System transient issues from northeast China circuit breaker failure operations and solutions

The problems of the electric grid transient unstability associated with network switchgear breaker failure operations are carefully analyzed; methods to enhance post-fault transient performance are employed and verified. The research is elaborate designed and conducted by using the Chinese Power System Analysis Simulation Package software to stimulate the 500kv and 220kv substation circuit breaker failure operation. Through stimulating symmetrical and asymmetrical line faults, the following breaker failure movements in northeast China electric power grid are modeled. Breakers that may trigger system transient issues are researched. Several reasons of transient problems are speculated and implied, using basic equal area criterion. Different transient characteristics led by various fault types are compared. Solutions that could help improve system transient stability are proposed and compared. In particular, a new method that is integrating Thyristor Controlled Series Compensation (TCSC) to the weak points is verified. Findings indicate that integrating TCSC could reduce generator angle fluctuation significantly.