基于网格曲线频率特性识别励磁涌流  

Identify inrush current based on frequency characteristics of grille curve

作　　者：马静[1] 王增平[1] 王政军[2] 

机构地区：[1]华北电力大学电力系统保护与动态安全监控教育部重点实验室,北京102206 [2]河北省电力建设第二工程公司,河北石家庄050041

出　　处：《电力自动化设备》2008年第7期29-32,36,共5页Electric Power Automation Equipment

基　　金：高等学校博士学科点专项科研基金项目(20060079009)~~

摘　　要：基于励磁涌流明显的奇异特征和短路电流近似正弦波的特点,提出了一种利用网格分形原理识别励磁涌流和内部故障电流的新方法。介绍了网格分形的基本概念和计算方法,利用该方法在提取突变和识别正弦波的同时,形成各自的标准化网格曲线。对网格曲线进行标准化处理,可使判据定值的选取更具普遍性。在此基础上,提出了一种基于标准化网格曲线基频分量与直流分量幅频比的新型变压器保护方案:网格曲线在涌流时变化剧烈,故障时恒为常数,因此其在频域上必然表现为前者的幅频比明显高于后者,据此可构成变压器保护判据。动模试验分析结果表明新原理能够有效区分励磁涌流和内部故障电流,对轻微匝间故障也有足够的灵敏度。For the waveform of inrush current distorts seriously,while that of fault current keeps nearly sinusoid,an algorithm using grille fractal is presented for distinguishing between them. The grille fractal concept and its calculation method are described and the normalized grille curve for extracting singularity and identifying sinusoidal characteristics is developed. The normalization of grille curve makes the threshold more universal, with little relation with the parameters of transformer. A protective scheme based on the ratio of fundamental frequency component to direct current component of the normalized grille curve is proposed ,which fluctuates periodically for inrush current but keeps almost constant for internal fault. The normalized grille curve＇s amplitude frequency ratio of the former is larger than that of the latter,which can be used as a protective criterion. The experimental results indicate that the proposed principle is reliable and sensitive to low level turn-turn faults.

关 键 词：变压器差动保护 网格曲线 励磁涌流 内部故障 

分 类 号：TM771[电气工程—电力系统及自动化]