【摘要】 和应涌流可能引起主设备保护的误动,目前还鲜有针对和应涌流的有效防范措施。分析了和应涌流的产生机理,指出和应涌流本身并不会引起差动保护误动。针对现场运行中较多采用的二次谐波制动原理,研究了该原理在发生和应涌流时,不同电流互感器(TA)传变特性下的适用性,指出由和应涌流引发的TA局部暂态饱和是导致差动保护误动的重要因素之一。最后,提出一种比率制动特性的修正方案以避免由于TA局部暂态饱和引起的差动保护误动。更多还原

【Abstract】 Sympathetic inrush may cause mal-operation of transformer or generator protection.Effective measures to avoid the mal-operation of differential protection caused by sympathetic inrush are still not found.The physical mechanism of emerging sympathetic inrush is analyzed.According to the characteristic of sympathetic inrush,mal-operation of differential protection should not be directly caused by sympathetic inrush.Due to 2nd harmonic restrain theory widely used in practice,its adaptability under different transferring characteristics of current transformer while sympathetic inrush happens is studied.It is concluded that current transformer partial transient saturation is one of the most important factors that results in mal-operation of differential protection.At last,one modified ratio restrain scheme for differential protection is proposed so that the mal-operation caused by current transformer partial transient saturation can be avoided.更多还原