Application of SMES Unit in Black Start

Blackout of large area is a serious threat to modern power system, so power system restoration which is called Black Start is a critical task for reducing economic losses and social unrest caused by blackout. Traditiona black start sometimes may suffer from inflexible black start units and overvoltage and serious oscillation. As a power storage unit, SMES has the ability of fast exchanging active and reactive power with power grid in all four quadrants, so it is proposed as a new solution to improve the black start process in this paper. Comparing to traditional black start, some unique advantages of SMES for black start are presented. Also SMES model and related control strategy are introduced in detail. A simulation model is established based on PSCAD/EMTDC to investigate the validity and flexibility of SMES in black start. Simulation results show that SMES unit can bring thermal generators online, and it has better performance on overvoltage restraint and amping oscillation than traditional black start. Also, the performance of nonlinear PID-controlled SMES is better than that of PID-controlled SMES.