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| Multi-Time Scale Collaborative Optimization Technology for Urban Rail Transit Flexible DC Converters Participating in Grid Reactive Power Compensation |
| Yu Wenjun1, Lin Junjie1, Cai Shilong2, Lu Chao2, Li Xiaoqian2 |
1. College of Electrical Engineering and Automation Fuzhou University Fuzhou 350108 China; 2. State Key Laboratory of Power System Operation and Control Department of Electrical Engineering Tsinghua University Beijing 100086 China |
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Abstract A flexible DC traction power supply system for urban rail transit can meet traction demands and provide surplus reactive power regulation capacity to support urban power grids. In existing power structures, the traction power system and the distribution network are supplied by the grid independently, lacking coordinated dispatch. However, the four-quadrant capability of flexible converters enables full exploitation of reactive power support from the traction system. Thus, this paper proposes a multi-time-scale coordinated optimization method for flexible converters in urban rail systems to participate in reactive power compensation. Firstly, at the day-ahead time scale, an improved particle swarm optimization (PSO) algorithm is employed to minimize the sum of network losses, voltage deviation variance, and the operation cost of discrete voltage regulation devices. Secondly, at the intra-day timescale, a flexible DC converter model and a method for evaluating reactive power compensation capability are established. Leveraging the four-quadrant adjustable reactive power compensation characteristics, a second-order cone programming (SOCP) approach is adopted to minimize grid losses and voltage deviation variance, achieving finer-grained reactive power optimization. Finally, a collaborative optimization strategy for multiple converters is proposed to enable mutual reactive power support among converters, addressing long-term equipment overloading issues. In the Changping regional grid of Beijing integrated with Metro Line 13 A, simulation results show that the proposed method restricts the maximum daily operations of on-load tap changer (OLTC) and capacitor bank (CB) to 5, reducing the total daily operational cost of these devices to ¥520, which is a 70.62% decrease compared to the static optimization method. By employing multi-time-scale reactive power optimization, the approach effectively suppresses voltage fluctuations and mitigates additional network losses arising from prediction errors in photovoltaic and load data. Compared with the non-optimized scenario and the day-ahead strategy-fixed scenario, network losses across the entire grid decrease by 7.30% and 2.09%, respectively, while voltage deviation variances drop by 30.09% and 13.02%, respectively. In the Huilongguan area, network losses are reduced by 12.79% and 6.50%, and voltage deviation variances by 17.60% and 1.78%, respectively. Moreover, the multi-converter collaborative optimization strategy maintains network losses and voltage deviation variance at similar levels. Meanwhile, the average high-load operation time ratio decreases from 92.6% to 74.7%. Thus, converter operational stress and losses are reduced, and the risk of equipment overloading is alleviated. The following conclusions can be drawn from simulation analyses. (1) The multi-timescale reactive power optimization strategy addresses temporal mismatch issues among devices and mitigates voltage violations and additional network losses caused by prediction errors. Fisher’s optimal partitioning method is applied to impose temporal constraints on day-ahead device operations, ensuring power system security. (2) A reactive power optimization framework incorporating urban rail flexible DC converters is developed. By constructing minute-level traction substation power models for traction load impact characteristics and metro operational peak-valley patterns, intra-day optimization further suppresses voltage fluctuations and reduces network losses. (3) A collaborative optimization technology for multiple rail transit flexible DC converters enables dynamic reactive power allocation among converters, addressing short-term reactive power inadequacy and long-term overloading issues, thereby extending equipment service life.
