The Influence And Countermeasure On The Distance Protection For High Voltage Distribution Network With Distributed Generation

Lots of the distributed generations connecting to the grid, could improve the power supply reliability of the traditional distribution network, and also be helpful for power supply distribution adjustment of the distribution network. However, series of problems also be brought in, for example, it may change the distribution network topology structure; change the original one-way power flow into a two-way power flow. When the fault occurs, the distributed generation access will change the fault current. Different location faults position and levels of DGs would produce a different role to relay system, influence the correct action to act, also can change the scope of protection and sensitivity, and influence the protection between the line and its superior line.Therefore, based on the established distribution network in typical model, firstly, this paper analysis the influence for the current protection and distance protection brought by the distributed power access respectively,study on the positive help increased current, reverse help increased current, and described the current etc. of the upstream and downstream protection. Then, research on the influence of the distance protection brought by the distributed power access to the network, mainly discusses the influence of the change of the DG access position and DG capacity for the distance protection is proceed. And then the simulation is mage to draw the conclusion.Finally,based on the characteristics analysis of the traditional distance protection, the setting algorithm of the adaptive distance protection Ⅱ segment and Ⅲ period which based on the distributed generation access to grid. Following the simulation result, the conclusion can be drawn as:(1) using the adaptive setting algorithm of the distance protection Ⅱ period, not only can increase the scope of protection, but also can improve the sensitivity, and don’t need to be adjacent to the next level line distance Ⅰ period;(2) using the adaptive setting algorithm of the distance protection Ⅲ, can improve the protection sensitivity as the far backup protection of the next level line greatly, and expand the protection scope. So the superiority of the adaptive setting algorithm of the distance protection is proved.