电力变压器和应涌流的产生机理及影响因素

Principle and Influencing Factors of Power Transformer Sympathetic Inrush

为鉴别正常运行的变压器是否产生和应涌流,以一台变压器正常运行,另一台与之并联的变压器空投时为研究对象,采用磁链分析法,分析了运行变压器和应涌流的产生机理及变化规律,指出和应涌流的变化具有落后于空载变压器激磁电流的特点,并根据它们出现时的时间差和幅值的变化,提出了利用时差法对和应涌流进行在线监测的观点,经MATLAB仿真验证了理论分析的正确性和在线监测的可行性。据此叙述了采用单片机系统对运行变压器的一次电流及差动电流进行在线监测的具体方法,对变压器的继电保护具有一定的实用价值和促进作用。

To identify weather sympathetic inrush occurs in a normal operating transformer,the generation mechanism and variation of sympathetic inrush was investigated by flux linkage analysis using two parallel transformers,one in normal operation and the other switching on with no load.It is found that the sympathetic inrush lags behind the no-load transformer exciting current.According to their changes in appearing time and amplitude,time difference method is proposed to be a useful method to monitor the inrush on-line.The correctness of the theoretical analysis and the feasibility of the online monitoring were verified by simulation using MATLAB.The concrete method of monitoring the primary current and differential current of the normal operating transformer on-line by single-chip microcomputer is provided to be valuable to transformer relay protection in practice.