Research On Protection Strategy Of Distributed Generation Penetrated Smart Distribution Grid

With the wide spread of renewable energy, distributed generation has been pay a lot attention due to its high efficency and flexibility utilizing renewable energy. However, the raidal structure of distribution grid has been changed along with large amount DG penetrated in. The changes continuesly lead to slow action and uncertiany of relay protection based on raidal distribution grid structure. Under this background, this paper study the influences of large amount DG penetrated into distribution grid to slove prolbems.First, this paper analyses the structure of existed distribution grid, characteristic of fault and protection installed to be familiar with protectio logic. Then catagorize control strategy of inverter based DG to analyse cooresponding fault current charateristics and infer DG’s influencs of distribution grid by theory. Furthermore, power and position of DG penetrated has been analysed.Deeply study the proection strategies of recent DG penetrated distribution grid, and analyse their advantages and disadvantages, specially on sectional piolt protection. Aiming to the problem of current protection’s low sensetivity at end point of section, this paper bring a new method of intelligence secitonalize tehnology which intend to build node information matrix. This matrix includes node connection, breaker installation, DG penetration and power and set value revise needed breaker number information. Then use this matrix to reset protection value. This method can correctely cut falut even under the situaion of large DG penetrated into which means high reliability.Modified sectional protection method can solve the problem of distributon grid when large DG penetrated into, make preparation for further development of DG and intelligence distribution grid.