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Received: 24 April 2025
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[1] 陈艳波, 刘宇翔, 田昊欣, 等. 基于广义目标级联法的多牵引变电站光伏-储能协同规划配置[J]. 电工技术学报, 2024, 39(15): 4599-4612. Chen Yanbo, Liu Yuxiang, Tian Haoxin, et al.Colla-borative planning and configuration of photovoltaic and energy storage in multiple traction substations based on generalized analytical target cascading method[J]. Transactions of China Electrotechnical Society, 2024, 39(15): 4599-4612. [2] 高艺宁, 胡海涛, 葛银波, 等. 电气化铁路沿线光伏分布式并网方案及其电气特性研究[J]. 电工技术学报, 2025, 40(21): 7062-7075. Gao Yining, Hu Haitao, Ge Yinbo, et al.Research on distributed photovoltaic integration scheme along electrified railways and its electrical characteri-stics[J]. Transactions of China Electrotechnical Society, 2025, 40(21): 7062-7075. [3] 高仕斌, 罗嘉明, 陈维荣, 等. 轨道交通“网-源-储-车”协同供能技术体系[J]. 西南交通大学学报, 2024, 59(5): 959-979, 989. Gao Shibin, Luo Jiaming, Chen Weirong, et al.Rail transit “network-source-storage-vehicle” collaborative energy supply technology system[J]. Journal of Southwest Jiaotong University, 2024, 59(5): 959-979, 989. [4] 胡海涛, 郑政, 何正友, 等. 交通能源互联网体系架构及关键技术[J]. 中国电机工程学报, 2018, 38(1): 12-24, 339. Hu Haitao, Zheng Zheng, He Zhengyou, et al.The framework and key technologies of traffic energy Internet[J]. Proceedings of the CSEE, 2018, 38(1): 12-24, 339. [5] Guo Jianbo, Ma Shicong, Wang Tiezhu, et al.Challenges of developing a power system with a high renewable energy proportion under China’s carbon targets[J]. iEnergy, 2022, 1(1): 12-18. [6] 刘华志, 李永刚, 王优胤, 等. 无功电压优化对新能源消纳的影响[J]. 电工技术学报, 2019, 34(增刊2): 646-653. Liu Huazhi, Li Yonggang, Wang Youyin, et al.Influence of reactive power and voltage optimization on new energy consumption[J]. Transactions of China 7 Electrotechnical Society, 2019, 34(S2): 646-653. [7] 叶润峰, 魏应冬, 李占赫, 等. 城市轨道交通柔性直流牵引供电系统钢轨电位快速计算方法[J]. 中国电机工程学报, 2023, 43(14): 5311-5319. Ye Runfeng, Wei Yingdong, Li Zhanhe, et al.Fast calculation of rail potential of flexible DC traction power supply system for urban rail transit[J]. Proceedings of the CSEE, 2023, 43(14): 5311-5319. [8] 金勇, 黄先进, 石春珉, 等. 城市轨道交通地面储能技术应用综述[J]. 电工技术学报, 2024, 39(15): 4568-4582, 4642. Jin Yong, Huang Xianjin, Shi Chunmin, et al.Review on wayside energy storage technology for urban rail transit[J]. Transactions of China Electrotechnical Society, 2024, 39(15): 4568-4582, 4642. [9] 王海, 李占赫, 白雪莲, 等. 城市轨道交通柔性直流牵引供电技术应用研究[J]. 电气化铁道, 2023, 34(1): 64-68. Wang Hai, Li Zhanhe, Bai Xuelian, et al.Application research on flexible DC traction power supply technology for urban rail transit[J]. Electric Railway, 2023, 34(1): 64-68. [10] 张钢, 郝峰杰, 王运达, 等. 城轨柔性牵引供电系统及优化控制研究[J]. 电工技术学报, 2022, 37(增刊1): 153-162. Zhang Gang, Hao Fengjie, Wang Yunda, et al.Research on flexible traction power supply system and optimal control of urban rail[J]. Transactions of China Electrotechnical Society, 2022, 37(S1): 153-162. [11] 廖钧. 城市轨道供电系统无功补偿方案研究[D]. 成都: 西南交通大学, 2017. Liao Jun.Research on reactive power compensation scheme of urban rail power supply system[D]. Chengdu: Southwest Jiaotong University, 2017. [12] Hao Fengjie, Zhang Gang, Chen Jie, et al.Distributed reactive power compensation method in DC traction power systems with reversible substations[J]. IEEE Transactions on Vehicular Technology, 2021, 70(10): 9935-9944. [13] Li Haixiao, Guo Ke, Hao Gaofeng, et al.Decentralized communication based two-tier volt-var control strategy for large-scale centralized photovoltaic power plant[J]. IEEE Transactions on Sustainable Energy, 2022, 13(1): 592-606. [14] 柯圣舟, 郑欢, 林毅, 等. 计及柔性直流输电系统损耗模型的交直流电网无功优化[J]. 电网技术, 2016, 40(10): 3052-3058. Ke Shengzhou, Zheng Huan, Lin Yi, et al.Reactive power optimization of AC-DC grid in consideration of VSC-HVDC transmission loss model[J]. Power System Technology, 2016, 40(10): 3052-3058. [15] 黄华, 徐泰山, 高宗和, 等. 