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01 May 2020, Volume 41 Issue 5
    

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  • SU Junni,ZHANG Xin,ZHAO Junwei,ZHANG Rui,QU Minghui,YANG Yanhong
    Electric Power Construction. 2020, 41(5): 1-8. https://doi.org/10.12204/j.issn.1000-7229.2020.05.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to optimize the economic operation of integrated electricity-gas system (IEGS) and take into account the effective cooperation of multi-energy storage (MES) equipment and integrated demand response (IDR), an optimal dispatching model suitable for regional IEGS is proposed in this  paper. In the optimal dispatching model, combined with the demand response characteristics of different energy loads, according to the prices of electric power and natural gas, the IDR of terminal users is described in detail from the aspects of curtailable load, shiftable load and transformable load, so that they can effectively cooperate with the operation of MES equipment in IEGS to minimize the operating costs of the system. The validity of the proposed model is verified by relevant examples. The simulation results show that the regional IEGS operators can fully utilize the space-time complementary characteristics of electric power and natural gas loads through the comprehensive application of MES and IDR, maximize the wind power accommodation capacity of the system, and further decrease the operation costs of the system.
  • LIN Zihan, JIANG Chenwei, CHEN Minghui, SHANG Huiyu, ZHAO Hongwei, YANG Zeng, WANG Yizheng, WEN Fushuan
    Electric Power Construction. 2020, 41(5): 9-18. https://doi.org/10.12204/j.issn.1000-7229.2020.05.002
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    An integrated energy system (IES) can effectively improve energy efficiency and solve problems such as environmental pollution. In this context, an optimal dispatch model of an IES considering flexible loads (FLs) and carbon trading is proposed. First, the carbon trading is introduced into the dispatch model, taking into account the carbon emissions of the entire energy supply chain, and an excessive emission penalty mechanism is established to further promote energy conservation and emission reduction. Next, FLs are divided into three categories, i.e., curtailable, transferable and shiftable ones, which are respectively modeled in detail. On this basis, electric network constraints, natural gas network constraints, together with internal constraints of energy hubs (EHs) are integrated into the low-carbon economic dispatch model with an objective of minimizing the operation costs including the carbon trading cost, FLs dispatching cost and system energy cost. Finally, a sample system is employed to demonstrate the proposed model, together with detailed analysis about the impacts of the penalty price on the carbon emission of the system and the effects of FLs on the accommodation of wind power, and energy conservation and emission reduction are examined as well.
  • XIAO Youqiang, LIN Xiaohuang, WEN Yunfeng
    Electric Power Construction. 2020, 41(5): 19-27. https://doi.org/10.12204/j.issn.1000-7229.2020.05.003
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    With the development of HVDC and renewable-energy power generation, many typical power grids with high penetration of HVDCs and renewables are forming where there are of abundant clean energy in China. Under asynchronous transmission mode with multiple HVDCs, the inertia level of these systems have considerably decreased as a great amount of wind and photovoltaic power replaces the synchronous units, which impairs the frequency response performance for resisting dangerous faults. Meanwhile, the spatial and temporal distribution of mechanical inertia becomes more obvious than ever before, which makes the inertia response mechanism of the power system more complex to be detected. Thus, it is critical and essential to carry out inertia assessment of these low-inertia systems. This paper proposes a multi-dimensional framework for assessing the inertia level from three aspects: the overall size, the time-varying characteristics and the geographical distribution based on three quantitative indices, i.e., the kinetic energy of units, the change rate of inertia and the inertia distribution index. Case study and application are carried out on Yunnan Power Grid, and the simulation results verify the effectiveness of the proposed method for assessing inertia level of power systems.
