环境温度变化对含局部过热缺陷的油纸套管温升特性影响研究

Impact of Ambient Temperature Changes on Temperature Rise Characteristics of OIP Bushings with Local Overheating Defects

由于油纸绝缘套管内部缺陷温度难以测定,局部过热缺陷在初期很难发现,因此开展内部过热缺陷与套管本体温升的关联性研究对现场运维具有重要的指导意义。本研究基于电磁-热耦合方法,建立了110 kV油纸绝缘套管在局部过热缺陷下内部与外部温度分布仿真分析模型,计算了不同接触电阻情况下套管整体温度场分布,并研究了环境温度、故障时间、温度日变化等工况对套管内部与伞裙温升的影响。结果表明:10倍接触电阻劣化情况下套管表面伞裙温升2.3℃,为套管早期故障表征;外界环境温度较低时套管伞裙表面温升绝对值较高,而在环境温度较高时套管内部温升绝对值较高;油纸套管温升会在较短故障时间内快速增长,并于12 h时达到饱和;冬夏两季温度日变化下套管温度变化会滞后于环境温度突变,且套管温升随环境温度骤升会突然下降,反之亦然。本研究所得结论可结合现场红外测温数据实现油纸套管智能运维,并为变压器套管数字孪生体构建提供数据支撑。

Due to the difficulty of measuring internal defects′temperature in OIP bushings and the challenge of detecting local overheating defects early,studying the correlation between internal overheating defects and the temperature rise of bushings is crucial for field maintenance.This study uses an electromagnetic-thermal coupling method to establish a simulation model for the temperature distribution of a 110 kV OIP bushing with local overheating defects.It calculates the temperature field distribution under different contact resistance conditions and examines the effects of ambient temperature,fault duration,and daily temperature variations on the internal temperature rise and the skirt temperature.Results show that with tenfold contact resistance deterioration,a 2.3℃rise on the bushing′s skirt surface indicates an early fault.Lower ambient temperatures result in higher absolute temperature rises on the skirt surface,while higher ambient temperatures result in higher internal temperature rises.The temperature rise of the OIP bushing increases rapidly within a short fault duration and saturates at 12 hours.During winter and summer daily temperature variations,bushing temperature changes lag behind sudden ambient temperature changes.The temperature rise of the bushing decreases suddenly with a rapid increase in ambient temperature and vice versa.These findings can be combined with on-site infrared temperature data for intelligent OIP bushing maintenance and provide data support for constructing digital twins of transformer bushings.