引入IIR滤波器对换流变增量差动暂态性能的影响分析

通过分析比较特高压直流工程与传统直流工程中换流变保护配置的异同,指出特高压直流工程中换流变保护引入了IIR数字滤波器进行数据预处理。分别从数字滤波器型式及阶数两个角度,利用滤波器辅助设计工具进行了滤波器参数设计,对引入IIR数字滤波器进行数据预处理对换流变及引线大差增量差动保护暂态性能影响进行了仿真分析,仿真结果表明在满足继电保护系统对低通滤波频率特性的要求下,采用4阶巴特沃斯低通滤波器为最优,满足相关规范对其暂态性能要求。

Analysis of the impact of Using IIR filter in Incremental differential protection of converter transformer

Based on the analysis and comparison of protection configuration difference between UHVDC and the traditional HVDC engineering,it is pointed out that the IIR digital filter is used for data preprocessing in converter transformer protection for UHVDC engineering.In this paper,the filter parameter is designed by means of filter aided design tool from two perspectives of filter type and filter order.The effect on transient performance of converter transformer and connecting line incremental differential protection is analyzed through simulation,which is caused by using IIR digital filter for data preprocessing.On the premise of satisfying the low frequency characteristic of relay protection system,simulation results show that the 4-order Butterworth low-pass IIR filter is used as the optimum,which can meet the transient performance requirements of relevant specifications.