温度对车载高压电缆终端局部放电特性的影响研究

Influence of Temperature on Partial Discharge Characteristics of Cable Terminals for High-speed Trains

摘要:

电缆终端作为高速列车的一个重要设备，在接触网与列车之间的能量传递中起着重要作用。然而由电缆终端界面缺陷引起的局部放电，严重影响着电缆终端的绝缘性能与列车的行车安全。通过实验的方法，制作了含有不同长度气隙的电缆终端试验品，并在27.5 kV的电压条件下进行了实验，探究了不同缺陷长度的电缆终端在不同环境温度下的局部放电特性。结果表明，相同气隙长度的电缆终端在27.5 kV的电压条件下，其局部放电量随着环境温度呈现出先上升后下降的趋势。根据这一特性可以知道在一定的电压等级之下，电缆终端的放电量主要受温度影响，当超过某一温度后，由于温升导致的电缆终端内部压力变化成为影响局部放电量的主要因素，并且随着气隙长度的增加，同一温度下的局部放电起始电压呈现增加的趋势。

Abstract:

As an essential equipment of high-voltage system of high-speed electric multiple units, cable terminal playsan important role in energy transmission. However, partial discharge caused by detects at the interfaces of cable terminal affect seriously the insulation performance of cable terminals and the safety of trains. Cable terminals containing air gaps of different lengths are fabricated by an experimental method. The experiments are conducted at 27.5 kV to investigate the partial discharge characteristics of cable terminals with different defect lengths under different ambient temperatures. The results show that the partial discharges of cable terminals with the same air-gap length show a tendency of increasing and then decreasing with the ambient temperature under the voltage condition of 27.5 kV. According to this characteristic, it can be known that the discharge of cable terminals is mainly influenced by the temperature under a certain voltage level. The change in pressure inside the cable terminal due to temperature rise becomes the primary factor impacting the partial discharge when a certain temperature is exceeded. The partial discharge initiation voltage at the same temperature shows an increasing trend as the air gap length increases.