Table of Content

05 July 2021, Volume 54 Issue 7

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Qinghai Energy Demand Forecasting and Development Strategy Research under the Background of Construction of Clean Energy Demonstration Province

LI Hongxia, ZHANG Xiangcheng, LI Fang, ZHANG Haining, LI Nan, MA Xue

2021, 54(7):  1-10,26.  DOI: 10.11930/j.issn.1004-9649.202007277

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In 2018, Qinghai Province was approved to build the National Clean Energy Demonstration Province and proposed the "Qinghai Province National Clean Energy Demonstration Province Work Plan (2018-2020)" in the same year. The work plan takes the greennesss, high efficiency and safety as the overall goal, and promotes the revolution in energy production and consumption, so as to make a contribution to the clean transition of China’s energy and the construction of a modern energy system. Under this background, a study is made on the Qinghai energy demand forecasting and clean development strategy under the background of clean energy demonstration province construction. Firstly, the paper analyzes the current status and challenges of clean energy development in Qinghai Province. Then, a DMDE-BPNN hybrid prediction model is established by optimizing the BP neural network prediction model with the double mutation differential evolution algorithm. By taking Qinghai Province as an example, the annual energy demand in typical years is forecasted, and some measures are proposed for the development of clean energy in Qinghai Province.

Investigations on the Impact of New Infrastructure on Electricity Forecast and Power System Planning during the 14th Five-Year Plan Period

YU Xiaoxiao, SONG Fulong, ZHOU Yuanbing, LIANG Haifeng

2021, 54(7):  11-17.  DOI: 10.11930/j.issn.1004-9649.202010049

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In recent years, China has incorporated “new infrastructure” into its national development strategy, clearly stating that a modern infrastructure system should be developed on the basis of new and high technology infrastructure. This infrastructure system is expected to be intensive, efficient, affordable, intelligent, green, safe, and reliable. During the 14th five-year plan period, the new infrastructure will become an investment priority in order for post-pandemic economic recovery and high-quality development driven by innovation. This paper focuses on the development trend and energy consumption model of the new infrastructure, such as 5G base stations, data centers, and electric vehicles. The electricity demand of the new infrastructure in the 14th five-year plan period is forecasted, and the impact of new infrastructure on power system is analyzed, which will provide a reference for the energy and power system planning in the 14th five-year plan period.

Planning Model for Renewable Energy with Energy Storage Replacing Thermal Power Based on Time Series Operation Simulation

REN Dawei, JIN Chen, HOU Jinming, XIAO Jinyu, DU Ershun, ZHOU Yuanbing

2021, 54(7):  18-26.  DOI: 10.11930/j.issn.1004-9649.202009017

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As the cost for wind power and photovoltaic power generation continues to decline, the economic conditions are gradually becoming feasible for wind power and photovoltaic power to replace thermal power. At the same time, as the scale for wind power and photovoltaic power to replace the thermal power increases, the power system needs to introduce energy storage to cope with the increasing net load fluctuations of the power system. In order to quantify and evaluate the economy and scale for renewable energy with energy storage to replace thermal power in a more scientific way, this paper firstly established a joint power generation and energy storage optimization planning model based on the operation simulation of refined time series curves with consideration of the flexibility requirements of the power system. By taking the lowest total system cost as the optimization goal and considering the investment decision-making constraints and operation constraints, the proposed model can coordinate and optimize the capacities of power generation and energy storage under different cost scenarios. The economic analysis process for renewable energy with energy storage to replace thermal power is proposed. Secondly, the proposed model and method were used to optimize the power generation and energy storage capacities for a regional power grid under three scenarios of high-, medium-, and low-cost, and the evolution process for renewable energy with energy storage to replace the thermal power under different cost scenarios was quantitatively analyzed. Finally, the conditions for renewable energy with energy storage to replace thermal power in varying degrees are proposed.

