基于坡印亭矢量的电缆无功功率计算及电缆沟环境对其影响规律的研究

Reactive Power Calculation of Power Cable Based on Poynting Vector and Influence Caused by Cable Duct Environment

电力电缆的内部结构和运行环境影响其线路参数,间接影响电缆的无功功率。当电缆内部结构和运行环境改变时,难以从"路"的角度计算线路参数的改变规律,研究了基于坡印亭矢量的电力电缆功率传输模型,在此基础上研究了电缆偏心和积水情况下的无功功率变化规律。结果表明:电缆外部积水对电缆的无功影响可以忽略,电缆内部进水会导致容性无功大量增加;电缆容性无功损耗随着电缆偏心程度的增加而增加,当电缆进水且电缆偏心2.5mm时容性无功增量达到了51.98%。因此从场的角度研究电缆沟环境对电缆无功功率的影响规律有十分重要的工程价值。

Both the inner structure of power cable and the operating environment affect the line parameters which affect the reactive power indirectly. When the inner structure and operating environment changed, it is hard to calculate the variation of reactive power in circuit way. Therefore, this paper studied the power transmission model of power cable based on Poynting vector. On the basis of that, the variation rules of reactive power of the cable with excentric structure and in ponding situation were studied. The results show that water outside the cable has a negligible effect on reactive power while water inside the cable will lead to a substantial increase in the capacitive reactive power. Capacitive reactive power loss of cable increases with the increase of cable eccentricity degree, and the increment of capacitive reactive power can be up to 51.98% when the cable is with water inside and an eccentricity of 2.5 ram. So the research on the influence of cable duct environment on the reactive power in field way has important engineering value.