电力电缆循环加热试验中热力学工态研究

The Research of Power Cable Cyclic Heating Thermodynamic

为研究电力电缆热循环载流量试验中电缆的温升特性,以及介质损耗和环境温度对电力电缆温升的影响,完善了空气中电缆集中参数等效热路模型,建立了暂态下对导体损耗、介质损耗和环境温度进行实时修正的热流微分方程.仿真计算给电缆施加恒定电流时电缆导体、金属套的温升,介质损耗对温度的工态影响,电缆热循环载流量试验中电缆各层的暂态温升和自然冷却曲线,并与实际试验所测得的温升曲线进行拟合验证.研究结果表明,高压电力电缆热循环试验中,介质损耗对电缆温升影响较大,试验中需要对导体损耗、介质损耗和环境温度进行实时修正.

In order to study the temperature characteristics of the voltage power cables current carrying capacity thermal cycling test and influence of ambient temperature and dielectric loss on temperature rise of power cables,in this paper,we improved the cable lumped parameter model equivalent thermal circuit in the air,We established the heat flow equations of the real-time correction for the conductor loss,dielectric loss and the ambient temperature under transient conditions. We simulated the temperature rise of cable conductor and the metal sleeve when applying a constant current to the cable and the influence of dielectric loss on temperature in the working state. We also simulated the transient temperature rise and natural cooling curve of the each layer of in cable thermal cycling current carrying capacity test and fitted with the actual temperature rising curve which had been measured. The results show that： In the high voltage power cables thermal cycling test,the dielectric loss has greater impact on the cable temperature characteristics. We need to correct the conductor loss,dielectric loss and the ambient temperature in real-time.