The Research Of Protection Device For Distribution Network With Distributed Generation

The distributed power usually access medium or low voltage of distribution system, and will have extensive and far-reaching impact. The traditional distribution system is designed only to send users with distribution function of electric power, and distribution system is expected to become a power exchange medium in future, in other words, it can collect power and transmit them to any place,and distribut them. Therefore it may not be a "Power system" but a "electric switching system (Power delivery system)" in the future. Distributed generation has scattered, random change for a characteristic, lots of the distributed power of access to power systems have great impact on the safe and stable operation.When distributed generation join in distribution system, the traditional relay protection already can't play its original function. With respect to this situation, this paper puts forward a method to compare type protection principle of longitudinal united on the basis of high permeability distribution system under DG area, and developed protection device according to the plan. The plan through different position of fault direction components, can compare movement state conveniently, determine the position of the breakdown of the fault accurately, in order to realize the rapid resection, ensure the normal running of the fault part. The protection system uses a form more than a Lord of the longitudinal league protection structure equation and inquires feeder longitudinal league protection of communication solution, protection from the machine can be greatly simplified the hardware and software structure and logical action and decrease the cost of system and maintenance.The positive direction of components adopt "top-down" configuration mode, need only testing its installation points downstream, make its detection fault the sensitivity of the distributed power operation not influenced by the way, improve the protection system adaptability.By a set of riginal longitudinal league protection system to realize the whole distribution substations and all its feed the longitudinal league main protection qualify, and complement the backup protection from the machine protection function, it can achieve good protection performance under high permeability, meet DG distribution system of relay protection needs and don't add much cost and cost. The development in the device use modular design ideas, according to design need to choose the superior performance to make hardware system, development of chips for hosting a set of power for intelligence failure detection and isolation system software. This software to VS.net for development platform, introduce a SQL Server database system, using the object-oriented programming design thought. Program can realize fault simulation, failure results from machine query and host and communications functions, which makes the device to achieve the best performance, and built the optical fiber communication platform on the device's performance testing.This protection scheme proposed that solved under high permeability distribution system DG failed to reliable, excision of green environmental protection energy for further widely used and distributed generation in power distribution system wide application have laid a good foundation. The corresponding protection, fill a prototype development in contains micro nets distribution system in protection device, promote the blank in the research of theory with practice process. The plant performance testing, further proved the success of the correctness of the proposed protection principle, also proved the rationality of the design of protection device.