Based on the analysis of main fault types of LV (Low Voltage) flameproof motor, the negativesequence protection principle is proposed for its asymmetric short circuit fault and open phase fault.
Zero-sequence current criterion, negativesequence current criterion and phase current variation can be used to improve the performance of breaker failure protection for ACF sub-bank.
In typical six-phase transmission system, half positive sequence, half zero sequence and half negative sequence fault components are independent of the variance of system impedance.