二次回路异常引起变压器差动保护误动的研究

Research on Malfunction of Transformer Differential Protection Caused by Secondary Circuit Abnormality

变压器差动保护由于要进行相位校正及幅值平衡,生产现场经常出现由于CT极性接反、CT接线组别错误、定值中平衡系数计算整定错误等人为因素导致变压器差动保护误动情况。通过对变压器差动保护进行相位校正的"外转角"和"内转角"方式的特点和要求进行对比,引用实例对生产现场常见的二次接线及整定错误情况进行分析研究,找出导致接线及整定错误的原因。同时针对"外转角"常规接线的错误情况给出差动保护二次接线修正方案,制定生产现场检查与发现二次接线错误的方法,并通过实例进行分析,提出生产现场防止二次接线及整定错误的措施。这些措施对避免因二次回路异常引起变压器差动保护误动有现实指导意义。

Due to the phase correction and amplitude balance of the transformer differential protection, Misoperation of transformer differential protection caused by human factors such as CT polarity reversal, CT wiring group error, balance value setting error often occur at the production site. This article compares the characteristics and requirements of the ＂outer corner＂ and ＂inner comer＂ modes for phase correction of transformer differential protection, analyzes and studies the common secondary wiring errors and setting errors in the production site with examples, and points out the causes of wiring errors and setting errors. It proposes correction methods of secondary wiring for differential protection for the error condition of the ＂outer comer＂ conventional wiring. It develops methods for checking and finding secondary wiring errors at the production site and analyzes it with example. This article proposes measures to prevent secondary wiring and setting errors at the production site. These measures have practical guiding significance for avoiding the misoperation of transformer differential protection caused by secondary circuit abnormalities.