发电机和大型异步电动机纵差保护的几个问题

some Questions About the Differential Protection for Generator and Large Asynchrorous Motor

发电机纵差保护的整定计算中，不适当地垮大了不平衡电流，混淆了制动系数Ｋ和制动特性斜率ｍ，结果造成定值过大，影响了机内短路的灵敏度。大型异步电动机自启动过程中，由于纵差保护两侧互感器暂态特性不一致，自启动暂态过程较长，使纵差保护多次误动，急待采取技术措施解决。

In set Value calculation of enerator longitudinal differential protection, unbalancer current is unsuitably exaghgerat-ed and restraint ratio Kres and restrasint characteristic sloope m are mixed up, thus resulting in excessive set valuewhich harm the short-circuit sensitivity in generator/ During automatic start of large asynchronous motor, dueto the non-uniform transient charateristic of nsformers on both sides of the differential protection and thelonger transient process of the automatic start, the differential protection often maloperates. Those above have tobe solved as soon as possible.