Coordinated Control Scheme for Superconducting Magnetic Energy Storage Unit to Boost Transient Stability of Wind Farm Connected Power System

The wind power penetration in power system is increasing yearly, and the requirement of low voltage ridethrough (LVRT) is put forward. Yet all kinds of LVRT schemes commonly used in wind turbines tend to change the running state of the wind turbine and bring double impact to the transient stability of the system. This paper combines the output power of wind turbine with the equivalent mechanical power of the system, deducing the mathematical relationship between them. On this basis, it analyzes the mechanism of the influence of LVRT on the transient stability of the system, simultaneously proposing a superconducting magnetic energy storage (SMES) coordinated control scheme to improve the transient stability of the wind farm connected power system. At the same time that the LVRT is achieved by the crowbar of the rotor, compensatory strategy of SMES, according to the influence law on the mechanical power of the equivalent system, is adjusted to achieve higher transient stability performance of the system. Finally, the effectiveness of the proposed control scheme is demonstrated by simulation in MATLAB/Simulink.