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CSEE Journal of power and Energy Systems 2022年第3期8卷 710-720页

作者： Lin Yu Huadong Sun Shiyun Xu Bing Zhao Jian Zhang state Key Laboratory of power grid Safety and Energy Conservation China Electric Power Research InstituteBeijing100192China

The power system is experiencing a higher penetration of renewable energy generations(REGs).The short circuit ratio(SCR)and the grid impedance ratio(GIR)are two indices to quantify the system strength of the power system with REGs.In this paper,the critical short circuit ratio(CSCR)is defined as the corresponding SCR when the system voltage is in the critical stable state.Through static voltage stability analysis,the mathematical expression of the CSCR considering the impact of GIR is derived.The maximum value of CSCR is adopted as the critical value to distinguish the weak power system.Based on the static equivalent circuit analysis,it is proved that the CSCR is still effective to evaluate critical system strength considering the interactive impact among REGs.Finally,we find that the GIR can be neglected and the SCR can be used individually to evaluate the system strength when SCR>2 or GIR>5.The correctness and rationality of the CSCR and its critical value are validated on ADPSS.

关键词： Critical short circuit ratio critical value grid impedance ratio maximum power transfer theorem static equivalent circuit analysis

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 state Key Laboratory of power Transmission Equipment & System Security and New Technology Chongqing University

The increasing penetration of renewable energy sources(RESs) brings great challenges to the frequency security of power systems. The 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 cost. In 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 model. Then, we develop a multi-direction decomposition algorithm to solve the MFCUC efficiently. The original MINLP is decomposed into a master problem and subproblems. The subproblems check the nonlinear frequency dynamics and generate linear optimization cuts for the master problem to improve the frequency security in its optimal solution. Case studies on the modified IEEE 39-bus system and IEEE 118-bus system show a great reduction in operational costs. Moreover, 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： Security Frequency response Load modeling Indexes Costs Sensitivity power system dynamics

Non-intrusive Load Monitoring Based on Graph Total Variation for Residential Appliances

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Journal of Modern power Systems and Clean Energy 2024年第3期12卷 947-957页

作者： Xiaoyang Ma Diwen Zheng Xiaoyong Deng Ying Wang Dawei Deng Wei Li the College of electrical Engineering Sichuan University state grid Chongqing electric power Company state grid Sichuan electric power Company state grid Hubei electric power Company Limited research institute

Non-intrusive load monitoring is a technique for monitoring the operating conditions of electrical appliances by collecting the aggregated electrical information at the household power inlet. Despite several studies on the mining of unique load characteristics, few studies have extensively considered the high computational burden and sample training. Based on lowfrequency sampling data, a non-intrusive load monitoring algorithm utilizing the graph total variation(GTV) is proposed in this study. The algorithm can effectively depict the load state without the need for prior training. First, the combined Kmeans clustering algorithm and graph signals are used to build concise and accurate graph structures as load models. The GTV representing the internal structure of the graph signal is introduced as the optimization model and solved using the augmented Lagrangian iterative algorithm. The introduction of the difference operator reduces the computing cost and addresses the inaccurate reconstruction of the graph signal. With low-frequency sampling data, the algorithm only requires a little prior data and no training, thereby reducing the computing cost. Experiments conducted using the reference energy disaggregation dataset and almanac of minutely power dataset demonstrated the stable superiority of the algorithm and its low computational burden.

关键词： Load monitoring Costs Home appliances Hidden Markov models Training Kernel Clustering algorithms

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 faults.The 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 model.The 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 test.The 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 kN.The 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 load.The research results provide an important theoretical reference for the axial stability structure of transformers.

关键词： axial correction structure

Optimized Auxiliary Frequency Control of Wind Farm Based on Piecewise Reduced-order Frequency Response Model

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Journal of Modern power Systems and Clean Energy 2024年第3期12卷 791-802页

作者： Xu Zhang Chen Zhao Junchao Ma Long Zhang Dan Sun Chenxu Wang Yan Peng Heng Nian the School of electrical Engineering Zhejiang University electric power research institute of state grid Zhejiang electric power Corporation

