VOCATIONAL TRAINING PRESENTATION2014 - 15

NAME : LAKHAMAN B. VADHER

DEPTT : ELECTRICAL

COLLEGE : GOVERNMENT ENGNEERING COLLEGE BHARUCH

Introduction

• In India 70% of total power is generated by the Thermal Power Stations.

• Essar power is one leading company in electrical power generation

• Essar Power Salaya

• Capacity:- 1200 MW (2*600 MW)• It is based on coal fired power plant• Project site area :- 330 Ha• Narmada water used as condenser cooling water Boiler

water• Power evacuation at 400 KV to state utility

Major Learning

• Boiler Unit • TG (Turbine Generator) Unit• Transformer Yard• Switchyard(HV,MV,LV)• Coal Handling System• Ash Handling System• ESP (Electrostatic Precipitator)• Cooling Tower• Different type of Motor and Pump•

Basic Layout of Thermal Power Plant

Boiler

• Boiler is steam generator. It convert water into high pressure and high temperature steam

• In Essar power plant Salaya Subcritical type of boiler is used.

• A subcritical steam generator is a type of boiler that operates at subcritical pressure

• Main steam flow:- 2060 TPH• Main steam outlet pres.:- 17.50 Mpa• Main steam outlet temp.:- 541°C• Feed water pres.:- 19.492 Mpa• Feed water temp. :- 281.7 °C• Reheat steam flow :- 1725.9 TPH

6

Schematic Diagram of subcritical Boiler

BOILER SIDEVIEW

7

Steam Turbine

• A steam turbine is a device that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft

• And main output shaft is coupled with electrical generator• Turbine divided into 3 Stage

I. HP (High Pressure Turbine)II. IP (Intermit Pressure Turbine)III. LP (Low Pressure Turbine)

• Rated Output :- 600 MW• Rated Speed :- 3000 RPM• Steam pressure :- 16.7 Mpa• Steam temperature :- 538 °C• Direction of rotation :- Clockwise

Steam Turbine

Electrical Generator

• Electric generator is a device that converts mechanical energy to electrical energy.

• Main part of generator are stator and rotor.• Output of electrical power taken from stator terminal.• D.C. supply to the rotor winding through brush and slip

ring.• In Essar power water hydrogen cool synchronous

generator is used

Generator

Generator Specification

Parameter Value

MW Rating 600MW

Rated Voltage 20KV

Rated Stator current 20377 A

Rated Speed 3000 RPM

Rated Frequency 50 Hz

Generator Cooling

• Cooling needed in large size generator Two Type of Cooling system

I.Water cooling II.Hydrogen cooling

• Water is used for stator cooling.• Hydrogen are used for rotor cooling as well as stator

cooling

STATOR COOLING

WATER TANK

STATOR COOLING

WATER TANK

MM

MM

COOLER A

COOLER A

COOLER B

COOLER B

STATOR COOLING WATER PUMP A

STATOR COOLING WATER PUMP B

GENERATORGENERATOR

STRAINER B

STRAINER A

Stator water cooling cycle

Transformer Yard

Main Equipment used Trafoyard

I. GCB (Generator Circuit Breaker)II. ST (Station Transformer)III. UT (Unit Transformer)IV. GT (Generator Transformer)V. NGR (Neutral Grounding Resistor)

Transformer Yard SLD

GCB

• Protection of the Generator against system-fed shortcircuit currents

• The GCB is an effective protection device for the transformer and the generator

I. Starting and maintenance stages

II. Synchronization and normal conditions

III. Abnormal conditions including• Overvoltages, un-balanced load•

Short circuit–

Step up transformer side–

Generator side•

Out of Phase Requirements

Station Transformer

• ST is used supply station common load such as Coal handling,DM plant, etc.

• Transformer used in salaya power plant is three winding transformer

• Specification

Parameter Value

Rated MVA 70 MVA

Voltage 20/11/33KV

Frequency 50Hz

Number Phase 3

Vector Group Dyn11yn11

Unit Transformer

• Unit Transformer supply separate unit load such as Boiler auxiliary,Cooling tower and Turbine auxiliary etc.

• Specification

Parameter Value

Rated MVA 45MVA

Rated Voltage 20/11.5KV

No. Of Phase 3

Vector Group Dy11

GT(Generator Transformer)

• As an essential element of all nuclear, thermal or hydraulic power stations.

