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Table of Content

    28 July 2023, Volume 57 Issue 7 Previous Issue    Next Issue
    New Type Power System and the Integrated Energy
    Cost Sharing Mechanisms of Pumped Storage Stations in the New-Type Power System: Review and Prospect
    LIU Fei, CHE Yanying, TIAN Xu, XU Decao, ZHOU Huijie, LI Zhiyi
    2023, 57 (7):  757-768.  doi: 10.16183/j.cnki.jsjtu.2021.516
    Abstract ( 1281 )   HTML ( 56 )   PDF (2464KB) ( 632 )   Save

    Driven by the carbon peaking and carbon neutrality goals, the power system is transforming to the new structure which is dominated by renewable energy and is facing a new supply-demand balance situation. Pumped storage, as the most mature energy storage technology at present, can provide flexible resources with different time scales to ensure the safety of the power system and promote the consumption of renewable energy. However, the operation strategy and cost sharing mechanism of the pumped storage station (PSS) are not clear, which hinders its further development under the new situation. In this context, the technical characteristics and functions of PSS are sorted out first. Then, the investment cost model is established from the perspective of the whole life cycle. After that, the evolution path of pricing mechanism and cost sharing mode are described in view of the different stages of electricity market development, providing a feasible scheme for the marketization of PSS. Finally, the future development of PSS is summarized and prospected.

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    Review of Energy Efficiency Management for Logistic Center Microgrid Toward Dual-Carbon Goal
    JIANG Si, FANG Sidun
    2023, 57 (7):  769-780.  doi: 10.16183/j.cnki.jsjtu.2022.052
    Abstract ( 406 )   HTML ( 25 )   PDF (6797KB) ( 285 )   Save

    Logistics center is the key node of the logistics network, which connects the regional logistics network and the external transportation system. Its operation and management have great impacts on the overall efficiency of the logistics system. Therefore, it has always been the fundamental issue of logistics management. In recent years, with the development of e-commerce and corresponding express services, the transportation tasks undertaken by logistics companies have continued to grow, which has posed great challenges to the operation of logistics centers. In order to fulfill the national “dual-carbon” target, logistics centers urgently need to control carbon emission intensity while ensuring the efficiency of transportation. In this context, this paper takes the logistics center as the focus, integrates the concept of microgrid, and summarizes its operation management and emission reduction measures, in order to promote the energy utilization of logistics enterprises while improving the quality and efficiency, and to ensure their sustainable development.

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    Optimization of Day-Ahead Dispatch Time Resolution in Power System with a High Proportion of Climate-Sensitive Renewable Energy Sources
    YE Zhiliang, LI Canbing, ZHANG Yongjun, LI Licheng, XIAO Yinjing, WU Yuhang, TAI Nengling
    2023, 57 (7):  781-790.  doi: 10.16183/j.cnki.jsjtu.2022.277
    Abstract ( 284 )   HTML ( 14 )   PDF (2692KB) ( 197 )   Save

    The time resolution of scheduling plan refers to the length of each time interval in the scheduling plan. With the increasing proportion of climate-sensitive renewable energy sources (RES), the volatility of net load during the dispatch interval is significantly enhanced, resulting in an insufficient system climbing capacity and abnormal frequency. Therefore, the setting of time resolution at different renewable energy penetration rates becomes an urgent problem to be solved at present. A global sensitivity-based day-ahead dispatch time resolution selection optimization method is proposed to select the time resolution for different volatility grids. To achieve a balance between the degree of refinement and the accuracy of load prediction, the global sensitivity analysis method based on Sobol' method and sparse chaos expansion is used to evaluate the impact of net load volatility and uncertainty on dispatch at different time resolutions, and an appropriate time resolution is chosen to optimize the scheduling effect. The analysis and simulation results show that the choice of time resolution is mainly determined by the net load fluctuation rate. The appropriate time granularity is chosen according to the net load fluctuation rate, which minimizes the unbalanced power, and the purpose of improving the optimal scheduling effect and reducing the dispatching cost is achieved.