With the increasing wind power penetration in the power system, the auxiliary frequency control(AFC) of wind farm(WF) has been widely used. The traditional system frequency response(SFR) model is not suitable for the wind power generation system due to its poor accuracy and applicability. In this paper, a piecewise reduced-order frequency response(PROFR) model is proposed, and an optimized auxiliary frequency control(O-AFC) scheme of WF based on the P-ROFR model is proposed. Firstly, a full-order frequency response model considering the change in operating point of wind turbine is established to improve the applicability. In order to simplify the fullorder model, a P-ROFR model with second-order structure and high accuracy at each frequency response stage is proposed. Based on the proposed P-ROFR model, the relationship between the frequency response indexes and the auxiliary frequency controller coefficients is expressed explicitly. Then, an OAFC scheme with the derived explicit expression as the optimization objective is proposed in order to improve the frequency support capability on the premise of ensuring the full release of the rotor kinetic energy and the full use of the effect of time delay on frequency regulation. Finally, the effectiveness of the proposed P-ROFR model and the performance of the proposed OAFC scheme are verified by simulation studies.

关键词： Frequency control Frequency response Rotors Analytical models Indexes Optimization Delay effects

Traveling Wave Characteristics Based Pilot Protection Scheme for Hybrid Cascaded HVDC Transmission Line

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Journal of Modern power Systems and Clean Energy 2024年第3期12卷 971-980页

作者： Dalin Mu Sheng Lin Xiaopeng Li the School of electrical Engineering Southwest Jiaotong University the state grid Sichuan electric power research institute

The hybrid cascaded high-voltage direct current(HVDC) transmission system has various operation modes, and some operation modes have sharply increasing requirements for protection rapidity, while the traditional pilot differential protection(PDP) has poor rapidity, and even refuses to operate when faults occur on the DC line. Therefore, a novel pilot protection scheme based on traveling wave characteristics is proposed. First, the adaptability of the traditional PDP applied in engineering is analyzed for different operation modes. Then, the expressions of the forward traveling wave(FTW) and backward traveling wave(BTW) on the rectifier side and the inverter side are derived for different fault locations. From the theoretical derivation, the difference between the BTW and FTW on the rectifier side is less than zero, and the same is true on the inverter side. However, in the event of an external fault of DC line, the difference between the BTW and FTW at nearfault terminal protection installation point is greater than zero. Therefore, by summing over the product of the difference between BTW and FTW of the rectifier side and that of the inverter side, the fault identification criterion is constructed. The simulation results show that the proposed pilot protection scheme can quickly and reliably identify the short-circuit faults of DC line in different operation modes.

关键词： HVDC transmission Inverters Rectifiers Delays Partial discharges Fault diagnosis Valves

Multi-Time Scale Operation and Simulation Strategy of the Park Based on Model Predictive Control

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Energy Engineering 2024年第3期121卷 747-767页

作者： Jun Zhao Chaoying Yang Ran Li Jinge Song grid Center State Grid Shanxi Electric Power Company Electric Power Science Research InstituteTaiyuan030000China

Due to the impact of source-load prediction power errors and uncertainties,the actual operation of the park will have a wide range of fluctuations compared with the expected state,resulting in its inability to achieve the expected economy.This paper constructs an operating simulation model of the park power grid operation considering demand response and proposes a multi-time scale operating simulation method that combines day-ahead optimization and model predictive control(MPC).In the day-ahead stage,an operating simulation plan that comprehensively considers the user’s side comfort and operating costs is proposed with a long-term time scale of 15 min.In order to cope with power fluctuations of photovoltaic,wind turbine and conventional load,MPC is used to track and roll correct the day-ahead operating simulation plan in the intra-day stage to meet the actual operating operation status of the park.Finally,the validity and economy of the operating simulation strategy are verified through the analysis of arithmetic examples.

关键词： Demand response model predictive control multiple time scales operating simulation

Analysis and Modeling of Time Output Characteristics for Distributed Photovoltaic and Energy Storage

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Energy Engineering 2024年第4期121卷 933-949页

作者： Kaicheng Liu Chen Liang Xiaoyang Dong Liping Liu China electric power research institute Beijing100192China electric power research institute State Grid Gansu Electric Power CompanyLanzhou730000China state Key Laboratory of power grid Safety Beijing100084China

