Table of Content

30 June 2022, Volume 0 Issue 6

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Overview

Review on Research Methods of Relay Storage Reliability

LI Jiuxin, WANG Zhaobin, ZHU Jiamiao

2022, 0(6):  1-5.  doi:10.16628/j.cnki.2095-8188.2022.06.001

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It is of great significance to study the reliability and life prediction of relays.The mechanism of relay storage failure is summarized,and the research status of relay storage reliability is analyzed.The definition of relay degradation is explained,and the advantages of life prediction based on the degradation law are introduced.The application and characteristics of reliability evaluation by the random degradation model are summarized,such as Wiener model,Gamma model and Weibull model.Finally,the application of accelerated storage test method in the field of relay reliability prediction is briefly summarized,and the shortcomings of relay storage reliability analysis and the future research direction are summarized.

Review on Estimation Methods of Vacuum Circuit Breaker’s Moment-Close Point for Online Monitoring

LIU Cheng, DAI Daoli, WANG Ning, CHEN Lingling, CHEN Jichuan

2022, 0(6):  6-9.  doi:10.16628/j.cnki.2095-8188.2022.06.002

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In order to obtain the mechanical characteristic information of the vacuum circuit breaker,it is necessary to perform the parameter measurement and state analysis,and to calculate the closing speed of the circuit breaker.It is necessary to obtain the moment-close point of the moving and static contacts.First,several methods for testing the mechanical characteristics of circuit breakers are introduced,and the existing methods for extracting the moment-close point are compared.The advantages and disadvantages of each method are clarified.Combined with the filter derivation method,the moment-close point of a certain type circuit breaker is extracted and compared with the real moment-close point.For online monitoring applications,the above methods can extract the moment-close point of the circuit breakers.There must be some trades-off in practice.

Research & Analysis

Research on Pull-In Process of AC Contactor with Various Contact Gaps

YANG Chunen, ZHENG Zhe, REN Wanbin

2022, 0(6):  10-14.  doi:10.16628/j.cnki.2095-8188.2022.06.003

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The pull-in process is closely related to the response time and the reliability of the AC contactor.Firstly,an AC contact experimental system which can adjust the contact gap is introduced,and the waveforms of the contact voltage,moving iron core displacement and coil current are recorded in real time.Furthermore,the influence of the contact gap on the pull-in time,bounce duration,and stability duration is studied.Finally,the pull-in characteristics of AC contactor with the different contact gaps are discussed.

Research on Key Technology of HVDC Contactor Arc Breaking

LI Sihong

2022, 0(6):  15-19.  doi:10.16628/j.cnki.2095-8188.2022.06.004

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For the high voltage DC contactor with the differentiated development according to the technical characteristics,under the premise of unpressurized design,the DC arc breaking technology of air medium is studied by comparing the breaking waveform from the different angles such as contact opening distance,arc extinguishing grid,arc driving magnetic field,breaking speed and arc burning gas flow.The comparative analysis of the results shows that the reasonable layout of gas channel and arc extinguishing grid is the key to the extinction of arc,the arc driving magnetic field in a certain range can ensure the effective stretching of the arc,and a certain contact opening distance and breaking speed can effectively control the arc burning time.

Experimental Study on Influence of Arc Extinguishing Structure of AC Contactor on Electrical Endurance

HU Guowei, ZHANG Hongwei, JI Xinhua, WANG Zhenkun, ZHENG Bin, RONG Liangzhang

2022, 0(6):  20-23.  doi:10.16628/j.cnki.2095-8188.2022.06.005

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In order to improve the electrical endurance of AC contactor,combined with the arc extinguishing principle and arc extinguishing method,three different structures of arc extinguishing systems are proposed.The experimental results show that the setting of arc channel on the cover plate of the arc extinguishing chamber,the upward inclination angle of the arc striking plate and the bending angle of the last arc-extinguishing grid can have an important impact on the electrical endurance of AC contactor.This has a certain reference significance for the arc extinguishing system design of AC contactor.

