Solid State Current Limiter For Two-way Trend Developed

Along with the expanding power network, the fault current has increased greatly. The short circuit current of many area especially the economically advanced area is close to and even more than the present line breakers' breaking capacity. It will bring hidden troubles to the security, stability, credibility of the power system. So how to find effective current-limiting technique has become the pressing problem in electric power system.The faculties in Zhejiang University have begun the research of solid states power switch and fault current limiting technology. They provide a novel solid stats fault current limiting technology, which possesses flexible control mode. The experimental prototypes of 380V/200A transformer coupling three phase bridge type solid state fault current limiter (SSFCL) and 10Kv/500A transformer coupling three phase bridge type SSFCL with bypass inductance have been developed successfully.Based on the predecessors' research findings this paper does some research on the application when SSFCL is in bi-directional current conditions. Firstly, the paper expatiates on the damages caused by faults and some ordinary current-limiting methods. Then it makes a summary on some existing FCL technologies.Second, based on the main circuit topology and operating principle of new SSFCL, this paper does some seminar on the topology, control strategy, previously charge magnetism before enablement and the impact to the system when it is enabled of the bi-directional current SSCL.Third, the paper makes explanation on the hardware, control system, control software and anti-interference methods.And then, based on the multi-power simulation model this paper do some emulation research on the SSFCL when it is enabled normally, and when three phases and two phase short circuit happen in bi-directional current conditions.Finally, the double source small model test system (including the small SSFCL model and weakly circuit test system) and single source high-current test system are established. These tests as following have been done, normal starting, synchronizing and closing, current-limiting test in double source and weak circuit conditions, and normal enablement, burn-in test, modify definite value current-limiting test, no-load current-limiting test. The results of these tests have been detailed analyzed. It provesthat the SSFCL have favorable control performance and current-limiting effectiveness during its normal starting, operation or on accident current-limiting condition.