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    Collaborative Optimization Scheduling of 5G Base Station Energy Storage and Distribution Network Considering Communication Load and Power Supply Reliability
    LI Junshuang, HU Yan, TAI Nengling
    2023, 57 (7):  791-802.  doi: 10.16183/j.cnki.jsjtu.2021.542
    Abstract ( 569 )   HTML ( 24 )   PDF (4126KB) ( 291 )   Save

    The electricity cost of 5G base stations has become a factor hindering the development of the 5G communication technology. This paper revitalized the energy storage resources of 5G base stations to achieve the purpose of reducing the electricity cost of 5G base stations. First, it established a 5G base station load model considering the communication load and a 5G base station energy storage capacity schedulable model considering the energy storage backup power demand of the 5G base station and the power supply reliability of the distribution network. Then, it proposed a 5G energy storage charge and discharge scheduling strategy. It also established a model for 5G base station energy storage to participate in coordinated and optimized dispatching of the distribution network. Finally, it compared the economy of optimized dispatch of 5G base station energy storage of different schemes. The analysis results show that the participation of idle energy storage of 5G base stations in the unified optimized dispatch of the distribution network can reduce the electricity cost of 5G base stations, alleviate the pressure on the power supply of the distribution network, increase the rate of new energy consumption in the system, and realize a win-win situation between the communication operator and the grid.

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    Optimal Dispatch of Integrated Energy System Based on Flexibility of Thermal Load
    HU Bo, CHENG Xin, SHAO Changzheng, HUANG Wei, SUN Yue, XIE Kaigui
    2023, 57 (7):  803-813.  doi: 10.16183/j.cnki.jsjtu.2021.534
    Abstract ( 314 )   HTML ( 10 )   PDF (4261KB) ( 234 )   Save

    The flexibility of thermal loads of buildings is a valuable balancing resource for operation of the heat and electricity integrated energy system (HE-IES). Considering the characteristics of large scale and small single load capacity of the themal load, the non-intrusive data-driven method has become an effective means to quantify the flexibility of building thermal load. However, due to the inaccuracy of the model or the lack of data, this method inevitably produces errors and brings epistemic uncertainty to the optimal dispatch of the HE-IES. An optimal dispatch model of the HE-IES that is compatible with the epistemic uncertainty of demand flexibility in the thermal loads of buildings is proposed. First, a data-driven flexible demand assessment method for building thermal load is described. The measurement errors are modeled as epistemic uncertainty and the multiple error sources are combined by using the D-S evidence theory. Then, the representative scenarios are selected to represent the epistemic uncertainty of the demand flexibility based Latin hypercube sampling(LHS) method, and the scenarios are reduced by the fuzzy clustering method. Finally, the representative scenarios are embedded in the coordinated and optimized dispatch of the HE-IES to realize the comprehensive consideration of the thermal load flexibility and related epistemic uncertainty of the building. The results demonstrate that considering the epistemic uncertainties of the thermal load demand is crucial for reducing the wind power curtailments and improving the operational flexibility of HE-IES.

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    Optimal Scheduling of Integrated Energy System Considering Integration of Electric Vehicles and Load Aggregators
    WANG Jing, XING Haijun, WANG Huaxin, PENG Sijia
    2023, 57 (7):  814-823.  doi: 10.16183/j.cnki.jsjtu.2022.029
    Abstract ( 471 )   HTML ( 17 )   PDF (1703KB) ( 313 )   Save

