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
For high-voltage direct current(HVDC)power grid transmission with higher voltages,the energyconsuming branch of the DC circuit breaker is required to dissipate huge energies of more than megajoules in a short time in ...For high-voltage direct current(HVDC)power grid transmission with higher voltages,the energyconsuming branch of the DC circuit breaker is required to dissipate huge energies of more than megajoules in a short time in the case of a fault and short circuit.The requirements for huge volume and weight are difficult to meet with energy-consuming equipment based on ZnO.In this paper,a new energy consumption method is proposed based on gallium indium tin(GaInSn)liquid metal in the arcing process,and a test platform with adjustable short-circuit current is built.The mechanism triggering GaInSn liquid metal arcing energy consumption is studied.It is found that short-circuit current and channel aperture are the key parameters affecting the energy consumption of liquid metal arcing.The characteristics of GaInSn liquid metal energy consumption are investigated,and four stages of liquid metal energy consumption are found:oscillatory shrinkage,arc breakdown,arc burning phase change and arc extinction.The influence of short-circuit current and channel aperture on the energy consumption characteristics of GaInSn liquid metal is investigated.To further explore the physical mechanism of the above phenomena,a magneto-hydrodynamic model of energy consumption in the GaInSn liquid metal arcing process is established.The influence of short-circuit current and channel aperture on the temperature distribution of the liquid metal arc is analyzed.The mechanism of the effect of short-circuit current and channel aperture on peak arc temperature and the temperature diffusion rate is clarified.The research results provide theoretical support for this new liquid metal energy consumption mode DC circuit breaker.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.
基金supported by National Natural Science Foundation of China(No.U1966602)the Excellent Young Scientists Fund of China(No.51922090).
文摘For high-voltage direct current(HVDC)power grid transmission with higher voltages,the energyconsuming branch of the DC circuit breaker is required to dissipate huge energies of more than megajoules in a short time in the case of a fault and short circuit.The requirements for huge volume and weight are difficult to meet with energy-consuming equipment based on ZnO.In this paper,a new energy consumption method is proposed based on gallium indium tin(GaInSn)liquid metal in the arcing process,and a test platform with adjustable short-circuit current is built.The mechanism triggering GaInSn liquid metal arcing energy consumption is studied.It is found that short-circuit current and channel aperture are the key parameters affecting the energy consumption of liquid metal arcing.The characteristics of GaInSn liquid metal energy consumption are investigated,and four stages of liquid metal energy consumption are found:oscillatory shrinkage,arc breakdown,arc burning phase change and arc extinction.The influence of short-circuit current and channel aperture on the energy consumption characteristics of GaInSn liquid metal is investigated.To further explore the physical mechanism of the above phenomena,a magneto-hydrodynamic model of energy consumption in the GaInSn liquid metal arcing process is established.The influence of short-circuit current and channel aperture on the temperature distribution of the liquid metal arc is analyzed.The mechanism of the effect of short-circuit current and channel aperture on peak arc temperature and the temperature diffusion rate is clarified.The research results provide theoretical support for this new liquid metal energy consumption mode DC circuit breaker.
