Table of Content

15 February 2020, Volume 0 Issue 2

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Research & Analysis

Measurement and Analysis of Relationship between Reeds and Arc Motion of Clapper Relay

ZHANG Xing, LIU Xiangjun

2020, 0(2):  1-7.  doi:10.16628/j.cnki.2095-8188.2020.02.001

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In the process of breaking AC load,a small clapper power relay will generate high-energy arc which will erode the contact.At the same time,due to the reed vibration,the arc often runs out of the contact and damage the reed,which will seriously affect the electrical life and reliability of the relay.In order to study the impact of reed vibration on the arc motion and provide the foundation for the optimal design of the relay structure,this paper presented a test method based on high speed camera technology to test images of the reeds and electric arcs synchronously and obtains their motion curves by image processing.Then the stiffness of the moving reed and the static reed was modified by the control variable method and the key factors affecting the arc motion were analyzed.The results show that reducing the reed vibration is beneficial to reducing the arc motion range and making the arc relatively stable on the contact surface.

Influence Analysis of Characteristic Parameter Weights of AC Contactor Based on Adaptive Optimal Weight

JIANG Yanzhen, LIU Shuxin, CAO Yundong

2020, 0(2):  8-14.  doi:10.16628/j.cnki.2095-8188.2020.02.002

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Aiming at the problem that the accuracy of the characteristic parameters affecting the AC contactor performance degradation state is not high,this paper proposed an adaptive optimal weight based AC contactor characteristic parameter weight calculation method.Firstly,the contactor degradation state test platform was built,and the test was carried out according to the national standard AC-4 to obtain the characteristic parameter test data.Secondly,according to the principle of moving contact impact speed,arcing phase angle,closing phase angle and bounce time,the corresponding characteristic parameters were extracted.Finally,an improved adaptive weighting method was used to calculate the weight of the feature parameters,define the optimal solution,calculate the weight value close to the optimal solution,and estimate the weight of the characteristic parameters of the AC contactor.The experimental results show that the improved adaptive weights proposed in this paper can better calculate the weights of the characteristic parameters,truly reflect the working state of the AC contactor,and improve the accuracy of the AC contactor performance degradation model.

Study on Effect of Arc Stagnation Time on AC Circuit Lifetime Performance

YANG Yizheng, YANG Wenxue, YANG Yuan, LI Huimin

2020, 0(2):  15-19.  doi:10.16628/j.cnki.2095-8188.2020.02.003

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Through the study of arc stagnation time,the influence of arc stagnation time on AC lifetime performance was obtained.Combined with the test data of the test prototype,the stagnation time of arc under different technical schemes and corresponding electrical life performance were studied.The results show that the shorter the arc stagnation time,the higher the electrical life performance of the circuit breaker.

Experimental Study on Influences of Metal Particle on High-Altitude Discharge Characteristics

WANG Kunlin, DENG Yunkun, TIAN Zengyao, ZHAO Hu, WANG Ke, PENG Jing, MA Yi

2020, 0(2):  20-24.  doi:10.16628/j.cnki.2095-8188.2020.02.004

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With the trends of high-voltage,high-capacity and miniaturization in aircraft power system,the working voltage of the power system is higher,and the arrangement of each component is denser,which increases the probability of partial discharges of the aircraft power equipment greatly.In order to analyze the influence of aircraft complex working environment on air gap breakdown characteristics,the characteristics of air gap breakdown under conditions of low-pressure,micro-distance,and metal particle were studied experimentally.Aluminum foils are used to simulate the metal particles in aircraft power system.Discharge experiments with different pressure and gap distances were carried out.The motion of metal particles was recorded by a high-speed camera.The dependence of air gap breakdown voltage on pressure,gap distance and metal particles was analyzed and discussed.The results show that there is a certain critical pressure value,and metal particles have no effect on air gap breakdown characteristics when the pressure is lower than this value.When the pressure is greater than this value,the breakdown voltage of the air is stabilized at a small value due to the motion of the metal particles.

Analysis on Arcing Characteristics of Carbon-Copper Electrodes at Different Polarities

LIU Zhiwei, CHEN Shaokun, LI Chengkun, ZHU Yinlong, GAO Jinfeng

2020, 0(2):  25-29.  doi:10.16628/j.cnki.2095-8188.2020.02.005

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Arc erosion significantly affects the life of electric contact material as well as its work reliability.Based on the arc ablation experimental platform,the arc ablation experiment of different polarities under carbon-copper pairing was carried out to explore the process of arc erosion.From the voltage and current waveforms during the arcing process,the arcing spectrum,and the electrode topography,the following conclusions were drawn.When carbon and copper were paired,the anode corrosion was dominant.When the copper is the anode,the surface of the copper electrode is eroded to form molten copper.When the carbon is the anode,the surface material is transferred seriously,and the surface of the carbon material forms an ablation pit.And the material transfer will affect the arc root movement,which will affect the arc ablation and change the material transfer.This research has done some basic work for the arc erosion behavior of carbon and copper materials,enriching the theory of electrical contact.

