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Hierarchical Task Planning for power Line Flow Regulation

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CSEE Journal of power and energy Systems 2024年第1期10卷 29-40页

作者： Chenxi Wang Youtian Du Yanhao Huang Yuanlin Chang Zihao Guo the Ministry of Education key Lab for Intelligent Networks and Network security Xi'an Jiaotong UniversityXi'an 713599China the state key laboratory of power grid Safety and energy conservation China Electric Power Research InstituteBeijing 100192China

The complexity and uncertainty in power systems cause great challenges to controlling power *** a popular data-driven technique,deep reinforcement learning(DRL)attracts attention in the control of power ***,DRL has some inherent drawbacks in terms of data efficiency and *** paper presents a novel hierarchical task planning(HTP)approach,bridging planning and DRL,to the task of power line flow ***,we introduce a threelevel task hierarchy to model the task and model the sequence of task units on each level as a task planning-Markov decision processes(TP-MDPs).Second,we model the task as a sequential decision-making problem and introduce a higher planner and a lower planner in HTP to handle different levels of task *** addition,we introduce a two-layer knowledge graph that can update dynamically during the planning procedure to assist *** results conducted on the IEEE 118-bus and IEEE 300-bus systems demonstrate our HTP approach outperforms proximal policy optimization,a state-of-the-art deep reinforcement learning(DRL)approach,improving efficiency by 26.16%and 6.86%on both systems.

关键词： Knowledge graph power line flow regulation reinforcement learning task planning

Ag-doped Ti_(3)C_(2)T_(x) sensor:A promising candidate for lowconcentration H_(2)S gas sensing

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High Voltage 2024年第3期9卷 537-545页

作者： Fuping Zeng Xiaoxuan Feng Xiaoyue Chen Hao Qiu Yiming Yan Qiang Yao Ju Tang School of Electrical Engineering and Automation Wuhan UniversityWuhanChina Hubei key laboratory of power Equipment&System security for Integrated energy Resources WuhanChina state grid Chengdu Electric power Supply Company ChengduChina state grid Chongqing Electric power Research Institute ChongqingChina state key laboratory of power Transmission Equipment&System security and New Technology Chongqing UniversityChongqingChina

Trace hydrogen sulphide(H_(2)S)could reflect the severity of insulation faults in gas-insulated switchgear(GIS),therefore,accurate and fast detection of low-concentration H_(2)S is important for on-line monitoring,fault diagnosis,and state evaluation in ***-Ti_(3)C_(2)T_(x) chemiresistive-type sensors were fabricated via drop-coating with self-reduction synthesised Ag-doped Ti_(3)C_(2)T_(x).The as-prepared sensors exhibited an excel-lent sensitivity and selectivity to H_(2)S with an extremely low detection of limit of 18.57 parts per billion(ppb)at 25℃(room temperature).The response of Ag-Ti_(3)C_(2)T_(x) sensor to 10 parts per million(ppm)H_(2)S was enhanced~12 times than that of the pristine Ti_(3)C_(2)T_(x) *** compositing of Ti_(3)C_(2)T_(x) with Ag nanoparticles(NPs)enabled the fast response/recovery time for H_(2)S *** analysis found that the enhanced H_(2)S sensing performances could be attributed to chemical sensitisation,adsorbed oxygen species regulation and high Brunauer–Emmett–Teller(BET)surface *** study paves the way for Ag-Ti_(3)C_(2)T_(x) as room-temperature sensing materials to detect low-concentration H_(2)S in GIS.

关键词： insulation diagnosis attributed

Influence characteristics of water penetration on fibre-reinforced polymer/rigid polyurethane foam interface of the composite cross-arm considering natural ageing

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High Voltage 2024年第1期9卷 81-93页

作者： Jun Xie Zhe Zhou Ziqian Liu Haonan Tian Sigang Zhang Qing Xie Hebei Provincial key laboratory of power Transmission Equipment security Defense North China Electric Power UniversityBaodingChina state grid Gansu Electric power Company LanzhouChina

Fibre-reinforced polymer(FRP)/rigid polyurethane foam(RPUF)interface is susceptible to moisture intrusion in addition to natural ageing during *** study investigated the influence of moisture intrusion on the FRP/RPUF interface under natural ageing using experiments and molecular dynamics(MD)*** absorption,shear strength,and leakage current tests were used to clarify the changes in the interface *** degradation mechanism of moisture intrusion at the interface under natural ageing was revealed by MD simulation and *** results show that the natural ageing of interfacial materials will slightly reduce the quality of the interface but will reduce the water resistance of the material and promote the process of water intrusion into the *** addition,water mainly invades the interface through *** water penetration,the interfacial bonding strength and insulation performance significantly *** and hydrolysis of interfacial materials are the main reasons for decreased interfacial *** can cause irreversible damage to the interface,increasing interface defects and water *** vicious cycle of material hydrolysis is the ultimate cause of interfacial *** polar molecules produced by this process and the water absorbed by the interface caused the degradation of the interface insulation performance.