Closed Loop Feedback Control Strategy of AC Contactor Current Slope Based on Multi Condition Judgment

YANG Cheng, LIU Xiangjun

2022, 0(6):  24-31.  doi:10.16628/j.cnki.2095-8188.2022.06.006

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Aiming at the problem of sharp contact bounce in the starting process of AC contactor,by adopting the two-stage step current starting mode,the current slope closed-loop feedback control strategy based on multi condition judgment is proposed.Through the multi software joint simulation model and orthogonal test,the better starting current is calculated,and the feasibility of the proposed control strategy is verified by simulation.The control system is designed to verify the control strategy.The results show that the control strategy can effectively reduce the contact bounce and has the characteristics of high control reliability.

Research on Virtual Prototype Model of Electromagnetic Relay with Bridge Polarized Magnetic System and Influence of Armature Position Deviation

LIU Guilin, LIANG Huimin, WEI Zitong, CHEN Junfeng, DENG Liming, ZOU Liang

2022, 0(6):  32-38.  doi:10.16628/j.cnki.2095-8188.2022.06.007

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The electromagnetic relay with the bridge-type polarized magnetic system has the advantages of small size,light weight and high sensitivity.However,the armature position deviation in actual production affects the electromagnetic force and spring force,which is not conductive to the improvement of the electrical life of the relay.Firstly,the virtual prototype model of the electromagnetic relay with the bridge polarized magnetic system is established,and the static characteristics of the electromagnetic force and spring force of the relay are simulated through electromagnetic system and contact spring system simulation model.Secondly,based on the measured armature position offsets,the process of electromagnetic force and spring force are investigated when there is armature position deviation by the theoretical analysis and simulation.Finally,the influence of different armature position offsets on pull-in voltage,release voltage and electrical life of relay are analyzed according to the cooperation between electromagnetic force and spring force.The above investigation provides the theoretical foundation for the demand of strictly controlling the spot-welding energy of armature and small axis for avoiding the armature position deviation.

Identification & Prediction Technology

Operation State Identification of AC Contactor Based on Vibration Signal

LI Ruixin, LIU Shuxin, CAO Yundong

2022, 0(6):  39-44.  doi:10.16628/j.cnki.2095-8188.2022.06.008

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The state recognition of AC contactor is an important prerequisite to ensure its normal operation.In view of the characteristics of multivariate,multi-attribute interaction and dynamic change of AC contactor operation state,an AC contactor operation state recognition method based on Grey Wolf optimizer support vector machine (GWO-SVM) is proposed.The time domain and frequency domain features are extracted from the vibration signal of the contactor contact opening and closing stage,and the Pearson correlation coefficient is used to select the parameters to obtain the optimal feature subset.Finally,the contactor operation state is identified by GWO-SVM method.By comparing other identification algorithms,it shows that the proposed method is better in the recognition accuracy of the contactor operation state.

Research on Life Prediction of Electromagnetic Relay Based on Weighted Optimation Combination Model

GUAN Xin, LV Zhiguo, YUE Baoqiang, ZHANG Weijia

2022, 0(6):  45-50.  doi:10.16628/j.cnki.2095-8188.2022.06.009

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Through the degradation parameters of the sealed electromagnetic relay,the prediction of the product storage life is used to improve the reliability of each stageof the product.Based on the grey model and the BP neural network model,the combined prediction model is constructed by the weighted combined single prediction method,and the combined weight value is optimized by using the error optimal least square method,the reciprocal of mean square error method and the equal weight distribution method.The storage life of the sealed electromagnetic relay is predicted to be 13.17 years by the combined prediction model with the best accuracy.The results show that the combined prediction model with the optimized weight value can effectively improve the prediction accuracy,which provides a new idea for predicting and improving the reliability of such products in important fields.

Hum Fault Feature Extraction of AC Relay Based on Parameter Optimization VMD

XIE Hongkai, BAO Guanghai

2022, 0(6):  51-56.  doi:10.16628/j.cnki.2095-8188.2022.06.010

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Aiming at the problem of poor performance of AC relay hum fault feature extraction under large background noise,a fault feature extraction method based on the parameter optimization variational modal decomposition (VMD) is proposed.First,the salp swarm algorithm is used to optimize the parameters of VMD,and the obtained optimal value is used to perform VMD decomposition of the fault signal to obtain a number of intrinsic mode functions (IMF).Then the decomposed IMF components is filtered according to the kurtosis criterion,the IMF component with the largest kurtosis is selected as the effective component,and the Hilbert envelope demodulation analysis is performed to extract the feature of the hum fault.Finally,the analysis results of the simulation signals and experimental datas show that the proposed method is feasible and effective in extracting the hum fault characteristics of AC relays and has higher application value compared to the empirical mode decomposition (EMD) method.