• GT are step-up transformer with delta connected LV side and star connected HV side

• In Essar power salaya OLTC is used and GT consist of three single phase transformer unit.

GT SpecificationParameter Value

Rated MVA 250MVA

Rated Voltage at no load 21/420KV

Vector Group YNd1

Type Of cooling ONAN/ONAF/OFAF

NGR(Neutral Grounding Resistor)

• The suitable Neutral Grounding Resistance (NGR) should be installed between neutral point (star point) and the ground to restrict the earth fault current to 50 Amps

• it is used to limit the current flowing through ground.• it measures the resistance between the neutral and the

GND.• There two consideration to Select NGR

1) Plant capacity2) Current carrieng capacity

Bus Duct

• Different types of bus-ducts are provided as per application/ current and voltage rating.

I. IPBD (Isolated phase bus duct)II. SPBD (segregated phase bus duct)III. NSPBD (non segregated phase bus duct)

IPBD: In 20 kV,22000A Generator to Generator transformer main run

SPBD:-11kV, 1500 A between Unit transformer to Unit switchgear

NSPBD:-0.433kv, 3333.43A between service transformer to PMCC and MCC

IPBD (Isolated phase bus duct)

SPBD (segregated phase bus duct)

NSPBD (non segregated phase bus duct)

Switch Yard

• Three type of switch yard in Essar salaya power it’s divided in based on voltage levelI. HV (High Voltage Switch yard )II. MV (Medium voltage)III. LV (Low Voltage)

HV Switch yard

• Electric power is generated in Generation Station. The voltage at which is power is generated in generation station lies between 11kv to 25kv.

• SwitchYard Definition It is switching station with incoming and outgoing feeders but without the transformer. It is a type of substation but incoming feeders and outgoing feeders are of same voltage level. Some times, the out door area of a substation where the circuit breakers are located are also called switchyard of the substation A switchyard connects and disconnects lines on the grid for various reasons. The operations and equipment are essentially all at the same voltage level.

Equipment in switch yard

Main Equipment used in HV switch yard

CVT(capacitive voltage transformer) CT(current transformer) Isolator Circuit Breaker Bus bar Wave trip EMVT( electromagnetic voltage transformer) LA (lighting arrester) Earth switch

CVT(capacitive voltage transformer)

• Capacitor Voltage Transformers convert transmission

class voltages to standardized low and easily

measurable values, which are used for metering,

protection and control of the high voltage system.

CT (current transformer)

• A current transformer (CT) is used for measurement of alternating electric currents.

• A current transformer produces a reduced current accurately proportional to the current in the circuit, which can be conveniently connected to measuring and recording instruments.

Isolator

• Isolator is an off load device which is operated by remote control or local. Isolators provided in switchyard are central break type.

Types of Electrical Isolators1) Double Break Isolator2) Single Break Isolator3) Pantograph type Isolator

Circuit Breaker

• A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit

• Its basic function is to detect a fault condition and interrupt current flow

Busbar

• A busbar in electrical power distribution refers to thick strips of copper or aluminium that conduct electricity within a switchboard, distribution board, substation, or other electrical apparatus

• The size of the busbar is important in determining the maximum amount of current that can be safely carried.

Wave trap

• Wave traps are used for communication purpose during fault conditions. Wave traps offer high impedance path for high frequency signals & low impedance path for power frequency current.

EMVT (electromagnetic voltage transformer)

EMVT- Electromagnetic voltage transformer . As the name says its works in the principle of electromagnetic induction principle.Its just a stepdown transformer,stepdown voltage i.e higher voltage to meserable voltage by instruments connected to measurement and protection.

LA (lighting arrester)

• A lightning arrester is a device used on electrical power systems and telecommunication systems to protect the insulation and conductors of the system from the damaging effects of lightning

• Earth switches used in substation . in that when isolator OPEN condition earth switch is CLOSED. here any induction that passes through earth switch to ground. when isolator in CLOSED condition Earth switch should be Open 

Earth Switch

CONCLUSION

The Overview of this project is about the various techniques involved in 400 KV Switchyard Of Essar Power Plant. By this we get To Know About the operation of different equipments in Switch Yard and its maintenance.

THANK YOU