考虑分布式电源稳定助增效应的电压修正反时限过电流保护方案  

A Voltage Correction based Inverse-time Overcurrent Protection Scheme Considering Distributed Generation Stable Infeed Effect

作　　者：喻锟[1] 林湘宁[1] 李浩[1] 赵航[1] 李正天[1] 黄景光[2] 薄志谦[3] 

机构地区：[1]强电磁工程与新技术国家重点实验室(华中科技大学),湖北省武汉市430074 [2]三峡大学电气信息学院,湖北省宜昌市443002 [3]许继集团有限公司,河南省许昌市461000

出　　处：《中国电机工程学报》2018年第3期716-726,共11页Proceedings of the CSEE

基　　金：国家自然科学基金项目(51477090,51577077);国网湖北省电力公司科技项目(SGTYHT/15-JS-191)~~

摘　　要：为解决由于分布式电源（distributed generation,DG）助增效应导致传统保护方案难以同时满足选择性和灵敏性要求的难题,从理论上揭示DG接入前后反时限过电流保护动作行为特性随故障点位置移动的变化规律,分析DG接入对反时限过电流保护性能造成的影响,提出一种具有高灵敏性的电压修正反时限过电流（voltage correction based inverse-time overcurrent,VCITO）保护方案,利用故障下电网电压的自然分布与测量电压随故障位置移动的变化规律,构造电压修正因子与电压梯度指数对反时限特性曲线进行修正。VCITO保护方案基于保护本地信息整定动作时间,在确保保护选择性的同时实现速动性最优化。利用PSCAD/EMTDC建立典型35k V含DG电网模型对VCITO保护方案进行验证,仿真结果表明该方案能有效解决传统反时限过电流保护在DG接入场景中存在的选择性失配与速动性弱化问题,且具有较强的灵敏性。To solve the problem that traditional protection scheme can hardly satisfy the requirements of both coordination and sensitivity with distributed generation（DG） infeed effect, the operating behavior characteristics of inverse-time overcurrent protection with the changing of fault location with and without DG connection were revealed. The impacts of DG to the performance of inverse-time overcurrent protection were analyzed. A voltage correction based inverse-time overcurrent（VCITO） protection method with high sensitivity was proposed in this paper. Voltage correction factor and voltage correction gradient exponent, which are constructed based on the voltage natural distribution under fault and the change law of measuring voltage with the changing of fault location, was used to correct the inverse-time characteristic curve. The operating time of VCITO protection was obtained based on local information and it can ensure the coordination meanwhile the optimization of operating speed. A typical 35 k V model with DG was established in PSCAD/EMTDC and the simulation results proved that VCITO protection can solve the coordination and operating speed problems with DG connection and its sensitivity is high.

关 键 词：分布式电源 保护选择性 电压修正反时限过电流保护 电压修正因子 电压梯度指数 

分 类 号：TM77[电气工程—电力系统及自动化]