  • AI Xin, YANG Zihao, HU Huanyu, WANG Zhidong, PENG Dong, ZHAO Lang
    Electric Power Construction. 2020, 41(5): 28-36. https://doi.org/10.12204/j.issn.1000-7229.2020.05.004
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    The construction of energy internet integrates the Internet of Things, artificial intelligence, cloud computing and other technologies into the power grid. As the basic unit of energy internet, virtual power plant (VPP) will change its aggregation and operation mode. In view of how virtual power plants can effectively participate in power grid operation, this paper proposes a VPP load curve clustering method based on principal-component dimension-reduced analysis, aggregation level clustering and k-means clustering, and studies the application of the clustering results. Firstly, combined with the data obtained from the information physical network, the principal-component analysis method is adopted to analyze the characteristics of different loads participating in the VPP aggregation, so as to standardize the data and reduce the dimension. Then, the algorithm combining aggregation hierarchical clustering and k-means clustering is used to cluster all load output curves participating in the aggregation, to obtain load curve clusters of the same class and find out the clustering center. Finally, the clustering results are analyzed, and the corresponding evaluation system is established. Through comprehensive evaluation, appropriate load combinations are selected to participate in the VPP aggregation.
  • DU Cheng,WEI Zhenbo
    Electric Power Construction. 2020, 41(5): 37-44. https://doi.org/10.12204/j.issn.1000-7229.2020.05.005
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    Aiming at the uncertainty of wind power and load in microgrid, a two-stage optimal scheduling model based on price demand response and incentive demand response is proposed. In the day-ahead stage, according to the response of the user's demand to the electricity price, the user's response model is established by introducing the demand price elasticity. In the real-time scheduling stage, in order to mine the corresponding enthusiasm of different users to participate in the demand, the dynamic incentive schemes of different users are calculated by using the fuzzy tools to improve the participation of demand-response projects. The analysis results show that the two-stage scheduling model can not only improve the stability of the system operation, effectively solve the problem of wind power accommodation, but also increase the economic benefits of the grid and users.
  • LI Peng,YANG Shenbo,LI Huixuan,TIAN Chunzheng,LI Meng,TAN Zhongfu
    Electric Power Construction. 2020, 41(5): 45-57. https://doi.org/10.12204/j.issn.1000-7229.2020.05.006
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    The difficulty of clean energy accommodation is one of the problems affecting the sustainable development of park integrated energy system (PIES). This paper constructs a comprehensive price demand response model based on the design of time-of-use prices of power and heat and the conversion demand response model including power to gas (P2G), electric refrigerator (ER) and electric boiler (EB). Firstly, a park integrated energy system, which is composed of an energy supply center and an energy conversion center, and its trading strategy, are constructed. Secondly, on the basis of considering the comprehensive price demand response and the conversion demand response, an optimal scheduling model with the objective function of maximum system net income is constructed with the constraints of the energy balance before and after the demand response. Then, the performance evaluation indicators are constructed from economic and environmental aspects. Finally, an example analysis is carried out to verify that the model has the effect of improving clean energy consumption and system economy.
  • GAO Chong, ZENG Guangxuan, ZHANG Junxiao, CAO Huazhen,TANG Junxi,YU Tao
    Electric Power Construction. 2020, 41(5): 58-65. https://doi.org/10.12204/j.issn.1000-7229.2020.05.007
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    Goal-oriented method is used to assess distribution network cyber-physical system reliability. According to the structure and application of cyber system, cyber equipment and function reliability models are established and success probability is used to depict the influence of cyber system on physical system. Reliability models of distribution network cyber-physical system are built on the basis of dependent relationship among cyber components, physical components, and cyber physical systems. Failure rates and average failure time of load points are calculated on the regional basis, which can be used in system reliability index calculation. This method is compared with Monte-Carlo method in a test system and the results verify the effectiveness of the proposed method. The results also show the efficiency advantage in large-scale distribution information physical system.
