With the functions of peak shaving

valley filling and emergency using

PSPS （pumped-storage power station） is an important part of power system

which has advantages such as flexible startup and quick response. Compared with traditional pumped storage unit

stepless speed regulation unit can improve running efficiency in different conditions

realize self-starting and electric braking

and is compatible with automatic frequency regulation of the power system. For these reasons

stepless speed regulation unit is widely adopted abroad. However

there is still no utility record in China. Considering this situation and based on the features of PSPS and stepless speed regulation unit

this article studied the mathematics model and control strategy in different conditions

and made simulation experiment according to parameters of a project abroad. The result of the simulation proved the correctness of the control strategy

which provides a theoretical foundation for further engineering application.