| 摘要 |
PROBLEM TO BE SOLVED: To obtain an accident phase selector that correctly selects an accident phase as a single line ground fault accident, even when a system frequency in a current flowing in a transmission line fluctuates. SOLUTION: The accident phase selector selects an accident phase in a transmission line accident based on the current value flowing in the transmission line. The selector calculates differences in phase currents for each phase at different detection timing, calculates scalar values of difference line currents between phases based on the calculated difference phase currents, respectively, calculates difference scalar values by subtracting previous scalar values from present scalar values, and determines the accident phase as the single line ground fault accident when only one of the difference scalar values is below a predetermined value. COPYRIGHT: (C)2011,JPO&INPIT |
