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Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
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Energy Internet
Development Analysis of the Ubiquitous Power Internet of Things
Lidan ZHOU, Zujia CAO, Gang YAO, Dong LIU
2021, 38(2): 119-128.   doi: 10.19725/j.cnki.1007-2322.2020.0326
[Abstract](0) [FullText HTML](0) [PDF 599KB](0)
Abstract:
Ubiquitous power Internet of Things (UPIoT) is of significance for green and healthy development of China’s power grids in future. To expound the meaning of UPIoT more clearly, firstly, the concept, construction goals and existing problems of UPIoT were analyzed in detail. Secondly, the technologies such as big data, cloud computing, blockchain and artificial intelligence, as well as their applications in power system were researched. Finally, the application scenarios of UPIoT were summarized and analyzed, and relevant suggestions for future development of ubiquitous power Internet of Things were proposed.
A Multi-Agent Based Hierarchical Distributed Energy Coordination Method for Integrated Energy System
Ming MENG, Chennan MA, Wanchen XUE, Yang LUO, Cong SHANG
2021, 38(2): 129-137.   doi: 10.19725/j.cnki.1007-2322.2020.0256
[Abstract](0) [FullText HTML](0) [PDF 1249KB](0)
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Effective energy coordination is an important foundation to ensure the stable and economic operation of integrated energy system (IES). A multi-agent system (MAS) based energy coordination scheme for IES was proposed, and a hierarchical and distributed structural model of MAS composed of local layer, energy center layer, network layer and system layer was constructed. Both the agents of energy center layer and the agent of system layer were set as the target agents in the MAS structure, and they possessed the energy coordination strategy which took the optimum economy as the objective. Meanwhile, based on the contract network protocol, the communication modes and strategies for the MAS in different layers were defined to realize the ordered data interaction among MAS. Finally, using JAVA language, the complete structural framework for the proposed MAS was built on the JADE software platform, and the proposed method was verified by the simulation examples of the modified IEEE 5-node distribution system and the 7-node natural gas system. Simulation results show that under various operating environments the MAS can run stably and generate the energy coordination optimization strategy for IES.
Electricity Market
Short-term Power Load Interval Prediction Based on CEEMDAN-SE-LSTM and KDE
Huiru ZHAO, Shiying ZHANG, Yihang ZHAO, Hongyu LIU, Baohong QIU
2021, 38(2): 138-146.   doi: 10.19725/j.cnki.1007-2322.2020.0329
[Abstract](0) [FullText HTML](0) [PDF 1125KB](0)
Abstract:
Short-term power load possesses strong randomness and volatility, and the accuracy of its prediction is of importance to raise both power supply reliability and power system operation economy. In allusion to the disadvantage that traditional deterministic prediction cannot reflect future load fluctuation, based on the idea of "point forecast plus interval estimation" a short-term load interval prediction method was proposed. Firstly, based on complete ensemble empirical mode decomposition with adaptive noise method (abbr. CEEMDAN), the load series was decomposed into multi modal components, and according to the calculation results of sample entropy (abbr. SE) of different sequences the sequences were reconstructed to reduce the computation. Secondly, on this basis, a long and short-term memory (abbr. LSTM) neural network prediction model was constructed respectively for each component to obtain the predicted value of the future load point. Finally, based on above-mentioned work, the kernel density estimation (abbr. KDE) method was utilized to estimate the distribution of the prediction error, further, combining with point prediction results the interval prediction of future short-term load was implemented. Comparing the proposed model with other models, the results show that using the proposed model a lower point prediction error can be implemented, meanwhile, the proposed model exerts a better combination property in the interval prediction.
Smart Grid
Robust Optimization Algorithm for Islanded Microgrid in Uncertain Environment
Dong WANG, Pengyuan ZHENG, Yidan REN, Yiqi YANG, Ran MAO
2021, 38(2): 147-155.   doi: 10.19725/j.cnki.1007-2322.2020.0344
[Abstract](1) [FullText HTML](0) [PDF 1047KB](0)
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In allusion to the uncertainty of renewable energy sources and loads, based on day-ahead planning and intra-day scheduling a robust optimization algorithm for islanded microgrid was designed. In this algorithm, aiming at the uncertainty of renewable energy sources and loads that might appear, the day-ahead planning searched the worst case scenario under the uncertain environment and utilizing column constraint generation algorithm the problem was decomposed into primal problem and subproblem, then by means of interactive iteration the optimal economic dispatch scheme under the scenario was solved; in the intra-day scheduling phase, utilizing current realtime measured information of renewable energy sources and loads and based on the dispatching results of day-ahead planning the realtime secondary optimization of the adjustment cost was performed, and the segmented punishment for wind power curtailment and PV power curtailment was implemented, thus renewable energy sources was furthest accommodated. Results of calculation example show that the designed algorithm can make the microgrid kept satisfied robustness and economy in the uncertain input and output environment brought by forecast error, so the effectiveness of the designed algorithm is verified.
