Research On A Fault Current Limiter With Series Compensation Based On High Speed Switch

The national economy of China develops so fast in recent years, and thegrowing demand for power all walks of life has resulted in a correspondingdevelopment of power system, in addition the requirement for the stability of thedistance and large power system has increased. The system capacity is beingextended gradually lead to its short-circuit capacity increase, and utilities are facedwith fault current which can exceed the rated capacity of the installed circuit breakersand other equipments, and the fault often result in short-circuit current increasesrapidly at the same time with a serious voltage sag which can make the power qualitylower. Fault current limiter performs well in the numerous methods of limiter faultcurrent. Recently FCL has become a popular researching focus both at home andabroad.Several kinds of FCL are introduced in this article, and at the same time it hasanalyzed the advantages and disadvantages of various fault current limiters withreference to the research achievements of short-circuit current limiters that have beenreported, and puts forward a kind of based on high speed vacuum switch a faultcurrent limiter with series compensation. It is composed of a reactor and in serieswith a compensation capacitor, which is paralleled with other capacitor. The FCLoperates in two modes, in normal conditions, it is used as a compensation capacitor;in fault conditions, quickly switch rapid movement the shunt capacitance and accesscircuit, series compensation capacitor and shunt capacitance in parallel and thecurrent limit after series inductance on the current limit. First, the topology of thefault current limiter is proposed together with the principle and characteristic of thefault current limiter, second, the design method of fault current limiter’s parametersis presented. A model of one machine-infinity bus system is established by thesoftware which is MATLAB, in which some short circuit faults are simulated, resultshows the FCL is effective in limiting the fault current.A two dimensional (2D) finite element method is applied to analyze thedynamic characteristics of the electromagnetic repulsion mechanism. In order to verify the validity of the simulation results, a simplified electromagnetic repulsionmechanism is established. Analyzing the factors which influence the velocity of therepulsion driver (including the thickness, radius of the metal plate; turns, radius,thickness of the coil; the distance between the metal plates and the coil; the capacityand the voltage of capacitance etc.), and find out the fundamental laws that howthese factors influence the repulsion force and its function time, and detailedinvestigations are performed.The fault current online monitoring system design is analyzed. The extractionand simulation of short circuit faults signal from power system using the RogowskiCoil short current measure element. At the same time a new processing of fault signalwas abstracted, the results prove that it can fast and accurate judgment of the faultsignal through the theoretical analysis and simulation.