断路器的弧后电流是断路器开断性能的重要参量,为了获取高精度、低干扰的弧后电流,本文提出了一种基于真空开关、转移电阻、保护间隙和高精度电流传感器构成的弧后电流测量方法,其中真空开关负责导通大电流,在电流过零前电流转移到转移...断路器的弧后电流是断路器开断性能的重要参量,为了获取高精度、低干扰的弧后电流,本文提出了一种基于真空开关、转移电阻、保护间隙和高精度电流传感器构成的弧后电流测量方法,其中真空开关负责导通大电流,在电流过零前电流转移到转移电阻上,然后利用高精度电流传感器间接测量弧后电流。建立了弧后电流装置的电流转移过程模型,分析了电流转移完成时刻和转移电流峰值受转移电阻、电流大小和真空开关刚分时刻的影响。基于仿真得到弧后电流测量装置的参数,设计了弧后电流测量装置样机,对转移电阻进行了特殊无感设计并与保护间隙实现配合保护。最后进行了10 k V真空断路器在合成回路试验中的弧后电流测量,在开断5 k A电流时,弧后电流峰值为500 m A左右,脉宽5μs,弧后测量干扰小,波形平滑。对比试验结果和前人研究成果,验证了基于电流转移原理的弧后电流测量装置的可行性和准确性。展开更多
In this paper, a computational model is constructed to investigate the phenomenon of the initial plasma formation and current transfer in the single-wire electrical explosion in a vacuum. The process of the single-wir...In this paper, a computational model is constructed to investigate the phenomenon of the initial plasma formation and current transfer in the single-wire electrical explosion in a vacuum. The process of the single-wire electrical explosion is divided into four stages. Stage Ⅰ： the wire is in solid state. Stage Ⅱ： the melting stage. Stage Ⅲ： the wire melts completely and the initial plasma forms. Stage IV： the core and corona expand separately. The thermodynamic calculation is applied before the wire melts completely in stages Ⅰ and Ⅱ. In stage Ⅲ, a one-dimensional magnetohydrodynamics model comes into play until the instant when the voltage collapse occurs. The temperature, density, and velocity, which are derived from the magnetohydrodynamics calculation, are averaged over the distribution area. The averaged parameters are taken as the initial conditions for stage Ⅳ in which a simplified magnetohydrodynamics model is applied. A wide-range semi-empirical equation of state, which is established based on the Thomas-Fermi-Kirzhnits model, is constructed to describe the phase transition from solid state to plasma state. The initial plasma formation and the phenomenon of current transfer in the electrical explosion of aluminum wire are investigated using the computational model. Experiments of electrical explosion of aluminum wires are carried out to verify this model. Simulation results are also compared with experimental results of the electrical explosion of copper wire.展开更多
文摘断路器的弧后电流是断路器开断性能的重要参量,为了获取高精度、低干扰的弧后电流,本文提出了一种基于真空开关、转移电阻、保护间隙和高精度电流传感器构成的弧后电流测量方法,其中真空开关负责导通大电流,在电流过零前电流转移到转移电阻上,然后利用高精度电流传感器间接测量弧后电流。建立了弧后电流装置的电流转移过程模型,分析了电流转移完成时刻和转移电流峰值受转移电阻、电流大小和真空开关刚分时刻的影响。基于仿真得到弧后电流测量装置的参数,设计了弧后电流测量装置样机,对转移电阻进行了特殊无感设计并与保护间隙实现配合保护。最后进行了10 k V真空断路器在合成回路试验中的弧后电流测量,在开断5 k A电流时,弧后电流峰值为500 m A左右,脉宽5μs,弧后测量干扰小,波形平滑。对比试验结果和前人研究成果,验证了基于电流转移原理的弧后电流测量装置的可行性和准确性。
基金Project supported by the National Science Foundation of China(Grant Nos.51322706,51237006,and 51325705)the Program for New Century Excellent Talents in University,China(Grant No.NCET-11-0428)the Fundamental Research Funds for the Central Universities,China
文摘In this paper, a computational model is constructed to investigate the phenomenon of the initial plasma formation and current transfer in the single-wire electrical explosion in a vacuum. The process of the single-wire electrical explosion is divided into four stages. Stage Ⅰ： the wire is in solid state. Stage Ⅱ： the melting stage. Stage Ⅲ： the wire melts completely and the initial plasma forms. Stage IV： the core and corona expand separately. The thermodynamic calculation is applied before the wire melts completely in stages Ⅰ and Ⅱ. In stage Ⅲ, a one-dimensional magnetohydrodynamics model comes into play until the instant when the voltage collapse occurs. The temperature, density, and velocity, which are derived from the magnetohydrodynamics calculation, are averaged over the distribution area. The averaged parameters are taken as the initial conditions for stage Ⅳ in which a simplified magnetohydrodynamics model is applied. A wide-range semi-empirical equation of state, which is established based on the Thomas-Fermi-Kirzhnits model, is constructed to describe the phase transition from solid state to plasma state. The initial plasma formation and the phenomenon of current transfer in the electrical explosion of aluminum wire are investigated using the computational model. Experiments of electrical explosion of aluminum wires are carried out to verify this model. Simulation results are also compared with experimental results of the electrical explosion of copper wire.
