Table of Content

30 September 2021, Volume 0 Issue 9

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Overview

Current Status and Prospects of Demonstration Projects of Source-Network-Load-Storage in Regional Power Systems

DENG Ming, HUANG Jiyuan, WU Donglin, ZENG Linjun, PENG Qingwen

2021, 0(9):  1-9.  doi:10.16628/j.cnki.2095-8188.2021.09.001

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In view of the huge pressure of my country’s energy transition and the deep integration of energy transition and information technology,the coordinated and interactive development of source-network-load-storage is imperative.Based on the development of the Energy Internet,firstly,it focuses on the problems faced by the current regional power grids,and elaborates the necessity of developing a coordinated control system for source-network-load-storage.The system architecture and business model are compared and analyzed.Then,the overall system framework of the source-network-load-storage coordinated control system based on the regional power grid is proposed.Finally,combined with the current situation of my country's development,summarized and prospected for future development directions.

Overview of Key Technologies for Lithium-ion Battery Life Prediction Based on Data-Driven Methods

LI Jianlin, WANG Zhe, XU Dezhi, MA Fuyuan, MENG Gaojun

2021, 0(9):  10-18.  doi:10.16628/j.cnki.2095-8188.2021.09.002

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In recent years,applications in the fields of electric vehicles,electronic products and aerospace systems have placed higher and higher requirements on lithium-ion batteries.The timely replacement of lithium-ion batteries at the end of their life is conducive to the rational use of lithium-ion batteries.performance.This article first combs the traditional data-driven methods of lithium-ion battery life prediction,then analyzes the existing methods of lithium-ion battery life prediction,and then compares the traditional and existing methods of lithium-ion battery life prediction,and finally compares them.By analyzing the advantages and disadvantages of traditional and existing lithium-ion battery life prediction methods,the management and control of the lithium-ion battery energy storage system are more effective.

Integrated Energy System

Optimization Study of Integrated Energy System of Park Considering Grid Peak-Valley Suppression

MA Chunyan, DUAN Qing, SHA Guanglin, ZHAO Caihong, GAO Jian

2021, 0(9):  19-26.  doi:10.16628/j.cnki.2095-8188.2021.09.003

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The integrated energy system exchanges energy with the grid to meet the load demand within the system.Meanwhile,the energy consumption characteristics of the system aggravate the peak valley phenomenon of the power grid.In order to play the role of peak load regulation of integrated energy system,this paper introduces time of use price regulation strategy,which is used to optimize the output of equipment in different periods.It can not only meet the economic and efficient operation of the system,but also alleviate the peak valley contradiction of the power grid.To this end,the optimal scheduling model of the park system is constructed and solved in this paper,and the results obtained can guide the optimal operation of the integrated energy system.At the same time,in order to compare the similarities and differences between different methods,two types of typical methods,the mixed integer programming method and particle swarm optimization algorithm,are used to solve the problem,which can provide a reference for future research.

Research on Multi-Source Coordinated Regulation Strategy from the Perspective of Regional Energy Internet

HUANG Zhao

2021, 0(9):  27-31.  doi:10.16628/j.cnki.2095-8188.2021.09.004

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Energy Internet is the inevitable development trend of the global power system.The coordinated regulation of diversified energy equipments has become a key problem to be solved.Based on the perspective of regional Energy Internet,considering the supply demand of clients,the coordinated regulation strategy between multiple sources was explored,under the access of both electric vehicles and energy storage battery.Firstly,the difference between load peak and valley is taken as the optimization objective.Meanwhile,the time-of-use (TOU) price mechanism is adopted to guide the charging/discharging behavior of electric vehicle owners.The compensation capacity of the energy storage battery is dynamically calculated according to the real-time load change,so as to realize peak cutting and valley filling of the regional load curve,and ensure the safe and orderly operation of the power system.Finally,the feasibility of the regulation strategy is verified based on MATLAB simulation results.

Optimal Scheduling Strategy of Wind,Fire and Energy Storage Considering Battery Capacity Degradation

GUO Binqi, ZHANG Jiangfeng, SU Ye, WU Jiping, SUN Jiandong

2021, 0(9):  32-39.  doi:10.16628/j.cnki.2095-8188.2021.09.005

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Energy storage technology provides a new way to deal with wind power access to the grid,however,frequent use of energy storage power stations will cause the battery capacity decline and the operation costs of power stations increase.This paper proposes a combined optimal scheduling model of wind,fire and energy storage,which considers the battery capacity degradation,thermal power start-up,shutdown and ramp up,wind power abandonment,system branch capacity and system reserve,etc.The model is linearized and calculated by calling CPLEX solver.The simulation results of 4-machine 14 bus system show that the model can alleviate battery capacity attenuation,thermal power climbing shortage,wind power curtailment and line capacity shortage.This paper provides a practical and feasible scheduling scheme for the healthy and reliable operation of energy storage power station.

