电工技术学报2024，Vol.39Issue(7)：2072-2088,17.DOI:10.19595/j.cnki.1000-6753.tces.230157
基于变电站高频滤波边界特性的配电网线模行波选线方法
The Faulty Line Selection Method Using Line Mode Traveling Wave Based on High-Frequency Filtering Characteristics of the Substation Line Boundary in the Distribution Network
摘要
Abstract
Currently,the distribution network system usually adopts a neutral non-effective grounding method.How to accurately select the faulty line has been a problem for a very long time.In recent years,with the widespread application of line selection devices based on the transient-based method,the success rate of fault line selection has improved significantly.However,when high resistance faults and small phase angle grounding faults occur,the weak fault characteristics still easily cause the failure of various existing line selection methods. It should be noted that the above existing transient-based line selection methods are all based on the zero mode traveling waves.The main reason for such consideration is that when the substation busbar is equipped with parallel shunt capacitors,the line mode traveling waves on the normal line is very weak due to the high-frequency filtering effect of the shunt capacitors while zero mode traveling waves are almost unaffected because they cannot loop in an ungrounded capacitor bank.Although the line selection methods based on zero mode traveling waves have achieved good results in practical applications,the following problems still exist:(1)Because zero mode traveling wave attenuates quickly,it may be very difficult to extract the zero mode traveling waves accurately when high resistance fault and small phase angle grounding fault occur at the end of a long feeder.(2)Currently,only two-phase current transformers are installed in many distribution network system,which makes it difficult to obtain zero mode traveling waves.Therefore,the above drawbacks will become a constraint to improve further the performance of the current line selection methods based on the zero mode traveling waves. Inspired by the high-frequency filtering effect of busbar shunt capacitors on line mode traveling waves,this paper skipped the perspective of faulty line selection method design based on zero mode traveling waves and proposes a new method using line mode traveling waves based on the substation boundary characteristics in the distribution network.Firstly,the researches confirm that the smart substation line boundary composed of the electronic voltage transformers,the metal-oxide arresters,and the remaining apparatus's stray capacitance has strong high-frequency filtering characteristics,and its refraction attenuation effect is almost independent of the busbar system operation mode,which is of excellent robustness and can lay a foundation for the design of the proposed line selection method.Then,based on the Teager energy operation,a new line selection criterion is constructed based on the difference of the high-frequency instantaneous energy of the line mode traveling waves between the normal line and the faulty line,which has high sensitivity under the conditions of high resistance faults and small phase angle grounding faults. Finally,the proposed method is based on the PSCAD/EMTDC platform to verify its effectiveness,sensitivity,and reliability.It can accurately identify the fault line and reliably distinguish the busbar fault.Otherwise,the proposed fault line selection method has fast operation speed,strong anti-noise performance,simple algorithm principle,clear physical meaning,no manual threshold setting,and is unaffected by shunt capacitors.It can realize reliable line selection under arc faults and 3 kΩ high resistance faults in the distribution network.Indeed,the proposed line selection method only applies to the smart substation installed with the electronic voltage transformers.But luckily,the smart substation has become the main construction form of the current substation,which provides a practical basis for the wide application of the proposed new line selection method.关键词
配电网/故障选线/线模行波/边界特性/高频瞬时能量Key words
Distribution network/faulty line selection/line mode traveling wave/boundary characteristic/high-frequency instantaneous energy分类
信息技术与安全科学引用本文复制引用
吴宇奇,李正天,林湘宁,黄梓欣,黎钊..基于变电站高频滤波边界特性的配电网线模行波选线方法[J].电工技术学报,2024,39(7):2072-2088,17.基金项目
国家重点研发计划(2021YFB2401000)和国家电网有限公司总部科技项目(SGSDDKK00WJJS2200105)资助. （2021YFB2401000）