    Fully tapping into the role of user side regulation helps reduce the energy cost of integrated energy system (IES). Demand response (DR) and electric vehicle (EV) as schedulable resources on the user side are important regulation means for optimal scheduling of IES. However, in the actual operation process, due to the influence of load aggregator (LA) economic incentives and EV travel, the economic impact of the uncertainty of user side DR on IES cannot be ignored. Based on this, this paper proposes an IES optimal operation model considering the robust stochastic optimization of EV and the participation of LA which considers the energy purchase cost of IES from the superior network and the economic loss cost of LA. First, the response rate model and EV uncertainty model based on economic incentive are constructed. Then, the robust optimization model of EV is built, and the load demand of EV travel uncertainty is analyzed. Finally, a simulation example is given to analyze the impact of user DR uncertainty and EV uncertainty on IES operation economy and power balance. The simulation results show that considering the uncertainty of DR and EV can optimize the economic operation of IES and reduce the economic loss of LA and the total cost, which verifies the effectiveness and economy of the proposed models.

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    Distributed Prescribed-Time Consensus Based Cooperative Control for DC Microgrids
    ZHOU Ruchang, WANG Ziqiang, WANG Jie
    2023, 57 (7):  824-834.  doi: 10.16183/j.cnki.jsjtu.2022.050
    Abstract ( 312 )   HTML ( 12 )   PDF (1964KB) ( 252 )   Save

    A microgrid control method based on prescribed time control is proposed to solve the cooperative control problem of distributed energy resources (DER) in DC microgrid. First, a current control method based on prescribed time control is proposed, which can allocate the power output of each DER proportionally within a pre-defined time. Meanwhile, the outlet voltage of each distributed power supply can be adjusted to be near the rated value and the observation value can be kept at the rated value. Then, the microgrid system is simulated through MATLAB/Simulink and the effectiveness of the proposed control strategy is verified in different working conditions. Afterward, the finite-time control strategy is established in the simulated system. A comparison of the conservative power quality of the system current with the estimated time of system convergence in the scheduled-time control strategy verifies the advantages of the proposed strategy.

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    Low-Carbon Optimal Dispatch of Electric-Thermal System Considering Demand Response and Wind Power Consumption
    LIU Zixu, MI Yang, LU Changkun, FU Yang, SU Xiangjing
    2023, 57 (7):  835-844.  doi: 10.16183/j.cnki.jsjtu.2022.056
    Abstract ( 311 )   HTML ( 10 )   PDF (3821KB) ( 216 )   Save

    To solve the problems of large thermoelectric coupling in combined heat and power, high carbon emission of thermal power units, and insufficient resource flexibility on the load side in cogeneration units, a low-carbon dispatching model is established for the electricity-heat system. First, heat storage and carbon capture equipment is added on the source side while the demand response of electricity price and the heat load inertia of heating buildings are considered on the load side. Then, the sum of unit operating cost, carbon transaction cost and wind abandonment penalty cost are taken as the objective function with relevant constraints and solved by calling Gurobi solver. Finally, a comparative analysis of the economic cost, wind power consumption, and carbon emission rate of the system in different cases is conducted, which shows that the dispatching strategy proposed in this paper can improve the wind power consumption capacity while taking economy and low carbon emission into account.

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    Probabilistic Forecasting of Wind Power Generation Using Online LASSO VAR and EGARCH Model
    WANG Peng, LI Yanting, ZHANG Yu
    2023, 57 (7):  845-858.  doi: 10.16183/j.cnki.jsjtu.2021.377
    Abstract ( 341 )   HTML ( 21 )   PDF (20159KB) ( 229 )   Save

    Wind power generation has uncertainty due to the high fluctuation of wind speed. In traditional wind power prediction models, the uncertainty is measured by normal distribution with zero mean and constant variance. However, the variance may vary with time, which means the variance has heteroscedasticity. To improve the prediction accuracy, this paper proposes a new integrated probabilistic wind power prediction model for wind farm considering heteroscedasticity based on online least absolute shrinkage and selection operator and vector autoregression (LASSO VAR) and the exponential generalized autoregressive conditional heteroskedasticity (EGARCH) model. First, online LASSO VAR is used to forecast power output. Then, heteroscedasticity of residuals is validated by autoregressive conditional heteroskedasticity test. Considering heteroscedasticity, the news impact curve and dynamic significance line verify that positive and negative residuals affect future volatility asymmetrically. Thus, the EGARCH model is used to forecast the residuals to obtain the conditional variance of point prediction results. Finally, the probabilistic result of total power output is obtained by summing the power output of turbines in the wind farm considering the correlation of the active wind power of wind turbines. This method is applied to forecast the power output of a wind farm in East China and is proved effective in improving the prediction accuracy.

