一种防止外部故障切除后变压器差动保护误动的新算法  

A new algorithm to prevent the mal-operation of transformer differential protection after removing external fault

作　　者：金恩淑[1] 孙世勇[1] 齐正[2] 吴颖[1] 陈险峰[1] 戈政[1] 

机构地区：[1]东北电力大学电气工程学院,吉林吉林132012 [2]清华大学电机系,北京100084

出　　处：《电力系统保护与控制》2011年第12期27-30,共4页Power System Protection and Control

摘　　要：外部故障切除后变压器差动保护误动时有发生,目前主要通过改变比率制动的动作区与制动区来防止误动,却给快速切除转换性故障带来不利影响。对差流的谐波进行了详细的仿真分析,依据误动期间三次谐波含量比二次谐波含量大的特点,提出了一种防止外部故障切除后变压器差动保护误动的新算法。该算法在二次谐波制动的差动保护基础上,利用差流中二次谐波和三次谐波占基波的比例构成新的制动判据。通过大量仿真试验,表明该算法简单易行,既能有效防止外部故障切除后变压器误动,也能迅速切除外部故障切除后的转换性故障。The mal-operation of the transformer differential protection occasionally takes place after external fault being removed.At present,the mal-operation is prevented by means of changing the acting area and braking area of differential protection,which adversely affects the clear of transitional fault.This paper analyses the differential current harmonic component by simulation,a new algorithm is proposed according to the features that the triple frequency harmonic is greater than the second harmonic in the period of the mal-operation.The new algorithm is based on the differential protection of the second harmonic braking,and the new braking criterion is presented using the rate of the second harmonic and the triple frequency harmonic in the fundamental harmonic.Simulation results show that the new algorithm is simple and effective,can avoid the mal-operation,and clear transformer transitional fault quickly.

关 键 词：变压器 差动保护 CT饱和 三次谐波 转换性故障 

分 类 号：TM407[电气工程—电器]