Table of Content

30 January 2021, Volume 0 Issue 1

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Overview

Game Problems in Micro-grid and Its Development Trend

CHEN Mengkai, FU Baochuan, WU Zhengtian, CHEN Zhenping, WU Jianhan

2021, 0(1):  1-8.  doi:10.16628/j.cnki.2095-8188.2021.01.001

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As a means of grid connection of distributed energy,micro-grid has become an important part of smart grid,which also makes the grid present diversified characteristics.How to balance the interests of multiple parties has become one of the problems to be solved in micro-grid.As an advanced optimization tool,game theory can deal with complex multi-objective optimization problems and balance the interests of all parties,so it has been widely used in the field of micro-grid.Based on the analysis of the game problems in each part of micro-grid,this paper analyzes three core elements containing renewable energy and electric vehicle grid connection,development of energy storage technology and trading strategy in power market,and points out the ideas and development trend of applying blockchain and artificial intelligence to the micro-grid game model.

Research & Analysis

Research on Source-Net-Load Bi-Level Programming of Active Distribution Network

LI Jiyu, FAN Ying

2021, 0(1):  9-15.  doi:10.16628/j.cnki.2095-8188.2021.01.002

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This paper constructed a source-network-load coordinated and optimized active distribution network two-level programming model.This model introduces the current “electricity reform” policy into the model from the perspective of the retail company,highlighting the weight of user satisfaction.The upper level of the model,based on the comprehensive cost of the whole year,takes the lowest value as the objective function,and the lower layer takes the lowest voltage deviation rate as the objective function.The environment,policies and operating conditions are considered comprehensively to make the location and capacity of DG,energy storage devices,and flexible loads more reasonable and effective.The IEEE-33 node power distribution system is taken as an example to verify the effectiveness of the proposed model.

Analysis of Power Load and Resumed Load during Epidemic Period Based on Meteorological-Load Correlation

WU Xu, WANG Zhengfeng, LI Youliang, FU Rong, JI Juan

2021, 0(1):  16-21.  doi:10.16628/j.cnki.2095-8188.2021.01.003

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Accurately forecasting the power consumption of the whole province is a reasonable premise and basis for arranging the start-up of generator sets in the province to ensure reliable power supply to the power users in the province.Especially during the epidemic,it is necessary to strengthen the analysis of power load and resumed production load.This paper is based on the data of electricity consumption load and meteorological factors of a province in recent years.Based on the big data platform,this paper analyzes the correlation coefficient between load and meteorological indicators,and identifies the most relevant meteorological index,and then uses this meteorological index and the meteorological load to establish the load forecasting model and sensitivity change relationship.Taking into account the impact of the epidemic,to calculate the general industrial and tertiary industry suspension of business load during the epidemic.Finally,according to the requirements of provincial government enterprise to resume work and resume production and load changes,it analyzes the general industry and tertiary industry resumption of production.

Research on Relation Between Electromagnetic Force and Coil Ampere Turns of Direct-Acting Electromagnetic Mechanism

LIANG Huimin, ZHU Xuqing, ZHANG Kun, YOU Jiaxin, XIE Yuanhao

2021, 0(1):  22-28.  doi:10.16628/j.cnki.2095-8188.2021.01.004

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This article classifies many direct-acting electromagnetic mechanisms from the perspective of the number of equivalent working gaps and the series-parallel relation between the permanent magnet magnetic potential and the coil magnetic potential.Based on the equivalent magnetic circuit,the calculation models of the working gap magnetic flux and the electromagnetic force that works on the moving iron core are established.Then,this paper analyzes the characteristics of the electromagnetic force curves of various electromagnetic mechanisms and the relations between the coil ampere-turns and the working gap magnetic flux,the initial electromagnetic force when the moving iron core is at the release position.On this basis,a calculation model of the critical coil ampere-turns corresponding to the maximum initial electromagnetic force of the direct-acting electromagnetic mechanism with permanent magnet is built.The research conclusions have certain guiding effect on the reliability design of the direct-acting electromagnetic mechanism with large output force requirements.

