边界保护的理论基础 第一部分 故障暂态分析

近年来 ,基于单端暂态量的输电线路保护新原理不断涌现出来 ,这种利用故障产生的暂态分量是否透过线路边界的特征构成的具有全线速动的保护称为边界保护 ,边界保护成立的条件有两个 ,其一是区内外故障时 ,暂态分量存在差异 ;其二是该差异有规律性 ,可以被提取并且很明显 ,足以构成保护判据。基于这个目的 ,对输电线路区内外故障时的暂态分量的频谱进行了分析 ,发现并提取该差异 ,为边界保护的研究提供理论基础。全文共分为三个部分 ,第一部分是故障暂态分析 ;第二部分是线路边界折反射系数的频谱分析 ;第三部分是区内外故障暂态分量频谱差异的提取和EMTP仿真。本文是第一部分 ,利用网格法对输电线路在区内、正方向区外和反方向三个典型位置故障时的暂态分量进行分析和比较 ,并发现了不同故障方向时暂态分量的差异和正方向区内外故障的差异 ,前者的差异主要体现在线路边界的反射系数的频谱特征中 ,后者主要体现在线路边界的透射系数的频谱特征中

The basic theories of boundary protection Part I Fault transient analysis

In recent years,novel protection principle for transmission line based on single-ended fault induced transients,we called Boundary Protection,have been developed using the high frequency band components.Two conditions are required for constructing the criterion of Boundary Protection:there must exist different characters between internal and external faults,and the information of different characters can be extracted largely enough to construct criterion. For such purpose, the spectrum of fault-induced transients is analyzed here. The whole paper comprises three parts: fault transient analysis;reflective and refractive coefficient of line boundary spectrum analysis;the extraction of fault information and EMTP simulation tests.This paper is the first part,which theoretically analyzed the fault transients at single end and two different characters are discovered:the different character between positive and reverse directional fault is controlled by the reflective coefficient,and that between the internal and external fault at positive direction is controlled by refractive coefficient of line boundary.