电流互感器暂态误差对发电机纵差保护影响的对策

Effect and Countermeasure of Transient Error of Current Mutual Induntance Implement to Generator Longitudinal Mistake Protection

讨论了电流互感器的暂态误差对纵差保护的影响,分析了保护用P级电流互感器在暂态过程的技术性能。指出考虑暂态特性的TP级电流互感器虽然可解决纵差保护误动问题,但其造价较高,互感器体积大,安装有困难,特别是大型发电机出口封闭母线很难安装TP级互感器。现有P级电流互感器适当提高制动系数,尽量减小二次负荷,提高额定准确限值系数等,都是行之有效的措施。

This paper discusses the effect of transient error of current transformer to longitudinal protection. And it analysises the technologic capabilities of the protective P current transformer during the transient process. The TP current transformer that suggests the transient characteristic can resolve the mal-operation on longitudinal differencial protection, but it cost much and is difficult to be installed. The cubage of the current transformer is also great. It is particularly difficult to install the TP current transformer in the close busbar of large-scale generator. All of these measures are effective such as increasing the braking coefficient of the P current transformer properly , reducing the quadratic charge and increasing the rated restrictive coefficient etc.