ELECTRICAL SYSTEM COMMISSIONING

Jafar AliManager/TG

ELECTRICAL SYSTEM

All auxiliaries/systems in a power plant are dependent on electrical power in one way or other.

Electrical system starts from switch yard in one end and it is scattered in whole power plant and goes up to coal yard.

ELECTRICAL COMMISSIONING

Electrical commissioning in a Power Plant start from commissioning of construction power supply.

But mainly Electrical Commissioning start from Switch Yard Charging Station Transformer Charging or Generator Transformer Back Charging.

SUAT /UAT Charging

ELECTRICAL COMMISSIONING ACTIVITIES

Switch Yard (Extension if applicable) ChargingStation Transformer ChargingGenerator Transformer Back ChargingUAT/SUAT Charging 11KV/6.6KV/3.3KV MV Board ChargingLV transformer chargingHV motor commissioning 415V LVMCC chargingLV motor commissioningControl and Protection panel chargingGenerator System CommissioningSynchronisation

Switch Yard Commissioning/Charging

Following Equipments must be commissioned before switch yard charging.

HV Circuit BreakerIsolatorsCTPTLABus Bars

Commissioning Checks/Tests to be carried out on HV CB

IR of HV CBHV CB Contact ResistanceIR of Spring Charging MotorDC Resistance of Spring Charging Motor Operation of Spring Charging Motor Closing and Opening of HV CB from Local

(Mechanical and Electrical) and RemoteOpening and Closing time of breakerPole discrepancy

Commissioning Checks/Tests to be carried out on Isolator

IR of IsolatorIsolator Contact ResistanceIR of Operating Motor (if motor operated)DC Resistance of Operating Motor Operation of Operating Motor Closing and Opening of Isolator from Local

(Mechanical and Electrical) and RemoteChecking of Opening and Closing interlock of

Isolator

Commissioning Checks/Tests to be carried out on CTs

Visual InspectionPolarity CheckIR measurement of CTWinding Resistance measurementRatio MeasurementCharging /magnetisation current

measurement Ich@Vk/2 Knee Voltage

Commissioning Checks/Tests to be carried out on PTs

Visual InspectionPolarity CheckIR measurement of PTWinding Resistance measurementRatio MeasurementCharging /magnetisation current

measurement

Commissioning Checks/Tests to be carried out on Transformers

IR measurement of HV and LV windingWinding Resistance measurement of HV and LV

windingRatio MeasurementCharging /magnetisation current measurementPressurisation of Transformer for leakages Vacuum checking also for leakagesOil filling in the transformerCentrifuging of OilBreak Down Voltage (BDV) of Transformer oilDGA analysis of Transformer oilTransformer ChargingSoaking of Transformer

Commissioning Checks/Tests to be carried out on MVMCC Switch Board

IR measurement of Bus BarsContact resistance measurement of Bus barsProtection Checking of In-commer and out going

feeders Checking of Closing and opening time of all Breakers Pole discrepancy of BreakersMV board ChargingCommissioning of Out going feeders

Commissioning Checks/Tests to be carried out on LVMCC Switch Board

IR measurement of Bus BarsContact resistance measurement of Bus barsProtection Checking of In-commer and out going

feeders LV board ChargingCommissioning of Out going feeders

Commissioning Checks/Tests to be carried out on Motors

IR measurement of Motor windingDC resistance measurement of Motor windingBump Check for Direction of Rotation (DOR) of Motor Starting of MotorTrail run of Motor

PRE-COMMISSIONING CHECKS ON GENERATOR

•DC Resistance Measurement of Stator Winding •Insulation Resistance measurement of Stator Winding •DC Resistance Measurement Rotor Winding.•Insulation Resistance measurement of Rotor winding.•Impedance measurement Generator rotor winding•Insulation Resistance measurement of RTDs•DC Resistance Measurement RTDs•IR Measurement Generator Bearing and seal Body

PRE-COMMISSIONING CHECKS ON MAIN & PILOT EXCITER

• DC Resistance Measurement of Main Exciter Field• Insulation Resistance Measurement of Main Exciter Field• DC Resistance Measurement of Main Exciter Armature

winding • Insulation Resistance Measurement of Main Exciter

Armature winding• Insulation Resistance measurement of RTDs• DC Resistance Measurement RTDs• DC Resistance Measurement of Pilot Exciter stator

winding.• IR measurement of stator winding of pilot exciter• IR measurement of quadrature axis coil.

Before M/c starting ensure following systems are commissioned

• Seal Oil System, Excitation System, Lube Oil System, Stator Water System and Gas system,

After starting M/c following tests should be carried out.• Measurement of Pilot Exciter no load Voltage• Short Circuit characteristics. • Open circuit characteristics.• Checking of Protection Systems & Relays.• Shaft Voltage Measurement• Loading of generator

COMMISSIONING CHECKS ON GENERATOR

• Stator Voltage and Current• Frequency and Power factor• Field Voltage and Current• All Winding and Core Temperatures• Hot gas and cold gas/air temperatures• Stator Water flow and temperature (if

applicable).• Seal Oil Flow, DP and Temperatures• Bearing Oil and Metal Temperatures. • Bearing and Shaft Vibrations.

MONITORING OF GENERATOR PARAMETERS AFTER SYNCHRONISATION

Thank You