关键词： interface polyurethane interfacial

Study on the dynamic mechanical properties of winding-block axial structure considering short circuit strain rate effect

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High Voltage 2024年第2期9卷 380-390页

作者： Xinyu Wang Ping Wang Jianghai Geng Zikang Zhang Fangcheng Lü Shuguo Gao Hebei Provincial key laboratory of power Transmission Equipment security Defense North China Electric Power UniversityBaodingChina state grid Hebei Electric power Research Institute ShijiazhuangChina

Transformers may suffer multiple short-circuit impacts during long-term operation,and axial instability is one of the typical types of serious accidents caused by short-circuit *** axial instability form of the winding-block structure is analysed,and the dynamic solution of the winding short-circuit electromagnetic force is obtained by estab-lishing the three-dimensional magnetic-circuit-force multi-physical field coupling simulation *** influence of strain rate on the cushion block constitutive equation is corrected,and the modified model is verified by short-circuit impact test and quasi-static *** research results show that for 110 kV 31.5 MVA transformers,the maximum electromagnetic axial resultant force of winding is 363.16 kN,and the ultimate tilt force is 1214.2 *** pre-tightening force configuration is accordingly recom-mended to range from 363.16 to 608.28 kN,which is narrowed by 18.49%compared with the static calculation method;Meanwhile,adding a logarithmic strain rate correction term to the classical constitutive equation of the cushion block can achieve a good correction of the stress-strain relationship with the coefficient of determination above 0.99,and the cushion block has a larger elastic modulus under high strain rate *** research results provide an important theoretical reference for the axial stability structure of transformers.

关键词： axial correction structure

Safety monitoring method for powerline corridors based on single‐stage detector and visual matching

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High Voltage 2024年第4期9卷 805-815页

作者： Jinheng Li Hanbo Zheng Peng Liu Yanshen Liang Feng Shuang Junjie Huang Guangxi key laboratory of power System Optimization and energy Technology Guangxi UniversityNanningChina China Southern power grid Guangxi power grid Company Ltd. NanningChina state grid Hubei Electric power Research Institute WuhanChina

Effective monitoring and early warning of overhead power lines are critical for ensuring power supply stability and personnel ***,existing methods that rely solely on single vision or light detection and ranging(LiDAR)have limitations such as numerous invalid alarms,hardware equipment constraints,and lack of real-time monitoring *** article proposes an intelligent monitoring method for safety distance of the powerline corridor based on heterogeneous sensor ***,an optimised single-stage detector is designed to detect safety hazard *** the detector,the backbone network and the sample matching strategy are improved;in addition,the learning strategy is ***,the pose transformation relationship is obtained through the visual matching of prior LiDAR information and *** back projection transformation of 2D–3D is achieved according to the ***,a monocular camera-based end-to-end distance measurement scheme is proposed by combining 2D object information with coordinate transformation *** scheme is applied to the distance measurements from hazard objects to *** experimental results show that the optimisation method improves the detection accuracy and reduces the computational complexity of the ***,case experiments with continuous frame data verify the effectiveness of the safety distance monitoring scheme.

关键词： visual hardware matching

Multi-area Frequency-constrained Unit Commitment for power Systems with High Penetration of Renewable energy Sources and Induction Machine Load

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Journal of Modern power Systems and Clean energy 2024年第3期12卷 754-766页

作者： Leibao Wang Hui Fan Jifeng Liang Longxun Xu Tiecheng Li Peng Luo Bo Hu Kaigui Xie the state grid Hebei Electric power Research Institute Shijiazhuang 050021China state key laboratory of power Transmission Equipment&System security and New Technology Chongqing UniversityChongqing 400044China

The increasing penetration of renewable energy sources(RESs)brings great challenges to the frequency security of power *** traditional frequency-constrained unit commitment(FCUC)analyzes frequency by simplifying the average system frequency and ignoring numerous induction machines(IMs)in load,which may underestimate the risk and increase the operational *** this paper,we consider a multiarea frequency response(MAFR)model to capture the frequency dynamics in the unit scheduling problem,in which regional frequency security and the inertia of IM load are modeled with high-dimension differential algebraic equations.A multi-area FCUC(MFCUC)is formulated as mixed-integer nonlinear programming(MINLP)on the basis of the MAFR ***,we develop a multi-direction decomposition algorithm to solve the MFCUC *** original MINLP is decomposed into a master problem and *** subproblems check the nonlinear frequency dynamics and generate linear optimization cuts for the master problem to improve the frequency security in its optimal *** studies on the modified IEEE 39-bus system and IEEE 118-bus system show a great reduction in operational ***,simulation results verify the ability of the proposed MAFR model to reflect regional frequency security and the available inertia of IMs in unit scheduling.