Mode Combination of Fault Limiting Operation Based on Multiple Resistance Superconducting Fault Current Limiter

CAO Langheng, WANG Dongpeng

2021, 0(1):  29-35.  doi:10.16628/j.cnki.2095-8188.2021.01.005

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Based on a brief analysis of the quenching mechanism and basic model of conventional resistance superconducting fault current limiters,and in order to alleviate the inherent defects of conventional resistance superconducting fault current limiters,a combination of fault current limiting operation modes based on multiple resistance superconducting fault current limiters was proposed.A custom model of resistance superconducting fault current limiter was built on the PSCAD/EMTDC simulation platform,and based on the Nan’ao 160 kV multi-terminal flexible DC transmission system,the influence of the superconducting fault current limiter on the power system during system failure was preliminarily studied to show the correctness and necessity of the custom model.The advantages and disadvantages of conventional resistance superconducting fault current limiters was compared to the mode combination under the same current limiting effect,which provides a theoretical basis for the selection of superconducting fault current limiters in flexible DC transmission systems.

Method for Improving Loop Response Capability of Four Switch Buck-Boost Circuit

CAI Yili, XU Yuzhen, ZHENG Qingliang

2021, 0(1):  36-44.  doi:10.16628/j.cnki.2095-8188.2021.01.006

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The common four switch Buck-Boost converter with multi-mode control operating mode switching control strategy is a single compensation method.The pole-zero point in Boost mode is used as the main basis for designing the compensation network,but the dynamic response performance in other operating modes is ignored.The method can only make the system have good stability and dynamic response performance within the input voltage range.In order to improve the overall stability and dynamic response speed of the system,a new mode switching compensation control strategy is proposed.The converter system is modeled by the energy conservation method and the average modeling method of switching elements.Open loop transfer functions of various modes are derived from the small signal model,and the compensation switching circuit is designed.Finally,simulation models and experimental circuits are built for research,which verify the feasibility of the proposed compensation method and improve the response ability of the loop.

Electrical Design & Discussion

Optimal Design for Lower Incoming Wiring of Residual Current Protection Circuit Breaker

WANG Hanpei, WANG Yongzhong

2021, 0(1):  45-48.  doi:10.16628/j.cnki.2095-8188.2021.01.007

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In order to solve the problem that the residual current protection circuit breaker is easy to burn and cannot work reliably in the reverse wiring scenario,this paper analyzed the working principle of the residual current protection controller when the circuit breaker is lower incoming wiring.Comparing the differences between the upper incoming wiring and lower incoming wiring,and recognizing the insufficient design of the residual current protection circuit breaker on lower incoming wiring,two design improvements were proposed.Additional prototype testing and verification before and after improvement were done.The results show that the purpose of optimizing the design and improvement is achieved,which provides the best solution for the product to operate reliably on the market side.

Design and Implementation of MCB-adapted Driving Device with IoT Function Block

LIAN Shijun, WU Jianwen, ZHANG Luming, WANG Suhua, LIU Kexin

2021, 0(1):  49-53.  doi:10.16628/j.cnki.2095-8188.2021.01.008

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This paper introduced a new type of mechanical drive and information processing integrated device system,which can not only adapt to MCB but also determine the state.After the system is adapted to MCB to realize IoT function upgrade,it can not only achieve remote closing and opening,fast-tripping,but also well interact with MCB and maintain its original electrical characteristics.The device uses the user set in the kernel control unit,the specific secret order and external control instructions,and the built-in position sensor.After the comprehensive judgment based on the monitoring process,the device uses a novel mechanical mechanism to drive the external MCB to complete the effective application of trip or load flow interruption and send out the status information.The new technology solution under the device is a low-cost selection scheme for users who need intelligent upgrade based on traditional MCB and also want to obtain IoT experience.

Design of Miniaturized Low Power Consumption Current Sampling Circuit

ZHANG Chunya, LIU Song

2021, 0(1):  54-57.  doi:10.16628/j.cnki.2095-8188.2021.01.009

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This paper introduced the necessity of current-mode control in switching power and analyzed the disadvantages of the traditional current sampling method.Based on the analysis and calculation of inductive current,a current sampling circuit current design with miniaturization and low power consumption was proposed.Physical verification was carried out according to this theory.A DC/DC power module with input voltage of 5~24 V and output voltage of 3.3 V was designed,which verifies the stability and reliability of the design.

Detection & Experiment

Detection of Common Foreign Matters on Power Grid Lines Based on Faster R-CNN

ZHU Hongzhi, SUN Zhen, LAN Qiaoqian, SHEN Liangyi, ZHANG Chong, HE Xing

2021, 0(1):  58-63.  doi:10.16628/j.cnki.2095-8188.2021.01.010

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Foreign matters hanging on the power grid line and electrical equipment are easy to cause the contact short circuit between the lines which threatens the safety and stability of the power grid.In this paper,a high-precision object detection model based on Faster R-CNN was proposed for common foreign matters in power grid,such as kites,balloons,birds’ nests.Aiming at the problem of insufficient sample size of pictures,the data augmentation method is designed to effectively expand the data of the training set.Multi-scale processing of sample images is also carried out to improve the training speed of the model and the adaptability of the model to different scales.The accuracy and recall rate of the model can reach 93.12% and 94.75% respectively.It is proved that the target detection model based on Faster R-CNN trained by the training set with data enhancement has achieved better detection results.

