{"title":"Two-Timescale Volt/var Control Based on Reinforcement Learning with Hybrid Action Space for Distribution Networks","authors":"Yuan Zhou;Yizhou Peng;Leijiao Ge;Luyang Hou;Ying Wang;Hongxia Niu","doi":"10.35833/MPCE.2024.000643","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000643","url":null,"abstract":"In volt/var control (VVC) for active distribution networks, it is essential to integrate traditional voltage regulation devices with modern smart photovoltaic inverters to prevent voltage violations. However, model-based multi-device VVC methods rely on accurate system models for decision-making, which can be challenging due to the extensive modeling workload. To tackle the complexities of multi-device cooperation in VVC, this paper proposes a two-timescale VVC method based on reinforcement learning with hybrid action space, termed the hybrid action representation twin delayed deep deterministic policy gradient (HAR-TD3) method. This method simultaneously manages traditional discrete voltage regulation devices, which operate on a slower timescale, and smart continuous voltage regulation devices, which function on a faster timescale. To enable effective collaboration between the different action spaces of these devices, we propose a variational auto-encoder based hybrid action reconstruction network. This network captures the interdependencies of hybrid actions by embedding both discrete and continuous actions into the latent representation space and subsequently decoding them for action reconstruction. The proposed method is validated on IEEE 33-bus, 69-bus, and 123-bus distribution networks. Numerical results indicate that the proposed method successfully coordinates discrete and continuous voltage regulation devices, achieving fewer voltage violations compared with state-of-the-art reinforcement learning methods.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 4","pages":"1261-1273"},"PeriodicalIF":5.7,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10834450","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Energy Management of Photovoltaic-Battery Energy Storage System for Stable Frequency Support Based on Flexible Power Reserve Considering SOC Recovery","authors":"Tianqi Liu;Yulong Shi;Qiao Peng","doi":"10.35833/MPCE.2024.000725","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000725","url":null,"abstract":"The reduced frequency regulation capability in low-inertia power systems necessitates enhanced frequency support from photovoltaic (PV) systems. However, the regulation capability of PV system under conventional control scheme is limited, which requires flexible power control and support from battery energy storage systems (BESSs). This paper proposes an energy management strategy of PV-BESS to provide stable frequency support to the grid. The proposed strategy initially develops a maximum power point tracking (MPPT) -based power reserve control (PRC) for PV power reserve. At this stage, the BESS is manipulated to buffer the power fluctuations caused by MPPT execution and environmental variability. To enhance the regulation capability of BESS and mitigate battery aging, the proposed strategy incorporates a flexible PRC for state of charge (SOC) recovery. Subsequently, the battery can be rationally charged or discharged during the PRC process to maintain SOC. Simulation results obtained from MATLAB/Simulink and experimental results from the StarSim platform validate that the proposed strategy achieves stable PV power reserve, mitigates fluctuations induced by environmental uncertainties, enables efficient SOC recovery, and improves grid frequency quality. Overall, the proposed strategy ensures stable operation of PV-BESS both under steady-state conditions and during frequency events.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 5","pages":"1617-1629"},"PeriodicalIF":6.1,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10819339","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145090143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hai Xie;Jun Yao;Wenwen He;Dong Yang;Sheng Gong;Linsheng Zhao
{"title":"Transient Stability Analysis and Improved Control Strategy of PMSG-based Grid-forming Wind Energy Conversion System Under Symmetrical Grid Fault","authors":"Hai Xie;Jun Yao;Wenwen He;Dong Yang;Sheng Gong;Linsheng Zhao","doi":"10.35833/MPCE.2024.000484","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000484","url":null,"abstract":"The transient synchronization characteristics and instability mechanism of the permanent magnet synchronous generator (PMSG)-based grid-forming wind energy conversion system (GFM-WECS) under symmetrical grid fault have received little attention to date. In this paper, considering the dynamics of DC-link voltage, the transient stability and an improved control strategy of PMSG-based GFM-WECS are studied in detail. Firstly, considering the dynamic interactions between the machine-side converter and the grid-side converter, the large-signal equivalent model of GFM-WECS is established. Furthermore, a novel Lyapunov function is derived to evaluate the transient stability margin and instability boundary of GFM-WECS during grid voltage sag. Additionally, the impacts of current-limitation control on the transient stability of GFM-WECS are revealed. Then, a stability evaluation index is proposed to evaluate the transient stability margin of GFM-WECS. Moreover, an improved control strategy is proposed to enhance the transient response characteristics and low voltage ride-through (LVRT) capability of GFM-WECS under symmetrical grid fault. Finally, simulations and experimental results are conducted to verify the effectiveness of the proposed control strategy.