SIX WEEK INDUSTRIAL TRAININGREPORT

AT 66KV SUB-STATION RAIKOT

SUBMITTED TO: ELECTRICAL Department

GURU NANAK DEV ENGINEERING COLLEGELUDHIANA

SUB-STATION

A Substation may be defined as an assembly of equipments, witch changes one or more characteristics of supply .The main characteristics required to be change by substation are.1. Voltage step up/down2. Rectification from AC to DC3. Frequency4. Power factor

66KV SUB-STATION(RAIKOT)

This station is situated in bypass road (Raikot). This is P.S.P.C.L (Punjab State power corporation limited) concerned. It has 66/11KV 2 power transformers of 20MVA and 16/20MVA witch control 66/11KV supply. The incoming supply of 66KV is received from 220KV substation PAKHOWAL . This substation mainly control the supply 18 feedersThis sub station is controlled by SSE Raikot. Er. Jagjit Singh is substation engineer. All the power cut and other message related to power control Patiala

SUB-STATION ACCESSORIES

SUB-STATIONThe assembly of apparatus uses to some characteristic of electrical supply is called SUB-STATION

ACCESSORIES1. BUS-BAR2. ISOLATING SWITCH3. POWER TRANSFORMERS4. CIRCUIT BREAKERS5. LIGHTING ARRESTORS6. INSULATORS7. INSTRUMENT TRANSFORMER I. CURRENT TRANSFORMER II. POTENTIAL TRANSFORMER8. METERING AND INDICATING INSTRUMENTS 9. MISCELLANEOUS EQUIPMENT

TYPES OF SUB-STATION

CALASSIFICATION OF SUB-STATIONTwo most important ways of classifying them are:1. According to service requirement2. According to constructional features1. According to service requirement:- A substation may be called

upon change voltage level to improve in power factor or convert A.C power to D.C power etc. it may be classified into:

I. Transformer sub-stationII. Switching sub-station.III. Power factor correction sub-stationIV. Frequency changer sub-station.V. Converting sub-stationVI. Industrial sub-station

ACCORDING TO CONSTUCTIONAL FEATURES:

A substation many components (e.g. circuit breakers, switches, fuses, instruments etc.) witch must be housed properly to ensure continuous and reliable service. Are classified as:-I. Indoor sub-stationII. Out door sub-stationIII. Underground sub-stationIV. Pole- mounted sub-station3. TRANSMISSION SUB-STATION:A transmission sub-station is one whose main purpose is to connect together various transmission lines.4. DISTRIBUTION SUB-STATION: A distribution substation is one whose main purpose is to transfer power from transmission system to the distribution system of some area.

EXPLANATION OF SUB-STATIONLAYOUT

I. STATION TRANSFORMER ROOM:- In station transformer room there is one transformer of 50KVA rating. This transformer provides supply to this 66KV station in Raikot.

II. OFFICE:- in office electrical staff is there to do file work related to 66KV substation and to keep an eye on the various feeders and their working.

III. STORE:- in store tool, some extra equipment, cables, transformer oil, silica gel, etc is there.

IV. PLC ROOM (POWER LINE COMMUNICATION ROOM):- in this room communicate network is arranged by this PLC room in Raikot is in touch wt other station connect to it.

V. BATTERY ROOM:- in battery room 110 batteries are connected in series to get 220v D.C. each voltage 2V.

VI. FILTER ROOM:- In filter room , he transformer oil from MOCB’s is filtered to remove its carbon particles etc to reused.

TRANSFORMER

INTRODUCTION:- A transformer is an electrical device witch transfers electrical power from one circuit to another of same frequency. It can raise or lower the voltage in circuit, but corresponding decrease or increase in current.

It consists of two independent winding wound over laminated iron core. The winding witch ic connected to the source of supply is called primary and other from witch the power delivered is called secondary.

CLASSIFICATION OF TRANSFORMER:Classification basis of working:I. Step- up transformerII. Step-down transformerClassification basis of connection of phases:-III. Single phase transformer.IV. Three phase transformer.

At substation only three phase transformer is used on basis of connection of winding three phase transformer are further classification as follows.

V. star-star 3 phase transformer.VI. Star-delta 3 phase transformer.VII. Delta-star 3 phase transformer.VIII. Delta-delta 3 phase transformer

MAIN PARTS OF TRANSFORMER

I. TRANSFORMER TANKII. COREIII. CONSERVATOR TANKIV. OIL LEVEL INDICATORV. DRAIN COCKVI. COOLING TUBESVII. HIGH VOLTAGES BUSHESVIII. LOW VOLTAGE BUSHESTEMPERATURE GAUGEXI. BUCHHOLZ RELAYXII. WINDING TEMPERATURE GAUGEXIII. BREATHER TANKXIV. TAP CHANGER

POWER TRANSFORMERThe power transformer is the main equipment of the substation its main function is step-up or step-down the voltage.The primary winding of this transformer is connected to 66KV supply. The secondary winding is stepped- down this voltage 11KV are star-star connected.

