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Table of Content

    28 February 2025, Volume 0 Issue 2
    Research & Analysis
    Research on Contact Resistance Degradation Mechanisms of Relay with Contact Bridge Structure Under Continuous Current Loading
    YANG Xinyu, WU Chengchuang, HE Yubin, ZHANG Chao, REN Wanbin
    2025, 0(2):  1-5.  doi:10.16628/j.cnki.2095-8188.2025.02.001
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    An experimental study is carried out on the electrical contact reliability of relay with contact bridge structure under the condition of continuous current loading in high temperature environment.By monitoring the curve of the contact resistance change with power-on time and the degradation trend after several cycles, it is found that the contact resistance has a typical characteristic of gradual increase.Further, by testing the mechanical properties of the reed, it is confirmed that the decrease of the stiffness coefficient of the reed and the imbalance of the contact bridge are the main reasons leading to the increase of the contact resistance and finally the failure of the relay.

    Classification and Identification of AC Contactor Operational States Based on Weighted Grey Target and LPSO-BP Algorithm
    ZHOU Houlin, XING Chaojian, XU Jing, LIU Shuxin, MING Xin, LIU Bingze
    2025, 0(2):  6-14.  doi:10.16628/j.cnki.2095-8188.2025.02.002
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    In response to the problems of unclear boundaries,insufficient division criteria,and premature convergence of training algorithms,an algorithm model for dividing and identifying the operational states of AC contactors based on weighted grey target and Levy Flight Particle Swarm Optimization (LPSO) algorithm is proposed.Firstly,the threshold denoising and feature selection are performed on the raw data.Secondly, by using the Analytic Hierarchy Process (AHP) to weight and improve the grey target algorithm,the grey target value of the entire life cycle of the AC contactor is obtained as the data basis for dividing the operational state into three states: good, general, and high-risk.Finally, the BP neural network optimized by LPSO (LPSO-BP) algorithm is used for classification prediction,and compared with other algorithms to verify that the proposed algorithm has better stability and accuracy.

    Research on Method of Improving Load Capacity Within Limited Volume of Crystal Cover Sealed Electromagnetic Relay
    ZHANG Yongjian, YOU Jiaxin, WU Di, XUE Yutong, GONG Shijia, ZHAN Xiaoyu
    2025, 0(2):  15-23.  doi:10.16628/j.cnki.2095-8188.2025.02.003
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    Sealed electromagnetic relays used in the aerospace field are characterized by small size and strong environmental adaptability.In view of the demand of high load capacity under the limited volume of the relay,firstly,the product failure mechanism of the relay under high load condition was analyzed.Based on the single factor analysis method,the main influencing factors of the shape and position parameters affecting the maximization of space were determined by taking the maximum threshold of the holding force and the maximum suction voltage of the electromagnetic system as the upper and lower limits.The design scheme of maximizing the increase of contact opening distance was realized.Subsequently,schemes such as installing a heat sink,adding SF6 arc extinguishing atmosphere,and adding a permanent magnet arc extinguishing in the limited space were tried respectively.Based on the comparison of the test results,the design of the relay within the limited volume was determined,and the principle prototype was made and the production test was carried out.Finally,according to the results of the high-temperature life test,it was determined that the installation of heat sink was the optimal design scheme.

    Research on Method of Three-Level Circuit Loss Analysis and Temperature Rise Optimization
    CHEN Kunpeng, XIAO Wenxun
    2025, 0(2):  24-28.  doi:10.16628/j.cnki.2095-8188.2025.02.004
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    Aiming at the problem of unbalanced loss distribution in the diode neutral-point-clamped (NPC) three-level circuit,the active neutral-point-clamped (ANPC) three-level circuit is adopted.Different current paths are selected to disperse the device losses among different switching tubes.Through theoretical calculation of losses,thermal simulation and experimental verification,the comparative analysis of the device losses and temperature rises of the two circuits is carried out.The results show that the ANPC circuit has a significant effect on balancing the device losses and reducing the device temperature rise.

    Research on Autonomous Simulation Software for Dynamic Characteristics of Low Voltage Contactors
    TANG Lingzhi, SUN Hao, WANG Zifeng, NIU Chunping, WU Yi
    2025, 0(2):  29-35.  doi:10.16628/j.cnki.2095-8188.2025.02.005
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    A software for calculating the dynamic characteristics of contactors is developed based on the domestic electromagnetic simulation platform Simdroid.The software calculation process consists of three parts:finite element static magnetic field calculation,current calculation,and motion calculation.The finite element static magnetic field calculation is implemented by Simdroid.In the current calculation,the main circuit parameters are input based on the static magnetic field results to calculate the current at each time.During the motion calculation,the position of the iron core at each time is determined by the forces acting on it.After updating the position,the finite element static magnetic field calculation is performed again,and the iteration continues until the termination condition is reached.Experiments show that the displacement and current curves of the moving iron core show good agreement between the experimental and simulated results.Therefore,the proposed software can be an effective numerical tool for analyzing the dynamic characteristics of contactors.

