如今大中型城市电缆线路使用率逐渐升高，但由于电缆线路对地电容大，其广泛使用可能导致负荷低谷时出现容性无功倒送，甚至末端电压升高。为应对该问题，以电缆线路对城市配网变电站无功功率可能造成的影响为研究对象进行了分析。采用青岛电网实际运行参数，运用前推后推法首先对不同负荷下单条电缆出线的电路模型进行了分析。然后在此基础上应用叠加原理对具备多条电缆出线的变电站进行分析。最后得出结论，现有青岛配网运行情况下，电缆线路的增多很难造成无功倒送或者线路末端电压升高的情况，亦无需配置感性无功补偿设备，为城市配电网工程建设提供参考。%Nowadays, the cable use probability increases in major city, which may lead to lots of problems at low load such as surplus reactive power and terminal voltage increase because of its large capacitance to the earth. To solve this problem, this paper researches the effects of cable on reactive power of urban distribution network. It uses back/forward sweep method to do flow calculation based on the established model of distribution network for single cable line. On this basis, super position theorem is used to analyze the model of transformer substation with multiple cable lines. According to the results, this paper proposes the conclusion that the increasing of cable hardly cause surplus reactive power and terminal voltage increase. Meanwhile, configuring inductive reactive-load compensation equipments is also unnecessary, which provide references for projects.
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