LOW VOLTAGE APPARATUS

Research on Life Prediction Models of HVDC Contactors

GU Zhihao, WU Chengchuang, ZHANG Chao, HE Yubin, REN Wanbin

2025, 0(1): 1-5. doi:10.16628/j.cnki.2095-8188.2025.01.001

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Higher reliability and longer service life have been the development directions for high voltage DC (HVDC) contactors.An electrical endurance test of an HVDC contactor is carried out.The degradation trends of featured parameters such as pick-up time, release time and arcing time are analyzed.In addition, according to the degradation and failure mechanisms of the contactor, the lifespan prediction models based on the function fitting and autoregression are established using the release time as the featured parameter.By comparing the prediction results, it is concluded that the lifespan prediction model based on autoregression has the best prediction accuracy.

Life Prediction Method of Low Voltage Circuit Breaker Based on Arc Energy Estimation

XU Jianing, YANG Haowen, GAO Caizhi, CHEN Silei, LI Xingwen

2025, 0(1): 6-13. doi:10.16628/j.cnki.2095-8188.2025.01.002

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Predicting the remaining life of low voltage circuit breakers is crucial for ensuring the safety and stability of power systems.The current life prediction methods rely on the measurement and analysis of data such as contact mass and vibrations, which involve high costs and complex processing.In response to this, a life prediction method for low voltage circuit breakers based on arc energy estimation is proposed.Initially, the time and electrical signals are collected to compute a dataset of single arc duration and single arc energy, and their correlation is analyzed.Subsequently, a fitting function is established to estimate the accumulated arc energy, which is used to construct a remaining electrical life prediction model.Finally, the validation using the life test data from a specific molded case circuit breaker (MCCB) demonstrates that the model achieves a satisfactory level of prediction accuracy.The proposed method provides the theoretical and practical foundations for the life prediction of low voltage circuit breakers.

DC Fault Arc Diagnosis Method Based on GWO-LSSVM

LIU Shuxin, LIU Bingze, XING Zhaojian, MING Xin, ZHOU Houlin, LÜ Xianfeng

2025, 0(1): 14-22. doi:10.16628/j.cnki.2095-8188.2025.01.003

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In order to solve the problem that the identification accuracy of DC arc faults is not high under different working conditions,a gray wolf optimization least squares support vector machine (GWO-LSSVM) is proposed to diagnose DC arc under multi-load conditions.Firstly,the improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN) is applied to perform the intrinsic mode function (IMF) decomposition on the DC arc current signals obtained from the mixed load of the reference high-speed railway station under the different operating conditions.Secondly,the relevant components are screened and combined with multi-scale permutation entropy (MPE) to construct the feature vectors.Finally,in response to the slow convergence speed of the diagnostic model and the tendency of the model to fall into the local optima,the LSSVM model optimized by GWO is applied for the fault state recognition.The experimental results show that the accuracy reaches 98.33%.By comparing with other algorithms,the efficiency of the proposed method has been confirmed.

Research on Partial Discharge Type Diagnosis of Switchgear Based on Multi-Sensor Information Fusion

LI Gangyi

2025, 0(1): 23-27. doi:10.16628/j.cnki.2095-8188.2025.01.004

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During the operation of the switchgear,the insulation defects may lead to the occurrence of partial discharge.If it can not be found and dealt with measures in time,it will further cause the insulation breakdown failure.In order to effectively diagnose the type of partial discharge,based on the multi-sensor information fusion technology of D-S evidence theory,a scheme combined with BP neural network for the partial discharge pattern recognition is proposed.Experiments show that the accuracy of discharge type recognition with the multi-sensor information fusion is about 13 percentage higher than that of single sensor mode.The overall recognition accuracy is better than 96.08%, which verifies the effectiveness and rationality of the algorithm.