Coordinated Development Strategy for Nuclear Power and New Energy in the Evolution Process of Power System with High Penetration of New Energy

ZHENG Kuan, XU Zhicheng, LU Gang, ZHANG Fuqiang, FENG Junshu, ZHANG Jinfang

2021, 54(7):  27-35.  DOI: 10.11930/j.issn.1004-9649.202007278

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As important components of non-fossil energy, the nuclear energy and new energy are playing a significant role in constructing the clean, low-carbon, safe and efficient energy system in China. With large scale integration of new energy, the power system is confronted with enormous challenges in safe and stable operation. Nuclear power is stable in output and large in moment of inertia, which can provide necessary power, electricity and inertia support for the power system with high penetration of new energy. For coordinated development of nuclear power, new energy and other power sources in the evolution process of power system with high penetration of new energy, and with consideration of the mutual effects of system planning and operation, this paper establishes a complete set of analytical models based on the mid-long term power planning model (GESP) and the stochastic production simulation model of power system (GridView). It also proposes the reasonable development scale, structure and layout of nuclear power and new energy in China. Considering the influence of nuclear power and other power sources participating in power grid peak regulation with different modes on new energy accommodation and system operation economy, some strategic suggestions are proposed to promote the coordinated operation of nuclear power and new energy, which may provide a decision-making support for promoting orderly and healthy development of nuclear power and new energy, and advancing the energy transformation in China.

Electric Energy Substitution Planning for the “14th Five-Year Plan” Period Based on Characteristics of Energy Consumption Structure of Subdivided Industries

TANG Wei, XU Zhao, SHAN Baoguo, ZHANG Yu, WU Peng, JIA Yuelong, ZHANG Chuncheng, TAN Qingkun

2021, 54(7):  36-45.  DOI: 10.11930/j.issn.1004-9649.202005159

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The implementation of "electric energy substitution" strategy has pushed forward the transformation of energy development mode and will play a crucial role in the future high-quality development of China's energy sector. Firstly, we investigate the existing situation of China's terminal energy consumption and energy supply and the development status quo of electric energy substitution. On this basis, a theoretical potential calculation model of electric energy substitution is proposed based on the characteristics of industrial energy consumption. Secondly, considering the policy, technology and other factors in the planning period, a calculation method of electric energy substitution potential is designed for the“14th Five-Year Plan”period. Thirdly, based on the potential calculation, a planning method of electric energy substitution is proposed for the“14th Five-Year Plan”period. Finally, the development prospect of electric energy substitution is forecasted. Based on the proposed model and methods, it is predicted that the electric energy substitution potential in the operation area of State Grid will exceed 100 billion kW·h, and the planned electric energy substitution will be around 500 billion kW·h during the“14th Five-Year Plan”period. This study can provide a theoretical support for government departments to formulate relevant policies and for the power grid enterprises to implement alternative energy work.

An Integrated Optimal Allocation Method of Multi-energy Supply and Demand Side Resources for Load Resilience Enhancement of Distribution System

ZHU Xi, ZENG Bo, XU Hao, LIU Jiaomin

2021, 54(7):  46-55.  DOI: 10.11930/j.issn.1004-9649.202103067

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To deal with the issue of load resilience enhancement of distribution systems under extreme weather, this paper studied the integrated optimal allocation method of multi energy supply and demand side resources considering the effects of hurricane events. Firstly, the load characteristics of end consumers and the distributed energy resources in the prosumer community were modelled. On this basis, a two-stage robust optimization model was further constructed with the objective of minimizing the cost of multi-energy resources, realizing the emergency optimal allocation of mobile emergency generator(MEG), distributed energy coupling equipment and demand side resources in distribution system. Besides, the impact of hurricane on distribution lines was described via the uncertainty set with adjustable conservative degree. In addition, the column-and-constraint generation (C&CG) algorithm was used to efficiently solve the above model. Finally, the IEEE 33-bus distribution test system was adopted for simulation analysis, and the results show that the comprehensive utilization of multi-energy resources can effectively enhance the load resilience of the distribution systems under hurricane events in a more economical way.

Robust Co-planning of Water-Energy Nexus for Industrial Parks

LIU Zhisong, WANG Tao, FENG Yan, LIU Xiaoyang, GAO Ning, WANG Cheng

2021, 54(7):  56-66.  DOI: 10.11930/j.issn.1004-9649.202006326

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With the continuous development and utilization of renewable energy and the continuous emergence of efficient energy conversion technologies, the interdependence among power, natural gas, heating and other energy systems is increasly strengthened, and the energy supply system develops in a multi-energy coupling way. Water is one of the most necessary substances in the process of energy production and conversion, while the operation of water pump in the water supply system depends on electric energy drive, thus forming a two-way coupling relationship between the energy supply system and water supply system. By taking an industrial park as the object, and taking its water resources and various energy needs into comprehensive consideration, this paper studies the water-energy coupling system planning of industrial parks, and establishes a water-energy nexus cooperative planning model based on multiple scenarios. At the same time, considering the output uncertainty of the distributed solar power generation in the park, a robust programming method is proposed for the water-energy nexus system to ensure the reliability of energy supply and water supply. The column and constraint generation algorithm is used to solve the robust programming model. The simulation results have verified the validity and rationality of the proposed model. The proposed co-planning can effectively improve the flexibility of the water-energy coupling system, and reduce the cost for investment planning and operation of energy and sources system.

