电网三相不平衡下农网低电压治理的研究

Research on the Low Voltage of Three-Phase Unbalance in Rural Grid

通过对农网低电压和三相不平衡问题的研究,分析了目前解决农网低电压和三相不平衡措施中所存在的一些问题,并针对这些问题提出了一种分序叠加调节法。以最简单的单线路农网为模型,在其结构的基础上得到相应的等效电路,并对该等效电路进行相应的潮流分析,从而揭示出电压损耗和功率损耗与无功功率之间的关系。利用潮流分析的结论确定了先不考虑电网三相不平衡影响的调节法调节原则,同时引入调节限定曲线以配合该调节法。然后再在此基础上考虑三相不平衡的影响,结合已经提出的平衡网络下的调节法和对称分量法,得到适用于解决三相不平衡农网低电压问题的分序叠加调节法。最后将该分序叠加调节法实际应用于平凉市西华供电公司,试验结果验证了该方法解决三相不平衡农网低电压问题的有效性。

Through studies on the low voltage and unbalance problem in the rural grid, this paper analyzes the current measures taken to solve the problem and finds out the disa-dvantages of these measures. In view of the disadvantages, this paper proposes a sequence superposition adjustment method to solve the low voltage and unbalance more effectively. Taking the single line power supply network as a model to get the equivalent circuit, the paper analyzes the power flow for it,thereby reveals the relationship between the voltage-power loss and reactive power. The regulating principle of the adjustment method is determined without considering the unbalance provisionally, and the limit curve of adjustment is introduced to match the principle. Furthermore, on this basis, considering the influence of unbalance of the grid as well as the symmet-rical component method and adjustment method in the balanced grid, the paper obtains the sequence superposition adjustment method suitable for solving the low voltage and unbalance problem in the rural power grid. Finally,the engineering example has proved the effectiveness of the method.