering, Manufacture, Supply, Erection, Testing and Commissioning of 8 Bays of 765 kV & 2 Bays of 400kV, along with 7 Nos. of 333 MVA (Single Phase) 765/400 kV Power Transformers and 7 Nos. of 110 MVAR (Single Phase) 765 kV Shunt Reactor & 4 Nos. 63 MVAR (Single Phase) 765 kV Reactors. The project is expected to be commissioned in July 2011.
The project is of strategic importance for entry into market of 765 kV Substations globally and widens up the horizon for the entire product range of CGL
Overview of substation:-
As we said earlier the whole substation is divided in three parts:132kv site ,400/220kv site and 765 kv site 765 kv sit is on under construction. The civil work is completing by L&T Company. Other part of project Design, Engineering, Manufacture, Supply, Erection, Testing and Commissioning of Bays will complete by CGL.
In 400/220kv switchyard following outdoor instrument used:
1. One 400kv transfer bus control bus coupler
2. Two 100MVA 220/132kv autotransformer
3. Two 315MVA 400/220kv autotransformer
4. Five 50MVAR shunt reactor
5. Two 63MVAR bus reactor
6. 15 lighting tower
7. SF6 circuit breaker
8. Capacitor voltage transformer(CVT)
9. Current transformer(CT)
In whole switchyard following main equipment are used:
i) One 400kv transfer bus control bus coupler.
ii) Two 100MVA 220/132 KV auto transformer manufactured from BHEL.
iii) Two 315 MVA 400/220 KV auto transformer manufactured from BHEL.
iv) Five 50 MVAR shunt reactor manufactured from BHEL.
v) Two 63 MVAR bus reactor manufactured from HITACTI.
vi) Circuit breaker from CGL.
vii) Isolators from S&S.
viii) Current transformer from WS and CGL.
ix) CVT
x) Wave trap
xi) Lighting arrester
xii)Surge capacitor
Single line diagram of Refinary substation:-
Brief Description Of all Outdoor Equipment:-
Power transformer:-
Various types of transformers have been provided at 220& 400 KV Substation from IOCL.
Capacity and voltage ratio wise 100 MVA , 315MVA & 160 MVA and 220/132/11 kV. 400/220 kV, These transformers are of TELK, BHEL, GEC, NGEF, C & G, Hitachi and Bharat Bijlee make and have most of the features common except few accessories which may be different. In this substation all transformers made by BHEL. These
transformers have following main components:
1. MAIN CORE & WINDING.
2. BUSHING :-
(a) 220 kV High voltage bushings:
Condenser type bushings with insulating body and central conducting tubebackelised with paper wound capacitor have been provided. Innermost of the capacitor layer is electrically connected to the tube and outermost to the mounting flange on insulating body. The central tube insulating body and mounting flange are oil filled assembled. High dielectric Strength oil is filled between central tube and insulating body. Oil level indicators are provided on the bushing.
(b) 132 kV Medium voltage bushing:
These bushing are also of condenser type and are of similar construction as in the
case of 220 kV bushing in 200 MVA transformers. In 40 & 20 MVA transformers 132 kV bushings are also of oil filled type in which oil is filled up when the transformer tank is topped up. Necessary air vent screws are provided on top of the bushings for release of trapped air at the top of oil fitting.
(c) 66 kV. 33 kV. & 11 kV. Bushings:
These are oil filled bushing and simpler in construction.
3. TAP CHANGER:-
The transformers have been provided with on load tap changer, which consists of diverter switch installed in an oil compartment separated from transformer oil and the tap selector mounted below it. The tap changer is attached to the transformer cover by means of tap changer head, which also serves for connecting the driving shaft and the oil conservator.
4. PROTECTIVE RELAYS:-
Generally there are two protective buchholz relays, one for main transformer tank and other for tap changer. In 40MVA GEC transformers oil surge relay has also been provided in tap changer.
