Pressure- Relieving Valve For Hydro Power

Generally, when the sum (LV/H) of a long diversion pressure tunnel of a SHP station is more than 15 to 20, it needs to set up a surge tank. But, the setting up of surge tank requires ideal topography and large amount of civil works, which would eventually lengthen the construction period. So, replacing the surge tank with a pressure relieving well for a SHP station has reduced both the overall investment cost and the construction period.

The functions of pressure-relieving valve are:
(1) When the unit rejects load and the wicket valve gets quickly closed, the pressure-relieving gate would quickly open and drain away the water flowing through the unit.

(2) After the unit is shutdown, the pressure-relieving valve would slowly close to slow down the flow in the diversion system and prevent the water pressure in the diversion system from rising and to avoid runaway situation for the unit.