Robust Non-fragile Fuzzy Control of DC Microgrid Containing Constant Power Load
Hong ZHANG, Lin YUAN, Bowen LI, Weidong LI
2021, 38(2): 156-163.   doi: 10.19725/j.cnki.1007-2322.2020.0245
[Abstract](0) [FullText HTML](0) [PDF 1526KB](0)
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The damping in DC microgrid will be decreased due to the cascade connection of the load possessing constant power characteristics with the converter at source side and it will affect the stability of the system. In allusion to this problem, the TS fuzzy model was adopted to establish the model for the nonlinear DC microgrid containing constant power load. To effectively resist the uncertainty of DC microgrid and parameters in control system, a robust non-fragile controller was designed, and on the basis of computing parameter uncertainty matrix the Lyapunov exponential stability condition stability condition expressed by linear matrix inequality wad derived. Results of Matlab/Simulink platform based simulation testing show that the designed controller can satisfy the demand of DC microgrid for stability, and can improve the transient performance of the close-loop system; besides, there is a stronger robustness for the uncertainty within the system and the controller.
Research on Steady-state Reactive Power Capacity of Flexible MMC-HVDC Converter Station
Binghui WANG, Tianxiao HUANG, Tao WU, Huan XIE, Changyu LI, Rui CHEN
2021, 38(2): 164-170.   doi: 10.19725/j.cnki.1007-2322.2020.0282
[Abstract](1) [FullText HTML](0) [PDF 758KB](0)
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By use of modular multilevel converter(MMC), the independent control and rapid regulation of reactive power can be implemented, flexible MMC-HVDC converter station can be used as a plant-level (or station-level) adjustment resource to promote the optimization level of regional power system reactive power. Therefore, a research on reactive power regulation capability of flexible MMC-HVDC converter station was performed. Firstly, according to the topology of typical single-terminal flexible MMC-HVDC converter station a mathematical model was proposed. Secondly, two major categories of influence factors, i.e., the equipment capability constraint influencing the reactive power regulation capability and the operating state of the system, were analyzed, and three constraint conditions, i.e., the rated capacity of converter transformer, the overcurrent withstand level at the valve side of converter transformer and the voltage modulation ratio, were put out, besides, the calculation steps of reactive power regulation capability was derived. Finally, taking Zhangbei ±500 kV four-terminal flexible HVDC project for example, its reactive power regulation capability under such steady state operating conditions as different active loads, DC voltage and voltage at grid-connected point and corresponding main constraint conditions were expounded, thereby, the obtained results provide the basis for the design of reactive voltage control strategy of flexible MMC-HVDC converter station as well as for the reactive power security margin control.
Meteorological Load Forecasting Based on Growth Curve and Temperature Accumulation Effect
Qiuqiao ZHANG, Bing WANG, Haishan WANG, Zhijie CAO
2021, 38(2): 171-177.   doi: 10.19725/j.cnki.1007-2322.2020.0234
[Abstract](0) [FullText HTML](0) [PDF 1395KB](0)
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The power load obviously increases in summer due to significant increase of air temperature. In allusion to the difficulty of obtaining meteorological loads and the low forecasting accuracy of meteorological load, a new method to forecast meteorological load was proposed. Firstly, to obtain accurate data of meteorological load, the growth curve was applied to describe the growth characteristics of baseload and by means of eliminating baseload the data of meteorological load could be obtained. Secondly, considering the temperature accumulation effect of high-temperature weather in summer, daily highest temperature in the high-temperature weather had to be revised, thus a meteorological load based temperature correction method and corresponding model were proposed. Finally, a particle swarm optimization-extreme learning machine load forecasting model was established to forecast the total load and meteorological load. Analysis results of numerical example show that based on the growth curve and temperature accumulation effect the load forecasting results are improved, and the effectiveness of the proposed algorithm and model are verified.
Optimal Energy Management in Micro-grid Based on DistributedEvent-triggered Consensus Predictive Compensation under DoS Attack
Yaohong LI, Wei HUANG, Beibei SUN, Xinhe ZHANG, Yiming XUE
2021, 38(2): 178-186.   doi: 10.19725/j.cnki.1007-2322.2020.0233
[Abstract](0) [FullText HTML](0) [PDF 1516KB](0)
