超高压输电线路单端暂态量保护元件的频率特性分析

为有效利用故障暂态量中含有的丰富故障信息，需要对其在输电系统上的传播特性进行深入的分析。为此从输电系统的频域模型着手，全面分析了输电线路、母线和阻波器的频率特性，指出母线对地等效电容和阻波器的阻抗显著地不等于线路的特性阻抗，由此提出"线路边界"的概念。通过对线路边界的透、反射系数的进一步分析发现：暂态信号的高频段(特别是阻塞频带)穿越线路边界时将大为衰减，而低频段(1~10kHz)几乎不衰减；为弱化线路的传输影响而突出线路边界的作用，宜选用100kHz以下的信号分量。文中的分析结果对其他行波或暂态量的应用研究具有参考价值。

Single-Ended Transient-based Protection for EHV Transmission Lines Basic Theory

Study on characteristic of transmission system in detail is important to effectively use fault transient components, which contain abundant fault information. The paper applies frequency domain model of transmission system to analyze the frequency characteristics of transmission line, busbar and line trap. Then presents that the surge impedance of busbar capacitance and line trap is different from transmission line, and based on which proposes the concept 'line boundary'. Through discussing further the reflective and refractive coefficients of line boundary, the features of line boundary are as follows: the attenuation of high frequency band (especially in band of line trap) of transient components generated by fault through line boundary is obvious, whereas the low frequency band (1~10kHz) components are hardly influenced. Moreover, the transient components below 100kHz should be adopted in purpose of outstanding the line boundary and weakening the transmission influence of transmission line. The paper is significant for other traveling-wave or transient-based protection researches.