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    Improved Self-Excited Resonant Wireless Power Transmission System
    ZHAO Zhibin, LUO Bin, TANG Ting, WANG Chunfang, SUN Zhonghua
    2023, 57 (7):  859-867.  doi: 10.16183/j.cnki.jsjtu.2022.427
    Abstract ( 298 )   HTML ( 17 )   PDF (3593KB) ( 207 )   Save

    Aimed at the main power tube with problems of weak driving ability, poor soft switching performance, and large switching loss in a self-excited resonant wireless power transmission (WPT) system, an analysis of the working principle of resonant main circuit is conducted, which indicates that the root cause of the problem is that two uncontrollable diodes limit the driving resistance of main power tube. Thereofre, an improved self-excited resonant circuit is proposed by using a fully controlled low power switch instead of the diode. The circuit theoretical analysis of four working modes suggests that the main power tube of the improved circuit has a stronger driving ability. To further obtain the optimal parameters of the improved system, a nonlinear programming model of the system is established by considering the tolerance limit of each parameter, and a hybrid optimization algorithm is designed to obtain the system global optimal solution. A comparison of the results of system simulation and experimental prototype shows that the improved WPT system has an excellent soft switching performance. The temperature of the switch tube is reduced by about 7 ℃, and the efficiency is increased by about 4%.

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    A Comprehensive Evaluation Model of Buildings Based on Improved TOPSIS
    JIANG Yi, FU Juncheng, LI Zewen, ZHANG Yuqing, YIN Jungang, YAO Jiangang
    2023, 57 (7):  868-877.  doi: 10.16183/j.cnki.jsjtu.2022.117
    Abstract ( 320 )   HTML ( 8 )   PDF (1198KB) ( 218 )   Save

    In order to evaluate the operation of energy consumption, environmental protection, and economy, a multi-index comprehensive evaluation model based on an improved technique for order preference by similarity to ideal solution (TOPSIS) is proposed. Based on the analysis of building operation, a multi-index evaluation system is constructed. Then, an improved TOPSIS evaluation method is introduced and a distance measure of the TOPSIS evaluation model by the gray correlation algorithm and analytic hierarchy process (AHP)-entropy weight method is determined. Next, a multi-attribute weighted evaluation model is established to analyze the building operation comprehensively. The multi-index evaluation of eight power office buildings indicates that the building comprehensive evaluation results vary with time and the energy consumption index score plays the main role in all indexes. A comparison of the evaluation results with those obtained by other evaluation methods verifies the effectiveness of the proposed building multi-index evaluation model.

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    A High-Efficiency Modulation Method of Two-Stage Inverter with Low Voltage Input and High Voltage Output
    KUANG Yonghong, XIE Wei, TIAN Li, LIN Yuan, ZHOU Xifeng
    2023, 57 (7):  878-886.  doi: 10.16183/j.cnki.jsjtu.2022.102
    Abstract ( 236 )   HTML ( 10 )   PDF (3576KB) ( 251 )   Save

    Miniaturization, lightweight, and high power density are development trends of vehicle-mounted inverters. The existing vehicle mounted single-phase inverter with DC 110 V input voltage adopts two-stage independent modulation between Boost circuit and full bridge inverter circuit, which has the problems of low efficiency and low power density. To solve these problems, a two-stage cooperative modulation between Boost circuit and full-bridge inverter circuit is studied. According to the relationship between the absolute value of input voltage and output voltage, the Boost circuit and the full-bridge inverter operate with different modes in the proposed method, which optimizes the insulated gate bipolar transistor(IGBT) switching state and diode on-off state to reduce the loss of the inverter and improve the efficiency of the inverter. At the same time, the output harmonics of the full-bridge inverter circuit can be reduced to decrease the size of the filter and improve the power density of the inverter. A 2.75 kV·A prototype is designed and fabricated. Experiments are conducted to verify the correctness and feasibility of the proposed method.

