Abstract：Running in the same 6kV bus 6 high-voltage motor configuration is SIEMENS 7SJ62 Multi-Functional protection, but the secondary voltage of the bus fault, low voltage protection action is different, Three trip, three no. In view of the accident, the technical personnel make a painstaking investigation, careful analysis, determine the instability caused by locking U<logic operation time, then by graphic proportion method measured phase voltage phase angle, simulate the fault voltage protection action confirmed the reason of malfunction.Subsequently proposed resetting calculation or update the protection device to solve the problem.
2016, Vol. 17 
