Research and Design of Distributed Static Synchronous Series Compensator

The flexible AC transmission system(FACTS) technology can significantly improve the stability and reduce the operation cost of power system. However, there are several disadvantages for concentrated FACTS controller, such as large size and high-voltage insulation. While the distributed FACTS is introduced to fix up the disadvantages above. In the paper, the distributed static synchronous series compensator (DSSC) topology structure and its operating principle is analyzed. The DSSC's capacity and its effective reactance operating range is discussed as well. Then a DC voltage and power flow decoupling control strategy based on the orthogonal decomposition of injected voltage of DSSC is proposed and proved by simulation. The protection principle of DSSC is discussed and the active overvoltage protection and automatic bypass protection circuit is designed. Experimental verification is carried out on the DSSC prototype. The results show that the control process is smooth with the capacitive or inductive compensation output, and the automatic bypass function under abnormal conditions protects the device. It provides the foundation for the engineering application.