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    Calculation Method of Network Usage Charge for Market-Oriented Trading in Distributed Generation Market
    WU Lei, HAN Dong, MAO Guijiang, LIU Wei, ZHOU Yangfei
    2023, 57 (7):  887-898.  doi: 10.16183/j.cnki.jsjtu.2022.061
    Abstract ( 455 )   HTML ( 14 )   PDF (26758KB) ( 258 )   Save

    With the gradual advancement of the market-oriented process of distributed generation, it is difficult to accurately distinguish the use degree of power grid assets by prosumers via pricing method of uniform calculation of network usage charge according to user access voltage. Therefore, this paper proposes a calculation method of network usage charge suitable for market-oriented trading of distributed generation. The characteristics of the peer-to-peer (P2P) trading model and the community-based (CB) trading model in distributed generation market are discussed from the perspective of prosumers. Meanwhile, the power trading models of the P2P model and the CB model are constructed. The optimal power flow model based on second-order cone relaxation is used to determine the distribution of power flow in distribution network, and the distribution locational marginal price is calculated with the economic significance of dual multiplier. Considering the transitivity of dual multipliers, calculation models of the network usage charge of the P2P trading model and the CB trading model are established by coupling the power trading model and the optimal power flow model. The limitations of the CB trading model are analyzed, and the Shapley value method is used to realize the fair allocation of network usage charge according to marginal contribution. By using the improved IEEE15 bus and IEEE123 bus test systems, the availability and feasibility of the proposed calculation method of network usage charge in distributed generation market are verified.

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    Effect of Binder and Compression on Pore Structure and Gas Permeability of Gas Diffusion Layer in PEMFC
    LIAO Yifeng, LI Weipeng
    2023, 57 (7):  899-909.  doi: 10.16183/j.cnki.jsjtu.2022.113
    Abstract ( 351 )   HTML ( 15 )   PDF (18900KB) ( 204 )   Save

    During the production of gas diffusion layer (GDL), hydrophobic binding treatment and assembly compression lead to changes in pore structure and permeability. In this paper, a GDL model based on stochastic reconstruction is developed with binder and inhomogeneous compression. Single-phase flow of gas is simulated by utilizing the Lattice Boltzmann method and the effect of binder and compression on pore structure and permeability of GDL is explored. The results show that both the binder and the compression cause porosity to decrease and small-scale pore volume to increase, leading to the shrink of permeability. The change is basically consistent with the theoretical relationship between porosity and permeability. Moreover, the decrease of permeability caused by compression is higher than that caused by binder when porosity is similar.

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    Performance of Solar Vacuum Tube Water Heater-Air Source Heat Pump System in Cold Area
    LI Jinping, DONG Yuhui, LI Caijun, DAI Jingbo, NIU Yinan, NOVAKOVIC Vojislav
    2023, 57 (7):  910-920.  doi: 10.16183/j.cnki.jsjtu.2022.005
    Abstract ( 368 )   HTML ( 15 )   PDF (4225KB) ( 291 )   Save