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To solve the problems appeared in microgrid communication such as denial of service (DoS) attack, locality of information and bandwidth-constrained, a DoS attack and distributed event-triggering based model-free predictive compensation energy of microgrid optimization management and control method is proposed. Firstly, to make energy supply for microgrid optimized and the profit maximized, a minimum cost function, which considered the microgrid power loss to maintain the balance between supply and demand, was given. Secondly, regarding each part in the microgrid as an agent and considering the limited communication bandwidth, a distributed event-triggered consistency algorithm was proposed. Thirdly, an input and output data based model-free predictive control algorithm was put forward, by means of tracking the mismatched power between supply and demand at the moment before the attack the power data loss of the agent at current moment and those of many moments after the attack would be predicted and compensated. The effectiveness of the proposed microgrid energy management method based on distributed event triggered consistency prediction compensation is verified by simulation example
Power Equipment Manufacturing Technologies
A Novel Voltage Sag Generator for Wind Farm
Hao WU, Shuhong WANG, Jianwen CAO, Ruiteng GAO, Yifan WANG
2021, 38(2): 187-192.   doi: 10.19725/j.cnki.1007-2322.2020.0307
[Abstract](0) [FullText HTML](0) [PDF 1532KB](0)
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Low voltage ride through capability is one of the most challenging requirements to the wind power generation unit in the operating instruction for wind farms all around the world. The performance of the wind power generation unit in the course of the low voltage ride through and the magnitude of the current not only relates to type of the failure, but also to the phase of power grid voltage while the fault occurs. To research and measure the low voltage ride-through performance of wind power generation unit under the most serious failure situation, adopting AC contactless switch an impedance form based power network voltage asymmetrical sag generator was developed to absorb the overvoltage at both ends of insulated gate bipolar transistor (abbr. IGBT) by the absorbing circuit composed by resistance-capacitance-diode (abbr. RCD), besides, the phase angle of power network voltage was computed by the improved arctangent function and the single-chip microcomputer was used as the controller. Experiment results show that the developed device can fairly accurately simulate the fault of power network voltage asymmetrical sag at the given phase angle of power network, and it possesses such advantages as simple in structure, convenient to achieve, relative low manufacturing cost and good practicability.
Energy Storage
Optimal Configuration of Energy Storage for Integrated Load Aggregator Based on Information Gap Decision Theory
Bo SUN, Xudong WU, Jingdong XIE, Xin SUN
2021, 38(2): 193-204.   doi: 10.19725/j.cnki.1007-2322.2020.0305
[Abstract](0) [FullText HTML](0) [PDF 1948KB](0)
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The energy storage configuration is one of crucial means for integrated load aggregator (ILA) to participate integrated energy system (IES) and to ensure the development of its self-development. However, in existing reports about ILA research the research related to the optimal energy storage configuration at ILA side have been seldom reported. For this reason, on the basis of establishing joint market mechanism of electricity-gas the IGDT method was led in to research this topic. Firstly, a joint market mechanism of electricity and gas was constructed, in which the minimum annual cost of ILA was taken as the objective to establish the optimal model of energy storage configuration for ILA under market mechanism. Secondly, in allusion to the uncertainty of real-time electricity price and gas price in electricity-gas market, the information gap decision theory (IGDT) was led in to obtain two optimized energy storage configuration models of ILA with two different risk attitudes. Finally, by means of analyzing calculating example, the capacities of energy storage configurations of ILA under different risk attributes as well as corresponding purchasing and selling strategies of electricity and gas were obtained, and the influences of different day-ahead electricity price and gas price on energy storage configuration as well as the influences of different energy storage configuration schemes on the economy of ILA were analyzed, and the influences of different energy storage configuration schemes on the economy of ILA were analyzed.
Economic Feasibility in Secondary Frequency Regulation Considering Hybrid Energy Storage Cycle Life Model
Jie MENG, Quan DING, Xiaoyu CHEN, Guoming QIAN, Chao HUANG
2021, 38(2): 205-212.   doi: 10.19725/j.cnki.1007-2322.2020.0303
[Abstract](0) [FullText HTML](0) [PDF 1199KB](0)
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In allusion to the life loss of the energy storage battery participating in the secondary frequency regulation of power grid, a control strategy for hybrid energy storage participating in frequency regulation, in which the lifetime of the battery was taken into account, was proposed. Firstly, in a hybrid energy storage system containing lithium iron phosphate battery and lead-carbon battery, considering such factors as the depth of discharge, the cycle times and so on, a battery life model was built. Secondly, in the link of power distribution, the first order low pass filter was utilized to divide the high frequency signal in area regulation requirement from the low frequency signal. And then, overall considering such constraints as loss of hybrid energy storage, demand of frequency regulation and evaluation indices and taking the filtering time constant as the optimization variable, a frequency regulation model of hybrid energy storage system, which took the maximized economic benefit as the object, was established. This secondary frequency regulation model of regional power grid containing hybrid energy storage was simulated and verified by Matlab/Simulink, and simulation results show that the proposed model not only can improve the frequency regulation performance effectively, but also possesses importance in reducing both battery loss and later-stage replacement cost.
