高压电动机磁平衡差动保护

Magnetic Balance Differential Protection of High-voltage Motor

2 MVA及以上的高压电动机,当与配电装置距离较远时,采用比率制动差动保护由于两侧电流互感器的二次阻抗不匹配,有较大不平衡电流,影响保护的灵敏度,而采用磁平衡差动保护则整定值低,灵敏度高,更合理。同时对不同型式的电动机进行磁平衡保护整定计算。

When high-voltage motors （2MVA or above） are installed at a relatively long distance from the power distribution system, large unbalance current may occur which will affect the protection sensitivity due to mismatched secondary resistances of current transducers on both sides when ratio restraint differential protection is adopted. The application of magnetic balance differential protection can guarantee low setting value and high sensitivity and is thus more reasonable. In addition, magnetic balance protection setting calculation is conducted on motors of different types.