基于互补约束和绝对值线性化松弛的日前无功计划优化[J]. 电力系统自动化, 2025, 49(3): 156-169. Huang Hua, Xu Taishan, Gao Zonghe, et al.Day-ahead reactive power schedule optimization based on complementary constraints and absolute value linearization relaxation[J]. Automation of Electric Power Systems, 2025, 49(3): 156-169. [16] 钱立群, 魏卿, 胡鹏飞, 等. 基于数据驱动预测控制的低感知度配电网在线无功优化方法[J]. 电力系统自动化, 2025, 49(13): 61-69. Qian Liqun, Wei Qing, Hu Pengfei, et al.Online reactive power optimization method based on data-driven predictive control for distribution network with low situation awareness[J]. Automation of Electric Power Systems, 2025, 49(13): 61-69. [17] Zhang Cuo, Xu Yan, Wang Yu, et al.Three-stage hierarchically-coordinated voltage/var control based on PV inverters considering distribution network voltage stability[J]. IEEE Transactions on Sustainable Energy, 2022, 13(2): 868-881. [18] 杜红卫, 尉同正, 夏栋, 等. 基于集群动态划分的配电网无功电压自律-协同控制[J]. 电力系统自动化, 2024, 48(10): 171-181. Du Hongwei, Wei Tongzheng, Xia Dong, et al.Reactive voltage self-regulation and coordination control in distribution networks based on cluster dynamic partition[J]. Automation of Electric Power Systems, 2024, 48(10): 171-181. [19] 张蕊, 李铁成, 李晓明, 等. 考虑设备动作损耗的配电网分布式电压无功优化[J]. 电力系统保护与控制, 2021, 49(24): 31-40. Zhang Rui, Li Tiecheng, Li Xiaoming, et al.Dis-tributed optimization for distribution networks volt/var control considering the operation cost of equipment[J]. Power System Protection and Control, 2021, 49(24): 31-40. [20] 秦龙庆, 郑景文, 廖小兵, 等. 基于概率场景驱动的柔性配电网分布式无功优化[J]. 高电压技术, 2025, 51(1): 200-209. Qin Longqing, Zheng Jingwen, Liao Xiaobing, et al.Distributed reactive power optimization of flexible distribution network based on probability scenario-driven[J]. High Voltage Engineering, 2025, 51(1): 200-209. [21] 葛磊蛟, 范延赫, 李小平, 等. 计及日前随机-日内滚动分布式的高比例光伏配电网无功优化方法[J].电网技术, 2026, 50(3): 1071-1084. Ge Leijiao, Fan Yanhe, Li Xiaoping, et al.A reactive power optimization method for high percentage of PV distribution networks taking into account day-ahead random and intraday rolling distributions[J]. Power System Technology, 2026, 50(3): 1071-1084. [22] 寇凌峰, 吴鸣, 李洋, 等. 主动配电网分布式有功无功优化调控方法[J]. 中国电机工程学报, 2020, 40(6): 1856-1865. Kou Lingfeng, Wu Ming, Li Yang, et al.Optimization and control method of distributed active and reactive power in active distribution network[J]. Proceedings of the CSEE, 2020, 40(6): 1856-1865. [23] 李鹏, 钟瀚明, 马红伟, 等. 基于深度强化学习的有源配电网多时间尺度源荷储协同优化调控[J]. 电工技术学报, 2025, 40(5): 1487-1502. Li Peng, Zhong Hanming, Ma Hongwei, et al.Multi-timescale optimal dispatch of source-load-storage coordination in active distribution network based on deep reinforcement learning[J]. Transactions of China Electrotechnical Society, 2025, 40(5): 1487-1502. [24] Yang Qiuling, Wang Gang, Sadeghi A, et al.Two-timescale voltage control in distribution grids using deep reinforcement learning[J]. IEEE Transactions on Smart Grid, 2020, 11(3): 2313-2323. [25] 倪爽, 崔承刚, 杨宁, 等. 基于深度强化学习的配电网多时间尺度在线无功优化[J]. 电力系统自动化, 2021, 45(10): 77-85. Ni Shuang, Cui Chenggang, Yang Ning, et al.Multi-time-scale online optimization for reactive power of distribution network based on deep reinforcement learning[J]. Automation of Electric Power Systems, 2021, 45(10): 77-85. [26] 胡丹尔, 彭勇刚, 韦巍, 等. 多时间尺度的配电网深度强化学习无功优化策略[J]. 中国电机工程学报, 2022, 42(14): 5034-5045. Hu Daner, Peng Yonggang, Wei Wei, et al.Multi-timescale deep reinforcement learning for reactive power optimization of distribution network[J]. Proceedings of the CSEE, 2022, 42(14): 5034-5045. [27] 张沛, 朱驻军, 谢桦. 基于深度强化学习近端策略优化的电网无功优化方法[J]. 