A SUMMER TRAINING PRESENTATION ON

132 KV CHAMBAL G.S.S., JAIPUR

IntroductionThe 132 KV Chambal G.S.S. was established in 1962 by Rajasthan Rajya Vidyut Prasaran Nigam Ltd.It is located at Hawa Sadak, Jaipur.The 132 KV Chambal G.S.S. steps down the incoming voltage of 132 KV to 33 KV and 11KV.There are 3 incoming lines to this G.S.S.: 1) Directly from Heerapura G.S.S. 2) Heerapura G.S.S. to Nallah Power House(N.P.H.) then to Chambal G.S.S. 3) Sanganer G.S.S.to Chambal via Mansarovar G.S.S.

Equipments Assembled in the yard1)Transformers2)Capacitive voltage transformer3)Wave trap4)Coupling capacitor5)Capacitor bank6)Bus bars7)Insulators8)Isolators9)Lighting arrestor10)Circuit Breaker11) Transformer protection 12) Bucchloz relay 13)Control room

Power TransformerIt is a static device used in transmission & distribution system to step up & step down A.C. voltage.

There are 6 Power Transformer assembled in the Chambal G.S.S.Four 132/11 KV, 16/20 MVA.Two 132/33 KV, 40/50 MVA.

Sl. No.

T/F No.

Capacity Type Make

1) 01 16/20 MVA 132/11 KV

T/F s & RECTIFIERS (I) Ltd.

2) 02 16/20 MVA 132/11KV

T/F s & RECTIFIERS (I) Ltd.

3) 03 16/20 MVA 132/11 KV

G.E.C. ALSTOM

4) 04 16/20 MVA 132/11 KV

CROMPTON

5) 05 40/50 MVA 132/33 KV

T/F s & RECTIFIERS (I) Ltd.

6) 06 40/50 MVA 132/33 KV

T/F s & RECTIFIERS (I) Ltd.

Description of Transformer

Outgoing Feeders1) T/F 01 & 02 : (A)RAM NIVAS BAGH-I (B)NIRMAN NAGAR (C)MAHESH NAGAR (D)NEW SANGANER ROAD (E)RESIDENCY (F)ESI

Outgoing Feeders contd.2) T/F 03 & 04 : (A)RAM NIWAS BAGH-II

(B)QUEEN’S ROAD (C)AJMER ROAD (D)KHASA KOTHI (E) 22 GODAM (F)LAL KOTHI (G)GANDHI NAGAR 1 (H)GANDHI NAGAR 2 (I)JAMUNA NAGAR (J)N.B.C. (K)PRATAP LINES

2) T/F 05 & 06 : (A)KHASA KOTHI

(B)DURGAPURA (C)MNIT(FORMER MREC) (D)LAL KOTHI (E)E.S.I. (F)SEWAGE FARM (G)BISALPUR (H)22 GODAM (I)VIDHAN SABHA

Potential Tranformer-T/F s used for voltage measurements .-They make the ordinary low voltage that is suitable for measurement of high voltage and isolate them from high voltage.-The primary winding of the PT is connected to the main bus bar of switch gear installation and the secondary winding to various indicating and metering instrument and relays.-When the rated high voltage is applied to the primary of P.T. the voltage of 110 volts appears across the secondary winding.

Current TransformerThey are connected in A.C. power circuit to feed the current coils of indicating & metering instrument (ammeters, watt-meters, watt-hour meters) & protective relays. Thus the circuit broadens the limits of measurements & maintains a watch over the current flowing in the circuit& over the power loads.

The current t/f basically consists of iron core which are wound by a primary & one or two secondary windings.

CAPACITIVE VOLTAGE TRANSFORMER: It allows the carrier signals to pass through it. These signals are then send to the “carrier set”.

COUPLING CAPACITOR:Coupling capacitor is used to minimize the noise & disturbance in the communication line. This is connected b/w wave trap & communication line. It consists of high frequency receiver transmitted to one of the line conductor. It is also called dead tank breaker.

Wave TrapIt is used to trap the communication signals & send it to the PLCC control room through CVT. This wave trap allows the power frequency to pass through it & obstructs the communication signals & allows them to pass through CVT. It has inductive coil of 0.5 mH. It reduce interference b/w station. It acts like filter.

POWER LINE CARRIER COMMUNICATIONThere is no use of telephone lines in the exchange of important information between grid sub-station. This information are received by wave traps in GSS. These wave traps are connected with 132 KV lines in series with L.A. & coupling capacitors.•The main work of wave trap is interchange of electrical waves into sound waves & sound waves into electrical waves.•When information is send b/w one GSS to the other GSS, sound waves get trapped& these waves are converted into electrical waves& these electrical waves get in other GSS through main line.