Comprehensive Evaluation of Electrochemical Energy Storage Power Station for New Energy Consumption

JIANG Xiaofeng, CHANG Luyu, CHEN Jue, ZHANG Meng

2021, 0(9):  40-44.  doi:10.16628/j.cnki.2095-8188.2021.09.006

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Research on the comprehensive evaluation method of the electrochemical energy storage power station is proposed. First,the current situation of comprehensive evaluation systems for energy storage systems at home and abroad is studied;secondly,the evaluation indicators are selected from the perspectives of comprehensiveness and accuracy,and the hierarchical model of energy storage system is constructed;finally,the analytic hierarchy process (AHP) is selected,and subjective and objective are selected. The combined weighting method determines the index weights and conducts a comprehensive evaluation of the energy storage power station,which provides references for various needs such as early-stage investment and construction planning and later-stage operation strategy selection and improvement.

Economic Optimal Scheduling of Integrated Energy Systems Considering Multi-Energy Complementary Supply Characteristics

ZHAO Fengzhan, LI Qi, ZHANG Qicheng, WAN Zhongyang, SU Juan, WU Ming

2021, 0(9):  45-50.  doi:10.16628/j.cnki.2095-8188.2021.09.007

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The integrated energy system (IES) achieves the purpose of improving the overall efficiency of the system through the complementary optimization of multiple energy sources.In this paper,considering the characteristics of multi energy complementary supply of IES,the structure of IES and the mathematical model of each energy equipment are determined.And then an economic optimal dispatch model is established with the objective of minimizing the sum of energy purchase cost,environmental pollution penalty cost and energy loss cost.In this model,the output of each energy conversion equipment is controlled to improve the operation performance of the system.Finally,an example is used to verify that the optimal control method can improve the operation economy and environmental protection of the IES,and promote the complementary supply of multiple energy sources and meet the demand of multiple loads.

Research and Implementation of Integrated Energy Planning Design and Simulation Analysis Software

WANG Kun, HUANG Lijun, LI Xianwei, LIU Xiaoxiao, HE Wei

2021, 0(9):  51-55.  doi:10.16628/j.cnki.2095-8188.2021.09.008

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In order to support the development of integrated energy services business,the functional requirements analysis,overall architecture design,main function design and development of integrated energy planning design and simulation analysis software were carried out.The software can carry out resource analysis and energy supply and consumption prediction according to the local wind,solar,temperature,geothermal and other energy resource endowments of the project.Through the balance of supply & demand and multi-objective optimization algorithms,it can realize the macro location of distributed energy station,the equipment selection and capacity of multi energy supply system and energy storage system,and meet the comprehensive energy demand of schools,hospitals,enterprises,commercial complexes,parks and other typical energy consumption scenarios through the comparison and selection of energy supply technology route and the generation of design scheme,the feasibility analysis and preliminary planning and design of the project are realized.

Electrical Design & Discussoin

Simulation of Contact Resistance for Flexible Spring Components Within Electromagnetic Relays

ZHAO Zien, ZHANG Chao, REN Wanbin

2021, 0(9):  56-61.  doi:10.16628/j.cnki.2095-8188.2021.09.009

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Contact resistance is an important parameter for electrical contact reliability of flexible spring components widely used in electromagnetic relays.In this paper,the coupled mechanical-electrical field simulation of the typical bridge-type structure is conducted by the commercial software COMSOL Multiphysics to obtain the distributions of the contact stress and electrical current lines.Thus,the variations in contact resistance as a function of contact displacement is determined.The simulation results agree well with the experimental results.Finally,the effects of the curvature radius of the movable contact and the flexible spring length on the contact force and contact resistance are further analyzed.The conclusions could be directly applied to the optimal design of the spring component in the electromagnetic relay.

Influence of Spring Structure on Arcing Balance of Molded Case Circuit Breaker Research

ZHOU Lulu, SHEN Qiuchen, FAN Leilei

2021, 0(9):  62-66.  doi:10.16628/j.cnki.2095-8188.2021.09.010

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The double-break contact structure of molded case circuit breaker is theoretically symmetrical,but due to the existence of the floating gap in the center of the rotor shaft,when a short-circuit fault occurs,the arcing of the two ports will not be completely consistent.When the imbalance reaches a certain level,it will cause the failure of short circuit protection.In order to study the influence of different rotor springs on the arcing balance of the double-breakpoint circuit breaker.The phase of short-circuit fault is changed through experiments,and arcing balance under different structures is compared by intuitive graphs and data.The results show that the spring structure has a significant impact on the arcing balance,and the compression spring design has more advantages in terms of balance,which provides support for perfecting the circuit breaker rotor design.

Design and Implementation of Trip Current Consistency of AC Type Leakage Protector Chip

WANG Hongxiang, WANG Xuejun, ZHOU Zijian, LU Jianfeng

2021, 0(9):  67-72.  doi:10.16628/j.cnki.2095-8188.2021.09.011

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For the traditional leakage protector chip,high level generated by leakage electrical signal amplification and comparison are used to drive silicon controlled rectifier trip and power off.There is a problem of poor consistency of the tripping current.An innovative design idea is proposed.Which is setting the FUSE trimming module in the leakage protector chip amplifier unit and designing the circuit structure of high precision test of the amplifier.During wafer testing,input sensitivity accuracy of leakage protector chip is greatly improved and input sensitivity is controlled between 5.8~6.2 mV.The test result shows that the tripping current is controlled within 5%,which greatly improves the tripping current consistency,reliability and interference capability of the AC type leakage protector.

