Substation

STUDY OF 220/132/33 kV SUBSTATION

Presented by:N.PRADEEP(09HQ1A0232)

N.KALYANI(09HQ1A0231)

M.D.NOORULLAH(09HQ1A0230)

S.SIVA PRASAD (09HQ1A0247)

V.PRAVEEN KUMAR(10HQ5A0206)

Guided by:Mr. N. V. A. Ravi Kumar

CONTENTSINTRODUCTION TO SUBSTATIONLINE DIAGRAM OF 220/132/33kV SUBSTATIONEQUIPMENT USED IN SUBSTATIONRELAYSDIFFERENT PROTECTION SCHEMESEARTHINGCONTROL & RELAY PANELSSTORAGE BATTERY BANKCONCLUSION

INTRODUCTION

SUBSTATION: A substation is a part of an electrical generation, transmission, and distribution system. Substations transform voltage from high to low or low to high.

A substation may include transformers to change voltage levels between high transmission voltages and lower distribution voltages, or at the interconnection of two different transmission voltages.

In b/w the power plant and ultimate consumer a number of transmission and switching stations have to be created . This is done by substation.

BASIC ELECTRICAL POWER SYSTEM

The requirement of land for construction

of SubStation:

1.400 kV - 20.0 Hectare

2. 220 kV - 6.0 Hectare

3. 132 kV - 3.5 Hectare

  Generally, the relation between Voltage level and the power to be transmitted is as follows:

1) Up to 150 MVA 132 KV.

2) From 150 MVA to 300 MVA 220 K.V.

3) 300 MVA to 1000 MVA 400 K.V

Line diagram of 220/132/33kV sub sation

Incoming and out going lines of substation

There are totally 5 inputs and 10 outputs into and from the substation respectively. All

the 5 inputs are the fed to 220kV bus bar and out of the 10 outputs two are from the

220kV bus bar and eight are from the 132kV bus bar. The input and output details are

as follows

Inputs to the 220kV bus bar: VSS-1 VSS-2 GAJUWAKA SUBSTATION UPPER SELERU DAIRY FARM

Outputs from the 220kV bus bar: GARVIDI-1 GARVIDI-2

Inputs to the 132kV bus bar:

Input is taken from the power transformer of the 220kV bay

Outputs from the 132kV bus bar:

SIMHACHALAM-1SIMHACHALAM-2KASIMKOTA-1KASIMKOTA-2ANANDAPURAMJINDALGOLD STARLVS

Equipment used in substation Lightening arrestors C V T Wave trap Isolator Current transformer Circuit breaker Bus bar Potential transformer Auto Transformer.

Lightening arrester

The lightening

arrestors do not let the lightening to fall on the station.

If some lightening occurs the arrestors pull the lightening and ground it to the earth.

CAPACITOR VOLTAGE T/F & WAVE TRAPER:

Wave trap

A device used to exclude unwanted frequency components, such as noise or other interference, of a wave.

CVT:This forms a carrier communication network

throughout the transmission network.Measures voltage of line and leakage current.

ISOLATORSIsolator is a device

which acts like a switch.It separate the

equipment from the main supply

Isolators must be opened only after when the circuit breakear gets opened

CURRENT TRANSFORMERCurrent transformers are basically used to take the readings of the currents entering the substation. This transformer steps down the current from 800 amps to 1 amp.

This is done because we have no instrument for measuring of such a large current. amps to 1 amp.

The main use of this transformer (a) distance protection(b) backup protection (c) measurement

SF6 CIRCUIT BREAKER

The circuit breakers are used to break the circuit if any fault occurs in any of the instrument. These circuit breaker breaks for a fault which can damage other instrument in the station..

Here sf6 gas is used as a medium to quench the arc produced during the opening of circuit breaker.

Sf6 is a high electronegative gas so it absorbs the ions which are responsible for forming the arc and thus arc is quenched

POTENTIAL TRANSFORMER

The instrument potential transformer (PT) steps down voltage of a circuit to a low value that can be effectively and safely used for operation of instruments such as ammeters, voltmeters, watt meters, and relays used for various protective purposes.This transformer is to measure the voltage

through the bus.  The main use of potential transformer is (a)measurement (b) protection.

AUTO TRANSFORMER

t/f):

A transformer has no internal moving parts, and it transfers energy from one circuit to another by electromagnetic induction without change in freqency.

Transformers are typically used because a change in voltage is needed.

A step-down transformer receives energy at a higher voltage and delivers it at a lower voltage for distribution to various loads

RELAYS A relay is an electrically operated switch. A protective relay is a device that detects the fault and

initiates the operation of the C.B. to isolate the defective element from the rest of the system.

RE LAY CHARACTERISTICS: SENSITIVITY SPEED SELECTIVITY RELIABILITY

MEASUREMENT: MAGNITUDE MEASUREMENT RATIO MEASUREMENT PROTECT MEASUREMENT LOGIC MEASUREMENT

DIFFERENT PROTECTION SCHEMES:transformer protection

BUCHHOLZ RELAY(makes alarm or trips during during fault conditions)

DIFFRENTIAL PROTECTION

TRANSMISSION LINE PROTECTION: Distance relay:

.

TYPES OF DISTANCE RELAYS: Impedance relayReactance relayMho relayModified impedance relay.

EARTHING

Earthing should be done in order to protect the equipments during high voltages.

Earth is at zero potential so any amount of high voltages can be simply diffused into the earth

ADVANTAGE OF GOOD EARTHING:a. Good earth should have low resistanceb. It should stabilize circuit potential with respect to

ground and limit overall potential rise.

CONTROL & RELAY PANELS

These are used to control the operations of breakers, isolates, through protective relays installed on these panels various protection schemes for transformers, lines etc, are provided on these panels

STORAGE BATTERY BANK

The primary role of the substation battery system is to provide a source of energy that is independent of the primary ac supply, so that in the event of the loss of the primary supply the substation control systems that require energy to operate can still do so safely.

CONCLUSION

Electrical substation consists of Transformers, bus bars, circuit breakers, isolators, relays, instrument transformer and other equipments.

The basic electrical quantities which are likely to change during the abnormal conditions are current, voltage, phase angle and frequency. If a fault occurs in element of a power system an automatic protective devices are used to achieve un interrupted power supply in substation.

WE HAVE STUDIED THE VARIOUS EQUIPMENT AT 220 kV/132 kV/33 kV PENDURTHI, SUB STATION AND VARIOUS PROTECTION SCHEMES EMPLOYED FOR THEM”

QUIERIES????

THANK Q………