Relay Protection Of Distribution System With Distribution Generations

Energy is basis for the existence and development of human society. However, these years, with the accelerated development of our society, our need for energy is increasing greatly. To make matters worse, the primary energy is dying up and ecological environment is also destroyed. So, in response to the potential energy crisis and destroyed ecological environment, the Distributed Generation is predicted to play a quite important role in the power system because of its high efficiency, environmental-friendly, and reliable during the adjustment of energy structure in many countries. So far, the distributed generation has been rapid developed around the world.However, with the interconnection of a large number of distributed generation to distribution network, it will have a profound impact on the protection of distribution systems. Most distribution systems especially rural systems are operated in a radial configuration supplied by one generation, and the protection of distribution systems are based on this configuration. The access of distributed generation, will greatly change the topology of the distribution network, and will make the power flow in multiple directions, which will deeply affect distribution network operating and controlling to make it more complex. The basis of the original protection design has changed, which makes original protection system no longer applicable or bring traditional protection system new problems, such as sensitivity decrease, mis-operation and malfunction, which will bring great risks to power system safe and stable operation.therefore it is very necessary to analyse the influence of the distributed generation to the distribution network protection and propose coping strategies, which is of great significance for the application and development of distributed generation technologies.This paper establishes a typical10kV distribution network, and based on this, it analyses how different location, capacity, quantity of distribution generation and fault location and other factors affect the traditional distribution network protection. And against the results, it proposes intelligent protection schemes in the light of the traditional distribution network including DG. The program is based on computer or communication to collect information between adjacent lines to achieve the identification of fault sections, then by mainly installing the direction elements and circuit breakers to cut off the fault sections. As a basis, considering more DGs interconnection, it needs to modify partial protection settings, and calculate the maximum capacity of DG allowed to interconnect to the distribution network. And finally it uses MATLAB to simulate and verify the feasibility.