考虑电压跌落差异的有源配电网功率差动保护  

Power Differential Protection for Active Distribution Networks Considering Voltage Drop Differences

作　　者：罗国敏[1] 谭颖婕 吴梦宇 和敬涵[1] 唐平舟 Luo Guomin;Tan Yingjie;Wu Mengyu;He Jinghan;Tang Pingzhou(School of Electrical Engineering Beijing Jiaotong University,Beijing 100044 China;Guangxi Power Grid Co.Ltd,Nanning 530000 China)

机构地区：[1]北京交通大学电气工程学院,北京100044 [2]广西电网有限责任公司,南宁530000

出　　处：《电工技术学报》2025年第4期1287-1306,共20页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(U23B6007)。

摘　　要：随着大量逆变型分布式电源的接入,配电网的系统结构、潮流方向和运行方式等将发生变化,传统的单端保护显然难以满足需求。差动保护以其优良的选择性和灵敏性在新型配电网中更具优势。然而,对于中低压配电网,分布式电源和负荷多采用T型方式(即T接)接入线路,这种方式带来的不可观测性破坏了原有的故障特性,使得保护难以兼顾选择性和灵敏性。为解决这一问题,结合分布式电源在低电压穿越期间的输出特性,通过挖掘配电线路两端故障分量正序差动功率的幅值和方向特征,提出一种故障分量有功功率比幅判据,解决了由T接分支导致的正常不平衡电流与故障电流难以辨识的问题。另外,为了解决低电压跌落故障下故障分量特征不显著的问题,通过两侧电气量较为准确地推断各分支功率来构建功率差动判据,从而提高了保护的灵敏度。计算这两个判据的保护范围,提出相应的配合方法。通过测试验证,该保护能够可靠地识别区内、区外故障,有效地提高了差动保护在含有T接分支的配电网中的适应性。With the integration of a large number of inverter-interfaced distributed generators,the system structure,power flow direction,and operation mode of the distribution network have changed,and traditional single-end protection is rugged to meet the requirements.Differential protection has advantages in new distribution networks due to its excellent selectivity and sensitivity.However,for medium voltage distribution networks,because distributed power sources and loads are mainly connected through T-connected,the unobservability damages the original fault characteristics,making it difficult to balance selectivity and sensitivity in protection.This paper proposes a power differential protection method for distribution networks with T-connected IIDGs and loads.Firstly,considering the output characteristics of inverter-interfaced distributed generators during low voltage ride through,an amplitude comparison criterion using fault component positive sequence is proposed.When a near-end fault without grounding resistance occurs,the voltage drop of the line is high,and the fault component characteristics are significant.By mining the amplitude and directional characteristics of the positive sequence differential power of the fault components at both ends of the distribution line,a protection strategy is constructed to adapt to high-voltage drop faults.Besides,the dead-zone problem of power differential protection is solved.Secondly,regarding the insignificant fault component characteristics,a power differential criterion is constructed by approximately calculating the power of each T-connected IIDG or load through the electrical quantities at both ends to improve protection sensitivity.The protection ranges of these two criteria are estimated,and protection setting coordination is proposed.This protection can identify faults inside and outside the zone,effectively improving the adaptability of differential protection in distribution networks with T-connected IIDGs and loads.Finally,a simplified simulation model of a 10 kV d

关 键 词：有源配电网 分布式电源接入 电压跌落 不可测分支 

分 类 号：TM773[电气工程—电力系统及自动化]