  • YANG Lei1,LI Shengnan,HUANG Wei,ZHANG Dan,MA Hongsheng,XU Shoudong,YANG Bo
    Electric Power Construction. 2020, 41(5): 66-74. https://doi.org/10.12204/j.issn.1000-7229.2020.05.008
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     This paper designs a passivity-based linear feedback control (PBLFC) for permanent magnetic synchronous generator (PMSG) for maximum power point tracking (MPPT). First, a storage function is built on the basis of passivity theory while the beneficial nonlinearities are remained for the purpose of improving the transient responses by analyzing the physical meaning of each term. Then, the linear feedback control is employed as an additional input, upon which the energy in storage function is quickly dissipated by energy reshaping, so that PMSG can effectively realize MPPT under the fast time-varying wind speed. In addition, the closed-loop system stability is thoroughly analyzed to verify its stability. Simulations of four cases are carried out, including step change of wind speed, stochastic wind speed, voltage drop and parameter uncertainties. Simulation results demonstrate that PBLFC can extract the optimal wind power and improve the ability of fault ride-through (FRT) and robustness in various operation conditions compared to that of vector control (VC) and feedback linearization control (FLC).
  • SONG Jian, SHU Hongchun, DONG Jun, LIANG Yuting, LI Yulong, YANG Bo
    Electric Power Construction. 2020, 41(5): 75-80. https://doi.org/10.12204/j.issn.1000-7229.2020.05.009
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    Aiming at the limitation of the single forecasting model in power load forecast, this paper proposes a combined model based on BP neural network and GM (1,1) residual correction to improve the precision of load forecasting model.  The algorithm combination is used to model the system. First, the GM (1,1) model is used for prediction to obtain the gray residual sequence, which is used to establish the BP residual correction model. The model is used for residual prediction. Finally, the residual correction value and GM (1,1) are used. The model predicted values are superimposed to obtain the finally required load predicted value. The model is verified in a simulate case, whose results show that the modified model has high prediction accuracy and practicability.
  • ZHAO Haibing, ZHANG Huanyun, GE Yang, CHENG Haoyuan, GAO Wenhao, AI Qian
    ELECTRIC POWER CONSTRUCTION. 2020, 41(5): 81-92. https://doi.org/10.12204/j.issn.1000-7229.2020.05.010
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    In recent years, large-scale renewable energy has been widely integrated into the power system, and the dominant form of distribution system has also gradually changed from traditional distribution network to microgrid cluster. To optimize the integration of renewable resource with uncertainty into the power system, considering the intelligent management of microgrid cluster to improve the distribution network performance, this paper proposes a new bi-level multi-objective dynamic energy management strategy based on the cell-tissue theory. The relationship between active distribution network and microgrid cluster are classified, and described by the energy game matrix and bi-level multi-objective control strategy. Finally, this paper adopts the hierarchical genetic algorithm-NSGA-Ⅱ to solve the energy management problem, and verifies the advantages of the proposed control strategy in power consumption, energy efficiency and simulation operation time through the analysis on the IEEE 33-node network based on microgrid cluster.
  • QI Bing, YE Xin, LI Bin, CHEN Songsong, LI Yuanfei, SHI Kun
    Electric Power Construction. 2020, 41(5): 92-99. https://doi.org/10.12204/j.issn.1000-7229.2020.05.011
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    How to connect the load management system and load equipment on the user side to the ubiquitous power Internet of Things (IoT) system is one of the urgent problems to be solved in the current power IoT construction. On the basis of analysis on the user-side device IoT system and the structure of meter reading system, referencing standards on smart grid and IoT by standard organizations such as the International Electrotechnical Commission (IEC), this paper puts forward the user-side power architecture of IoT, which supports user-side load polymerization system, energy management system and automatic control system of user load to be integrated into ubiquitous power IoT. Taking the demand-response service as an example, this paper introduces the execution process of power grid interaction service in the user-side power IoT environment. At the same time, the paper proposes the standardization requirements of user-side IoT information exchange interface to meet the needs of information exchange in the process of power grid operation and demand-side management.
