Ma J.,North China Electrical Power University |
Wang Z.,North China Electrical Power University |
Ma W.,North China Electrical Power University |
Wang S.,State Grid Corporation of China |
And 3 more authors.
Dianwang Jishu/Power System Technology | Year: 2014
The zone 3 of local distance protection is easy to be affected by incident overload and it leads to the malfunction. To overcome this defect, a complex phasor plane based adaptive overload identification method is proposed. Firstly, according to geometrical distribution of phasors measured under different operating conditions, the virtual voltage drop equation is established and on this basis the computing formula of adaptive setting coefficients is derived to construct the criterion of adaptively identifying the overload for the zone 3 of distance protection; then this criterion is combined with the action characteristic of zone 3 of distance protection to distinguish overload from symmetrical fault. Using the proposed method, on the one hand, the malfunction of the zone 3 of distance protection, which is caused by overload, can be avoided, on the other hand, under such a condition that the overload is accompanying with symmetrical fault the zone 3 of distance protection can still play a role of backup protection effectively. The correctness of the proposed method is validated by IEEE 10-machine 39-bus system.