Establishment and Solution Strategy of Galloping Equation of Iced Conductors

LIU Hui, MA Zengtai, LIN Jikeng

2021, 54(7):  67-75.  DOI: 10.11930/j.issn.1004-9649.202003002

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The galloping of iced overhead conductors is one of the key factors for tripping fault of transmission lines, and threatens the security and stability of power system. It is thus needed to accurately capture such conductor’s galloping characteristics as displacement and frequency for solving the galloping problems. A 3-DOF (vertical, horizontal and torsional) galloping motion equation is established based on the Lagrange principle, and the modal perturbation method is used to describe the relative positions of the infinitesimals of galloping conductors. Considering the geometric nonlinearity of iced conductor’s galloping, the galloping motion equation is solved using the Newmark-β method combined with Newton-Raphson iteration, and an effective solving algorithm is proposed. The simulated displacement amplitude and frequency of the galloping in the case study are very close to the measured ones, which proves the effectiveness of the proposed model and algorithm. It is concluded that the galloping of iced conductors is a kind of self-excited vibration with vertical motion as principal and its frequency close to the natural frequency of the vertical vibration of the iced conductor system. The strain model and aerodynamic coefficients of the iced conductor galloping were improved significantly in this paper, and the modal perturbation method greatly reduced the calculation amount and improved the calculation accuracy of the galloping displacement, thus laying a good basis for accurate estimation of the line tripping probability caused by galloping.

Application Function Design for UPFC Online Operation Optimization Decision-making

LI Feng, PENG Huimin, YUAN Huling, WAN Fangru, HUANG Tiangang, LI Wei

2021, 54(7):  76-82.  DOI: 10.11930/j.issn.1004-9649.202001021

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Due to the lack of guide tools for UPFC real-time operation optimization, the powerful power flow control capability of UPFC cannot be played flexibly. An UPFC operation optimization decision-making application function is designed based on the smart grid dispatching control system. According to the power flow calculation characteristics of UPFC project under actual quota working mode, the sensitivity of the UPFC control measures is solved. Parallel computing of the UPFC multi-control target set is carried out using the rich online computing resources, and the UPFC static security control measures and power flow optimization control measures are obtained. The designed application function makes full use of the UPFC control capability to improve the flexibility of power grid operation, and provides decision-making support for dispatching operators. The calculation process for UPFC online operation optimization is illustrated through a case study of the 500 kV UPFC project of Suzhou southern power grid. The results show that the proposed method can effectively solve the static security problem of the region near UPFC and optimize the near region network loss.

Exploration of Bundled Transaction Model for All Clean Energy Transmission of Qing-Yu UHV DC Project

HE Yuankang, LIU Ruifeng, CHEN Tian'en, BIE Zhaohong

2021, 54(7):  83-92.  DOI: 10.11930/j.issn.1004-9649.202007220

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At present, the Qing (Qinghai)-Yu(Henan) UHV DC Project for all-clean energy transmission has been put into operation, but the supporting power sources have not been fully put into production yet. Due to the big output difference of hydropower between flood and dry seasons, and the stochastic, intermittent and fluctuating characteristics of wind and photovoltaic power output, it is hard to meet the requirements for large-power and stable transmission of Qing-Yu UHV DC Project by Qinghai Grid alone. Based on an investigation of the load and generation characteristics of the sending-end Qinghai Grid, a power balance analysis is carried out for the outbound transmission of the Qing-Yu DC Project. Aiming at the problems of surplus in peak time while shortage in valley time, and rich in flood season while poor in dry season for power output in the Qinghai Grid, the paper proposes a bundled clean energy transaction model for multiple provinces in the northwest region, so as to give a full play of the overall dispatching role of the Northwest Power Grid. Simulations are carried out under four scenarios, including the new energy enrichment and barren periods, the flood season and the dry season of the Yellow River. The results show that the bundled transaction of clean energy can significantly improve the stable outbound transmission level of the Qing-Yu UHV DC Project.