Collaborative Planning of Generalized Energy Storage and Transmission Network Considering Wind Load Fluctuation Similarity
Hongzhong LI, Guo FU
2021, 38(2): 213-220.   doi: 10.19725/j.cnki.1007-2322.2020.0415
[Abstract](0) [FullText HTML](0) [PDF 1129KB](0)
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The mismatch of wind power and power load increases the difference between peak load and valley load of daily net load, and it leads to the transmission congestion and higher pressure in power grid peak load regulation. By means of regulating the generalized energy storage resource the excessive difference between peak load and valley load of net load and short-time transmission network blockage under high wind power penetration can be mitigated. Firstly, according to the similarity among daily net load fluctuation curves in the planned year, the fluctuation curves were aggregated into different scenarios. Secondly, the investment cost of transmission network and generalized energy storage, as well as the similarity among fluctuation curves of rigid loads and output curves of generalized energy storages at all nodes were taken as optimization objectives, and the highest daily net load curves in each kind of aggregation results were selected as typical scenarios, and then by means of optimization solution the planning scheme, in which both transmission network and generalized energy storage were optimal, was obtained. Finally, the effectiveness of the proposed method was vilified by the modified garver-6 buses system.
Key Technologies for Electric Vehicle
Smart Grid Dispatching Strategy Considering the Difference of Electric Vehicle Demand
Wenlong SHI, Wenping QIN, Hongmin YAO, Yunjie ZHU, Jiayu LI
2021, 38(2): 221-229.   doi: 10.19725/j.cnki.1007-2322.2020.0283
[Abstract](1) [FullText HTML](0) [PDF 1379KB](0)
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Plug-in electric vehicle (PEV) has developed rapidly in recent years. Taking discrepant demand of the grid connected PEV into account, a smart grid dispatching strategy considering the demand difference among various kinds of PEVs was proposed. Firstly, according to the demand difference the PEV was divided into unordered charge PEV, schedulable charge PEV and schedulable charge-discharge PEV. Secondly, it was brought forward that considering the difference between high- and low-power regulation and control the schedulable PEV was divided into high-power schedulable PEV and low-power schedulable PEV. Finally, a multi-objective optimal dispatching model with the lowest operating cost of smart grid and the minimal paying fees for the electric vehicle was constructed. Results of calculating example show that considering the discrepant demand of the PEV the accommodation capability of renewable energy sources could be improved and the operating cost of smart grid as well as the paying fees of the owner for the PEV could be reduced by reasonable dispatching of the PEV.
Optimization of Charging Pile Layout Based on Cost Control and Collective Coverage Model
Mingyu PAN, Xukun SUN, Xianglong LI, Haiyang CHEN, Weixian WANG, Xiaoxi YUAN, Zhen CHEN
2021, 38(2): 230-236.   doi: 10.19725/j.cnki.1007-2322.2020.0374
[Abstract](0) [FullText HTML](0) [PDF 765KB](0)
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Unreasonable site selection of the charging pile has become an affecting factor hindering the promotion of electric vehicles. To improve this situation, firstly, by means of analyzing the influences of such factors as the coverage area of the charging pile, the spatial position of the demand point and the construction cost for various regions on the layout optimization of the charging pile, a set covering model was proposed and following items, i.e., the scope providing the charging could cover the specified area, the minimum number of charging piles and the lowest cost, were taken as the as objective functions. Secondly, combining with greedy algorithm and entropy weight method, the solving process of the proposed model was given. Finally, taking the Huangdao district of Qingdao city for practical calculation example, the feasibility of the proposed model was verified. The obtained conclusion form the calculation example shows that the proposed model can take both utilization rate of the charging pile and the cost into account.

MODERN ELECTRIC POWER(Since 1984)

Competent Authorities:

Ministry of Education of the People's Republic of China

Sponsor: North China Electric Power University

Editor and Publisher:

Editorial Department of Modern Electric Power

Editor-in-Chief: LIU Jizhen

Deputy Editor: ZHAO Dongmei

Specially Invited Editor-in-chief: CHEN Shuyong

Director of Editorial Department: SONG Shufang

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ISSN 1007-2322 CN 11-3818/TM CODEN XDIIC2

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