采用自适应数据窗电流的励磁涌流鉴别方法  

A Magnetizing Inrush Identification Method Applying Adaptive Data-window Currents

作　　者：王业[1] 陆于平[1] 蔡超[1] 黄涛[1] 

机构地区：[1]东南大学电气工程学院,江苏省南京市210096

出　　处：《中国电机工程学报》2014年第4期702-711,共10页Proceedings of the CSEE

基　　金：国家自然科学基金项目(50977012;51377022)~~

摘　　要：为进一步提高励磁涌流鉴别的速度及精度,尤其是快速检测出带故障合闸时的涌流,使该情况下保护的开放时间缩短至一个周期内,提出一种采用自适应数据窗电流的励磁涌流鉴别方法。该方法在时间轴上下分别设置阈值??,利用该阈值及某段采样电流的极大值或极小值,确定出自适应数据窗的起点及终点;并在选取出的自适应数据窗内,根据采样间隔及数据窗长度,以此极值向左向右虚拟出一条标准正弦曲线,计算出该正弦曲线与原采样电流之间的相关系数,进而实现保护的闭锁和开放。相比先前励磁涌流鉴别方法,该方法能够更大程度地区分出涌流及故障电流,在变压器发生励磁涌流时,结合所提出的辅助加速闭锁判据,算法最迟在空载合闸后一个周期时闭锁差动保护;在内部故障时不误闭锁差动保护;还能在变压器带故障空载合闸时,快速开放差动保护;且具有较强的抗互感器饱和能力。动模试验验证了该方案的有效性及优越性,在变压器带1.7%匝间短路故障空载合闸时,算法于合闸后20 ms开放差动保护。To improve the speed and precision of inrush identification further, especially to shorten the time of opening protection to one cycle when switching into a transformer with a fault, a novel magnetizing inrush identification method applying adaptive data-window currents was proposed. This method set threshold ±ε above and below time-axis respectively. The starting and ending point of the adaptive data window can be determined according to the maximum or minimum value of sample currents and this threshold. The maximum or minimum value was used to simulate a standard sine curve respectively in the left and right direction according to the sampling interval and data window length which had been chosen out, then the correlation between the standard sine curve and original sampling current was calculated, thereby the protection could be blocked and opened according to the correlation. Compared with previous inrush identification methods, this method can discriminate between inrush and fault current better. When magnetizing inrush occurs, the algorithm can block differential protection after one cycle at the latest from switching on an unloaded transformer along with the auxiliary acceleration blocking criterion. The algorithm can also make the differential protection not be blocked in an internal fault and be opened quickly when switching on an unloaded transformer with a fault. Moreover, it had a strong ability to overcome the saturation of current transformer. Dynamic simulation experiment verifies its validity and superiority. The algorithm will open differential protection after 20 ms from switching on an unloaded transformer with 1.7%turns being short-circuited.

关 键 词：差动保护 变压器 励磁涌流 自适应数据窗 饱和 故障 

分 类 号：TM77[电气工程—电力系统及自动化]