Abstract：Power electronic transformer with cascaded H-bridge (CHB-PET) can realize the flexible interconnection of AC/DC microgrid and renewable energy sources such as energy storage devices and DC loads. In a practical project, CHB-PET is connected to different bus segments through two short leads that are standby for each other. Considering the fault occurring AC side of CHB-PET, the spare short lead needs to be put into operation quickly to realize the rapid recovery of power supply. However, the conventional scheme cannot distinguish whether there is a fault before the spare short lead is put into operation, and there is a risk of connecting the faulty short lead. To solve this problem, this paper proposes a scheme based on the cooperative control of CHB-PET and DC microgrid, which achieves safe input of short leads by actively injecting characteristic voltage. Firstly, CHB is blocked to achieve fault isolation after fault occurring. The energy storage device is switched to DC voltage control mode, maintaining the DC bus voltage and ensuring the normal operation of DC microgrid load and other equipment. Secondly, CHB is unlocked and switched to the U/f control. CHB-PET can inject characteristic voltage into the spare line to detect whether there is a fault point in the line. Furthermore, a fault detection method considering the current imbalance factor is proposed to reduce the time required for fault detection, so as to realize the rapid and safe investment of spare short lead. The verification results on PSCAD/EMTDC simulation platform show that the scheme based on characteristic voltage injection can give accurate detection results when the spare line is fault-free. When three-phase fault, phase-phase fault, double-phase to ground fault and single-phase to ground fault occur in the spare line, the transition resistance of the phase-to-phase fault is 200 Ω, and the transition resistance of the ground fault is 300 Ω. The proposed scheme can also give accurate detection results. Through the simulation verification and experimental verification of the proposed scheme in different scenarios, the consistent results are obtained, which confirms the accuracy of the simulation model and the feasibility of the proposed scheme. Through the simulation analysis, the following conclusions can be drawn: (1) The scheme uses the CHB-PET ontology to inject characteristic voltage with controlled amplitude and frequency into the standby line. According to the difference of electrical characteristics of the standby line in different scenarios, proposed scheme can accurately detect whether there is a fault in the standby line. (2) In three stages of the proposed scheme, the collaborative control of CHB-PET and DC microgrid energy storage device is used to ensure the normal operation of each equipment in the DC microgrid after the AC short lead fault, which is conducive to the rapid recovery after the fault. (3) In the fault detection stage of spare short lead, the fault detection criterion is constructed by using the product of the characteristic current imbalance factor and the current integral value. Compared with the direct use of the current integral value, the fault detection time under high resistance fault is reduced and the protection action speed is improved.
郑涛, 郭勇帆, 杨毅. 基于协同控制的级联型电力电子变压器备用交流短引线故障检测及安全投入方案[J]. 电工技术学报, 2025, 40(8): 2668-2678.
Zheng Tao, Guo Yongfan, Yang Yi. Fault Detection and Safety Investment Scheme of Power Electronic Transformer with Cascaded H-Bridge Backup AC Short Lead Based on Cooperative Control. Transactions of China Electrotechnical Society, 2025, 40(8): 2668-2678.
