基于PSCAD的动车组过分相时车载牵引变压器励磁涌流仿真分析

Simulation Analysis on Inrush Current of Vehicle-mounted Traction Transformer in the Case of Electric Multiple Unit Passing Neutral Section Based on PSCAD

在列车车载自动断电过分相过程中,动车组空载合闸时车载主变压器一次侧励磁涌流现象频繁发生,容易引起差动保护误动作,影响列车正常运行。针对以上问题,分析过分相时励磁涌流产生机理及实测电流谐波分量构成特点,利用PSCAD软件建立具有饱和特性的单相变压器仿真模型,考虑了剩磁、合闸角度对变压器励磁涌流的影响。结果表明,励磁涌流中高次谐波以二次谐波为主,且其比重超过基波分量的60%;变压器剩磁越大,合闸瞬间励磁涌流现象越严重;合闸角为0°时励磁涌流最大,合闸角为90°时涌流最小。

The inrush current occurring frequently when circuit breakers close no-load transformer in the process of electric multiple unit ( EMU) passing neutral section,may lead to protection device malfunction,and affect the operation safety of EMU.To address this phenomenon,this paper analyzed the generation mechanism of inrush current and the characteristics of harmonic components of measured current.In order to analyze the effects of residual magnetism and switching angle on inrush current,a simulation model of the single-phase transformer with saturation characteristics was established by PSCAD software.The results show that the second harmonic is the main high-frequency harmonics in the inrush current and its proportion exceeds 60% of the fundament component.The greater the remanence of the transformer,the worse the saturation.The saturation when the phase angle of the voltage at 0° is more serious than the phase angle of the voltage at 90° at the closing time.