Innovative Closure Law for Pump-Turbines and Field Test Verification

Abstract

Based on numerical simulation of hydraulic transients in a pump storage power station (PSP), different closure laws are investigated for use when a high-head pump-turbine load rejection occurs. According to the characteristics of the pump-turbine and main inlet valve (MIV), a novel closure law, combining closure of wicket gates (WG) and MIV, is presented. The proposed closure law can reduce the effects of S-shaped characteristics of a pump-turbine, and the maximum pressure in the spiral case, the maximum rotating speed of the runner, and the minimum pressure in the draft tube during the transient process can be mitigated. A simultaneous load rejection test on a double unit is conducted, and the numerical predictions agree well with the field test data.