变压器电流差动保护改进方法  

An Improved Method of Transformer Differential Protection

作　　者：金恩淑[1] 刘丽丽[1] 姜龙澈 薄志谦[3] 

机构地区：[1]东北电力大学电气工程学院,吉林省吉林市132012 [2]韩国全北大学,全州 [3]英国AREVA公司,斯塔福德

出　　处：《电力系统自动化》2008年第9期47-51,共5页Automation of Electric Power Systems

摘　　要：针对一种适用于Y,d或D,y接线变压器的电流差动保护改进方法进行了研究,该方法采用修正的差动电流来补偿励磁电流和剩磁的影响,制动电流与传统比率式差动保护相同。变压器铁心饱和前,采用一、二次侧相电流差作为差动电流;饱和后,则计算磁化电流来修正差动电流。该保护不受谐波和剩磁影响,不需要附加制动或闭锁技术。通过EMTP仿真将该保护与传统谐波制动原理的差动保护进行了比较,结果表明,励磁涌流和过励磁时,该保护能够保证不误动;内部故障时则不会像传统谐波制动原理的差动保护受制动信号影响而延迟动作。动模实验进一步验证了该保护的可行性和优越性。An improved current differential protection method for the Y, d or D, y connected transformers is presented, in which a new differential current is introduced to compensate the effects of the exciting current and the remnant flux. By this method, the differential current between the primary and secondary winding is used during the period prior to saturation, and a modified differential current which takes into consideration of the calculated magnetizing current is adopted after saturation. Using EMTP simulation, the performance of the proposed method is compared with that of the conventional current differential algorithm with harmonic blocking. Test results show that the proposed method remains stable under severe magnetic inrush and over-excitation conditions while offering fast operation speed for internal fault condition. In contrast, the operation speed of the conventional harmonic blocking method can be significantly delayed by its restraining signal. The feasibility and superiority of this method is further proved by the experiment using a real transformer. The new protection algorithm is not affected-by the harmonic and the level of remnant flux and does not require additional restraining or blocking signal to maintain stability.

关 键 词：差动保护 磁化电流 环流 励磁涌流 谐波制动 

分 类 号：TM772[电气工程—电力系统及自动化]