Impacts Of Distributed Generation On Distribution Network Protection And Countermeasures

As tension of conventional energy sources and increasingly serious environmental problems, more and more attentions are given to the development and utilization of renewable energy. As a result distributed generation technologies are developed rapidly. The application of distributed generation technology has brought significant changes to power system. At the same time it impacts the control and operation of power system. The impact of distributed generation on distribution network protection is a very important problem. The traditional distribution network protection must be adjusted and improved to meet the access requirements of distributed generation. Therefore, in-depth study of impact of distributed generation on distribution network protection and proposing countermeasures have great practical significance and value.Distributed generation technologies, including its concept, background, classification, operation mode and model building are introduced by this paper. Then the impacts of distributed generation on the existing distribution network protections are analyzed. Focus is made on the impacts of distributed generation on the three-zone current protection, inverse time overcurrent protection, distance protection and autoreclosure and the corresponding countermeasures are proposed.According to the characteristics of distribution network, a fast current protection with channel which is suitable for distribution network with distributed generation is proposed. The protection is based on the improvement of traditional three-zone current protection, so that it has quick action and flexible configuration. Moreover, it does not have to modify the protection values frequently after distributed resources connected to the system.The islanding problem of distributed resource is discussed. The islanding detection methods of synchronous generator are summarized. And based on a new anti-islanding method, paper has developed a new type of anti-islanding protection device. It is proved by dynamic simulation experiment that the new device has higher reliability and sensitivity than the existing anti-islanding protection device.Finally, the research contents are summarized, and future research directions are also prospected.