浅谈配电线路差动保护方案设计

Design of Differential Protection Scheme for Distribution Lines

摘要: 配电线路的安全运行是保证电力系统安全运行的重要条件，当配电线路发生故障时，快速、准确地切断和隔离故障线路并保持非故障线路的持续运行既是保证供电可靠性的要求，也是提高电力系统安全稳定运行必不可少的前提条件。基于基尔霍夫定律的电流差动保护无论对于何种形式的配电线路都是一种简单、可靠、选择性强的保护形式。首先，本文对目前线路保护的研究和实际应用情况进行了讨论和分析，比较了常用线路差动保护的实现原理和实现条件及优缺点。其次，针对常规相量电流差动保护易受正常负荷电流和故障过渡电阻影响的缺点，同时为加快差动保护的动作速度，本文将相间工频变化量差动保护与采样值差动保护结合起来，提出了一种基于相电流采样值变化量相间差的小电流接地保护的新方法，并对此保护方法的原理、判据、动作特性等作了讨论和分析。

Abstract: The safe operation of distribution line is an important condition to ensure the safe operation of power system. when the distribution line fails, cutting off and isolating the fault lines quickly and accurately and keeping the continuous operation of the Fei line is not only the requirement of en-suring the reliability of power supply, but also the essential prerequisite to improve the safe and stable operation of the power system. The current differential protection based on the kirchhoff law is a simple, reliable and selective protection form for any form of distribution line. First of all, this paper discusses and analyzes the current research and practical application of line protection, and compares the realization principle and realization condition, advantages and disadvantages of common line differential protection. Secondly, according to the conventional phase current diffe-rential protection is vulnerable to normal load current and fault transient resistance, at the same time, in order to speed up the movement speed of differential protection, this paper combines the alternating current differential protection with sampling value differential protection, proposes a new method of small current grounding protection based on the phase current sampling value change, and discusses and analyzes the principle, criterion and action characteristics of this pro-tection method.