Research On Optimization Of Reclosing Method And Setting Value For 110kv Line With Bilateral Power Source Of Regional Network

This paper established a reclosing simulation mode on 110kV line with bilateral powersource of regional network based on PSCAD, and then verified its correctness by simulatingpractical fault. On this basis, a simulated analysis for voltage and frequency dynamiccharacteristics of the island system with different initial power flow on the contact line wasdone. And the results showed that frequency of the island system changed greatly when theinitial active power flow on the contact line was larger. While the synchronous reclosingneeded to detect frequency and phase angle difference whether within the range and continuedthe setting delay time. The requirement was so strict that the probability of reliable action ofthe closing on island system reduced significantly.To solve this problem, this paper put forward automatic quasi-synchronization reclosing.Microcomputer quasi-synchronization reclosing could accurately control the closing advanceangle and made voltage phase angle difference between both sides near the zero degree at theclosing moment, so that impact on generator or system caused by voltage phase angledifference when circuit breaker closing was avoided. Meanwhile, the allowed frequencydifference of automatic quasi-synchronization reclosing was much larger than that ofsynchronous reclosing. Firstly, the paper introduced the research status of reclosing at homeand abroad, as well as the principle and concepts, principles and setting method ofsynchronous reclosing. Then disadvantages that it greatly affected by load type and the initialpower flow was pointed out when used on 110kV line with bilateral power source throughtheoretical analysis and simulation. So the program of automatic quasi-synchronizationreclosing was proposed. First of all, advantage of quasi-synchronization reclosing wasintroduced. And secondly the theoretical analysis on feasibility of quasi-synchronization wascarried on. Furthermore, this paper researched on setting methods about advance angle andadvance time as well as parameter measurement algorithm of quasi-synchronization reclosing.Finally, the control strategy and setting value for quasi-synchronization reclosing wasproposing. In addition, zero sequence current accelerating protection and distance acceleratingprotection was discussed.