Reachability Matrix and Bayes' Theorem Based Fault Section Location of Power Distribution Network with Distributed Generation

WANG Weizhang, WANG Chun, YIN Fagen

2021, 54(7):  93-99,124.  DOI: 10.11930/j.issn.1004-9649.201906001

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With the distributed generation connected to the power distribution network, the current becomes a bidirectional flow, which results in the traditional fault location method no longer applicable. In order to solve the problem of fault section location in power distribution network with distributed generation, a fault location method based on reachability matrix and Bayes' theorem is put forward. Different from the idea of using adjacency matrix to describe the network topology in traditional matrix algorithm, the reachable matrix which contained more information and had stronger global observability is used for topology description and matrix operation in this paper. To deal with information distortion, the Bayes' theorem is utilized in fault tolerance processing to find out the fault section(s). Simulation results of test cases show that the proposed method has good generality as it can handle both generator-based and inverter-based distributed generation in a uniform way. For single fault and multiple faults in the distribution network with distributed generation, the proposed method can locate fault section(s) accurately and has certain fault tolerance.

A DC Bias Current Reducing Method Considering Grounding Electrode Location and Receiving-end Grid Structure

LIU Lianguang, MA Chenglian

2021, 54(7):  100-108.  DOI: 10.11930/j.issn.1004-9649.201904098

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Based on the influence of the receiving-end grid structure and the grounding electrode location on DC bias current, this paper analyzes the DC bias current (DCBC) level of the converter station and the adjacent AC substation in the typical connection structure under different connection modes of the AC substations. The factors affecting the DCBC value of converter and AC transformers are analyzed, and the influence mechanism of the grounding electrode location and the receiving-end grid structure on the transformer DCBC value is expounded. Considering the structure of receiving-end grid and the location selection of grounding electrode, a DCBC value reduction method for converter and AC transformers is proposed. The measures to suppress the DC bias current can be analyzed from the aspects of system operation mode selection, grounding electrode location selection, power grid structure planning and designing, etc. This paper proposes to prevent the bias current of the converter and AC transformer during the planning and designing stage.

An Improved Method for J-A Hysteresis Parameter Identification of Current Transformer Core

ZHOU Shihao, PAN Benren, WAN Yong, WANG Guannan, ZHANG Yan, GUI Xiaozhi

2021, 54(7):  109-116.  DOI: 10.11930/j.issn.1004-9649.201908012

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To simulate the dynamic magnetization process of the current transformer core, an accurate hysteresis model needs to be established. The improved J-A hysteresis model can simulate the hysteresis characteristics of core more accurately. In this paper, an improved J-A hysteresis model parameter identification method for current transformer based on fireworks algorithm is proposed to determine the key parameter of the improved J-A hysteresis model. Firstly, the modified J-A model is established, and then the parameter identification model is constructed. The sum of the absolute error between the obtained magnetic induction and the known magnetic induction are taken as the objective function, and the model parameters are introduced into the fireworks algorithm as variables. When a new spark is generated, the check of whether the spark meets the constraints is added. Finally, the hysteresis curves of P-type and PR-type current transformers are identified by the proposed method. The results show that the obtained hysteresis curve has a small deviation from the actual curve. The added spark check link can reduce the number of iterations required for algorithm convergence. The effectiveness and adaptability of the proposed method has been verified by simulation results.

Simulation Analysis of Breakdown Characteristics in Isolation Switch Fracture in Same Frequency and Phase AC Withstand Voltage Test of 110 kV Three-Phase Cylindrical GIS

QIN Yifan, NIU Zheng, SUN Yunsheng, ZHENG Yibo, NING Linru, WU Haotian, LI Xuebao

2021, 54(7):  117-124.  DOI: 10.11930/j.issn.1004-9649.201912075

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The same frequency and phase AC withstand voltage test technology has been widely used in the insulation performance test of inspection or expansion in 220kV Gas Insulated Switchgear (GIS), which can avoid stopping running grid bus of the system. However, the technology has been promoted in the withstand voltage test of GIS equipment with 110 kV voltage level. The three-phase cylindrical structure is generally adopted in 110 kV GIS devices. Due to the small inter-phase space, the switch has a higher risk of breakdown when the three-station disconnecting switch is subjected to the withstand voltage test. In this paper, the EMTP-ATP simulation software is used to construct the breakdown model of 110 kV GIS equipment in the same frequency and phase AC withstand voltage test. The fault voltage and current characteristics of the same phase and wrong phase is obtained. The influence of the installation protection resistances on the breakdown characteristics is analyzed, and the suggestions for suppression of the breakdown characteristics are given. This paper can provide useful references for the application of the same frequency and phase technology in the AC withstand voltage test of 110 kV GIS equipment.

