超长海底电缆电流差动保护新方案  

New Scheme of Current Differential Protection for Ultra-long Submarine Cable

作　　者：黄玥 范春菊[1] 王国钰 HUANG Yue;FAN Chunju;WANG Guoyu(School of Electronic Information and Electrical Engineering,Shanghai Jiao Tong University,Minhang District,Shanghai 200240,China)

机构地区：[1]上海交通大学电子信息与电气工程学院,上海市闵行区200240

出　　处：《现代电力》2024年第3期584-592,共9页Modern Electric Power

基　　金：国家重点研发计划(2017YFB0903201)。

摘　　要：海底电缆作为确保海上风电场并网的重要纽带,其分布电容远高于架空线路,产生的电容电流不可忽略。目前的电流差动保护判据由于没有考虑分布电容且受到负荷电流的影响,抗过渡电阻能力较差,在超长海底电缆输电线路上的适用性不高。针对现有保护判据存在的问题,提出一种改进的电流差动保护判据,该改进判据对线路中较大分布电容电流进行了补偿,解决了正常运行以及区外短路时保护误动的问题,并减小了负荷电流对差动保护动作特性的影响,从而提升了抗过渡电阻能力。在PSCAD/EMTDC平台搭建220 kV长距离电缆线路模型,对所提的改进保护方案进行仿真分析,仿真结果表明,所提超长海底电缆电流差动保护新方案在确保区外故障可靠不动作的基础上,显著提高了区内故障的抗过渡电阻能力,是一种比较理想的高压电缆长线路电流差动保护方案。As an important link to ensure the grid connection of offshore wind farms,the distributed capacitance of the submarine cable is much higher than that of overhead lines,so the generated capacitive current cannot be ignored.The existing current differential protection criterion does not consider the distributed capacitance and is affected by the load current,besides,the anti-transition resistance ability is poor.Therefore,it is not highly applicable on ultra-long submarine cable transmission lines.In allusion to the defects in existing protection criterions,an improved current differential protection criterion was proposed,in the improved criterion the larger distributed capacitance current in the transmission line was compensated,so the protection malfunction during both normal operation and external short circuit was resolved,and the impact of load current on the action characteristic of differential protection was reduced,thus,the ability of anti-transition resistance was improved.A 220kV long distance cable line model was built on PSCAD/EMTDC platform to conduct the simulation analysis on the proposed improved protection scheme,simulation results show that on the basis of ensuring inaction under external faults the proposed new current differential protection criterion for ultra long submarine cable significantly improves the ability to resist transition resistance of faults in the area,so it is an ideal current differential protection scheme for the long high-voltage cable line.

关 键 词：长距离电力电缆 电流差动保护 分布电容 过渡电阻 电容电流补偿 

分 类 号：TM773[电气工程—电力系统及自动化]