Dynamic Simulation System for Short-Circuit Faults of Variable-Speed Pumped Storage Unit

This paper firstly investigates the equivalent model of variable-speed pumped storage units and puts forward the corresponding mathematical models and control strategies for these units. With the aid of the Simulink simulation platform, a simulation model of the generator-motor for variable-speed pumped storage units and its supporting AC excitation system is established. On this foundation, a full-process hydro-mechanical-grid dynamic simulation system for variable-speed pumped storage units is constructed. This integrated system is composed of a multi-branch generator-motor, an AC excitation system, a pump-turbine together with its governing system, and an infinite power grid. The paper elaborates on all constituent parts of the dynamic simulation system and clarifies the specific functions and operational roles of each component. Meanwhile, a structural design scheme featuring multi-tap stator and rotor windings is proposed for the multi-branch dynamic simulation test motor. In the final stage, a series of tests targeting internal stator and rotor inter-turn short-circuit faults of the generator are carried out. The test results fully verify the accuracy and practical effectiveness of the developed system. The construction of this simulation system also provides a reliable experimental platform for simulating internal winding short-circuit faults and validating protection strategies of variable-speed pumped storage units.