chapter - 1 introduction - Meghalaya State Pollution Control Board

Hills Cement Co. Limited.
system. The 110 VDC distribution board will cater to the needs of the above
essential auxiliaries loads.
LT & HT Switchgear room
The 11 kV generators switch board (GSB) will also be located within the
power house. The 415 V switchboards and motor control centers (MCC) for
turbo generator, boiler, ESP, Fuel Handling system will be located in ground
floor level. These LT boards will have provision for cable entry from bottom.
All cables within this room will be routed through civil cable trenches.
Adequate exhaust ventilation system will be provided for the switchgear
rooms.
Lightening Protection System
The plant earth grid as well as the turbo generator building-earthing grid will
be interconnected in order to limit the overall resistance of the earthing
system. The design of earthing station will be as per IS: 3043. Galvanized
steel flats will be used for earth mats. All electrical equipment and steel
structure will be earthed properly and distinctly at two points. Separate and
independent earthing connection will be made for electronic equipment in
order to make its functioning free from system disturbances. The entire
power plant buildings/structures at isolated locations will be protected against
lighting. The design of the lightning protection system will be as stipulated in
IS: 2309. The substation earthing system will be provided to keep touch and
step potential within limits. Earthing system consists of earthling station,
earthling conductors and accessories for providing complete earthling to
equipment and system earthing. The Shielding considered for protection of
all outdoor equipment from lighting strokes will be with GS spikes supported
on top of substation structures. Spikes will be connected to the substation
earthing. The lightening arrestors will be outdoor, heavy duty, gapless, ZnO,
non linear resistor, station type with the terminal suitable for outdoor bus
system and earth side terminal suitable for connection with galvanized MS
flats. The nominal discharge current ratings will be 10 kA.
Power monitoring system
Necessary electrical transducers to monitor the parameters such as bus
voltage, current, frequency, power, energy will be provided as part of the
electrical distribution system and these transducers will be wired to the main
DCS unit through remote I/O units for monitoring the power distribution
arrangement. Also contact inputs for various circuit breakers status positions
will be wired to the main DCS unit to monitor the status of the different
distribution breakers and fault condition.
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