电工技术学报2024，Vol.39Issue(8)：2360-2370,11.DOI:10.19595/j.cnki.1000-6753.tces.231576
基于固态断路器主动注入式直流故障测距方法
Active Injection DC Fault Location Method Based on Solid State Circuit Breaker
摘要
Abstract
Accurate and reliable fault location technology is crucial for DC fault repair and recovery with the rapid development and widespread application of DC distribution networks.The passive traveling wave ranging method has the issues of limited energy and insufficient traveling wave characteristic information.The traditional active traveling wave ranging method partially addresses these issues.However,the effects of line wave speed stability and sampling frequency are susceptible.This paper proposes an active injection DC fault location method based on a solid-state circuit breaker(SSCB).First,the SSCB is utilized to interrupt and actively inject signals with different pulse widths.The time difference between the first end of the injected pulse and the first end of the reflected wave is detected as the time interval of injection waveform propagation.This approach reduces errors caused by sampling frequency limitations.Then,the voltage line modulus of the cable line is extracted as the detection quantity,effectively weakening the coupling effect between the positive and negative lines and providing a stable wave speed measurement.Finally,based on the wavelet transform principle,an improved adaptive modulus maximum approach is proposed to detect the first and last moments of the pulse accurately.This approach also mitigates the impact of noise and transition resistance on ranging accuracy. The simulation results show that the proposed method achieves high fault location accuracy for single-pole ground and bipolar short-circuit faults in a distribution network with a total line length of 10 km.The fault location accuracy is less than 0.55%.Even at a high sampling frequency of 80 kHz in 10 km DC distribution lines,the relative error of fault location remians within 1.14%,which reduces dependence on sampling frequency and enhances the robustness of the method.Moreover,the method exhibits resilience to noise interference at different signal-to-noise ratios.With signal-to-noise ratios of 40 dB,20 dB,and 5 dB,the fault location accuracy with a relative error of less than 0.67%is consistently achieved.However,when the signal-to-noise ratio drops below 5 dB,the impact of noise on ranging and positioning increases,posing challenges for achieving high-precision fault location. The following conclusions can be drawn from the simulation analysis.(1)The proposed method achieves high-precision fault location under single-pole ground or inter-pole short-circuit faults in DC distribution networks.It does not require additional equipment and is simple to operate.(2)A detection method is introduced to measure the average time difference between the end of the transmitted pulse wave and the end of the reflected wave of pulses with different widths.This method reduces the dependence on sampling accuracy caused by the traveling wave ranging method.(3)An improved adaptive modulus maximum method is proposed based on the principle of wavelet transform.The method adaptively sets the threshold value for modulus maximum selection based on fault line parameters,enhancing the resistance to transition resistance and noise in the distance measurement method.(4)The proposed single-ended ranging method does not need communication,which is suitable for applications without communication functions.However,it has the limitation of a dead zone in near-end ranges.Future research will focus on addressing this issue.关键词
直流配电网/故障测距/固态断路器/主动注入/自适应模极大值Key words
DC distribution network/fault location/solid-state circuit breaker/active injection/adaptive modulus maximum分类
信息技术与安全科学引用本文复制引用
王伟,帅智康,李杨,何梨梨,方辰晨..基于固态断路器主动注入式直流故障测距方法[J].电工技术学报,2024,39(8):2360-2370,11.基金项目
国家自然科学基金项目(52125705)、博士后面上资助项目(2021M701137,2022M721082)、湖南省青年基金项目(2022JJ40066)、湖南省重点研发计划项目(2023GK2010)和湖南省研究生科研创新项目(CX20220394)资助. （52125705）
