高频谐波电场下电缆终端过热点的形成机理

为解决高频谐波电场下应力控制型电缆终端绝缘迅速损坏的问题,探讨了高频谐波电场下应力控制型电缆终端过热点的形成与谐波电压频率之间的关系.对中压电力系统高频谐波电场进行了模拟试验,对其电缆终端进行了红外热成像分析以及瞬态非线性电场分析.研究结果表明:在高频谐波电场下,电缆终端表面局部区域形成明显的过热点,过热点的温度随叠加谐波频率的增加而升高;叠加的高频电压成分对过热点的形成具有较大影响,导致在局部区域形成明显的高场效应;随着谐波电压频率从100 Hz增大到20 kHz,该电缆终端局部区域的电场和发热量都呈现明显增大的趋势.

Formation Mechanism of Hot Spot in Stress Control Cable Terminations under Harmonic Voltages

In order to investigate the premature failure of a stress control cable termination under high frequency harmonic voltages,the relationship between hot spot and applied voltage frequency was researched to the stress control cable termination.A high frequency harmonic generator was utilized to simulate practical harmonic voltage waveforms in a medium voltage power system.Infrared thermal images and non-linear transient electric field of the termination were analyzed under different frequency harmonic voltages.The research results show that with the rise in harmonic frequency,an obvious hot spot forms in local region on surface of the termination and temperature of the hot spot also rise.The hot spot is mainly connected to the high frequency components resulting in high electric field strength in the local region.From 100 Hz to 20 kHz,the electric field strength and the heating power both increase markedly in the local region on the surface of the termination.