[1] 高范强, 李子欣, 李耀华, 等. 面向交直流混合配电应用的10 kV-3 MV·A四端口电力电子变压器[J]. 电工技术学报, 2021, 36(16): 3331-3341. Gao Fanqiang, Li Zixin, Li Yaohua, et al.10 kV-3 MV·A four-port power electronic transformer for AC-DC hybrid power distribution applications[J]. Transactions of China Electrotechnical Society, 2021, 36(16): 3331-3341. [2] 李勇, 凌锋, 乔学博, 等. 基于网侧资源协调的自储能柔性互联配电系统日前-日内优化[J]. 电工技术学报, 2024, 39(3): 758-773, 923. Li Yong, Ling Feng, Qiao Xuebo, et al.Day-ahead and intra-day optimization of flexible interconnected distribution system with self-energy storage based on the grid-side resource coordination[J]. Transactions of China Electrotechnical Society, 2024, 39(3): 758-773, 923. [3] 何晓坤, 胡仁杰, 陈武. 一种适用于新能源中压直流汇集的无环流零电流软开关三电平谐振式复合全桥变换器[J]. 电工技术学报, 2023, 38(19): 5274-5287. He Xiaokun, Hu Renjie, Chen Wu.A novel circulating current free zero current switching three-level resonant composite full bridge converter for new energy medium voltage DC collection system[J]. Transactions of China Electrotechnical Society, 2023, 38(19): 5274-5287. [4] 徐展鹏, 梁远升, 李海锋, 等. 柔性互联配电网故障恢复的云边协同优化算法[J]. 电力系统自动化, 2023, 47(18): 171-184. Xu Zhanpeng, Liang Yuansheng, Li Haifeng, et al.Cloud-edge collaborative optimization algorithm for fault restoration of flexible interconnected distribution network[J]. Automation of Electric Power Systems, 2023, 47(18): 171-184. [5] 王怡, 杨知方, 余娟, 等. 考虑可靠性需求的配电网多种设备统一优化配置[J]. 电工技术学报, 2023, 38(24): 6727-6743. Wang Yi, Yang Zhifang, Yu Juan, et al.A unified optimal placement method for multiple types of devices in distribution networks considering reliability demand[J]. Transactions of China Electrotechnical Society, 2023, 38(24): 6727-6743. [6] 张博, 马梓耀, 王辰, 等. 含光储充一体化电站的城市交直流混合配电网韧性提升策略[J]. 电力系统自动化, 2023, 47(12): 28-37. Zhang Bo, Ma Ziyao, Wang Chen, et al.Resilience improvement strategy for urban AC/DC hybrid distribution network with photovoltaic-storage-charging integrated station[J]. Automation of Electric Power Systems, 2023, 47(12): 28-37. [7] 许寅, 和敬涵, 王颖, 等. 韧性背景下的配网故障恢复研究综述及展望[J]. 电工技术学报, 2019, 34(16): 3416-3429. Xu Yin, He Jinghan, Wang Ying, et al.A review on distribution system restoration for resilience enhancement[J]. Transactions of China Electrotechnical Society, 2019, 34(16): 3416-3429. [8] 马伟明. 关于电工学科前沿技术发展的若干思考[J]. 电工技术学报, 2021, 36(22): 4627-4636. Ma Weiming.Thoughts on the development of frontier technology in electrical engineering[J]. Transactions of China Electrotechnical Society, 2021, 36(22): 4627-4636. [9] Chen Zhengyu, Yu Zhanqing, Zhang Xiangyu, et al.Analysis and experiments for IGBT, IEGT, and IGCT in hybrid DC circuit breaker[J]. IEEE Transactions on Industrial Electronics, 2018, 65(4): 2883-2892. [10] 赵楠, 郑泽东, 刘建伟, 等. 级联H桥变换器IGBT开路故障分析与冗余方法研究[J]. 电工技术学报, 2023, 38(6): 1608-1619. Zhao Nan, Zheng Zedong, Liu Jianwei, et al.IGBT open-circuit fault analysis and fault-tolerant method for cascaded H-bridge converter[J]. Transactions of China Electrotechnical Society, 2023, 38(6): 1608-1619. [11] Zhang Fan, Mu Longhua, Guo Wenming.An integrated wide-area protection scheme for active distribution networks based on fault components principle[J]. IEEE Transactions on Smart Grid, 2019, 10(1): 392-402. [12] Muda H, Jena P.Superimposed adaptive sequence current based microgrid protection: a new tech-nique[J]. IEEE Transactions on Power Delivery, 2017, 32(2): 757-767. [13] Zhang Zhihua, Crossley P, Xu Bingyin, et al.Sequence current component and its power direction-based improved protection for spot network with DERs[J]. IET Generation, Transmission & Dis-tribution, 2017, 11(7): 1634-1644. [14] Zhang Qian, Qi Zhenxing, Cui Puyi, et al.Detection of single-phase-to-ground faults in distribution networks based on gramian angular field and improved convolutional neural networks[J]. Electric Power Systems Research, 2023, 221: 109501. [15] Wang Yangkun, Zhang Feng, Zhang Xueheng, et al.Series AC arc fault detection method based on hybrid time and frequency analysis and fully connected neural network[J]. IEEE Transactions on Industrial Informatics, 2019, 15(12): 6210-6219. [16] Wang Ting, Hussain K S T, Song Guobing, et al. Adaptive single-phase/three-phase reclosing scheme for transmission lines in passive network supplied by MMC-HVDC[J]. International Journal of Electrical Power & Energy Systems, 2019, 113: 597-606. [17] 陈福锋, 杨黎明, 宋国兵, 等. 面向主动探测式保护的变流器正交控制策略[J]. 电力自动化设备, 2024, 44(3): 75-81. Chen Fufeng, Yang Liming, Song Guobing, et al.Orthogonal control strategy of converter for active detection protection[J]. Electric Power Automation Equipment, 2024, 44(3): 75-81. [18] 汤耀景, 孔凡坊, 宋国兵, 等. 分布式光伏并网线路的相间故障主动探测式保护原理[J]. 供用电, 2023, 40(1): 41-48. Tang Yaojing, Kong Fanfang, Song Guobing, et al.Active detection protection method for interphase fault of distributed photovoltaic grid-connected line[J]. Distribution & Utilization, 2023, 40(1): 41-48. [19] 宋国兵, 王婷, 张保会, 等. 利用电力电子装置的探测式故障识别技术分析与展望[J]. 电力系统自动化, 2020, 44(20): 173-183. Song Guobing, Wang Ting, Zhang Baohui, et al.Analysis and prospect of detective fault identification technologies using power electronic device[J]. Automation of Electric Power Systems, 2020, 44(20): 173-183. [20] 戴志辉, 吴桐, 何静远, 等. 基于控保协同的有源配网主动注入式保护方法[J]. 电力系统保护与控制, 2024, 52(3): 94-103. Dai Zhihui, Wu Tong, He Jingyuan, et al.An active distribution network active injection protection method based on control-protection coordination[J]. Power System Protection and Control, 2024, 52(3): 94-103. [21] 方重凯, 牟龙华, 欧锐, 等. 基于控保协同的微电网注入式保护方法研究[J]. 中国电机工程学报, 2023, 43(9): 3389-3401. Fang Chongkai, Mu Longhua, Ou Rui, et al.Research on control-protection coordination based on injection protect scheme of microgrid[J]. Proceedings of the CSEE, 2023, 43(9): 3389-3401. [22] 康涛, 翁汉琍, 林湘宁, 等. 考虑储能系统控保协同体系的光伏场站送出线路突变量选相能力恢复策略[J]. 中国电机工程学报, 2024, 44(11): 4273-4285. Kang Tao, Weng Hanli, Lin Xiangning, et al.Phase selection capacity recovery strategy for transmission line of photovoltaic station based on the control and insurance cooperative of energy storage system[J]. Proceedings of the CSEE, 2024, 44(11): 4273-4285. [23] 褚旭, 刘琦, 吕昊泽, 等. 基于控保协同海底观测网供电系统保护方案[J]. 电工技术学报, 2023, 38(7): 1780-1792. Chu Xu, Liu Qi, Lü Haoze, et al.Protection scheme for subsea observatory power supply system based on control and protection coordination[J]. Transactions of China Electrotechnical Society, 2023, 38(7): 1780-1792. [24] Liu Haiyang, Ling Xiaobo, Zhu Yifan, et al.Optimization of backup power automatic switching strategy in the distribution network with distributed photovoltaics[C]//2021 IEEE/IAS Industrial and Commercial Power System Asia (I&CPS Asia), Chengdu, China, 2021: 1133-1137. [25] Zhang Dongying, Guo Yun, Zhang Xu, et al.A complete analytical method for fault diagnosis of power grid considering operation information of backup automatic switch[C]//2019 IEEE Sustainable Power and Energy Conference (iSPEC), Beijing, China, 2019: 1722-1727. [26] 陈志峰, 沈娜, 王玕, 等. 高渗透率水电接入的变电站备自投逻辑优化研究[J]. 