Ristributed Generation and Grid-Connection Technology

Research of LC Series Resonant Bidrectional DC/DC Converter

LUO Min, LIANG Hui

2020, 0(2):  30-40.  doi:10.16628/j.cnki.2095-8188.2020.02.006

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The traditional bidirectional DC/DC converter has large backflow power,limited soft switch range and switch off at peak current.On the basis of the original circuit,a resonance network was introduced to study LC series resonant DC/DC converter.The approximate equivalent circuit model of LC series resonant DAB converter was established by fundamental wave analysis,and the expressions of power transmission and output current of the converter were derived.The working principle,power transmission characteristics,soft switching conditions and three kinds of soft switching modes were described.Compared with the non resonant DAB converter,the LC series resonant DAB converter is more close to the sinusoidal,the switch off current is smaller,the switching loss is reduced,and the system EMC characteristics can be improved.Through MATLAB/Simulink simulation software,it validated the principle and control method of the system.The utilization and efficiency of the system performance were validated by the experimental results.

Research on Application of Intelligent Micro-Network System with User Side Light Storage and Charge Integration

SHAN Dongliang, LIU Xiangli, XU Likai, WANG Conghui

2020, 0(2):  41-46.  doi:10.16628/j.cnki.2095-8188.2020.02.007

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With the increasing power demand of electric vehicles,large-scale electric vehicles charging may cause the operation of the distribution network to exceed the limit.At the same time,it may also cause problems such as system peak load growth,which may put pressure on the system transmission and power generation capabilities.In view of the above problems,combining the characteristics of distributed energy,the advantages and disadvantages of different micro-network systems was analyzed,the principles and methods of project allocation were given,and the project revenue was analyzed.This paper realizes the use of light-raised piles,the peak shaving and valley filling,smoothing the fluctuation of charging load,reducing the grid capacity pressure,improving the reliability of power supply,which has a good prospect of promotion.

Maximum Power Point Tracking Strategy for PV Arrays Under Partial Shading Conditions

WANG Chuanjie, GU Tingkun, WU Hao

2020, 0(2):  47-53.  doi:10.16628/j.cnki.2095-8188.2020.02.008

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In the case of partial shading,a few local maximum power points appear in the P-U characteristic curve of the photovoltaic array.The traditional maximum power point tracking method can accurately track the maximum power point of the PV array under uniform illumination,but it is easy to fall into the local maximum power point under partial shading.In order to overcome this defect,the P-U and I-U characteristic curves of PV array under partial shading were analyzed.Also,the improved perturb & observe(P&O) was used to track the global maximum power point.And by means of MATLAB/Simulink simulation results,this method can track the global maximum power point accurately.

A Dual Boost Cascade High Gain DC/DC Converter

DUAN Wanyi, WANG Hui

2020, 0(2):  54-60.  doi:10.16628/j.cnki.2095-8188.2020.02.009

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This paper proposed a Boost cascaded high gain DC/DC converter and applied it to photovoltaic power generation systems.The converter utilizes Boost circuit cascading technology to provide high voltage gain with a simple structure and no complicated control strategy.In this paper,the working principle and performance characteristics of the proposed converter were analyzed.The correctness and feasibility of the theory were verified by the simulation model in PSIM environment and an experimental prototype with power of 400 W.The results show that the efficiency of the proposed converter in rated condition can reach 92.1%.

Distribution System Automation

Analysis of Comprehensive Electric Energy System Design to Meet the Requirements of DP3 Dynamic Positioning

JIA Yinghui, HAN Chaozhen

2020, 0(2):  61-66.  doi:10.16628/j.cnki.2095-8188.2020.02.010

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With the increasing number of marine engineering projects in our country,the requirements to the new technology for the complex operation of marine engineering projects are increasing.The 5 000 t hoisting and piping vessel (hereinafter referred to as the background engineering) is such a vessel with the demand for multi-function operations.The vessel uses a comprehensive electric energy system and meets the DP3 dynamic positioning requirements to ensure that the system was designed to meet all the complex operational requirements.Based on the analysis of comprehensive electric energy system framework which includes power load calculation,calculation of short-circuit current,voltage level determination,grounding mode confirmation,harmonic analysis,load flow calculation etc.of the background engineering in different working conditions,it can provide a design reference for similar hoisting and piping vessel.