SPECIFICATIONCapacity of transformer 20MVA H.V 66KV L.V 11KVMaximum current H.V 174.95 A L.V 1049.75

APhase 3Frequency 50 Hz

CURRENT TRANSFORMER

CURRENT TRANSFORMER:- A current transformer is a type of instrument is a type of instrument transform is designed to provide a current in its secondary winding proportional to the current flowing in it’s primary. They are commonly used in metering and protective relaying in the electric power industry where they facilitate the safe measurement of large currents, often in the presence of high voltage.

POTENTIAL TRANSFORMER

POTENTIAL TRANSFORMER:- The potential transformer (P.T) steps down voltage to at low value that can be effectively and safely used for operation of instrument such as ammeter, voltmeter , watt meters, and relays used for various protective purposes.

CIRCUIT BREAKERA circuit breaker is an automatically operated electrical switch designed to protect an electric circuit from damage caused by overload or short circuit. TYPES OF CIRCUIT BREAKERSI. MCB(MINIATURE CIRCUIT BREAKER):- The rated current for this

type is not more than 100 A.II. MCCB(MOULDED CASE CIRCUIT BREAKER):- The rated current

for this type up to 1000 A. III. AIR CIRCUIT BREAKER:- It has a rated current up to 10000 A.

VACUME TUBE CIRCUIT BREAKER(VCB):- It has a current rating up to 3000 A. these breakers interrupt the current by creating and extinguishing the arc in vacuum container. These can practically applied voltage up to about 3500V, which corresponding

roughly to the medium-voltage range of power system. Vacuum circuit breaker tends to have a longer life expectancies between overhaul than do air circuit breakers.

11KV SYSTEM

1. Raikot 11. C.Bank1 Feeder2. Jalaldiwal 12. Nurpura Feeder3. Bassian 13. Talwandi Feeder4. C.Bank2 14. Burj Hari singh Feeder5. Rajgarh 15. Gonwal Feeder6. Barmi 16. Telephone center Feeder7. Sukhana 17. Oswal Feeder8. Dadhahur 18. Grain Market Feeder9. Tajpur10. Sehabajpur

POWER LINE COMMUNICATIONThe main purpose of PLC is to transmit speech or to convey message from one substation to other substation through transmission lines at high frequencyEQUIPMENT USED IN POWER LINE CARRIER COMMUNICATION:I. WAVE TRAP:- wave trap contains a main coil, lighting arrestor

and a tuning device. All these are connected in parallel. It offers very low impedance to the power frequency signal or wave.

II. COUPLING CAPACTOR:- The coupling capacitors used for PLC have capacitance ranging from 2200pf to 1000 pf.

BUS BARA bus bar in electrical power distribution refers to thick strip of copper or aluminum that conduct electricity within a switchboard, distribution board, substation, or other electrical apparatus.VARIOUS ARRANGEMENTS OF BUS BAR:1. Single bus bar arrangements.2. Single bus bar system with sectionisation.3. Double bus bar arrangements.

CPACITOR BANK

It consist of large number of capacitors connected in series or parallel combination. They are installed in substation at bus bar for improving the power factor and remove the reactive power.

BATTERY ROOM

D.C supply is vary necessary for it is also called “BRAIN OF THE SUBSTATION”. In human body brain controls the whole process in similar way battery controls whole process in substation. With the supply all tripping circuits work. D.C supply is given to various types of relays and circuit breaker. Equipments in substation have the D.C supply for their working. If the battery is damage in any reasons in the substation then the substation will damage, so the various means are provide to protect the battery.

RELAYS

In power system, sooner or later some failure may occur somewhere when failure occurs on any part of the system. It must be quickly detected and disconnected from the system. This function is performed by the relays. The relay detects the fault or supply information to the circuit breaker, witch in turn, perform the function of circuit interrupted.

TYPES OF RELAYS1. Induction type over-current relay:- This relay works on

principle of electromagnetic induction

2. Distance type impedance relay:- These are double actuating relays with one coil energized by voltage and other by current.

3. Buchholz relay:- It is gas-actuated relay in the pipe connecting the conservator to the main tank of transformer

ISOLATOR SWICH

An isolator switch is a part of electric circuit and is more often found in industrial application. The switch does exactly what its name suggests in that in isolate the circuit or circuits that are connected to it. Such a switch is not used normally as an instrument to turn on/off the circuit in the way that a light switch does. Either the switch isolates circuit that are continually powered or is a key element witch enables an electrical engineer to safely work on the protected circuit.

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SWITCHGEARThe apparatus used for switching, controlling and protecting the electrical circuit and equipment is known as switchgear. ESSENTIAL FEATURES OF SWITCHGEAR:1. Complete reliability2. Absolutely certain discrimination3. Quick operation 4. Provision for manual control5. Provision for instruments

SWITCHGEAR EQUIPMENT:-I. SWITCHESII. FUSESIII. CIRCUIT BREAKERSIV. RELAYS

LIGHTNING ARRESTER

The lighting arrester provide a path for lighting electrical current between an electrical current between an electric circuit and earth at a time of over voltage caused by lighting.