Abstract：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 distribution network is constructed. The following conclusions are drawn. (1) The protection criteria based on the active power characteristics of fault components can overcome the influence of T-connected IIDGs and loads. High voltage drop faults can be accurately identified in the inside and outside zones. (2) In the proposed protection method, a real-time estimation algorithm is used for the fault power contribution of IIDGs and loads, enabling the protection method to withstand a 300 Ω transition resistance. (3) The proposed method is a differential protection using measurement data from both terminals. Additional measurement devices are not required for T-connected IIDGs and loads. Compared with over-current protection, the proposed method has a significant advantage in operating time. (4) The proposed protection method is not affected by fault types and locations, IIDG penetration rate, capacity of T-connected and loads, noise, and grounding methods, showing strong adaptability. The effectiveness of the proposed protection method is verified. It can serve as a powerful supplement to protect the current distribution network, thereby improving the reliability and sensitivity of protection.
罗国敏, 谭颖婕, 吴梦宇, 和敬涵, 唐平舟. 考虑电压跌落差异的有源配电网功率差动保护[J]. 电工技术学报, 2025, 40(4): 1287-1306.
Luo Guomin, Tan Yingjie, Wu Mengyu, He Jinghan, Tang Pingzhou. Power Differential Protection for Active Distribution Networks Considering Voltage Drop Differences. Transactions of China Electrotechnical Society, 2025, 40(4): 1287-1306.
[1] 李军徽, 赵寒杰, 朱星旭, 等. 基于区域间场景等值的配电网随机潮流加速算法[J]. 电工技术学报, 2024, 39(7): 1957-1970. Li Junhui, Zhao Hanjie, Zhu Xingxu, et al.Stochastic power flow acceleration algorithm for distribution network based on inter-regional scene equivalence[J]. Transactions of China Electrotechnical Society, 2024, 39(7): 1957-1970. [2] 陈冲, 贾利民, 赵天宇, 等. 去碳化导向的轨道交通与新能源融合发展—形态模式、解决方案和使/赋能技术[J]. 电工技术学报, 2023, 38(12): 3321-3337. Chen Chong, Jia Limin, Zhao Tianyu, et al.Decarbonization-oriented rail transportation and renewable energy integration development-configurations, solutions, and enabling/empowering technologies[J]. Transactions of China Electrotechnical Society, 2023, 38(12): 3321-3337. [3] 李军徽, 邵岩, 朱星旭, 等. 计及碳排放量约束的多区域互联电力系统分布式低碳经济调度[J]. 电工技术学报, 2023, 38(17): 4715-4728. Li Junhui, Shao Yan, Zhu Xingxu, et al.Carbon emissions constraint distributed low-carbon economic dispatch of power system[J]. Transactions of China Electrotechnical Society, 2023, 38(17): 4715-4728. [4] 李娟, 高厚磊, 朱国防. 考虑逆变类分布式电源特性的有源配电网反时限电流差动保护[J]. 电工技术学报, 2016, 31(17): 74-83. Li Juan, Gao Houlei, Zhu Guofang.Inverse-time current differential protection in active distribution network considering characteristics of inverterinterfaced distributed generations[J]. Transactions of China Electrotechnical Society, 2016, 31(17): 74-83. [5] 马静, 刘静. 基于故障稳态分量的含DG配电网自适应方向电流保护方案[J]. 电力自动化设备, 2018, 38(1): 1-9. Ma Jing, Liu Jing.Adaptive directional current protection scheme based on steady state component in distribution network with DG[J]. Electric Power Automation Equipment, 2018, 38(1): 1-9. [6] 王守相, 宋丽可, 舒欣. 分布式电源与多元负荷高渗透接入的主动配电网自适应过流保护方案[J]. 高电压技术, 2019, 45(6): 1783-1794. Wang Shouxiang, Song Like, Shu Xin.Adaptive overcurrent protection of active distribution network with high penetration of distributed generations and multiple loads[J]. High Voltage Engineering, 2019, 45(6): 1783-1794. [7] 袁智勇, 徐全, 徐刚, 等. 含大容量分布式电源接入的配电网电流保护优化方案[J]. 电网技术, 2021, 45(5): 1862-1868. Yuan Zhiyong, Xu Quan, Xu Gang, et al.Current protection optimization scheme in distribution network with large capacity distributed generators[J]. Power System Technology, 2021, 45(5): 1862-1868. [8] 韩国政, 李镇宇, 董霞, 等. 