5. PRESSURE RELIEF VALVE:-
40 MVA GEC make transformers have been provided with pressure relief valve which
operates in case of sudden pressure formation in side the transformer.
6. COOLING SYSTEM :-
100 MVA transformers have been provided with cooling bank installed on separate
structures. These cooling banks have provided with to groups of fans and 2 nos. pumps.
These fans and pumps automatically operate, depending upon the settings of winding
temperature Indicator.
7. TERTIARY BUSING:-
100 MVA transformers have been provided with tertiary bushing connected with 11 kv
capacitor and lighting arrestor t absorb switching surges.
ELECTRICAL PROTECTION :-
The following electrical protection have been provided on the transformers :-
(i) Differential Protection
(ii) Restricted Earth Fault
(iii) Winding temp high
(iv) Oil temp high
(v) Pressure relief valve
(vi) Oil surge relay
(vii) Over current relay
(viii) Local Breaker Back up protection
(ix) Surge arrestors on HV, MV & LV sides.
The main Tank - The transformer is transported on trailor to substation site and as far as possible directly unloaded on the plinth. Transformer tanks up to 25 MVA capacity are generally oil filled, and those of higher capacity are transported with N2 gas filled in them+ve pressure of N2 is maintained in transformer tank to avoid the ingress of moisture.
This pressure should be maintained during storage; if necessary by filling N2 Bushings -
generally transported in wooden cases in horizontal position and should be stored in that position. There being more of Fragile material, care should be taken while handling them.
Rediators –
These should be stored with ends duly blanked with gaskets and end plates to avoid in gross of moisture, dust, and any foreign materials inside. The care should be taken to protect the fins of radiators while unloading and storage to avoid further oil leakages.
The radiators should be stored on raised ground keeping the fins intact. Oil Piping. The Oil piping should also be blanked at the ends with gasket and blanking plates to avoid in gross of moisture, dust, and foreign All other accessories like temperature meters, oil flow indicators, PRVs, buchholtz relay; oil surge relays; gasket ‘ O ‘ rings etc. should be properly packed and stored indoor in store shed. Oil is received in sealed oil barrels . The oil barrels should be stored in horizontal position with the lids on either side in horizontal position to maintain oil pressure on them from inside and subsequently avoiding moisture and water ingress into oil.
The transformers are received on site with loose accessories hence the materials should be checked as per bills of materials.
The transformers that are used in Refinary substation have following specification:
Specification of 100 MVA 220/132/11 KV 3-Φ auto transformer:-
Types of cooling ONAN ONAF OFAF
Rating of H.V. & I.V.(MVA) 60 80 100
Rating of L.V. (MVA) 18 24 30
Line current H.V.(Amps) 157.4 209.9 262.4
Line current I.V. (Amps) 262.4 349.9 437.4
Line current L.V. (Amps) 944.8 1259.7 1574.6
No load voltage H.V. 220KV
No load voltage I.V. 132KV
No load voltage L.V. 11KV
Temp. Rise winding ˚C 55 55 60
[ Above ambient of 50 ˚C ]
Temp. rise oil ˚C 50 [ Above ambient of 50 ˚C ]
Phase 3
Frequency 50Hz
Connection symbol YNa0d11
Insulation level:
H. V. - LI950 AC395-AC38
L. V. - LI170 AC70
I. V. - LI550-AC230-AC38
Core & winding (Kg.) 54000
Weight of oil (Kg.) 39410
Total weight (Kg.) 127995
Oil quantity (liters) 45300
Transport weight (Kg. ) 69000
Untanking weight (Kg.) 54000
Specification of 315 MVA 400/220 KV 3- Φ auto transformer:-
Types of cooling ONAN ONAF OFAF
Rating of H.V. & I.V.(MVA) 189 252 315
Rating of L.V. (MVA) 105 105 105
Line current H.V.(Amps) 272.76 363.68 454.6