Water hammer control of pumped-storage power plant with two units under hydraulic short circuit operation

Abstract This paper investigates the water hammer control of pumped-storage power plant (PSPP) with two units under hydraulic short circuit operation (HSCO). Firstly, the numerical model of PSPP with two units is established. Based on the sequences of accident shutdown of units under HSCO, two combined operating conditions (COCs) are presented. Then, the control objectives of water hammer pressure are designed to verify the safety of PSPP under HSCO. The superposition time is selected as the decision variable, and the values of control objectives are obtained by the whale optimization algorithm. Finally, the extreme water hammer pressures of two COCs, successive load rejections and successive pump outages are compared. The results indicate the sequences of accident shutdown of two units under HSCO have an impact on the water hammer control. For the two COCs, when the initial operating condition is load rejection, the maximum draft tube pressure and minimum draft tube pressure are more dangerous. The minimum volute pressure is almost not affected. During the actual operation of the PSPP, the COC should be avoided. Compared with successive load rejections and successive pump outages, the accident shutdown under HSCO is the most unfavourable for the control of maximum draft tube pressure.