差动保护电流互感器“和电流”接法的问题研究

Research of the Problem of Accessing the Secondary Side of Current Transformer into Protection Device in the Way of Sum Current in Differential Protection

差动保护是变压器、母线、线路经常采用的主保护,必须保证能够准确快速地切除故障并防止误动。以变压器、母线、3/2线路差动保护为研究对象,分析了当差动保护电流互感器二次侧以"和电流"方式接入保护装置时,保护区内、区外发生故障时差动保护的动作情况,讨论了导致差动保护误动的原因,并提出了对策。

Differential protection is the primary protection for the transformer,bus and line,and it should be ensured that the protection can remove the fault accurately and rapidly without malfunction.In this paper,studies transformer,bus and 3/2 line differential protection,analyzes the reaction of differential protection to faults happened in or out of the area,where the protection should act while the secondary sides of current transformer are connected into the protection device in the way of sum current in differential protection,and discusses the causes that result the protection may malfunction when the fault happens outside of the protection area.In the end,the countermeasures are proposed.