Study on Arc Characteristics of DC Low Current Interruption in SF₆/N₂ Gas Mixture

WANG Zhoujing, CHEN Shizhe, ZHAO Dongxu, LI Xingwen

2025, 0(1): 28-32. doi:10.16628/j.cnki.2095-8188.2025.01.005

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To investigate the arc characteristics of the SF₆/N₂ gas mixture,a direct current (DC) lower current interruption platform was developed.A high-speed camera and a visual prototype were used to capture the arc combustion process at various SF₆/N₂ mixture concentrations and different operating conditions.The research showed that with the increase of filling pressure and SF₆ gas content,the arc radius decreased and the center brightness of arc increased.With the decrease of interrupting speed and the rise of current level,arc radiuses and arc brightness both increased.The arc burning time and arc voltage critical value were inversely correlated with SF₆ gas content,but positively correlated with filling pressure.The auxiliary analysis of arc images facilitated an understanding of the extinguishing mechanisms associated with SF₆/N₂ gas mixture,thereby advancing its application in switchgear technology.

Study on Factors Influencing Mechanical Characteristics of Magnetically Controlled Vacuum Circuit Breaker

ZHAO Ying, JIA Chenxi, HAN Yingshuang

2025, 0(1): 33-38. doi:10.16628/j.cnki.2095-8188.2025.01.006

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Opening and closing speed and closing bounce time are the key parameters that affect the electrical performance of vacuum circuit breaker.If they do not meet the requirements,the contact will be seriously worn or even ablated,and the service life of the interrupter will be shortened.The structure and working principle of magnetically controlled vacuum circuit breaker are introduced,and the several factors affecting its mechanical characteristics are analyzed in detail through a series of theoretical calculations.The related tests are carried out by the factor analysis method.Finally,the changing trend of mechanical characteristics parameters with the spring force,contact pressure and magnetic retention force is obtained,which provides a reference for designing and installing the magnetically controlled vacuum circuit breaker in actual production process.

Simulation on Pick-Up Characteristics of Contactors with Double Coil Structure Used in Aviation

ZHOU Yu, ZHANG Chao, REN Wanbin

2025, 0(1): 39-44. doi:10.16628/j.cnki.2095-8188.2025.01.007

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The pick-up process of contactors with double coil structure used in aviation is crucial for their response time and lifespan.A simulation analysis method for the pick-up process of contactors with double coil structure used in aviation is proposed based on COMSOL Multiphysics finite element software.This method enables the calculation of parameters such as coil current,electromagnetic force,contact displacement,and core displacement over time.The feasibility of the proposedmethod is demonstrated by comparing the measured coil current waveforms.

Design and Characteristic Simulation Analysis of Electromagnetic Tripper for Medium Voltage DC Circuit Breaker

WU Hao, MA Ziwen, WU Xuan

2025, 0(1): 45-49. doi:10.16628/j.cnki.2095-8188.2025.01.008

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As the core component of short-circuit breaking of medium voltage DC circuit breaker,the performance of electromagnetic tripper affects the breaking ability of circuit breaker.The static electromagnetic attraction characteristics and dynamic motion characteristics of an electromagnetic tripper are simulated and calculated,and the parameters of the electromagnetic tripper are determined according to the results.Finally,the test results of the tripping time of the electromagnetic tripper are consistent with the simulation results,which achieve the design goal.This simulation method can apply to the design and optimization of the electromagnetic tripper of the medium voltage DC circuit breaker.