Analysis on 220 kV Artificial Grounding Short Circuit Test Based on Weak Power Grid

DUAN Yu, JIAO Chunlei, ZHANG Feng

2021, 0(1):  64-69.  doi:10.16628/j.cnki.2095-8188.2021.01.011

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The area with weak grid structure is used as the research object,and the artificial grounding short circuit test is performed to verify the reactive dynamic response capability of reactive power compensation device (SVG) under large disturbances in the power grid and the support ability to the voltage of weak grid.At the same time,it analyzes the impact of photovoltaic power supply as new energy on short-circuit current,check the closeness of the current power system calculation model to the actual situation of the power grid.The test results show that SVG can provide reactive voltage support for the grid,photovoltaic as a new energy source helps increase short-circuit current during short-circuit faults in the grid.This test provides field test result data for the research of photovoltaic power supply models and modeling methods suitable for large-scale photovoltaic grid-connected interconnected systems,provides a solid technical foundation for further improving the power receiving capacity of the power grid and optimizing the grid frame and load structure.

Energy Management

Pricing Strategy and EV Charging Management of Electric Vehicle Agents in Business District under Green Electricity Trading Mode

HOU Jiawei, LIAO Shengtao

2021, 0(1):  70-76.  doi:10.16628/j.cnki.2095-8188.2021.01.012

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In view of the problems such as the increase of peak valley difference caused by the disordered charging of private electric vehicles in the central business district,this paper put forward a pricing strategy for the electric vehicle agents in the business district under the green electricity trading mode under the background of the gradual opening of the electricity selling market,and established a double-layer master-slave game model with the goal of maximizing the electricity selling profit of the agents in the upper level and minimizing the charging cost of the users in the lower level.The pricing strategy of the agents in the central business district proposed in this paper can effectively integrate the scattered electric vehicle users in the business district to participate in the green electricity transaction,reduce the peak valley difference in the business district and realize the minimum charging cost for users.The effectiveness of the strategy is verified by an example.

Research on Load Coordination Optimization and Regulation Technology Based on Household Smart Energy

LI Xinjia, CHEN Xiao, YAN Yonghui, WANG Liming, WU Heng

2021, 0(1):  77-83.  doi:10.16628/j.cnki.2095-8188.2021.01.013

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With the rapid load growth and the high permeability of various forms of energy in the residential district,there are serious problems such as transformer overcapacity and load peak-valley difference increase.Based on the analysis of area load regulating characteristics,this paper studied and established the area load coordinated control deployment architecture and control framework.Through the area load forecasting,optimizing interval evaluation,prior to the date of load arrangement and real-time monitoring and correction,it realized the ascension of area interruptible load ability,schedulable ability and area average load utilization rate,and the effectiveness of the technology is verified by engineering practice.

Modeling Method of Internal Impedance of Common Mode Noise Source in Switching Power Supply

LIN Subin, LU Wentao, ZHANG Liping, WU Qinwei

2021, 0(1):  84-89.  doi:10.16628/j.cnki.2095-8188.2021.01.014

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Taking the small communication power supply as the research object,the transmission mechanism of common mode noise is analyzed,and the key factors affecting the internal impedance of common mode noise source are clarified.Through theoretical analysis,a common mode noise source internal impedance modeling method based on insertion loss method is proposed.Based on this method,the common mode noise source internal impedance parameters of switching power supply can be accurately extracted,and the high-frequency equivalent circuit model of common mode noise source can be established.Finally,the accuracy of the proposed method is verified by experiments.

Research on Efficiency Evaluation of Power Grid Development Based on Value Maximization

GUO Li, FANG Xiang, WU Shuang

2021, 0(1):  90-97.  doi:10.16628/j.cnki.2095-8188.2021.01.015

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This paper constructs the value creation system of power grid from the three aspects,such as society,users and operation value,constructing the efficiency index system and the development effectiveness of power grid from the strategic result level and the operation process level.The evaluation model under the condition of multiple evaluation subjects is constructed by combining subjective and objective methods to assign weights to indexes.Finally,the rationality and effectiveness of the index system are verified by a concrete example.The results show that the evaluation system is valuable to investigate the implementation degree of power grid value proposition and the realization degree of specific value.