运行3~12年10 kV交联聚乙烯电缆电及理化特性试验

Experimental Study on Electrical and Physicochemical Properties of 10 kV Crosslinked Polyethylene Cable in Operation for 3~12 Years

为研究不同运行年限的交联聚乙烯(XLPE)电缆绝缘的电气和理化特性,抽取12只北京地区经过3~12年运行的10 kV交联聚乙烯电力电缆,利用静电计、差热扫描量热仪等仪器对其体积电阻率、介电常数、击穿场强、水树枝及相关理化指标等进行测试。试验结果表明:电缆绝缘性能下降初期,所有不同年限的电缆体积电阻率、相对介电常数、击穿场强、红外光谱等均在正常范围内,这些指标同运行年限关系不大,而运行10年以上的电缆介质损耗因数、熔点和结晶温度的数值明显变大。研究结果为供电企业选择评估电缆绝缘状态的方法提供实验依据和数据支撑。

In order to study the electrical and physicochemical properties of crosslinked polyethylene(XLPE)cable insulation with different operation years,12 cables of 10 kV XLPE power in Beijing area were selected,and their volume resistivity,dielectric constant,breakdown field strength,water branch and related physicochemical indexes were tested by using electrometer,differential scanning calorimeter and other instruments.The test results show that,at the initial stage of cable insulation performance decline,the volume resistivity,relative permittivity,breakdown field strength and infrared spectrum of all cables with different service life are in the normal range,and these indexes have little relationship with the service life,while the dielectric dissipation factor,melting point and crystallization temperature of cables with more than 10 years of service become larger.The research results provide experimental basis and data support for power supply enterprises to choose the evaluation method of cable insulation state.