Based on the self-shrinkage effect of liquid metal,liquid-metal energy dissipators(LMEDs)have good applications in the energy absorption branch of a high-voltage DC system.However,LMEDs instantaneously produce large a...Based on the self-shrinkage effect of liquid metal,liquid-metal energy dissipators(LMEDs)have good applications in the energy absorption branch of a high-voltage DC system.However,LMEDs instantaneously produce large amounts of liquid-metal vapor during operation;therefore,the varying characteristics of the pressure in the cavity affect their energy consumption capacity and service life.In this study,the force and motion of liquid metal were analyzed,a mathematical model of shrinkage time before the arc was constructed,the influence of shortcircuit current and pore size on shrinkage time was explored,and the key factors affecting shrinkage time were clarified.Based on the theory of magnetohydrodynamics,the entire process of liquid metal from the beginning of contraction to the truncation of the arc was simulated to obtain the change characteristics of physical parameters,such as pressure and Lorentz force,in the cavity during the shrinkage process and to study the influence on contraction time by adjusting the short-circuit current and aperture size.A GaInSn liquid-metal energy dissipation test platform was built.The pre-arc shrinkage characteristics of the GaInSn liquid metal were studied,the variation in the voltammetry characteristic curve during liquid-metal energy dissipation was detected,and the accuracy of the simulation model was verified using experimental data.This study provides a theoretical reference for the application of LMEDs to power systems of different grades.展开更多
The synthetic making test has been widely used in evaluating the break ability of high-voltage circuit breaker. However, the test research and application are still inadequate, especially in the condition of rated vol...The synthetic making test has been widely used in evaluating the break ability of high-voltage circuit breaker. However, the test research and application are still inadequate, especially in the condition of rated voltage. According to the realistic conditions of test stations in China, a control device based on pre-arcing current detection and phase control is proposed in this paper. A sample of the control device made up of DSP TMS320LF2407A is fabricated, in which the CPLD MAX7064 is used to transmit signals for EMC design. It can be applied in full voltage synthetic making test at a level of 126kV/63kA. The test results show that, it is accurate to control the making phase of the applied voltage, whether the closing is demanded at voltage peak or zero.展开更多
目前,选相合闸技术在无功补偿电容器组、特高压线路、滤波器场等场景应用广泛。本文综述了国内外断路器选相合闸技术的研究现状,介绍了断路器选相合闸技术的应用,深入归纳了介质强度下降率(rate of decrease of dielectric strength, RD...目前,选相合闸技术在无功补偿电容器组、特高压线路、滤波器场等场景应用广泛。本文综述了国内外断路器选相合闸技术的研究现状,介绍了断路器选相合闸技术的应用,深入归纳了介质强度下降率(rate of decrease of dielectric strength, RDDS)、温度、间歇时间等各种因素对断路器选相合闸精度的影响,总结了断路器选相合闸的关键技术和问题,分析了断路器合闸动作时间分散性的产生原因,对断路器选相合闸技术的研究提出一些建议。展开更多
基于自收缩效应的液态金属限流器(liquid metal current limiter,LMCL)有自动检测限流、故障排除后可自恢复、填充介质对环境友好、结构简单以及体积小的独特优点,具有良好的应用前景。通过测量不同情况下限流过程回路电流以及LMCL的电...基于自收缩效应的液态金属限流器(liquid metal current limiter,LMCL)有自动检测限流、故障排除后可自恢复、填充介质对环境友好、结构简单以及体积小的独特优点,具有良好的应用前景。通过测量不同情况下限流过程回路电流以及LMCL的电弧电压,实验研究了LMCL限流特性的影响因素,为LMCL结构的优化设计提供参考依据。实验结果表明:LMCL的限流效果随着弧前时间的缩短以及电弧电压的上升而愈加明显,弧前时间和电弧电压受预期短路电流和LMCL结构参数的影响;同时实验过程中发现,大电流下电弧压力对LMCL限流性能会产生不利的影响,为解决此问题,提出了一种带有压力释放功能的限流器结构,可以有效地改善限流效果。展开更多
基金supported by the Excellent Young Scientists Fund of China(No.51922090)National Natural Science Foundation of China(Nos.U19A20105,U1966602,and 51837009)。
文摘Based on the self-shrinkage effect of liquid metal,liquid-metal energy dissipators(LMEDs)have good applications in the energy absorption branch of a high-voltage DC system.However,LMEDs instantaneously produce large amounts of liquid-metal vapor during operation;therefore,the varying characteristics of the pressure in the cavity affect their energy consumption capacity and service life.In this study,the force and motion of liquid metal were analyzed,a mathematical model of shrinkage time before the arc was constructed,the influence of shortcircuit current and pore size on shrinkage time was explored,and the key factors affecting shrinkage time were clarified.Based on the theory of magnetohydrodynamics,the entire process of liquid metal from the beginning of contraction to the truncation of the arc was simulated to obtain the change characteristics of physical parameters,such as pressure and Lorentz force,in the cavity during the shrinkage process and to study the influence on contraction time by adjusting the short-circuit current and aperture size.A GaInSn liquid-metal energy dissipation test platform was built.The pre-arc shrinkage characteristics of the GaInSn liquid metal were studied,the variation in the voltammetry characteristic curve during liquid-metal energy dissipation was detected,and the accuracy of the simulation model was verified using experimental data.This study provides a theoretical reference for the application of LMEDs to power systems of different grades.
文摘The synthetic making test has been widely used in evaluating the break ability of high-voltage circuit breaker. However, the test research and application are still inadequate, especially in the condition of rated voltage. According to the realistic conditions of test stations in China, a control device based on pre-arcing current detection and phase control is proposed in this paper. A sample of the control device made up of DSP TMS320LF2407A is fabricated, in which the CPLD MAX7064 is used to transmit signals for EMC design. It can be applied in full voltage synthetic making test at a level of 126kV/63kA. The test results show that, it is accurate to control the making phase of the applied voltage, whether the closing is demanded at voltage peak or zero.
文摘目前,选相合闸技术在无功补偿电容器组、特高压线路、滤波器场等场景应用广泛。本文综述了国内外断路器选相合闸技术的研究现状,介绍了断路器选相合闸技术的应用,深入归纳了介质强度下降率(rate of decrease of dielectric strength, RDDS)、温度、间歇时间等各种因素对断路器选相合闸精度的影响,总结了断路器选相合闸的关键技术和问题,分析了断路器合闸动作时间分散性的产生原因,对断路器选相合闸技术的研究提出一些建议。
文摘基于自收缩效应的液态金属限流器(liquid metal current limiter,LMCL)有自动检测限流、故障排除后可自恢复、填充介质对环境友好、结构简单以及体积小的独特优点,具有良好的应用前景。通过测量不同情况下限流过程回路电流以及LMCL的电弧电压,实验研究了LMCL限流特性的影响因素,为LMCL结构的优化设计提供参考依据。实验结果表明:LMCL的限流效果随着弧前时间的缩短以及电弧电压的上升而愈加明显,弧前时间和电弧电压受预期短路电流和LMCL结构参数的影响;同时实验过程中发现,大电流下电弧压力对LMCL限流性能会产生不利的影响,为解决此问题,提出了一种带有压力释放功能的限流器结构,可以有效地改善限流效果。