    To improve the stability of solar heating and reduce the high cost of air source heat pump heating, the idea of air source heat pump assisted solar stable heating was proposed. A solar vacuum tube water heater-air source heat pump system was developed and bulit in Weiling Township, Qilihe District, Lanzhou, Gansu Province. The performance of the system was compared to analyze the heat collection efficiency, heat pump coefficient of performance (COP), solar energy guarantee rate, and energy efficiency ratio under sunny, overcast, and cloudy conditions. The results show that the effective heat obtained by solar energy under sunny, overcast, and cloudy conditions is 75.5 kW·h, 4.1 kW·h, and 49.2 kW·h respectively, the system heat collection efficiency is 61.3%, 26.6%, and 55.2%, the average coefficient of performance(COP) of the solar heat pump is 3.6, 3.4, and 3.6, the average COP of the air source heat pump is 0, 2.9, and 3.1, the actual heat supply of the system is 113.4 kW·h, 125.9 kW·h, and 124.8 kW·h, the system power consumption is 33.4 kW·h, 50.5 kW·h, and 42.7 kW·h, the system solar energy guarantee rate is 66.6%, 3.3%, and 39.4%, and the system energy efficiency ratio is 3.4, 2.5, and 2.9 respectively. The research results prove that the solar vacuum tube collector-air source heat pump system is feasible for heating and provide a new way for heating in cold areas.

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    Characteristics of Short-Circuit Current in Distribution Network with Doubly-Fed Wind Power System
    XI Xinze, XING Chao, QIN Risheng, HE Tingyi, HE Peng, MENG Xian, CHENG Chunhui
    2023, 57 (7):  921-927.  doi: 10.16183/j.cnki.jsjtu.2022.011
    Abstract ( 241 )   HTML ( 8 )   PDF (1011KB) ( 169 )   Save

    The doubly-fed induction generator (DFIG) is connected to the distribution network as a distributed power source, which turns a radial single power supply system into a dual power supply system and changes the topology of the distribution network. When a short-circuit fault occurs in the distribution network, the short-circuit current of the distribution network will be affected by the access to wind power. Aimed at the problem that the short-circuit current is affected by the access capacity of the wind turbine and the location of the access point when DFIG is connected to the distribution network by distributed power sources and a three-phase short-circuit fault occurs at different points in the distribution network, a theoretical derivation and a simulation analysis are conducted by combining the control strategy of DFIG. First, relational expression of short-circuit fault current of the distribution network including wind power is theoretically derived, and the short-circuit current provided by the wind turbine is analyzed. Then, model predictive control is introduced to be compared with classical vector control to analyze the impact of different control strategies on the short-circuit current. The changes in access capacity and location are analyzed when a three-phase short-circuit fault occurs at different points in the distribution network, and the impact of DFIG on the short-circuit current of the distribution network is summarized.

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    Assessment Method for Urban Energy Carbon Emission Peak Based on Mann-Kendall Trend Test
    CHEN Yun, SHEN Hao, WANG Xiaohui, ZHAO Wenkai, PAN Zhijun, WANG Jiayu, LI Siyuan, HAN Dong
    2023, 57 (7):  928-938.  doi: 10.16183/j.cnki.jsjtu.2021.524
    Abstract ( 517 )   HTML ( 17 )   PDF (1541KB) ( 332 )   Save

    Energy is an important component of urban carbon emissions. Assessing the peak of urban energy carbon is a necessary means to implement the national “double carbon” strategy. For this reason, this paper proposes an energy carbon peaking assessment method based on Mann-Kendall trend test for carbon emission of urban energy. By constructing a carbon monitoring system covering elements such as energy carbon emissions, clean energy generation, and transportation electric energy substitution, the total energy carbon emissions of the city are calculated by combining historical data. In view of the seasonality and randomness of energy carbon emissions, the Mann-Kendall trend test was used to establish a model for determining urban energy carbon peaking and to measure regional carbon emissions in different periods. Taking an administrative region in Shanghai as an example, the peak status of energy carbon in this region is judged from the perspective of year and quarter. The results show that based on the annual data, the region has reached its peak energy carbon in 2020. Based on quarterly data, peak energy carbon has been achieved in summer and autumn, while spring and winter are still in plateau. The methods proposed in this paper can be used to assess the carbon peak status in the city, and provide a reference for examining the carbon peak process in other provinces and cities.

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