Simulation And Test Study Of Fault Current Limiter With Series Compensation

The growth of electric power consumption has resulted in a corresponding development of power system, in addition, the requirement for the stability of the large system has increased. Utilities are faced with fault current which can exceed the rated capacity of the installed circuit breakers and other equipments. To correct this problem, a fault current limiter (FCL) is available.With the development of power electronics technology, solid-switch due to its quickness,permiting many times of operation .simple control, low cost and small size is considered to be a practical protection device for power systems in the future. Based on the advantage of the solid-switch, many FCLs with solid-state switch have been proposed. FCL with series compensation which could limit the fault current and also make compensation is more flexible and practical when compared to the others.In this paper, a type of fault current limiter with series compensation is studied. It is composed of a reactor and in series with a compensation capacitor, which is paralleled with a by-pass reactor controlled by a GTO pair. The FCL operates in two modes, in normal conditions, it is used as a compensation capacitor; in fault conditions, the GTO pair quickly switches on to get the by-pass reactor in operation to limit the current. First, the topology of the FCLis proposed together with the principle and characteristic of the FCL, second, the design method of FCL's parameters in the light of short-current is presented. To test the performanceof the FCL, a feeder fault is simulated by Matlab, results show the FCL is effective in limiting the fault current.For the low cost and convenient maintenance of SCM, a laboratory set-up in which the GTO pair is controlled by SCM is tested. As a key part of the set-up, the control system including hardware and software is illustrated in detail. In the part of hardware, each chip is introduced, in the software part, process flow and some program are presented. Results show the FCL mode is successful in laboratory testing and the project with SCM is feasible.To improve the stability of the system, optimal control of partial-output feedback is used, simulation results show the control objective can be met successfully.