Improving Power System Transient Stability with Static Synchronous Series Compensator

Problem statement: Modern power system consists of the complicated network of transmission lines and carries heavy demand. Thus they cause in the stability problem. One of the major interests of power utilities is the improvement of power system transient behavior. Approach: Static Synchronous Series Compensator (SSSC) is a power electronic based device that has the capability of controlling the power flow through a line. This study applies the SSSC to improve transient stability of power system. To verify the effect of the SSSC on transient stability, the mathematical model and control strategy of a SSSC is presented. The SSSC is represented by variable voltage injection with associate transformer leakage reactance and the voltage source. The series voltage injection model of SSSC is modeled into power flow equation and thus it is used to determine its control strategy. This study uses machine speed deviation to control it. The swing curves of the three phase faulted power system without and with a SSSC is tested and compared in various cases. Results: The swing curve of system without a SSSC gets increases monotonically and thus the system can be considered as unstable whereas the swing curves of system with a SSSC can be considered as stable. Conclusion: SSSSC can improve transient stability of power system.