关键词： Decomposition algorithm frequency response frequency-constrained unit commitment induction machine multi-area mixed-integer nonlinear programming(MINLP)

power Flow Model for Medium-voltage Distribution Systems Considering Measurement and Structure Characteristics

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Journal of Modern power Systems and Clean energy 2024年第2期12卷 571-583页

作者： Zhengmei Lu Wei Yan Dezhi Huang Junjie Tang Ferdinanda Ponci Antonello Monti state key laboratory of power Transmission Equipment&System security and New Technology Chongqing UniversityChongqing 400044China state grid Zhejiang Yiwu power Supply Company State Grid Zhejiang Electric Power CompanyYiwu 322001China Institute for Automation of Complex power Systems of the E.ON energy Research Center at RWTH Aachen University Aachen52074Germany Digital energy Fraunhofer FIT Aachen52072Germany IEEE

Medium-voltage distribution systems(MVDSs)mainly consist of a feeder head,lines,distribution transformers,and the equivalent load or power supply interfaced with the distribution *** information of such load or power supply can be measured via the three-wattmeter method(THM)and the two-wattmeter method(TWM).The measurements can be used to perform the control of the power supply and simulate the characteristics of the load,so the models of the load and the power supply need to consider the measurement *** research works on three-phase power flow(PF)just consider the measurement characteristics of ***,the PF equation of the bus measured via TWM is firstly *** on conventional measurements,an accurate and general model of the grounded and ungrounded slack bus is ***,the influence arising from the connection type and angle shift of distribution transformers on the admittance matrix is considered,and thus a general three-phase transformer model is summarized,which is applicable for all the transformers mentioned ***,Newton's method is adopted to solve the PF calculation,and the performance of the proposed PF model is demonstrated through designed tests.

关键词： Medium-voltage distribution system three-phase power flow calculation measurement characteristic slack bus modeling distribution transformer

Enhanced properties of stone coal-based composite phase change materials for thermal energy storage

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 206-215页

作者： Baoshan Xie Huan Ma Chuanchang Li Jian Chen key laboratory of Renewable energy Electric-Technology of Hunan Province School of Energy and Power EngineeringChangsha University of Science and TechnologyChangsha 410114China state key laboratory of Disaster Prevention and Reduction for power grid Changsha University of Science and TechnologyChangsha 410114China

Phase change materials (PCMs) can be incorporated with low-cost minerals to synthesize composites for thermal energy storage in building *** coal (SC) after vanadium extraction treatment shows potential for secondary utilization in composite *** prepared SC-based composite PCMs with SC as a matrix,stearic acid (SA) as a PCM,and expanded graphite (EG) as an *** combined roasting and acid leaching treatment of raw SC was conducted to understand the effect of vanadium extraction on promoting loading *** showed that the combined treatment of roasting at 900℃ and leaching increased the SC loading of the composite by 6.2%by improving the specific surface *** loading capacity and thermal conductivity of the composite obviously increased by 127%and 48.19%,respectively,due to the contribution of 3wt% *** data were supported by the high load of 66.69%and thermal conductivity of 0.59 W·m^(-1)·K-1of the designed *** obtained composite exhibited a phase change temperature of 52.17℃,melting latent heat of 121.5 J·g^(-1),and good chemical *** SC-based composite has prospects in building applications exploiting the secondary utilization of minerals.

关键词： thermal energy storage phase change material stone coal vanadium extraction secondary utilization

Transient Stability Analysis of Converter-based Islanded Microgrids Based on Iterative Equal Area Criterion Considering Reactive power Loop Dynamics and Varying Damping

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Journal of Modern power Systems and Clean energy 2024年第4期12卷 1170-1182页

作者： Xilin Li Jingyi Zhang Zhen Tian Xiaoming Zha Wei Wang Meng Huang Chong Shao Hubei key laboratory of power Equipment&System security for Integrated energy School of Electrical Engineering and AutomationWuhan UniversityWuhanChina NARI Technology Co. Ltd.NanjingChina state grid Gansu Electric power Company LanzhouChina

With the rapid increase in the installed capacity of renewable energy in modern power systems,the stable operation of power systems with considerable power electronic equipment requires further *** converter-based islanded mi-crogrid(CIM)systems equipped with grid-following(GFL)and grid-forming(GFM)voltage-source converters(VSCs),it is chal-lenging to maintain stability due to the mutual coupling effects between different VSCs and the loss of voltage and frequency sup-port from the power *** previous studies,quantitative transient stability analysis was primarily used to assess the active power loop of ***,frequency and voltage dy-namics are found to be strongly coupled,which strongly affects the estimation result of stability *** addition,the vary-ing damping terms have not been fully *** bridge these gaps,this paper investigates the transient stability of CIM consid-ering reactive power loop dynamics and varying ***,an accuracy-enhanced nonlinear model of the CIM is derived based on the effects of reactive power loop and post-disturbance frequency jump *** these effects will elimi-nates the risk of *** reactive power loop dynamics make the model coefficients be no longer constant and thus vary with the power *** evaluate quantitatively the effects of re-active power loop and varying damping on the transient stability of CIM,an iterative criterion based on the equal area criterion theory is *** addition,the effects of parameters on the stable boundary of power system are analyzed,and the dynamic interaction mechanisms are *** and experiment results verify the merits of the proposed method.

关键词： Transient stability converter iterative criterion reactive power loop post-disturbance frequency jump