Research of IC-CPD’s Residual Current Protection Characteristic Test Device

ZHANG Shuangrong, YANG Shijiang

2021, 0(9):  73-77.  doi:10.16628/j.cnki.2095-8188.2021.09.012

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In view of the shortcomings that the current residual current protection characteristic test device can’t fully meet the IC-CPD’s residual current protection characteristic test,this paper puts forward the research to meet the needs of IC-CPD’s residual current protection characteristic test device. Firstly,this paper compares and analyzes the current standards and test devices related to residual current protection devices,and makes clear the differences existing in IC-CPD’s residual current protection characteristic test;then it discusses in detail how to carry out circuit-loop design;then it studies and designs a digital waveform generation and power amplification scheme to meet IC-CPD’s composite wave residual current action characteristic test. The IC-CPD’s residual current protection characteristic test device designed in this paper has carried out the preliminary verification experiment,which meets the IC-CPD’s test requirements and makes up for the shortcomings of the existing test device.

Distribution System Technology

Study on DC System Ground Fault Detection Relating to Unbalanced Bridge and Wavelet Transform

XU Yichao, NIE Deyu, GU Yun, WANG Shuzheng

2021, 0(9):  78-84.  doi:10.16628/j.cnki.2095-8188.2021.09.013

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The insulation monitoring and fault branch location are the key problems of substation DC system.To deal with the shortcomings of the detection methods such as pull circuit and balanced bridge,a comprehensive method relating to unbalanced bridge and wavelet transform is proposed.By monitoring the insulation of busbars to the ground with an unbalanced bridge,this paper presents a method which combines bus voltage deviation rate and detection sensitivity to ground.The optimal wavelet basis function is selected to filter and reconstruct the branch current,and the complex wavelet transform is used to extract the amplitude and phase information of the signal to calculate the grounding resistance,so as to complete the location of the fault branch.The simulation results show that the proposed method has higher detection accuracy with regard to the Fourier analysis method,and can restrain the influence of the distributed capacitance of the system to a great extent.

Research on Fault Location of Distribution Network Based on Ant Colony Annealing Algorithm

ZHANG Ying, XU Xin

2021, 0(9):  85-90.  doi:10.16628/j.cnki.2095-8188.2021.09.014

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Ant colony algorithm is well used to solve the problem of distribution network fault location,but it is still insufficient to solve the problem of FTU distortion information,which can not meet the power supply reliability.Therefore,simulated annealing algorithm is introduced to improve it.Firstly,the evaluation function and switch function which can adapt to the structure of distribution network are constructed,then the roulette method and reversal strategy are introduced to optimize the updating of ant colony pheromone to avoid falling into the local optimal solution.Finally,the method of applying ant colony annealing algorithm to the fault location of distribution network under distributed generation is determined,focusing on the fault location of phase to phase fault and high current grounding system.The simulation results show that the algorithm has the advantage of fault tolerance.

Research on DC Bias Suppression of Dual Active Bridge Used in DC Distribution Network

HAN Wenhui

2021, 0(9):  91-99.  doi:10.16628/j.cnki.2095-8188.2021.09.015

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During the power transmission process of the dual-active-bridge DC-DC converter based on phase shift control,when the phase shift angle or load transient causes the inductor current and the transformer excitation current to generate a transient DC bias,which causes current stress in the switching device increase and the problem of transformer magnetic saturation.The traditional single-phase-shift control uses a 50% duty cycle square wave signal to operate the switches on the diagonal side of the primary and secondary H bridges simultaneously.In this paper,by analyzing the generation principle of the DC bias it can achieve the needful switching action to eliminated the problem of DC bias.A new switch independent (SID) control method is proposed to achieve a new steady state and eliminate DC bias within half a switching cycle.The simulation of MATLAB/Simulink verifies the feasibility of the proposed control method.

Multi-Source Data Processing and Fusion Model of Low Voltage Distribution Network Based on Hermite Network

FENG Yi, JIN Bin, ZHOU Xiang

2021, 0(9):  100-106.  doi:10.16628/j.cnki.2095-8188.2021.09.016

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The continuous upgrading and transformation of the low-voltage distribution network system has increased the complexity of the data information in the power grid.In order to effectively process the acquired multi-source data in real time and improve the calculation speed and fusion efficiency,this paper reforms the traditional neural network and proposes a Hermite orthogonal basis forward neural network based on the theory of polynomial interpolation and approximation.An algorithm model based on Hermite orthogonal basis forward neural network is built,and finally this algorithm is parallelized under the MapReduce framework.Through simulation verification, it is found that the model has higher processing efficiency,faster calculation speed and smaller error for multi-source data of low-voltage distribution network. Therefore, the multi-source data processing and fusion model of low-voltage distribution network based on Hermite orthogonal basis forward neural network proposed in this paper can better meet the real-time processing requirements of multi-source data in low-voltage distribution network.