    Electrical Design & Discussion
    Improved Design on Interlocking Device of High-Capacity Transfer Switching Equipment
    XU Minhang, ZHOU Liu, WAN Xiangjun
    2025, 0(2):  36-40.  doi:10.16628/j.cnki.2095-8188.2025.02.006
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    On the basis of the analysis of the main differences in mechanical interlocking between the new and old versions of GB/T 14048.11—2024 Low-voltage switchgear and controlgear-Part 6-1: Multiple function electrical apparatus-Transfer switching equipment,and considering the mechanical interlocking structure of a certain type of high-capacity transfer switching equipment(TSE),when the operating power switch Ⅰ and power switch Ⅱ are simultaneously closed in the off position,there is a phenomenon that the moving and fixed contacts are instantaneously connected and then tripped.A dual-interlocking improvement scheme is proposed,which adds a spindle interlock on the basis of the original tripping interlock.Through simulation analysis,it is verified that the proposed improvement scheme can effectively eliminate the instantaneous simultaneous connection phenomenon,enhance the application reliability of TSE and the feasiblity of practical engineering applications.

    Balance Optimization Design of Double-Break Moulded Case Circuit Breaker Contact System
    GAO Jingbo
    2025, 0(2):  41-46.  doi:10.16628/j.cnki.2095-8188.2025.02.007
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    The double-break moulded case circuit breaker have good current limiting capability and advantages in power distribution and installation.The balance and stability of their contact systems are the keys to product structure design.In response to a double-break point contact system with simple structure and easy installation,combined with the mechanical analysis and simulation calculation,the system structure is optimized.A structure design concept is proposed,which features provide a stable contact,good pressure consistency and automatic balancing performance,and can realize the function of repelling and getting stuck.

    Design of New Charging Module with Wide Input Voltage Range
    LIU Yanxin
    2025, 0(2):  47-52.  doi:10.16628/j.cnki.2095-8188.2025.02.008
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    In order to address the shortcomings such as the too narrow range of the AC input voltage and low stability of the DC charging modules in the current DC system of the substation,the overall design scheme of a new type of charging module with the wide input voltage range is proposed.Based on the comparative analysis of the charging module scheme based on the three-winding AC input and the charging module scheme based on the boost control,the charging module scheme based on the boost control is adopted.Taking the existing DC charging module as the basis,the parameters of the power conversion part are adjusted,and the auxiliary control and judgment units are added,and the prototype is developed.Through experimental verification,while maintaining the original electrical performance unchanged,when the grid fails and the voltage is low,the prototype can output a stable voltage normally (with the output power derated).

    Design of Single-Ended Flyback Synchronous Rectification Anti-Reverse Current Drive Circuit
    JIANG Dongyi, YANG Song, ZHANG Chunya
    2025, 0(2):  53-57.  doi:10.16628/j.cnki.2095-8188.2025.02.009
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    By analyzing the causes of the reverse current in the single-ended flyback synchronous rectification circuit,a design scheme for the externally-driven synchronous rectification drive circuit is proposed.The feasibility of the proposed scheme is verified by the theoretical calculations and simulation analyses.A prototype of the secondary power supply module with the output of 5 V/12 A is built.The results of the experimental measurements show that the prototype can achieve the quantitative control of the reverse current.

    Design of Voltage-Doubling Feedback Power Supply Circuit
    ZHANG Chunya, JIANG Dongyi, JIANG Yunyang
    2025, 0(2):  58-63.  doi:10.16628/j.cnki.2095-8188.2025.02.010
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    As an efficient energy conversion power device,switching power supply is widely used in various industries.Aiming at the problem of feedback power supply of switching power supply,the working principle and key problems are analyzed,a voltage-doubling feedback power supply circuit is desigued through theoretical calculation and simulation analysis,the correctness of the design scheme is verified.Finally,the circuit is applied to a 5 V/40 A forward synchronous rectification switching power supply.The measured feedback voltage fluctuates only by 1.5 V.The results show that the circuit has high stability and practicability,which is of great significance for improving the efficiency and reliability of switching power supply.

    Application
    Design and Implementation of Power Outage Plan Control Platform Based on i-State Grid
    XU Xiaodong, ZHOU Jiaqing, LIU Yihua
    2025, 0(2):  64-70.  doi:10.16628/j.cnki.2095-8188.2025.2.011
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    With the continuous expansion of the power grid,there are problems such as delayed power outage applications and frequent changes in power outage plans in the equipment power outage management control,making the statistical and analytical work of power outage plans cumbersome and complex.Firstly,a power outage plan full process control platform based on the i-State Grid platform is constructed to achieve monitoring and management of the entire power outage plan process.Then,using the power outage plan customer demand fluctuation monitoring technology,a customer demand fluctuation prediction model is established to achieve quantitative monitoring and analysis of customer demand fluctuation and cause tracing,improving the customer service management level and the lean service capacity of power outage.Finally,the experimental verification and analysis are conducted on the validation of the prediction model and the customer demand monitoring.The results show that the proposed customer demand fluctuation prediction model has good effects on the refined management of power outage plans and the full factor management and control.