Coil Offset Based Wireless Power Transfer System Parameter Optimization

CHEN Xiaojuan, JIA Min, LI Mingchen

2021, 54(7):  125-131.  DOI: 10.11930/j.issn.1004-9649.202101040

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In a magnetic coupling resonant wireless power transmission system, the relative position of the system coil is one of the main factors affecting its transmission performance. This article focuses on the efficiency loss caused by the offset of the coil in the traditional power transmission system, and proposes a Firefly algorithm based parameter design method to optimize the efficiency of the coil when placed non-coaxially. Firstly, the analysis of the mutual inductance of the coil at different positions is carried out, and then the bilateral LCC topology is applied to examine its transmission performance. The parameters optimization is carried out using the firefly algorithm, and finally the effectiveness of the method is verified through a finite element simulation and experimental platform. The results show that when the offset distance is less than the radius of the coil, the transmission efficiency of the system can maintain more than 85%, which is similar to the traditional SS topology of WPT. In comparison, the transmission efficiency of the optimized system is increased by an average of 20%, and the received power of the load remains at about 20 W.

Test Voltage Optimization and Safety Margin of Insulation Tools for Live Working of UHV AC Transmission Lines

ZHU Kai, FANG Yuqun, YU Guangkai

2021, 54(7):  132-140.  DOI: 10.11930/j.issn.1004-9649.202006146

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In view of the problem that the test voltage of live working insulation tools for 1 000 kV UHV AC transmission lines is too high, causing abnormal damage to the work tools, we made an in-depth analysis of the power frequency and operating overvoltage level for the live working condition of 1 000 kV AC transmission lines. And at the same time, a research was carried out on the voltage selection and safety margin for the 1 000 kV UHV live working insulation tool test. After comprehensive analysis, the reasonable test voltage and safety margin range are put forward, and the proposed revision values are verified by a number of tests including power frequency withstand voltage test, insulation material electrical performance test and live working safety test, which have fully proved the rationality of the proposed revision values.

Influence of Different Simulation Models for Electrical Characteristic Analysis of the Arrester of AC Filter

HUANG Xuemin, DENG Junwen, DENG Jing, LUO Xin, HAN Yongxia

2021, 54(7):  141-148.  DOI: 10.11930/j.issn.1004-9649.202006322

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AC filter is an important equipment in DC transmission system. This paper mainly analyzes the influence of simulation model on the electrical characteristics (overvoltage, current and absorbed energy) of the arresters for AC filter, and carries out the modeling and simulation calculation for the filter input and AC filter bus grounding fault based on PSCAD electromagnetic simulation program. The simulation result shows that when the AC filter is put into operation and the traditional large group model for a single filter (model 1) was used for simulation, the arresters of the working filters did not act, which is different from the actual situation; under the filter input and filter bus grounding fault, the overvoltage of the arrester of each group of filters in complete parameter model (model 3) was lowered by 21% compared to that in the original system model (model 2) and model 1, and the current was reduced by up to 53%, but the absorbed energy increased by up to 56%. Therefore, if the complete parameter model is not used in the insulation design, the voltage and current design value of the arrester could be too large while the energy design value could be too small. At the same time, the action of the arresters of other AC filters in the same group could be easily ignored when the filter is put into operation.

Influence of Pollution Components on Surface Electric Field of Composite Insulators

WANG Sihua, WANG Junjun, ZHAO Lei, CHEN Long

2021, 54(7):  149-157.  DOI: 10.11930/j.issn.1004-9649.202011094

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Surface pollution of insulators is the main cause of pollution flashover, and the pollution components have different effects on the electrical performances of insulators. In order to study the influence of pollution components on the surface electric field of insulators, a simplified model of composite insulators was established by taking Golmud city along the Qinghai-Tibet Railway as the actual operation environment of insulators. It is found through simulation that when the contaminants are dry, their influence on the surface electric field of insulator follows the tendency from high to low as CaSO₄＞KNO₃＞NaNO₃＞K₂SO₄＞NaCl＞MgSO₄, which is mainly determined by the relative dielectric constant of the medium; when the contaminants are wet, their influence follows the tendency as sodium chloride ＞ nitrate ＞ sulfate, and the conductivity of each polluted liquid becomes the main factor affecting the electric field distribution. The hydrophobicity also affects the electric field distribution of insulators, and the overall electric intensity of insulator with drying zone is higher than that without drying zone. The simulation results were verified by the experimental results. The conclusion explains the influence of pollution components on insulator’s insulation performance from the perspective of electric field distribution, and can provide a new idea for regional pollution classification and insulator contamination test in laboratory.