电力系统保护与控制, 2023, 51(4): 157-164. Chen Zhifeng, Shen Na, Wang Gan, et al.Logic optimization of a transformer substation busbar automatic transfer switch with high penetration of hydropower[J]. Power System Protection and Control, 2023, 51(4): 157-164. [27] Chen Yang, Li Lei, Lian Hongbo, et al.Analysis of the impact of MW-level grid-connected photovoltaic power station on backup automatic switch in distribution network[C]//2019 IEEE Sustainable Power and Energy Conference (iSPEC), Beijing, China, 2019: 2663-2669. [28] Yin Chaoyong, Li Gang, Xu Biao, et al.Principle and implementation of remote backup power automatic throw-in in serial power grid connection with multiple-communication modes[C]//2022 Asia Power and Electrical Technology Conference (APET), Shanghai, China, 2022: 138-142. [29] 李培强, 段克会, 董彦婷, 等. 含分布式混合储能系统的光伏直流微网能量管理策略[J]. 电力系统保护与控制, 2017, 45(13): 42-48. Li Peiqiang, Duan Kehui, Dong Yanting, et al.Energy management strategy for photovoltaic DC microgrid with distributed hybrid energy storage system[J]. Power System Protection and Control, 2017, 45(13): 42-48. [30] 米阳, 宋根新, 蔡杭谊, 等. 基于分段下垂的交直流混合微电网自主协调控制[J]. 电网技术, 2018, 42(12): 3941-3950. Mi Yang, Song Genxin, Cai Hangyi, et al.Autonomous coordinated control of hybrid AC/DC microgrids based on segmented droop[J]. Power System Technology, 2018, 42(12): 3941-3950. [31] 郑涛, 王赟鹏, 马家璇, 等. 基于特征电压注入的UPFC接入线路三相自适应重合闸方案[J]. 电力系统自动化, 2021, 45(5): 152-158. Zheng Tao, Wang Yunpeng, Ma Jiaxuan, et al.Three-phase adaptive reclosure scheme based on characteristic voltage injection for transmission line equipped with unified power flow controller[J]. Automation of Electric Power Systems, 2021, 45(5): 152-158. [32] 宋国兵, 侯俊杰, 郭冰. 基于主动探测式的柔性直流电网纵联保护[J]. 电网技术, 2020, 44(10): 4001-4010. Song Guobing, Hou Junjie, Guo Bing.Pilot protection of flexible DC grid based on active detection[J]. Power System Technology, 2020, 44(10): 4001-4010. [33] 宋国兵, 王婷, 张晨浩, 等. 利用全桥MMC注入特征信号的直流自适应重合闸方法[J]. 电网技术, 2019, 43(1): 149-156. Song Guobing, Wang Ting, Zhang Chenhao, et al.Adaptive auto-reclosing of DC line based on characteristic signal injection with FB-MMC[J]. Power System Technology, 2019, 43(1): 149-156. [34] 宋国兵, 侯俊杰, 郭冰. 基于主动探测式的混合MMC直流输电系统单端量故障定位[J]. 电网技术, 2021, 45(2): 730-740. Song Guobing, Hou Junjie, Guo Bing.Single-ended fault location of hybrid MMC-HVDC system based on active detection[J]. Power System Technology, 2021, 45(2): 730-740. [35] 陈福锋, 杨黎明, 宋国兵, 等. 主动探测式保护关键技术概述及展望[J]. 电力系统保护与控制, 2023, 51(15): 175-186. Chen Fufeng, Yang Liming, Song Guobing, et al.Overview and prospect of key technologies for active detection protection[J]. Power System Protection and Control, 2023, 51(15): 175-186. [36] 黄海宏, 颜碧琛, 王海欣. 并联级联H桥电源电流跟踪优化与环流抑制的模型预测控制[J]. 电工技术学报, 2023, 38(16): 4376-4390. Huang Haihong, Yan Bichen, Wang Haixin.Model predictive control of current tracking optimization and circulating current suppression for multi-parallel cascaded H-bridge power supplies[J]. Transactions of China Electrotechnical Society, 2023, 38(16): 4376-4390. [37] 徐瑞东, 常仲学, 宋国兵, 等. 注入探测信号的直流配电网接地故障识别方法[J]. 电网技术, 2021, 45(11): 4269-4276. Xu Ruidong, Chang Zhongxue, Song Guobing, et al.Grounding fault identification method for DC distribution network based on detection signal injection[J]. Power System Technology, 2021, 45(11): 4269-4276. [38] Luo Xunhua, Deng Zhiming, Wu Jingyang, et al.Fault nature identification and location scheme for distribution network based on active injection from IIDG[J]. International Journal of Electrical Power & Energy Systems, 2024, 156: 109706. [39] 徐丙垠, 李天友, 薛永端. 配电网继电保护与自动化[M]. 北京: 中国电力出版社, 2017.
2025, Vol. 40 
