The Research On Distribution Network Protection Strategy Based On The Analysis Of Fault Characteristics Of Inverter-based Distributed Generation

In recent years, with fossil energy nearly depletion, environmental pollution,land constraints and other issues, distributed generation technology that makes use of renewable energy such as wind and solar, has become one of the key development strategies in the energy field. However,a lot of problems have rised after distributed generation joining in distribution network. These problems have seriously restricted the efficient use of new energy. This paper has focused on the study of distributed generation fault characteristics and distribution network protection strategy.The paper outlined the development of distributed generation status based on new energy, and then analyzed the major problems of relay protection and the present status of research progress after the high penetration of distributed generation access to distribution network. In the aspect of the fault current's characteristics research of inverter-based distributed generation, this paper analyzed the present protection configuration of power electronic devices which can't bear oversize current. In different fault location, the short current characteristics of inverter-based distributed generation was discussed, and the simulation waveforms of fault current was given. Finally From the perspective of relay protection, this paper researched the influence of the protection from the fault current characteristics, and presented the notable problem during structuring the protection of distribution network with the distributed generations.The structure and operating principle of voltage source inverter under double loop control which was Commonly Used in china was analyzed, and then from the perspective of relay protection application, this paper put forward invert-based distributed generation equivalent model in the case of Symmetrical fault and Asymmetric fault. It was verified that the traditional method of sequence components could be used in short-circuit current calculation with this distributed generation.After distributed generation access to distribution networks, the different problems were brought for different locations. And based the finding, this paper put forward the Criteria, it could judge whether the former protection was able to operate reliably in distribution network with distributed generation. Impedance matrix analysis can be applied to examine the fault current consequences of installing a new DG. And then with high penetration of distributed power distribution network protection configuration verification scheme was present. The main purpose is to reduce the cost of transformation of the original distribution network protection.After high penetration of distributed power access to distribution network, Original setting principle and protection scheme need be improved. For the fault current polymorphism of invert-based distributed generation, the improvements of original over-current protection was given. In this paper, distance protection was applied in distribution network, and it was verified by simulation.To prevent asynchronous reclosing and arc reignition in distribution network with distributed power,some problems were researched . The other purpose increase fault ride-through capability of distributed generation. For the different capability under automatic former and back acceleration reclosure brake, relevant technical scheme of reclosing was put forward, and then the effectiveness of this scheme was verified by simulation analysis...