When a high-speed train approaches the insulated phase-splitting section embedded between neighbouring power supply arms, the vacuum circuit breaker (VCB) installed on trains must be disconnected to maintain the traction power supply system as a no-load condition for completing phase-switching action, as the train passes through the phase-splitting section depending on its inertia. However, when operating VCBs, the arc is easily triggered between the mobile contacts inside, accompanied by an overvoltage impulse. Herein, to explore the generating mechanism of inrush current and operational overvoltage, a model describing the ‘substation-catenary-train’ traction power supply system is launched based on an equivalent circuit modelling technique. Through the analysis of the transient VCB operational process, the phase of catenary voltage is directly related to the characteristics of the VCB switching-on overvoltage, as the traction current's phase angle is relevant to the amplitude-frequency characteristics of the VCB switching-off overvoltage. Inrush current as a noteworthy element is related to the traction transformer's remanence. The automatic phase-switching technique is utilised to suppress both operational overvoltage and inrush current, as the optimal combination of VCB switching-on and switching-off phases considering the balance between overvoltage and inrush current is achieved based on the particle swarm algorithm.

中文翻译：

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自动换相技术分析及抑制高速列车运行过电压和涌流

当高速列车接近相邻供电臂之间嵌入的绝缘分相段时，必须断开列车上安装的真空断路器（VCB），以保持牵引供电系统处于空载状态，完成分相。当列车根据其惯性通过分相部分时进行切换动作。但真空断路器在操作时，内部动触头之间很容易引发电弧，并伴有过电压脉冲。为了探究励磁涌流和操作过电压的产生机理，基于等效电路建模技术，建立了描述“变电站-接触网-列车”牵引供电系统的模型。通过对VCB暂态运行过程的分析，由于牵引电流的相位角与VCB分断过电压的幅频特性相关，所以接触网电压的相位与VCB合闸过电压的特性直接相关。 。浪涌电流作为一个值得注意的因素与牵引变压器的剩磁有关。利用自动换相技术抑制运行过压和浪涌电流，基于粒子群算法实现考虑过压和浪涌电流平衡的VCB合闸和分闸相位的最佳组合。