等效瞬时电感算法在Y-Δ接线变压器中的应用  

Application of equivalent instantaneous inductance algorithm to the Y/Δ three-phase transformer

作　　者：金恩淑[1] 刘丽丽[1] 杨明芳[1] 陈韬[1] 

机构地区：[1]东北电力大学电气工程学院,吉林吉林132012

出　　处：《电力系统保护与控制》2008年第20期5-9,14,共6页Power System Protection and Control

摘　　要：对于Y-△接线的三相变压器,等效瞬时电感算法会受到环流的影响,但目前尚没有确切的求取环流的算法,从而影响等效瞬时电感的准确计算进而影响保护的可靠动作。对此,提出一种新的算法,能够准确地计算出△侧绕组的环流,从而既能准确地计算出等效瞬时电感,使其不受△侧绕组内部环流的影响,同时又不会使差动保护存在死区,能够使保护灵敏可靠动作。EMTP仿真结果表明:该算法得到的等效瞬时电感能够准确、有效地识别励磁涌流与内部故障,不需要再测量△侧绕组的相电流,也无需改变CT配置方案,并且适用于超高压和220kV以下的电力变压器,具有工程实际应用价值。To the Y/△ three-phase transformer, the algorithm based on equivalent instantaneous inductance will be influenced by circulation. At present, there is no an accurate method to compute this circulation. Therefore, the accuracy of calculation of equivalent instantaneous inductance is influenced and the reliability of act of protection is also influenced. In this case, a new method is proposed in this paper. It can accurately compute circulation of delta winding, not only can compute the equivalent instantaneous inductance accurately to prevent it from the influence of circulation, but also can avoid the existence of ＂dead zone＂ and can act sensitively for the differential protection. The results of EMTP simulation show that the equivalent instantaneous inductance got by this algorithm can identify the inrush current and internal fault current. The measurement of phase current of delta winding is not needed and it is not necessary to change the configuration plan of current transformer. At the same time, this algorithm is also applied to the power transformer which has ultrahigh voltage or voltage under 220kV and has a practical value in the project.

关 键 词：等效瞬时电感 励磁涌流 变压器差动保护 Y-△接线的三相变压器 环流 

分 类 号：TM407[电气工程—电器]