The Application of Three Phase Soft Phase-Locked Loop in Portable IEC 61850 Test Equipment
Wu Zhenjie1, Fu Guanghui2, Wu Jing1, Tao Tao1
1. Hangzhou Power Supply Company of State Grid State Grid Zhejiang Electric Power Company, Hangzhou 310009; 2. Chengdu Tianjin Technology Co., Ltd, Chengdu 610041
Abstract：With the widely application of Merging Unit in the smart substation, the Digital Sample Value technique becomes an important part of the substation relay protection and control system. Assuming the grid frequency is fixed at 50Hz, the Merging Unit samples the power system with equal interval sampling technology at 80 samples per circle. When the frequency of the power grid changes, the Fourier algorithm will introduce the frequency leakage and the accuracy of both value and phase will greatly decline. To overcome this problem, the three phase soft phase-locked loop is adopted in portable IEC 61850 test equipment. Combining the three phase soft phase-locked loop and the re-sample technology, the portable IEC 61850 test equipment can still achieve high measurement accuracy when the system frequency is variable. The simulation confirms the conclusion.
2015, Vol. 16 
