工频和超低频交流电压下XLPE电缆局部放电特征对比分析研究

Comparative research on partial discharge of XLPE cable under ultra-lowfrequency and power frequency voltage

XLPE电缆局部放电实验技术能够及时发现设备绝缘缺陷,是目前电缆质量评价的重要手段。现有电缆局部放电实验多在超低频(0.1 Hz)电压和工频(50 Hz)电压下开展,为了深入挖掘两类电压下局部放电特征的关联性,本文在实验室内人工制作了四种典型XLPE电缆缺陷模型,包括断口不齐、绝缘划痕、夹层污染以及半导电层残留,开展了超低频、工频电压下XLPE电缆局部放电实验,依次从局部放电电压特征、放电活跃性、相基统计特征和放电统计时延四个维度对比分析了四种电缆缺陷的局部放电特性。结果表明,两类电压下局部放电特征有较高的一致性和等效性,且在不同放电类型下特征存在明显差异,可以较好地区分缺陷类型。此外,本文验证了超低频电压下局部放电测量的有效性和适用性,为XLPE电缆的绝缘状态评估提供了一定的技术依据。

Insulation defects can be timely found with the XLPE cable partial discharge experiment technology,which is an important means of cable quality evaluation.Existing partial discharge experiments of cables are mostly carried out under ultra-low frequency(0.1 Hz)voltage and power frequency(50 Hz)voltage.To deeply explore the correlation between partial discharge characteristics under above two types of voltages,this paper manually made four typical XLPE cable defect models in the laboratory,including uneven fracture,insulation scratch,interlayer contamination and semi-conductive layer residue.Then,partial discharge experiments of XLPE cables under ultra-low frequency and power frequency voltages were carried out.Finally,partial discharge characteristics of four cable defects were compared and analyzed from four dimensions,namely,partial discharge voltage characteristics,discharge activity,phase-based statistical characteristics and discharge statistical delay.Results show that characteristics under two types of voltages have high consistency and equivalence,and there are obvious differences between features,which can distinguish defects well.This paper quantifies the effectiveness and applicability of partial discharge measurement under ultra-low frequency voltage,and provides technical basis for the evaluation of XLPE cable insulation state.