UTTAR PRADESH POWER C0RPORATION LTD.

Vikash Raj (EE- 4th YEAR)

INTRODUCTION

In India Electrical power is Generated at a voltage of 11kv to 33kv ,which is taken stepped up to the transmission level in the range of 132kv or 220kv member of transmission and switching have to be created these are known as ”Substation”.

Substation is an assembly of apparatus ,which transform the characteristics of electrical energy from one form to another say from one voltage level to another level. hence a substation is an Intermediate link between the Generating station and consumer

FUNCTION OF THE SUBSTATION

The sub-station receives power from the generating station by a single or more feeders at a high voltage, transform the same to the different distribution voltages and sends to different consumers through distribution network.

TRANSFORMERSAlso known as the heart of substations. These are used to reduce the voltages at appropriate levelsCURRENT VOLTAGE TRANSFORMERSIt is a  used in power systems to step downextra high voltage signals and provide a low voltage signal, for measurement or to operate a protective relay

WAVETRAPTraps the high frequency signals

ISOLATORSUsed for maintenance of

the circuit in no load condition

CIRCUIT BREAKER used to protect the

eqiupment by opening the circuit for over

current and over voltages

LIGHTINING ARRESTER

Used for protecting the equipment from surge

voltages

MAIN EQUIPMENTS AT SUBSTATIONS

TRANSFORMERS

Transformer is a static machine, which transforms the potential of alternating current at same frequency. It means the transformer transforms the low voltage into high voltage & high voltage to low voltage at same frequency.

It works on the principle of mutual inductance. When the energy is transformed to a higher voltage, the transformer is called step up transformer and then it is transmitted at lower voltage it is called step down transformer.

There are 2 transformers in the ROBERTSGANJ substation: 60MVA & 40 MVA ( 132/33 KV)

LIGHTNING ARRESTER

A lightning arrester is a device used on electrical power systems to protect the insulation on the system from the damaging effect of lightning.

L.A CIRCUIT DIAGRAM

ALSO KNOWN AS SURGE ARRESTER

USED IN THE POWER SYSTEMS TO PROTECT FROM LIGHTNING

CIRCUIT BREAKER

A circuit breaker is equipment, which can open or close a circuit under normal as well as fault condition. These circuit breaker breaks for a fault which can damage other instrument in the station. It is so designed that it can be operated manually (or by remote control) under normal conditions and automatically under fault condition. Whenever a fault occurs trip coil gets energized, the moving contacts are pulled by some mechanism & therefore the circuit is opened or circuit breaks.

CURRENT VOLTAGE TRANSFORMER

A capacitor voltage transformer (CVT), or capacitance coupled voltage transformer (CCVT) is a transformer used in power systems to step down extra high voltage signals and provide a low voltage signal, for measurement or to operate a protective relay.

In its most basic form the device consists of three parts: two capacitors across which the transmission line signal is split, an inductive element to tune the device to the line frequency, and a transformer to isolate and further step down the voltage for the instrumentation or protective relay.

ISOLATOR

IsolatorUsed to ensure that an electrical circuit is completely de-energised for service or maintenance. Such switches are often found in electrical distribution and industrial applications, where machinery must have its source of driving power removed for adjustment or repair. High-voltage isolation switches are used in electrical substations to allow isolation of apparatus such as circuit breakers, transformers, and transmission lines, for maintenance. The disconnector is usually not intended for normal control of the circuit, but only for safety isolation. Disconnector can be operated either manually or automatically (motorized disconnector)

THANKS