ABC OF THERMAL POWER PLANT: COMMISSIONING OF ESP IN ATHERMAL POWER PLANT.

Collecting and emitting Rapping System Commissioning :

Geared motors :

- In case of emitting electrode rapping system confirm that heating elements are properly fixed.

- Confirm glands are properly placed

- Insulators are healthy, clean and rigid without crack.

- Confirm the mechanical clearance for each rapping system and decouple the motor.

- Confirm the tightness of motor terminated cables, proper earthing, proper dressing of cables.

- Megger the motor and record the IR value. Measure the coil resistance and record. Confirm IR value is at least 1Mohm. Otherwise heat the motor and till the IR value is satisfactory.

- Confirm the local push button station control supply terminal are properly done.

- Energise the concerned module and locally bump and confirm direction.

- If the direction is reverse, correct the direction.

- Couple and take trial run as per duty cycle of the motor to study the proper hammering. If the hammering is in the centre of shock pad in case of collecting rapping system for all the hammers and the hammer in the centre of shock beam in case of emitting rapping, stop the rapping motors.

- Clear for tack welding of all bolt and nuts of hammers etc.

- Commission all the rapping motors of all fields as above.

Disconnecting switches

- Ensure Insulators are healthy, clean and rigid

- HV bus terminal and earth connections inside are tight.

- Operation of moving blades with HV and HV and earth contact is smooth and proper.

- Copper cable between moving arm and insulator head is properly connected. Each disconnecting switch is provided with a danger plate and two external earth connections to earth mat.

- Doors are closed tightly

- Interlocks provided at doors handles are working properly.

INSULATOR HOUSING

- Insulators are clean, healthy and rigid

- Copper tubes are straight and not loose

- Heating elements are properly fixed

- Earthing is proper

- Screw legs and nuts for placement of alignment jigs are welded

- Doors are closed tightly

- Interlocks are working properly

- Each insulator housing is provided with a danger plate and two external earth connection to earth grid.

ELECTRICAL SYSTEM

High voltage transformer rectifier (HVR) with electronic controller (EC) :

The transformer rectifier supplies the power for particulate charging and collection. The basic function of EC is to feed the precipitator with maximum power input under constant current regulation. Whenever there is a flash between emitting and collecting electrodes, the EC will sense the flash over and quickly react by bringing the input voltage to zero an blocking it for a specific period.

After the ionized gases are cleared and the dielectric strength restored, the controller will quickly restore the power to a preset value and raise it to the original non sparking level. The EC ensures adequate power input to the precipitator while reckoning the electrical disturbances within the precipitator. Regulated ac power from EC is fed to the primary of the transformer precipitator, which is stepped up and rectified to give a full wave power output. The transformer-rectifier is mounted on roof of the precipitator which the EC is located in an air conditioned control room.

Auxiliary control panel(ACP)

This is an LTMCC of modular construction with individual modules for supplying power to the following equipment.

-Hopper heaters for each field

-Support insulator heaters

-Shaft insulator heaters

-Collecting electrode rapping for each field.

-emitting electrode rapping motor for each field.

-Opaque monitor

Safety interlock: A interlock system is incorporated to prevent accidental contact with live parts of the precipitator and to enable energisation only when the EP is boxed up.

Disconnecting switch: each field is provided with one disconnecting switch for isolation of emitting system from the associated transformer. In the ON position the emitting system is connected to transformer and in OFF position the emitting system is grounded