Cooling system architecture in Hydropower

The main function of cooling system is to cool Generating lubricating oil and turbine shaft seal. So, basically, two main consumer of cooling system in Power house are

a)     Generating lubricating oil cooler:   Generator bearing is cooled by Lubrication oil and Lubrication oil is cooled by the water, circulated by cooling system..

      Fig: Heat Flow Diagram

b) Turbine shaft seal: Water also used to cool/seal turbine shaft seal.

Water from draft tube/tailrace is used as coolant .Cooling system can be open loop or closed loop. In open loop cooling water system water is finally discharged to tail race level or MIV pit. However, in closed loop cooling the same water is recirculate back.

The major components of cooling system are as follows:

1)      Pump: An appropriate pump is used to circulate the water. Normally, there are two centrifugal pumps in parallel per unit. One will be the main pump and other will be stand-by pump. Standby pump will operate main pump fails thereby increasing reliability of the system.

2)      Filter/Strainer: Water is filtered by duplex/simplex filter to remove silt and abrasive material from it before reaching to consumer. Two or more filters of different capacity can be used in series connection based on the size of the particles to be filtered.

3)      Water Tank: Pumped water is stored in a tank. The Tank will acts as buffer

4)      Fitting and Arrangement: It consists of valves, Pressure switch, piping and pressure gauge.

5)      Heat exchanger: An appropriate heat exchanger is used to extract heat to water from the consumer.