  • LI Lin, XU Qingshan, WANG Xiaoqing, LING Jing, SUN Haixiang
    Electric Power Construction. 2020, 41(5): 100-107. https://doi.org/10.12204/j.issn.1000-7229.2020.05.012
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    An optimal scheduling method for industrial customers on the basis of sharing energy-storage station is proposed. Firstly, the concept of sharing energy-storage station is proposed and its business operation mode is analyzed. Then, sharing energy-storage station is applied to the optimal economic scheduling of industrial customers. By coordinating the charging and discharging power of the sharing energy-storage station for each industrial customer, the daily operation cost of customer group is optimized. Finally, case studies are carried out with three industrial customers in Jiangsu Province. Compared with the modes that customers not configuring energy storage or configuring energy storage independently, the proposed mode sharing energy-storage station can significantly reduce the daily operation cost of customers. Finally, the relationship among the income of service fee, static investment recovery period, return on investment and the service fee pricing of the sharing energy-storage station are analyzed.
  • LI Jikang, LI Sunwei, LI Wei
    Electric Power Construction. 2020, 41(5): 108-115. https://doi.org/10.12204/j.issn.1000-7229.2020.05.013
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     Wind energy is important in the mix of the renewable energy worldwide, and there are many methods and indicators available in the assessment of wind energy resources. Previous studies of wind resource assessments are focused on the resource abundance. In terms of siting offshore wind farms, in addition to the consideration of resource abundances, it is significant to study the stability indicator because it influences not only the maintenance of the offshore turbines, but also the cost for transmitting the generated power to the grid. For this purpose, this paper proposes a new index to evaluate the stability of wind resources (continuity coefficient), which measures the continuous rated power generation capacity of typical offshore wind turbine. In the practice, the continuity coefficient indicates the continuity and stability of the power generation of offshore wind farms when combining with the information on the wind speed probability distribution and the wind turbine characteristics. Via a hypothesized offshore wind farm constructed in the South China Sea, the present study demonstrates that continuity coefficient is a useful supplement to the commonly used wind resource abundance indicators in the site selection of offshore wind farms. Moreover, it is found in the present study that the proposed index implies a new promising area ignored by other indicators (northeast to the Zhongsha Islands).
  • ZHANG Zhirong, QIU Xiaoyan, SUN Xu, REN Hao, ZHANG Mingke
    Electric Power Construction. 2020, 41(5): 116-123. https://doi.org/10.12204/j.issn.1000-7229.2020.05.014
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    As renewable energy and DC loads in distribution networks have gradually increased, the development of DC distribution networks has been valued, and research on the optimal scheduling of AC/DC distribution networks has become one of the important topics. In order to promote the consumption of renewable energy, to coordinate the operating status of both the AC and DC sides, and to reduce the operating cost of the distribution network, divide the flexible load into transferable load and reducible load, consider the impact of energy storage participation in optimal scheduling, and take into account the losses of AC and DC lines, energy storages and converter stations, by scheduling the output power of distribution generation, energy storage systems and voltage source converter, an economic scheduling model based on second order conic relaxation, segmental approximate linearization and other technologies is proposed, which aims to minimize total cost of purchasing electricity, abandoning wind and solar power, suffering losses and scheduling flexible load. Finally, simulation analysis on a 50-node system verifies the effectiveness and rationality of the proposed scheduling scheme.
  • ZHANG Mingqi, LIU Qilin, ZHANG Yingmin
    Electric Power Construction. 2020, 41(5): 124-132. https://doi.org/10.12204/j.issn.1000-7229.2020.05.015
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    Aiming at the bipolar short-circuit fault of flexible DC transmission system applying MMC, on the basis of the expression of single-terminal fault current, the effects of station-level control, valve-level control and operation level of converter station on fault current are analyzed in detail. Using the method of proof by contradiction, through the combination of theoretical calculation and simulation verification, this paper concludes that the station-level control does not affect the fault current, the valve-level control has a nonlinear influence on the fault current, and the operation level affects the fault-current growth rate and peak time within 6 ms after the fault occurred. According to the conclusions obtained, the valve-level control optimization measures that can limit the fault current are proposed. Finally, a four-terminal MMC model is built on the PSCAD/EMTDC simulation platform to verify the effectiveness of the proposed optimization measures.