Research On Key Technologies Of Energy-saving Fault Current Limiter Based On Fast-switch

The power grid levels is continue increasing, power grid scale is expanding, large capacity of generators have been used in the power system, the growth of the load current is rapidly, the realization of the major regional power grid interconnection, all of these factors will lead to the fault current level continues to rise. Even in some areas, fault current has exceeded the current breaking capacity of the circuit breaker. In this condition, when the power system occurs a fault, it will cause serious security problems. In addition, the large fault current also increases the difficult of selecting system equipment. Therefore, the fault current must be paid enough attention and have effective measurement to solve the problem. Fault Current Limiter (FCL) as an effective way to limit the fault current has caused many attention.This paper based on the analysis of the popular FCL in domestic and foreign, analyzes and studies the fast switching type FCL, puts forward a new type FCL, which is based on fast switch and more energy saving, and studies the key technology of the new FCL. This paper has mainly done the following several aspects of work:Firstly, introduced the current development of FCL, analyzes the advantages and disadvantages of the various FCL, puts forward a topological structure of fast switching type FCL, and analyzes the principle of this FCL, and by doing mathematical calculations to recon the current limiting effect, and verify the current limiting effect of the FCL by simulation.Secondly, this paper studies the rapid identification technology of short circuit fault and the predictive technology of the time at which the fault current is zero. Applying these technologies to the fast switching type FCL, its switch response time can be shorted, and the fault current breaking capability of the FCL is improved, the using life of the switch is also longer.In addition, according to the IEC61850 standard protocol, this paper studies the technique of information transmitting between the FCL and relay protection device. The state information of the FCL is transferred to the relay protection device timely, when there is a fault in the power system but the breaker of the FCL doesn’t take action, the protection device can control the breaker, so the fault current is reduced.Finally, analyzes the impact on the power system after the FCL connected to the power grid. Mainly analyzes the influence on power system transient stability and whether the relay protection device work accurately after the FCL connected to the power grid. And proposes some methods to solve the problems that the new FCL brings to the power system.The results of this paper is the key to the new FCL applied in power system, ensure the new FCL fast and reliable act and improve its breaking capacity and service life, also eliminating some adverse effects on the power system by its application.