InsulatorsIn order to prevent the flow of current to earth from the support, the transmission lines or distributions lines are all secured to the supporting towers or poles with the help of insulators. Thus the insulators play an important part in the successful operation of the lines.There are many types of insulators in power system, but at extra high voltage transmission only 3 types of insulators are used.Strain type or tension type insulators (upto 33KV)Suspension type insulators or disc type insulators (above 33 KV)Post type insulator (for supporting the bus bar & disconnecting switches in sub-stations).

Capacitor BankMost of the load is inductive so that the line power factor becomes lagging and affects the regulation point of view. Since due to low power factor, voltage drop gets higher, the regulation of the line disturbs. So to improve the power factor, capacitor bank is erected or used at 132 KV G.S.S.Equipments used in capacitor bank Lightening arrestor Isolator with earthing table Circuit Breaker Residual voltage t/f Series reactor Cell Fuses Protection relay CT for protection

IsolatorAn isolator or disconnecting switch is used to open some given part of a power circuit after switching off the load by means of a CB. Thus isolators serve only for preventing the voltage from being applied to some given section of the bus switch gear installation or to one or another price of apparatus in the installation.In some cases isolators may be used as a C.B. device, their use for this purpose is strictly limited by definite conditions such as the power rating of the given circuit.There are 2 types of isolators: 1) Single pole isolators 2)Three pole isolators

Bus BarThe term “Bus bar” is used for main bar or conductor carrying an electric current to which many connections may be made.In some arrangement two buses are provided to which the incoming or outgoing feeders & the principle equipment may be connected. One bus is usually called “main bus “and the other is called “auxiliary bus”.

Lightning ArrestorIt is a protective device which conducts the high voltage surges on the power system to the ground. It is connected between the line and the earth.Types of lightning arrestor: 1)Rod gap type 2)Expulsion type(Used in Chambal G.S.S.) 3)Conventional valve type 4)Disc type or thyrite type

Circuit BreakerIt is a piece of equipment which can break a circuit automatically under fault condition. make a circuit manually or by remote control under fault condition.Types of Circuit Breakers:Oil Circuit BreakersVacuum Circuit BreakersSulphur Hexafluoride Circuit Breakers(SF6 CB) - The latest design for A.C. C.B. is SF6 gas type. In which SF6 gas works as quenching medium as well as insulating medium.-At 1000 C , SF6 gas split in to SF4, SF2, S2, F2, S and F. Soda lime (NaOH +CaO) and activated alumina is placed in the arcing chamber.-The major disadvantage is that it is considered at the low temperature.-It changes their states into liquid depend upon the atm. Pressure.

TRANSFORMER PROTECTION

If the electric transmission & distribution system is like as a human body then a transformer is as a back bone in human body. So protection for a transformer is necessary.

The following protections are provided to a power transformer mounted at G.S.S.

•Over current protection•Earth fault protection•Differential protection•Over pressure protection•Temperature over rise protection•Winding temperature rise protection•Oil temperature rise protection•Buccholz’s protection•Over voltage protection

BUCHHOLZ’S RELAYThe t/f is fitted with double float buchholz’s relay. It is fitted in the feed pipe from conservator to tank & is provided with two set of mercury contacts. The device comprises of a cast iron housing containing the hinged floats. One is upper part & the other part is the lower part. Each float is filled with a mercury switch leads of switch are connected to a terminal box.

Control RoomAll the remote operations of the transformers and feeders are done from the control panel in the control room.These panel are operated by DC supply. For providing D.C. voltage 55 dry cells are connected in series. The cable system generally operates at 110 V or 220 V. For laying these cables generally, ducts run from “Control Room” basement to centrally located “Junction Box” from where the conduits are send to the required points.

BATTERY ROOM The battery room has 55 batteries of 2 Volts each. Therefore total DC power available is 110 V for functioning of the control panel.

ConclusionThe 132 KV Chambal G.S.S. is maintained by the RRVPNL.There are 3 incoming lines to this G.S.S.: 1)From Heerapura G.S.S. 2) From Heerapura to Nallah Power House(N.P.H.) then to Chambal. 3) From Sanganer G.S.S.to Chambal via Mansarovar G.S.S.Incoming volts of Power Transmission of 132 KV is stepped down to 33 KV & 11 KV &then is supplied to consumer’s feeders from this G.S.S.There are 7 (33 KV) & 12(11 KV) outgoing feeders from this G.S.S.

reference

1. Materials provided by Mr. R.K Sharma(Assistant Engineer, in 132KV;G.S.S. Chambal, R.R.V.P.N.L,Jaipur)2. wikipedia3. google4. JB Gupta5.Sunil S Rao