Slide 1: MAINTAINANCE & PROTECTION AT 400 KV SUBSTATION,MURADNAGAR
TRIPURARI DAS GUPTA
ROLL NO. 0702921110 CONTENT : CONTENT POWER TRANSFORMER
EARTH WIRE POWER TRANSFORMER : POWER TRANSFORMER It contains primary winding , transformer coil(inductively coupled coil)& secondary winding.
A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core, and in the secondary winding.
There are three autotransformer two of them of 315 MVA & one 240 MVA at Muradnagar. CURRENT TRANSFORMER : CURRENT TRANSFORMER When current in a circuit is too high to directly apply to measuring instruments, a current transformer is used.
A current transformer has a primary winding, a magnetic core, and a secondary winding.
The alternating current flowing in the primary produces a magnetic field in the core, which then induces current flow in the secondary winding circuit POTENTIAL TRANSFORMER : POTENTIAL TRANSFORMER When voltage in a circuit is too high to directly apply to measuring instruments, a potential transformer is used.
Its principle of operation is same as that of power or current transformer.
In this transformer the number of turns in secondary winding is less than primary winding. ISOLATOR : ISOLATOR It is essentially off load device.
Isolators are manually as well as automatically operated.
These are fitted on both sides of transformer, circuit breaker or any equipment. RELAY : RELAY A relay is a fault sensing device on power system.
Many relays use an electromagnetism for switching mechanism.
Other types of relays are –solid state relay, microprocessor based relay and Buchholz relay. CIRCUIT BREAKER : CIRCUIT BREAKER A circuit breaker is a fault clearing device.
It is an automatically-operated electrical switch designed to protect an circuit from damage caused by overload or short circuit.
Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. BATTERY : BATTERY At 400 KV substation two sets of 220v & one set of 48 v .
The battery charging equipments comprises of a float charger and a boost charger.
Stabilization output voltage is provided in the float charger to float the battery at the correct level.
The battery can be boost charging after a prolonged mains failure by the boost charger. WAVE TRAP : WAVE TRAP It connected is series with power line.
It is basically an inductor of rating in millihenry.
It blocks the high frequency carrier waves (24 kHz to 500 kHz) and let power waves (50 Hz - 60 Hz) to pass through. SURGE ARRESTORS : SURGE ARRESTORS The protection against transient voltage surges is provided by surge arrestors.
They are usually connected between phase and ground. Surge arrestor discharges current impulse surge to earth and dissipates energy in the form of heat. EARTH WIRE : EARTH WIRE Earth wire in EHV transmission lines is used to provide safeguard against lightening other transient surges and efficient operation of protection system under fault condition. Slide 13: THANK YOU