Application Value Assessment of Grid Side Energy Storage Under Typical Scenarios in China

HUANG Bibin, HU Jing, JIANG Liping, LI Qionghui, FENG Kaihui, YUAN Bo

2021, 54(7):  158-165.  DOI: 10.11930/j.issn.1004-9649.202004027

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China attaches great importance to the energy storage development. Grid side energy storage is an important way to achieve large-scale energy storage development. Combined with the technical and economic characteristics of energy storage and the demand of power system, this paper introduces several general understandings of the gird side energy storage application in China. The grid side energy storage should be integrated into power planning with comprehensive consideration of the security, economic and social benefits, and it is necessary to optimize the total scale, layout and technical types of grid side energy storage. Based on the typical scenarios such as ensuring power system security, ensuring the function of power transmission and distribution, reducing the loss of power grid and improving the utilization level of new energy, a research is carried out on the grid side energy storage application value. The research results show that pumped storage, as a system-level regulation measure, should be planned with a certain scale. Electrochemical energy storage, whose cost is still relatively high, still needs to improve the economy through reasonable planning, and its future large-scale development relies on the market.

Multi-agent Coordination and Optimal Dispatch of Microgrid with CES Based on Ecological Game

LI Xianshan, CHEN Aobo, CHENG Shan, CHEN Minrui

2021, 54(7):  166-177.  DOI: 10.11930/j.issn.1004-9649.202005004

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Distributed energy storage can alleviate the randomness problem caused by a large number of distributed power sources connected to micro-grid, but high initial installation cost and operation and maintenance difficulties limit its large-scale promotion and application. In this paper, “cloud energy storage” system is introduced to micro-grid to provide users with efficient “virtual distributed energy storage” services. Based on the idea of natural ecosystems, a multi-agent ecological game coordination optimization dispatching model for microgrids with CES is proposed. According to interest appealing relationship, the multi-agent structure of the microgrid system is constructed with four intelligent agents, including micro-grid operator, general load aggregators, cloud energy storage and cloud storage users, and their optimization models were developed respectively. The micro-grid power ecosystem was constructed, and the game optimization model among agents and among power ecosystems was established. The reinforcement learning algorithm based on the Nash equilibrium was used to solve the multi-agent ecological game model. The simulation results show that the cloud energy storage service optimizes the load curve, reduces the electricity cost, and cloud energy storage operators also gain benefits, achieving a multi-party win-win effect.

Techno-economic Analysis of Key Equipment for Offshore Wind Farms with Multiple Scenarios

TANG Wei, GUO Yutong, YAN Shu, GUO Xiaojiang, SHI Shaoping

2021, 54(7):  178-184,216.  DOI: 10.11930/j.issn.1004-9649.202003215

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Offshore wind farms in China are moving into deep and open sea. The offshore distance and water depth have significant impact on the technology selection and cost of key equipment for offshore wind farms, subsequently influencing the unit power cost of wind farm investment. This paper analyzes the key equipment for offshore wind farms such as foundation structure and submarine cables in terms of the cost variation with different offshore distance and water depth, discusses the influence of technologies such as foundation structure, high voltage power collection and power transmission on project cost. It is concluded that by adopting flexible DC and high voltage power collection technologies, the unit power cost of key equipment for wind farms in open sea may be lower than that for the offshore wind farms under construction. For the wind farms in deep and open sea with 8 MW wind turbines, the unit power cost of key equipment will decrease by 2 200RMB/kW if advanced technologies for foundation structure and transmission system are adopted, remarkably lowering the project cost of wind farms in deep and open sea.

