This paper focuses on the self-starting strategy of variable speed pumped storage units(VSPSU)by the shorting machine stator. Firstly

the mathematical model

phasor diagram and characteristics of VSPSU are proposed while the machine stator is being short-circuited. Then a robust stator flux observer is created for the self-starting strategy with stator flux oriented control to accelerate the rotor for synchronization. The starting time

torque characteristics and estimated accuracy of this strategy are quantitatively analyzed by simulation. The results show that the strategy has good starting performance and robustness. This work is supported by Fundamental Research Funds for the Central Universities(No. 2014B04614)and State Grid Corporation of China.