一种新型的微机变压器差动保护CT二次回路断线判别原理

本文提出的ＣＴ二次回路断线判别原理，首次引入有符号突变量启动的方法，并将故障、断线、拉闸等分开来，使三者在判别时间上相互独立．在此基础上对故障采用高速的算法，使动作速度仅在１０ｍｓ左右；同时充分利用断电时的特征量和计算机的记忆存储和计算功能，并采用全波富氏加一阶差分滤波器算法，使断线判断具有很高的准确性，对拉闸采用躲过暂态的方法．上述原理在ＳＷＢＢ－１０型变压器保护装置的静态及动态模拟试验中效良好．

A new detecting method of break in secondary circuit of current transformer in micro-based differential protection of power transformer

This paper presents a detecting principle of the break in secondary circuit of current transformer in wnich method of initiation of sudden increasing with signal is introduced. The fault break and breaking off switcher are distinguished respectively, so that they are independent each other in the detecting period. Based on it, nigh-speed algorithm is used to detect the inner faults of power transformer which enable the trip impulse to be given out within about 10me. Meanwhile, the feather of break, the character of recalling,meorizing and calculation of single-Chip microcomputer and the fourior algoritm of full wave with the first differential are fully used for the purpose of high precision in dedecting the break of the secondary circuit transformer. The method of dedging transient detecting is supplied in the circumstance of breaking offswither. All above methods have performed both in motion and motionless tests which have proved that this Principle is quite a good way for the detecting of the break in the secondary circuit of current transformers.