利用工频电压信号的配电终端时钟同步方法[J]. 电力系统自动化, 2019, 43(24): 181-186. Han Guozheng, Li Zhenyu, Dong Xia, et al.Clock synchronization method of feeder terminal unit using power frequency voltage signal[J]. Automation of Electric Power Systems, 2019, 43(24): 181-186. [9] 肖澍昱, 林湘宁, 魏繁荣, 等. 面向含不可测分支配电线路不对称故障可靠辨识的负序电流比相保护判据[J]. 电工技术学报, 2023, 38(9): 2435-2447. Xiao Shuyu, Lin Xiangning, Wei Fanrong, et al.Phase comparison protection of negative sequence current for distribution lines with unmeasurable branches[J]. Transactions of China Electrotechnical Society, 2023, 38(9): 2435-2447. [10] 王伟杰, 曾鑫洁, 徐远途, 等. 基于正序突变量相轨迹辨识的可再生能源配电网电流保护[J]. 发电技术, 2024, 45(4): 753-764. Wang Weijie, Zeng Xinjie, Xu Yuantu, et al.Renewable energy distribution network overcurrent protection based on positive-sequence sudden-change component locus identification[J]. Power Generation Technology, 2024, 45(4): 753-764. [11] 李会新, 王兴国, 谢俊, 等. 一种基于虚拟电流制动量的电流差动保护[J]. 电力系统保护与控制, 2018, 46(9): 75-79. Li Huixin, Wang Xingguo, Xie Jun, et al.A transmission line current differential protection based on virtual brake current[J]. Power System Protection and Control, 2018, 46(9): 75-79. [12] Han Bowen, Li Haifeng, Wang Gang, et al.A virtual multi-terminal current differential protection scheme for distribution networks with inverter-interfaced distributed generators[J]. IEEE Transactions on Smart Grid, 2018, 9(5): 5418-5431. [13] 徐彬, 高厚磊, 袁通, 等. 基于拟功率定理的海上风电柔直并网线路纵联保护[J]. 电力系统自动化, 2023, 47(22): 44-54. Xu Bin, Gao Houlei, Yuan Tong, et al.Pilot protection for VSC-HVDC transmission line of grid-connected offshore wind farm based on quasipower theorem[J]. Automation of Electric Power Systems, 2023, 47(22): 44-54. [14] 马静, 裴迅, 马伟, 等. 基于故障分量虚拟阻抗的线路差动保护原理[J]. 电力自动化设备, 2014, 34(12): 58-64, 69. Ma Jing, Pei Xun, Ma Wei, et al.Differential protection principle based on virtual impedance of fault component for power transmission line[J]. Electric Power Automation Equipment, 2014, 34(12): 58-64, 69. [15] 晁晨栩, 郑晓冬, 桂强, 等. 适用于光伏场站汇集线路的高频突变量纵联保护[J]. 电网技术, 2022, 46(12): 4607-4615. Chao Chenxu, Zheng Xiaodong, Gui Qiang, et al.High frequency component-based pilot protection for photovoltaic station collection line[J]. Power System Technology, 2022, 46(12): 4607-4615. [16] 高岩, 李永丽, 陈晓龙, 等. 基于电流幅值比的有源配电网自适应差动保护原理[J]. 电力系统及其自动化学报, 2021, 33(2): 1-7. Gao Yan, Li Yongli, Chen Xiaolong, et al.Adaptive differential protection principle for active distribution network based on current amplitude ratio[J]. Proceedings of the CSU-EPSA, 2021, 33(2): 1-7. [17] 陈少宇, 黄文焘, 邰能灵, 等. 多端柔性直流配电网高频功率相关性纵联保护方法[J]. 电力系统自动化, 2020, 44(19): 150-159. Chen Shaoyu, Huang Wentao, Tai Nengling, et al.Pilot protection method for multi-terminal flexible DC distribution network based on correlation of high-frequency power[J]. Automation of Electric Power Systems, 2020, 44(19): 150-159. [18] 童晓阳, 连文超, 滕予非. 有限PMU下采用差动有功功率抗过渡电阻的广域后备保护[J]. 中国电机工程学报, 2018, 38(8): 2335-2347, 2543. Tong Xiaoyang, Lian Wenchao, Teng Yufei.The wide-area backup protection based on differential active power against transition resistance using limited PMUs[J]. Proceedings of the CSEE, 2018, 38(8): 2335-2347, 2543. [19] 潘学萍, 王卫康, 陈海东, 等. 计及低电压穿越影响的感应电动机动态分群[J]. 电工技术学报, 2024, 39(7): 2001-2016, 2032. Pan Xueping, Wang Weikang, Chen Haidong, et al.Dynamic grouping of induction motors considering the influence of low voltage ride-through[J]. Transactions of China Electrotechnical Society, 2024, 39(7): 2001-2016, 2032. [20] 侯来运. 考虑新能源故障特性的配网实用化短路电流计算[D]. 北京: 华北电力大学, 2022. Hou Laiyun.Practical short-circuit current calculation of distribution network considering new energy fault characteristics[D]. Beijing: North China Electric Power University, 2022. [21] 孙秋野. 电力系统分析[M]. 北京: 人民邮电出版社, 2012.
2025, Vol. 40 
