基于电流上升速率的柔性直流环网输电线路反时限保护  

Inverse-time Protection for Flexible DC Transmission Lines in Ring Network Based on Current Rising Rate

作　　者：束洪春[1,2] 安娜[1,2] 代月 薄志谦 SHU Hongchun;AN Na;DAI Yue;BO Zhiqian(Faculty of Electric Power Engineering,Kunming University of Science and Technology,Kunming 650500,China;Faculty of Mechanical and Electrical Engineering,Kunming University of Science and Technology,Kunming 650500,China)

机构地区：[1]昆明理工大学电力工程学院,云南省昆明市650500 [2]昆明理工大学机电工程学院,云南省昆明市650500

出　　处：《电力系统自动化》2023年第6期206-215,共10页Automation of Electric Power Systems

基　　金：国家自然科学基金资助项目(52037003,51807085);云南省重大科技专项计划资助项目(202002AF080001)。

摘　　要：针对柔性直流环网远端高阻接地故障保护灵敏度低及相邻非故障线路干扰严重问题,提出一种基于电流上升速率的反时限保护方法。文中通过计算故障电流及其上升速率初始值,分析比较了故障线路和非故障线路的本质差异。采用滑动时窗使得到的电流上升速率最接近实际,并具有一定的抗干扰能力。应用反时限方法,通过设置较低的启动值,使得高阻故障时保护能够可靠延时动作,设置合适的瞬时动作值保障了较低过渡电阻情况下能够快速切除故障,方法的反时限特性排除了非故障线路和非故障极的干扰。最后,分析了线路分布电容对电流上升速率的影响,并提出了相应的修正方法。大量仿真实验表明,所提方法具有高灵敏性、选择性和可靠性,并具有强耐受过渡电阻能力。Aiming at the problems of the low sensitivity of high resistance grounding fault protection at the far end of flexible DC ring network and serious interference of adjacent non-fault lines, an inverse-time protection method based on the current rising rate is proposed. By calculating the initial value of the fault current and its rising rate, the substantial difference between the fault line and the non-fault line is analyzed and compared. The sliding time window is used to make the current rising rate closest to the actual value, and has certain anti-interference ability. The inverse-time limit method is applied to ensure the reliable delay operation of the protection in case of high-resistance fault by setting a lower starting value. Setting an appropriate instantaneous operation value ensures that the fault can be quickly removed under the condition of low transition resistance. The inverse-time limit characteristic of the method eliminates the interference of non-fault lines and non-fault poles. Finally, the influence of the line distributed capacitance on the current rising rate is analyzed, and the corresponding correction method is proposed. A large number of simulation experiments show that the proposed method has high sensitivity, selectivity and reliability, and has strong ability to withstand transition resistance.

关 键 词：高压直流输电 柔性直流电网 电流上升速率 反时限保护 滑动时窗 

分 类 号：TM721.1[电气工程—电力系统及自动化] TM773