潮湿环境下中压电缆接头早期故障的演变规律及特性

Evolution Process and Characteristics of Medium Voltage Cable Joints' Incipient Faults in Humid Environment

由于目前缺乏对电缆接头早期故障演变过程的研究,为此根据实际运行场景设计了潮湿环境下的电缆接头早期故障模拟试验,得到不同放电次数下的电缆接头早期故障电流变化规律、绝缘损伤、气隙内积水位移等特征,分析早期故障演变过程,并根据故障时的电极构成特征将早期故障分为第1、第2阶段,提出了早期故障2个阶段各自的特征。在此基础上建立了电弧位置固定时的早期故障仿真模型,仿真分析了电弧温度的变化、固体绝缘部分的高温区域形成以及电弧区域的热量散失等现象。综合试验与仿真结果认为,移动位置电弧与重燃电弧共同构成早期故障的第1阶段。当电弧位置临近接头接地点,早期故障将进入第2阶段。当闪络痕迹贯穿绝缘表面时,将形成永久性故障。该研究结果为早期故障特征识别与监测提供了理论支撑。

For lack of research on the evolution process of incipient cable joint faults at present,this paper designed sim-ulation experiments for incipient cable joint fault in wet environment according to the actual operation scenario,obtained the characteristics of the change law of incipient cable joint fault current,insulation damage,water displacement in the air gap and so on under different discharge times,and analyzed the evolution process of incipient fault.According to the electrode composition characteristics,the incipient fault is divided into the first stage and the second stage,and the re-spective characteristics of the two stages are proposed.On this basis,an early fault simulation model was established when the arc position was fixed.Moreover,the changes in arc temperature,the formation of high-temperature areas in the solid insulation part,and the heat dissipation in the arc area are simulated and analyzed.Based on the experimental and simulation results,the moving position arc and reignition arc constitute the first stage of incipient fault.When the arc po-sition is near the joint ground point,the incipient fault will enter the second stage.When the flashover marks transfix the insulation surface,a permanent fault will be formed.The results of this paper provide theoretical supports for incipient fault feature recognition and monitoring.