Design and Implementation of an NFC Purchase Card Communication Tester Based on Embedded Platform

BAO Daiyuan, PAN Juntao, LI Weijian

2020, 0(2):  67-72.  doi:10.16628/j.cnki.2095-8188.2020.02.011

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Due to the different manufacturers and different production conditions,the performance of NFC purchase card differences,To improve conformance,this paper designed an NFC purchase card communication tester based on an embedded platform.Based on the embedded platform including FPGA and ARM.The paper realizes the modulation,demodulation,encoding and decoding of NFC communication through FPGA technology,and realizes the information exchange between PC and FPGA through ARM.In addition,by developing user interaction software used on PC,testing personnel can control instrument output parameters in real time to increase testers flexibility and applicability.

Research and Application of A Special Logic Verification Software for Secondary Equipment of Intelligent Substation

ZHANG Yiyuan, YAN Yuqi, ZENG Zhihong, YI Xiaofeng

2020, 0(2):  73-77.  doi:10.16628/j.cnki.2095-8188.2020.02.012

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The verification time of special logic accounts for a large proportion in the secondary intelligent equipment overhaul of intelligent substation.To shorten the verification time of special logic is an important task to reduce the power outage overhaul time and ensure the reliability of power supply.A special logic verification software for secondary equipment of intelligent substation was introduced.The smart station secondary equipment was reclassified.The question and answer table and circular judgment method was adopted.The correctness of the final results can be automatically determined by the test situation,and the standard test reports were generated.Through on-site commissioning,testing and application in actual production of the power grid in Zhangzhou,it proves that it can effectively shorten the special logic checking time,reduce power outage time and generate benefits.

Low Voltage DC Power Supply and Distribution Technology

SONG Jiangsong

2020, 0(2):  78-83.  doi:10.16628/j.cnki.2095-8188.2020.02.013

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For AC power supply and distribution systems with dual power / dual circuit lines,as it is not able to run in parallel in a long time,when there is a fault or flashover in a circuit,connect the normal circuit to the blackout circuit by bus switch .Because switching takes a certain amount of time ,it can't keep the continuity of the power supply,so as to cause the user load to jump,it is also possible to expand the scope of power supply failure.According to statistics and analysis,in low voltage power supply and distribution systems,DC power supply and distribution system has its unique advantages,the shortcomings of AC power supply can be overcome by using DC power supply on dual circuits.It can meet the requirement of continuity of power supply for users.A DC power supply and distribution technology for low voltage power supply and distribution system was developed.The actual run test proves that the power supply is safe and reliable with good continuity of power supply,and low running costs,small occupancy space,and there is a certain energy saving effect.

Detection & Experiment

Design and Development of Accelerated Degradation Mechanism Consistency Discriminant Testing Measurement and Analysis System

SI Shuang, YE Xuerong, WANG Shujuan, ZHENG Bokai, ZHANG Hongyu

2020, 0(2):  84-88.  doi:10.16628/j.cnki.2095-8188.2020.02.014

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An accelerated degradation mechanism consistency discriminant test system with data acquisition,derivation and manage functions was developed.For a certain type of resistor,firstly,the test cost is used as a limiting condition to improve the accuracy of accelerated degradation model parameter estimation.The sample amount and test time of the accelerated degradation mechanism consistency discriminant test are optimized,and then the test plan is given.According to the parameters of the required test,the software and hardware parts of the test measurement system are designed and developed.The system has the characteristics of high test accuracy,high degree of automation,large number of measurable samples,and many kinds of measurable devices,so that it provides a data foundation for failure mechanism consistency analysis and reliability assessment.

Research on Accuracy of Noise Measurement for Low Voltage Active Power Filter

ZHOU Dajun

2020, 0(2):  89-92.  doi:10.16628/j.cnki.2095-8188.2020.02.015

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For the noise test of low voltage active power filter device,this paper introduced the method of noise test,and expounded the principle model of noise test as well as the influence factor of noise test accuracy.Through the theory and demonstration of noise test accuracy,the precautions for noise test of low voltage active power filter device are proposed.

Study on Temperature Test Method of Electronic Current Transformer

HOU Chunguang, YAN Wenbo, GAO Youhua, CAO Yundong

2020, 0(2):  93-98.  doi:10.16628/j.cnki.2095-8188.2020.02.016

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The electronic current transformer is very different from the traditional electromagnetic current transformer in terms of working principle and structure.In this paper,the temperature characteristic of the active electronic current transformer is affected by the full temperature cycle test.The analysis shows that the environment temperature has a great influence on the Rogowski coil electronic current transformer,while the influence on the LPCT coil electronic current transformer is negligible.According to the characteristics of each component of Rogowski coil electronic current transformer system,the temperature and other disturbance factors affecting the performance of 12 kV Rogowski coil electronic current transformer were analyzed in detail,and the transformer was compensated by BP neural network algorithm.The results show that the compensated transformer meets the 0.5 level measurement accuracy requirement,the ratio difference is less than ±0.5% and the angular difference is less than ±10' in the temperature range of -40~70 ℃.The experimental results verify the effectiveness of BP neural network algorithm compensation.