Research On The Impact To System Of SSFCL Bridge Arm Failure

With the rapid development of electric power construction, power structures and system capacity are expanding, short-circuit current level is rapidly increasing. In many areas, especially in economically developed regions, system short-circuit current level is almost equal to or even exceed the allowable range. Some conventional restriction measures on short-circuit current, such as series reactor and stratified area, have a limited effect on limiting short-circuit current because they are limited by some factors like grid structure, operation mode, security and so on. In order to take effective short-circuit current limited measures, a more ideal "fault current limiter(FCL)" was raised in the seventies of the last century. With the developing of the power electronics technology, many FCL emerged, such as magnetic components current limiter, PTC, SFCL and so on. Based on the production already had Institute of Electrical Engineering of Zhejiang University proposed a new type of FCL.In this paper, the various topologies of solid-state current limiter are analysed and compared. Every topology's principle, its advantages and disadvantages are expounded. For the research of impact to system that solid-state current limiter's fault brings has not yet started, this paper summarized the fault causes and types of three-phase transformer-coupled bridge SSFCL. Using MATLAB software, this paper did very particular simulation studies in the case of system normal and occurrence three-phase short-circuit. By analyzing every fault reason, this paper obtains some conclusions, and brings forward control strategies to these conclusions.This paper also described the application and function in detail with SSFCL's DC sampling module, main and assistant DSP module, power net switching module, trigger module and main DSP system's communication with PC. And for achieving these functions, this paper completed the circuit design corresponding the modules, and also had an analysis and description of circuit theory.