电网技术, 2023, 47(2): 562-572. Zhang Pei, Zhu Zhujun, Xie Hua.Reactive power optimization based on proximal policy optimization of deep reinforcement learning[J]. Power System Technology, 2023, 47(2): 562-572. [28] Liu Yunjiang, Hu Haitao, Gang Ye, et al.A novel urban rail transit full DC flexible power supply system[J]. IEEE Transactions on Transportation Elec-trification, 2025, 11(5): 12608-12617. [29] 冯玎, 林圣, 孙小军, 等. 考虑高速铁路负荷特性的牵引变压器可靠性评估[J]. 铁道学报, 2017, 39(8): 62-69. Feng Ding, Lin Sheng, Sun Xiaojun, et al.Reliability assessment for traction transformer considering load characteristics of high-speed railway[J]. Journal of the China Railway Society, 2017, 39(8): 62-69. [30] 黄先进, 高冠刚, 刘宜鑫, 等. 增强牵引变流器过载的IGBT泵升驱动技术[J]. 铁道学报, 2024, 46(10): 33-39. Huang Xianjin, Gao Guangang, Liu Yixin, et al.IGBT pump-up drive technology to improve overload capability of traction converters[J]. Journal of the China Railway Society, 2024, 46(10): 33-39. [31] Shi Shanshan, Zhang Kaiyu, Su Yun, et al.Study on metro power supply load model and construction idea of virtual power plant[C] //2023 3rd International Conference on New Energy and Power Engineering (ICNEPE), Huzhou, China, 2023: 719-723. [32] 周雨桐, 田品慧, 朱永强, 等. 配电网综合电压偏差评价方法及应用[J]. 电气应用, 2025, 44(6): 20-28. Zhou Yutong, Tian Pinhui, Zhu Yongqiang, et al.Evaluation method and application of comprehensive voltage deviation in power distribution network[J]. Electrotechnical Application, 2025, 44(6): 20-28. [33] 王磊, 姜涛, 宋丹, 等. 基于灵活热电比的区域综合能源系统多目标优化调度[J]. 电力系统保护与控制, 2021, 49(8): 151-159. Wang Lei, Jiang Tao, Song Dan, et al.Multi-objective optimal dispatch of a regional integrated energy system based on a flexible heat-to-electric ratio[J]. Power System Protection and Control, 2021, 49(8): 151-159. [34] 于惠钧, 马凡烁, 陈刚, 等. 基于改进灰狼优化算法的含光伏配电网动态无功优化[J]. 电气技术, 2024, 25(4): 7-15, 58. Yu Huijun, Ma Fanshuo, Chen Gang, et al.Dynamic reactive power optimization of photovoltaic dis-tribution network based on improved gray wolf optimization algorithm[J] Electrical Engineering, 2024, 25(4): 7-15, 58. [35] Tang Zhiyuan, Hill D J, Liu Tao.Distributed coor-dinated reactive power control for voltage regulation in distribution networks[J]. IEEE Transactions on Smart Grid, 2021, 12(1): 312-323. [36] 黄大为, 王孝泉, 于娜, 等. 计及光伏出力不确定性的配电网混合时间尺度无功/电压控制策略[J]. 电工技术学报, 2022, 37(17): 4377-4389. Huang Dawei, Wang Xiaoquan, Yu Na, et al.Hybrid timescale voltage/var control in distribution network considering PV power uncertainty[J]. Transactions of China Electrotechnical Society, 2022, 37(17): 4377-4389. [37] 柴园园, 赵晓波, 吕超贤, 等. 基于Fisher时段划分的配电网源-网-荷-储多时间尺度协调优化调控策略[J]. 电网技术, 2024, 48(4): 1593-1606. Chai Yuanyuan, Zhao Xiaobo, Lü Chaoxian, et al.Coordinated multi-time scale optimal regulation for source-grid-load-storage of distribution network based on Fisher period division[J]. Power System Technology, 2024, 48(4): 1593-1606. [38] Gan Lingwen, Li Na, Topcu U, et al.Exact convex relaxation of optimal power flow in radial networks[J]. IEEE Transactions on Automatic Control, 2015, 60(1): 72-87. [39] Low S H.Convex relaxation of optimal power flow: part I: formulations and equivalence[J]. IEEE Transa-ctions on Control of Network Systems, 2014, 1(1): 15-27. [40] 陈艳波, 强涂奔, 田昊欣, 等. 考虑集中式与分布式新能源不确定性的输配协同负荷恢复方法[J]. 电工技术学报, 2026, 41(7): 2281-2299. Chen Yanbo, Qiang Tuben, Tian Haoxin, et al.Coordinated load restoration method of transmission and distribution networks considering the uncertainties of centralized and distributed renewable energy sources[J]. Transactions of China Electrotechnical Society, 2026, 41(7): 2281-2299. [41] Beerten J, Cole S, Belmans R.Generalized steady-state VSC MTDC model for sequential AC/DC power flow algorithms[J]. IEEE Transactions on Power Systems, 2012, 27(2): 821-829. |
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