反时限过载保护精确算法  

Precise algorithm for inverse-time overload protection

作　　者：牟龙华[1] 邢锦磊[1] 

机构地区：[1]同济大学电气工程系,上海200092

出　　处：《电力自动化设备》2008年第6期36-38,43,共4页Electric Power Automation Equipment

基　　金：上海市科学技术委员会资助(04ZR14137)~~

摘　　要：参考IEC反时限过流保护的标准,提出了一种适合微机保护系统采用的反时限保护算法。采用微分方程建立导体发热的连续模型,全面反映了导体温升随电流变化的过程。根据该模型得到的过流保护反时限动作特性曲线,与IEC反时限过流保护的标准一致,验证了所建立导体发热模型的准确性。在连续模型的基础上,经过严密的数学推导,建立了一种可以准确描述电气设备过载升温过程的离散算法模型,该算法物理概念清晰、易于实现。Matlab仿真结果表明,该算法精度高,计算量小。Referring to IEC standard for inverse-time over-current protection,an algorithm of inverse -time protection suitable for microcomputer-based protection system is put forward. A consecutive thermal model is founded with differential equation to perfectly reflect the temperature increase of conductor following current variation. The inverse-time characteristic curve of over-current protection derived from the model is in accord with IEC standard,which verifies its validity. With strict mathematic deduction based on the model,a discrete algorithm model is presented,which accurately describes the process of thermal effect caused by overload. It is clear in physical conception and easy to be realized. Simulation results with Matlab testify its high precision and low calculation load.

关 键 词：反时限 过载 热保护 微机保护 

分 类 号：TM744[电气工程—电力系统及自动化]