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 1","pages":"128-141"},"PeriodicalIF":5.7,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10807807","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143184040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Grid-Forming Control Based on Adaptive Reactive Power Allocation for Offshore Wind Farms Connected to Diode-rectifier-based HVDC System","authors":"Ganghua Zhang;Wang Xiang;Xia Chen;Rui Tu;Xuebo Qiao;Jinyu Wen","doi":"10.35833/MPCE.2024.00743","DOIUrl":"https://doi.org/10.35833/MPCE.2024.00743","url":null,"abstract":"Diode-rectifier-based high-voltage direct current (DR-HVDC) systems are considered an attractive solution for integrating offshore wind farms (OWFs). Grid-forming (GFM) control with a rational reactive power allocation capability is crucial for the safe operation of numerous wind turbines (WTs). Most typical GFM controls aim to share surplus reactive power of the system equally among WTs, easily rendering capacity overloads for WTs that are outputting high levels of active power. In this paper, a novel GFM control for OWFs is proposed, allowing for adaptively allocating the reactive power according to the actual active power output of WTs. Firstly, the reactive power characteristics of the AC collection networks and WTs are analyzed across a wide wind power range. Then, combining the positive correlation of WT active power with the output AC voltage, a Q-θ type GFM control for WTs is presented. The adaptive reactive power allocation mechanism and the parameter design of the Q-θ based reactive power controller are elucidated, ensuring that WTs with lower active power output contribute more reactive power to the system than WTs with higher active power output. The AC impedance models of WTs under various GFM controls are established to evaluate the impact of different reactive power controllers. Finally, the feasibility of the proposed control is validated in PSCAD/EMT-DC, accompanied by stability analysis.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 1","pages":"154-166"},"PeriodicalIF":5.7,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10807808","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143184063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhe Chen;Zhihao Li;Da Lin;Changjun Xie;Zhewei Wang
{"title":"Multi-Time-Scale Optimal Scheduling of Integrated Energy System with Electric-Thermal-Hydrogen Hybrid Energy Storage Under Wind and Solar Uncertainties","authors":"Zhe Chen;Zhihao Li;Da Lin;Changjun Xie;Zhewei Wang","doi":"10.35833/MPCE.2024.000606","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000606","url":null,"abstract":"Hybrid energy storage is considered as an effective means to improve the economic and environmental performance of integrated energy systems (IESs). Although the optimal scheduling of IES has been widely studied, few studies have taken into account the property that the uncertainty of the forecasting error decreases with the shortening of the fore-casting time scale. Combined with hybrid energy storage, the comprehensive use of various uncertainty optimization methods under different time scales will be promising. This paper proposes a multi-time-scale optimal scheduling method for an IES with hybrid energy storage under wind and solar uncertainties. Firstly, the proposed system framework of an IES including electric-thermal-hydrogen hybrid energy storage is established. Then, an hour-level robust optimization based on budget uncertainty set is performed for the day-ahead stage. On this basis, a scenario-based stochastic optimization is carried out for intra-day and real-time stages with time intervals of 15 min and 5 min, respectively. The results show that ①the proposed method improves the economic benefits, and the intra-day and real-time scheduling costs are reduced, respectively; ②by adjusting the uncertainty budget in the model, a flexible balance between economic efficiency and robustness in day-ahead scheduling can be achieved; ③ reasonable design of the capacity of electric-thermal-hydrogen hybrid energy storage can significantly reduce the electricity curtailment rate and carbon emissions, thus reducing the cost of system scheduling.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 3","pages":"904-914"},"PeriodicalIF":5.7,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10799930","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dynamic State Estimation Based Protection for Large-Scale Renewable Energy Transmission Lines","authors":"Meng Li;Ming Nie;Jinghan He;Huiyuan Zhang","doi":"10.35833/MPCE.2024.000633","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000633","url":null,"abstract":"The development of low-carbon energy systems and renewable energy sources (RESs) are critical to solving the energy crisis around the world. However, renewable energy generation control strategies lead to fault characteristics such as fault current amplitude limitation and phase angle distortion. Focusing on large-scale renewable energy transmission lines, the sensitivity of traditional current differential protection and distance protection may be reduced, and there is even the risk of maloperation. Therefore, a suitable transmission line model is established, which considers the distributed capacitance. Afterward, a novel dynamic state estimation based protection (DSEBP) for large-scale renewable energy transmission lines is proposed. The proposed DSEBP adopts instantaneous measurements and additional protection criteria to ensure the quick action and reliability. Finally, faults are identified by checking the matching degree between the actual measurements and the established transmission line model. The performance of the proposed DSEBP is verified through PSCAD/EMTDC and real-time digital simulator (RTDS) hardware-in-loop tests. The results demonstrate that the proposed DSEBP can identify various types of faults quickly and reliably. Meanwhile, the proposed DSEBP has a better capability to withstand fault resistance and disturbance.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 4","pages":"1188-1198"},"PeriodicalIF":5.7,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10785255","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jidong Xu;Jun Zeng;Gengning Ying;Minhai Wu;Junfeng Liu