State Feature Fusion Method of AC Contactor Based on DDAE

GAO Shizhen, LIU Shuxin

2022, 0(6):  57-63.  doi:10.16628/j.cnki.2095-8188.2022.06.011

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The extraction of AC contactor operating state features is a necessary prerequisite to accurately predict its remaining life.Aiming at the multivariate,multi-dimensional interaction and dynamic change operating state characteristics,the state feature fusion method of AC contactor based on the deep denoising autoencoder (DDAE) is proposed.Driven by the multi-dimensional characteristic parameters,the characteristic parameters related to electrical and mechanical parameters of AC contactor are fully extracted.The DDAE feature fusion model is constructed,and the feature fusion reconstruction is carried out on the basis of preserving the original feature information to the greatest extent.Through the verification and analysis of the experimental data,the results show that it has high characterization accuracy in the operation state feature fusion of AC contactor,which lays a foundation for the accurate prediction of the remaining life of AC contactor.

Electrical Design & Optimization

Vibration Mechanism Analysis and Optimization of AC Contactor Based on Mechanical Structure

ZHANG Zhiwen, ZHANG Xingdong, ZHU Yingping, HUANG Zhenshun

2022, 0(6):  64-68.  doi:10.16628/j.cnki.2095-8188.2022.06.012

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As an industrial control component,AC contactor has a wide range of applications and a large amount of production.The vibration and noise problems of AC contactors are the most obvious in manufacturing and customer complaints.In view of the above vibration and noise problems,this paper analyzes the causes of these problems from the angle of mechanical structure of AC contactor,and puts forward the solutions to suppress the vibration and noise.The results show that the vibration of AC contactor can be divided into electromagnetic vibration and mechanical vibration.Electromagnetic vibration is an inherent characteristic of AC contactors,which cannot be avoided by taking measures.The mechanical vibration is caused by the pole face of the iron core and the imbalance of the system.The vibration and noise caused by core problems and system imbalance can be suppressed and solved by taking corresponding measures.

Theoretical Analysis and Calculation of Solenoid Electromagnetic System for Miniature Circuit Breaker

WEI Bo, ZHAO Zhisheng, REN Changbin, ZHAO Ming, ZHAI Ziye, LI Haili

2022, 0(6):  69-74.  doi:10.16628/j.cnki.2095-8188.2022.06.013

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The overall analysis of the miniature circuit breaker(MCB) solenoid electromagnetic system is carried out based on the electromagnetic suction force.Starting from the analysis of the magnetic circuit,the suction formula of the DC solenoid electromagnetic system and the AC solenoid electromagnetic system are derived.The instantaneous value,maximum value and average value of the electromagnetic suction force are further analyzed and deduced by using the suction characteristics of the AC electromagnetic system.The electromagnetic system of DC and AC MCB is calculated in practice by using the suction formula,which provides the data support for the design of reaction springs.Finally,quantitatively analyzing the universality of DC and AC MCB,the adjustment method of the reaction force spring is given.

Development of Microgrid Compound Protection Miniature Circuit Breaker Based on Residual Current Protector

XUE Bing, YANG Ran, YANG Huanhong, SUN Shiqing, SHEN Miao, CHENG Xiangqun

2022, 0(6):  75-79.  doi:10.16628/j.cnki.2095-8188.2022.06.014

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Microgrid system contains a large number of power electronic converters.Due to the special requirements of converter equipment,such as the fast overvoltage protection and the auxiliary protection of islanding effect,the simple protection function of the existing miniature circuit breaker is insufficient.A new composite protection circuit breaker based on the existing residual current protector is proposed,which can realize the quick break protection of system overvoltage and the auxiliary protection of islanding effect.The proposed miniature circuit breakd has good practical value.