Powerhouse Mechanical Systems

Several mechanical systems are needed to support the operation of the powerhouse, including:

  • The station drainage and pumping system, which leads wash water and leakage water from the powerhouse floor drains to the station sump from where they are pumped out via an oil-water separator.
  • The unwatering system (or dewatering system), which is used to remove water from a turbine (when it is stopped and the inlet and outlet are closed with valves or gates), so that personnel can enter the turbine and carry out inspection or maintenance.
  • The station air system, which includes air compressors and air accumulators and a system of distribution pipes to deliver the compressed air to points in the powerhouse where it can be used for cleaning or powering air tools during inspection or maintenance.
  • A station water system, which takes water from the penstock or tailrace, passes it through a sieve and strainer and distributes this “raw water” in  a system of pipes to points around the powerhouse where it is needed for washing or to supply other water systems.
  • A cooling water system, which further filters the station water, supplies it to the generators and returns the heated water to the tailrace.
  • A potable water system, which takes water from the station water system, treats it by further filtration and disinfection, and distributes it in pipes to the washrooms and drinking fountains in the station.
  • A fire protection system, which takes water from at least two redundant sources (perhaps the penstock and the tailrace), boosts the pressure using fire pumps if necessary, and distributes the fire water to the fire hoses and sprinklers in the powerhouse; to the deluge nozzles in the generator enclosures; and to the spray bars around the generator transformers.
  • A waste water system, which collects grey water from the showers and wash basins and sewage from the toilets and urinals. A sump and sewage pumps are provided to lift the waste water to the surface where it might be stored for collection, or treated on site.
  • A heating, ventilating and air conditioning (HVAC) system, which takes outside air and heats or cools it to a temperature range that is suitable for powerhouse personnel and equipment, especially the solid state equipment. In many cases, the control room of the powerhouse is cooled more than the remainder of the powerhouse because it houses a concentration of computer and control equipment. The air pressure in the powerhouse is normally at a slightly higher pressure than the outside air (about 1 inch H2O of excess pressure) to ensure keep dust out of the powerhouse. The HVAC system supplies air to each zone in the powerhouse, and responds to the fire detection system by shutting down fans, closing dampers, etc. to keep personnel safe and exhaust smoke in the event of a fire in that zone.
  • A powerhouse crane and gantries, monorails and jibs, required to move pieces of equipment during installation or maintenance.
  • An oil handling system (on larger powerhouses), which has two large tanks to store clean oil and dirty oil. When a turbine is being serviced, the bearing oil is pumped to the dirty oil tank and replaced with clean oil from the clean oil tank. The dirty oil is then passed through a filtration and conditioning system and stored in the clean oil tank. 

Published by hydrogray

Hydropower specialist

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