{"title":"Virtual Power Angle Synchronous Control for Improving Transient Stability of Grid-Forming Converters","authors":"Jidong Xu;Jun Zeng;Gengning Ying;Minhai Wu;Junfeng Liu","doi":"10.35833/MPCE.2024.000684","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000684","url":null,"abstract":"The increasing adoption of grid-forming converters (GFMCs) stems from their capacity to furnish voltage and frequency support for power grids. Nevertheless, GFMCs employing the current reference saturation limiting method often exhibit instability during various transient disturbances including grid voltage sags, frequency variations, and phase jumps. To address this problem, this paper proposes a virtual power angle synchronous <tex>$(delta_{v}-text{SYN})$</tex> control method. The fundamental of this method is to achieve synchronization with the grid using the virtual power angle <tex>$delta_{v}$</tex> instead of the active power. The transient stability characteristics of the proposed method are theoretically elucidated using a novel virtual power angle-power angle <tex>$(delta_{v}- delta )$</tex> model. The key benefit of the proposed method is its robustness to various grid strengths and diverse forms of transient disturbances, eliminating the requirement for fault identification or control switching. Moreover, it can offer grid-forming support to the grid during grid faults. Hardware-in-the-loop experimental results validate the theoretical analysis and the performance of the proposed method.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 1","pages":"142-153"},"PeriodicalIF":5.7,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10785253","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143184041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Distributed Coordinated Control Strategy for Large-Scale Thermostatically Controlled Loads Considering User Comfort Constraints","authors":"Xiangyu Chen;Yujun Lin;Qiufan Yang;Yin Chen;Xia Chen;Jinyu Wen","doi":"10.35833/MPCE.2024.000430","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000430","url":null,"abstract":"Thermostatically controlled loads (TCLs) on the demand side have been a vital energy resource in smart grids. To efficiently utilize the large-scale TCLs and enhance the flexibility of micro-community systems, this paper proposes a distributed coordinated control strategy based on the distributed model predictive control (MPC). To achieve the adaptive coordinated control among TCLs and consider user comfort constraints, a distributed dual-layer internal control strategy based on MPC is established on a scalable communication network. This strategy achieves the efficient utilization of TCLs in a distributed manner and notably improves the convergence speed through sparse network communication between neighbors. For external resource utilization of TCLs, a multi-timescale scheduling framework is proposed to realize the pre-allocation of electricity. Furthermore, the feasibility of the proposed distributed coordinated control strategy is confirmed through comparative case analysis.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 3","pages":"1014-1025"},"PeriodicalIF":5.7,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10785254","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Weihua Zhou;Mohammad Hasan Ravanji;Nabil Mohammed;Behrooz Bahrani
{"title":"Effects of Control Loop Interactions on Maximum Power Transfer Capability of Weak-Grid-Tied Grid-Following Inverters","authors":"Weihua Zhou;Mohammad Hasan Ravanji;Nabil Mohammed;Behrooz Bahrani","doi":"10.35833/MPCE.2024.000136","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000136","url":null,"abstract":"The maximum power transfer capability (MPTC) of phase-locked loop (PLL)-based grid-following inverters is often limited under weak-grid conditions due to passivity violations caused by operating-point-dependent control loops. This paper reveals and compares the mechanisms of these violations across different control strategies. Using admittance decomposition and full-order state-space models for eigenvalue analysis, MPTC limitations from control loops and their interactions are identified. The small-signal stabilities of different control loops are compared under varying grid strength, and both static and dynamic MPTCs for each control mode are examined. This paper also explores how control loop interactions impact the MPTC, offering insights for tuning control loops to enhance stability in weak grids. For example, fast power control improves the MPTC when paired with a slow PLL, while power control has minimal effect when the PLL is sufficiently fast. The findings are validated through frequency scanning, eigenvalue analysis, simulations, and experiments.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 3","pages":"1078-1089"},"PeriodicalIF":5.7,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10778170","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144185293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaoping Gao;Guobing Song;Xiaoning Kang;Can Cui;Jifei Yan
{"title":"Pilot Protection Based on Backward Traveling-Wave Voltage Difference for Submarine Cables of Low-Frequency Transmission System with Integrated Offshore Wind Power","authors":"Xiaoping Gao;Guobing Song;Xiaoning Kang;Can Cui;Jifei Yan","doi":"10.35833/MPCE.2024.000448","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000448","url":null,"abstract":"Multiterminal low-frequency transmission system (LFTS) has promising potential for large-scale offshore wind power integration. Nevertheless, the existing protection suffers from low sensitivity, and even operates incorrectly because the converters connected to both ends of cables change fault characteristics substantially. To address this problem, this paper firstly inspects the adaptability of current differential protection, revealing the manner in which control strategies after fault impact the sensitivity of the existing protection. Then, based on the characteristics of armored three-core cable, phase-mode transformation is utilized to decouple the fault information and the specific moduli are selected to reflect all kinds of fault types. The expression of backward traveling-wave (BTW) voltage based on interpolation is derived under the condition of low sampling frequency. Finally, a pilot protection based on BTW voltage difference for submarine cables of LFTS with integrated offshore wind power is proposed, which has higher sensitivity because the difference between BTW calculated from local information and the one from remote information is considerable during fault transient period. Simulation tests compare the performance of the existing protection with that of the proposed protection. Extensive simulations corroborate that the proposed protection reliably identifies the fault cable in various fault scenarios.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 4","pages":"1176-1187"},"PeriodicalIF":5.7,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10778169","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}