Research On The Multi Index Nonlinear Control For Static Synchronous Series Compensator

With the development of the modern society, there is an increasing demand for electricity, which brings about a large capacity, long distance and extra-high voltage of the power system. The variety energy and complex network topology structure of the modern power system puts forward higher requirements for the safe and stable operation of the power grid. The coming of the Flexible AC Transmission System (FACTS) solved the problems of improving the transmission lines’capacity and strengthening the stability of the power system.Static Synchronous Series Compensator (SSSC), as the one of the most prospect application series compensator member of FACTS, which is added a controlled voltage source to the transmission line by the voltage type converter, could improves the transmission power of lines, suppressions the system power oscillation and guarantees the safe and stable operation of power system. The compensation characteristic of SSSC to system is determined by its internal controller, whose output performance directly affects the compensation of SSSC. In addition, as more and more FACTS equipment put into operation to the grid, which is bound to cause more interaction among FACTS controllers that would endanger the safe and stable operation of power system. Therefore, it is a practical engineering significance research work to investigation the interaction between FACTS device and coordinate control their controller from the global system.To solve the control strategy of SSSC, a coordinate controller consisted of SSSC and generator excitation model was given in this paper. The nonlinear dynamic model of SSSC was formed by its basic structural features and operation principle. The controller was based on a single machine infinite bus power system and adopted by the Multi-Index Nonlinear Control method. Finally, the simulation results showed that the coordinated controller had high control precision and good dynamic performance.To solve the interaction among FACTS controllers, a single machine infinite bus system furnished with SSSC and SVC was given, and a matrix of the system was computed by the Relative Gain Array method. The RGA matrix shows that there was an interaction between SSSC and SVC, moreover, the longer installation of electrical distance, the less influence of the main control channel affected by other channel. Finally, a MINC coordinated controller was designed to eliminate the interaction between them. The simulation results not only validated the controller was efficient, but also posed a new research idea for solving the multi FACTS interactions problems.