Due to the unpredictable output characteristics of distributed photovoltaics,their integration into the grid can lead to voltage fluctuations within the regional power grid.Therefore,the development of spatial-temporal coordination and optimization control methods for distributed photovoltaics and energy storage systems is of utmost importance in various scenarios.This paper approaches the issue from the perspective of spatiotemporal forecasting of distributed photovoltaic(PV)generation and proposes a Temporal Convolutional-Long Short-Term Memory prediction model that combines Temporal Convolutional Networks(TCN)and Long Short-Term Memory(LSTM).To begin with,an analysis of the spatiotemporal distribution patterns of PV generation is conducted,and outlier data is handled using the 3σ rule.Subsequently,a novel approach that combines temporal convolution and LSTM networks is introduced,with TCN extracting spatial features and LSTM capturing temporal features.Finally,a real spatiotemporal dataset from Gansu,China,is established to compare the performance of the proposed network against other models.The results demonstrate that the model presented in this paper exhibits the highest predictive accuracy,with a single-step Mean Absolute Error(MAE)of 1.782 and an average Root Mean Square Error(RMSE)of 3.72 for multi-step predictions.

关键词： Photovoltaic power generation spatio-temporal prediction temporal convolutional network long short-term memory network

Pathway Planning of Nuclear power Development Incorporating Assessment of Nuclear Event Risk

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Journal of Modern power Systems and Clean Energy 2024年第2期12卷 500-513页

作者： Xinxin Yang Yusheng Xue Bin Cai School of electrical Engineering Southeast UniversityNanjingChinaand they are also with State Grid Electric Power Research Institute(NARI Group Corporation)NanjingChina state Key Laboratory of Smart grid Protection and Operation Control NanjingChina state grid electric power research institute(NARI Group Corporation) NanjingChina

The nuclear event risk(NER)is an important and disputed factor that should be reasonably considered when planning the pathway of nuclear power development(NPD)to assess the benefits and risks of developing nuclear power more objectively.This paper aims to explore the impact of nuclear events on NPD pathway planning.The influence of nuclear events is quantified as a monetary risk component,and an optimization model that incorporates the NER in the objective function is proposed.To optimize the pathway of NPD in the lowcarbon transition course of power supply structure evolution,a simulation model is built to deduce alternative NPD pathways and corresponding power supply evolution scenarios under the constraint of an exogenously assigned carbon emission pathway(CEP);moreover,a method is proposed to describe the CEP by superimposing the maximum carbon emission space and each carbon emission reduction(CER)component,and various CER components are clustered considering the emission reduction characteristics and resource endowments of different power generation technologies.A case study is conducted to explore the impact of NER and its risk valuation uncertainty on NPD pathway planning.The method presented in this paper allows the impact of nuclear events on NPD pathway planning to be quantified and improves the level of coordinated optimization of benefits and risks.

关键词： Low-carbon transition power supply structure evolution nuclear power development(NPD) quantitative analysis nuclear event risk evaluation

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Experimental study on ice monitoring method for 10 kV transmission line with tangent tower in alpine landform

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High Voltage 2024年第1期9卷 182-194页

作者： Lin Yang Zhiqiang Chen Yanpeng Hao Xinhao Lin Lei Yu Yue Li Zhiyong Yuan Licheng Li School of electric power South China University of TechnologyGuangzhouChina electrical power research institute China Southern Power GridGuangzhouChina electric power research institute of Guizhou power grid Co.Ltd. GuizhouChina

Ice monitoring methods were applied for 110 kV and above transmission lines with tangent towers.However,the change in the vertical span is not considered,and a significant difference lies in the tower-conductor structure of 10 kV transmission lines.For this reason,a proposal is made about the ice monitoring method for the 10 kV transmission line with tangent tower in alpine landform,which includes the ice monitoring system based on pressure measurement and corresponding equivalent ice thickness calculating methods.Different methods calculate the vertical span under different height difference coefficients.A finite element simulation model and a simulated ice load experiment system are established based on real conductors and insulators.Experiments and simulations under four simulated terrains are conducted within 2.5–20 mm ice thickness range.The comparison is made between this method and the method without considering the change in vertical span.The results show that the two methods are consistent and the relative errors are lower than�4%in simulation and�10%in experiment when the height difference coefficient is 0.When it is not 0,the relative errors of this method fall between t0.38%and t6.78%in simulation and−6.40%to t6.60%in experiment,while the relative errors of the method without considering the change in vertical span ranges between−11.13%and−20.23%in simulation and−11.65%to−23.20%in experiment.

关键词： methods tangent method