Practical Method and Error Analysis for Distributed Photovoltaic Power Prediction Based on Spatial Correlation

SHAO Yinchi, YUAN Shaojun, SUN Rongfu, WU Linlin, CHEN Can

2021, 54(7):  185-191,207.  DOI: 10.11930/j.issn.1004-9649.202004223

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With the rapid rise of distributed photovoltaic (PV) generation capacity in the low-voltage distribution network, severe challenges have been brought up to the load forecasting of the dispatching department and the security of the grid operation because of its randomness of output. A practical power prediction method for low-voltage distributed PV is proposed. Firstly, a single concentrated PV station is chosen as reference for the distributed PV based on the spatial correlation principle of adjacent regions. Then the output relationship between distributed PV and reference station is established through existing daily generation data in order to calculate the operating capacity of distributed PV. Next, the predicted power of distributed PV is calculated by the output relationship with the power prediction data of the reference station. Thirdly, based upon the definition of the conversion factor of distributed PV, three kinds of error sources related to the proposed method are deduced. Hence, an error correction scheme for capacity constraint and performance difference between distributed PV and reference station is proposed. Case studies using a group of typical distributed PVs in Zhangjiakou area has verified the effectiveness of the method.

Design and Implementation of Blockchain-based Trust Gateway for Power Internet of Things

ZHAO Bingzhen, WANG Dong, QIAN Xue, LI Jun

2021, 54(7):  192-197.  DOI: 10.11930/j.issn.1004-9649.202101057

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In order to ensure the cyber security of bulk power system, a distributed dynamic gateway architecture based on blockchain and access authentication mechanism is proposed regarding the vulnerabilities of gateway to cyberattacks in the complex communication network of power Internet of Things, as well as the problems of heavy loading, low efficiency and potential security risks caused by the equipment access authentication mode in the centralized platform. The consensus mechanism of blockchain is applied to the dynamic switching process of the main gateway to form a distributed dynamic gateway structure. The device ID and other digital information involved in the access authentication process are stored in the blockchain data storage structure to improve the data security in the authentication process. To demonstrate the effectiveness of the method in theory and practice, security analysis and experiments are carried out. The results show that the proposed dynamic gateway architecture can boost the resistance to the general attacks of the Internet of Things. The access authentication mechanism can also provide access authentication assurance with high security for power Internet of Things devices.

Discussion on Application of Artificial Intelligence Technology in Thermal Power Industry

HUA Zhigang, FAN Jiaqing, GUO Rong, WANG Yong, WU Xiaoxiang

2021, 54(7):  198-207.  DOI: 10.11930/j.issn.1004-9649.202011001

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Based on an investigation of the status quo and technical routes of artificial intelligence development at home and abroad, the application scenarios and technical breakthroughs of artificial intelligence technology in thermal power industry is deliberated,, and the technical development direction of artificial intelligence in thermal power industry is discussed. An analysis is made of the technical routes for development of computer vision, big data, Internet of things, intelligent control, intelligent robot, which are needed in perception, decision making and execution in the production and operation process of thermal power enterprises. The application of artificial intelligence technology in safety management, production management and business decision-making scenarios is discussed, and the typical application cases are introduced. The key research direction of the artificial intelligence technology in thermal power industry in the future is put forward.

New Inspection Method and Experience by Introducing HoloLens into Information Fusion and Data Mining

GUO Guodong, GONG Yanfeng, WU Di, PAN Jianqiao, YU Fangzhao, PAN Bailang, LI Huan

2021, 54(7):  208-216.  DOI: 10.11930/j.issn.1004-9649.201909115

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At present, most inspection methods for substation have the problem of incomplete information acquisition, which is mainly reflected in two aspects: the loss of information caused by improper preservation of inspection information and the waste of information caused by the inability of the inspection system to obtain SCADA data in time. With the development of smart grid, power big data has more and more applications in equipment state estimation and so on. As a result, the contradiction between the data demand of the intelligent inspection system and the incomplete data acquisition occurs, and information fusion and data mining become much more important. The concept of Ubiquitous Internet of Things in Energy can be applied to the field of inspection. In this paper, the MR equipment HoloLens is used for substation inspection, and is used to connect people and objects. As a mobile human-computer interaction interface, the HoloLens seamlessly connects data and reality. The intelligent technology is used to acquire and store inspection data and call SCADA data to realize data flow interconnection. Based on the comprehensive information, the equipment condition assessment and failure rate calculation are carried out to provide auxiliary information for inspectors, consequently improving the quality and efficiency of inspection, and the new inspection contents and inspection experience are thus obtained. Finally, the results of user experience feedback from patrol inspectors are evaluated by fuzzy comprehensive evaluation, and the ideal results are achieved.