Simulation Study on Low Current Interruption Performance of SF₆/N₂ Gas Mixture Disconnector

LI Xin, CHEN Peilong, ZHU Shijian, OUYANG Zeyu, ZHONG Yao, WANG Dibo

2025, 0(1): 50-55. doi:10.16628/j.cnki.2095-8188.2025.01.009

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To verify the reliability of SF₆/N₂ gas mixture applied to the disconnector,in view of the bus-transfer current interruption of 252 kV disconnector,a magneto-hydro-dynamics (MHD) arc model was built to simulate the arc burning process of the SF₆ and SF₆/N₂ mixture under different gas ratios and contact velocities.Meanwhile,a post-arc breakdown evaluation method was proposed by calculating the critical breakdown voltage within 100μs after the current is zero.Then the effect of SF₆/N₂ gas mixture concentration and breaking speed on the arc extinguishing performance was quantitatively studied.The results show that 28%SF₆+70%N₂ gas mixture has good arc burning performance and back-arc breakdown characteristics,which can realize the replacement of SF₆ gas.The increase of the breaking speed can further improve the recovery strength of the mixed gas,but it puts forward higher requirements for the operating mechanism of the disconnector.

Simulation and Optimization on Electric Field of Environment-Friendly Gas Insulated Switchgear

KANG Jing, REN Zhaotian, LIU Zhendu, HUANG Wenhui, LIU Xueji, LIU Chang, WANG Jun

2025, 0(1): 56-60. doi:10.16628/j.cnki.2095-8188.2025.01.010

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Gas insulated switchgear requires absolute sealing.The electrical components in gas switchgear is reasonably designed to make the electric field distribution more uniform,achieve the more reliable insulation performance,and ensure the safe operation of high voltage switchgear in power distribution system.Taking the insulating support of environment-friendly gas switchgear as the research object,a three-dimensional finite element calculation model of electric field of high-voltage switchgear is established based on Ansys software.The distribution of electric field before and after the structural optimization of insulating support of environment-friendly switchgear is analyzed by the finite element method,which provides the reference for the design and development of actual products.

Application of Testing System for Medium and Low Voltage DC Switching Devices

WANG Jiajun, ZHANG Lixi, JIANG Zhiguo, ZHOU Xuan, FEI Wanqin

2025, 0(1): 61-67. doi:10.16628/j.cnki.2095-8188.2025.01.011

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To meet the testing needs of medium and low voltage DC switching device in rail transit,new energy and other fields,a large-capacity DC short-circuit test platform has been developed.The AC side power supply of the test platform adopts the optional 10 kV grid power supply and short-circuit impact generator dual-circuit option.The maximum short-circuit capacity reaches 3 200 MVA,and the maximum test capability reaches 2 kV/350 kA or 6 kV/120 kA.The platform adopts twelve pulse rectification technology,and the ripple coefficient of the DC output signal is less than 1.5%.A short-time withstand current test was conducted on a DC circuit breaker with a short-time withstand current of 150 kA and a withstand time of 200 ms.Additionally,the short-circuit breaking capacity tests was seperately perfomed on a DC fuse rated at 1 500 V voltage and 250 kA rated short-circuit breaking current,as well as on a DC circuit breaker designed for rail transit,which can withstand a short-circuit current of 135/95 kA under maximum fault conditions.The result show that the test platform can provide test current,ripple coefficient and time constant that meet the product needs and the standard requirements.

Research on Synthetic Testing Circuit for Common Tank Circuit Breakers

CHENG Junqi, LI Zheyuan, ZHOU Yin, WANG Zhi

2025, 0(1): 68-72. doi:10.16628/j.cnki.2095-8188.2025.01.012

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According to the testing requirements for common tank circuit breakers in the national standard GB/T 4473—2018“Synthetic Testing of High-Voltage Alternating Current Circuit-Breakers”,and taking into account the specific conditions of the testing equipment,control and measurement equipment,and testing site of the high-voltage switch testing station of the China Electric Power Research Institute,it was decided to use a three-phase composite testing circuit suitable for all phase currents introduced in this laboratory.The short-circuit current breaking test T100s(b)of a three-phase common tank circuit breaker was focused on.The transient recovery voltage values for the first interrupting and subsequent interrupting phases under the condition of a noneffectively grounded neutral point were analyzed and calculated.The simulation model was used to verify the parameters of the circuit,and the simulation results meet the standard requirements.

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