实现最大供电能力的配电网馈线与主变压器容量匹配

提出了一种新的配电网规划中馈线与变电站主变压器容量的匹配方法。首先,定义了达到最大供电能力下的馈线平均负载率和主变压器平均负载率两个指标,再分析其随馈线容量与主变压器容量比值的变化规律,发现两个指标无法同时达到最大。然后,根据馈线与变电站的建设成本差异,确定馈线与主变压器容量的最优配比,在该配比下单位供电能力的电网建设总投资最小。最后,分析得到多个算例的不同情况的馈线与主变压器容量的最优配比,该值随着馈线相对变电站造价比值的增加而减小;并随着馈线联络均衡度的增加而增加。在现有城网造价水平下建议配比取1.0~1.6,明显低于传统配电网以及规划经验值约1.5~2.0的区间。

Optimal Capacity Ratio Between Feeders and Main Transformers to Implement Total Supply Capability

A new method of planning the capacity ratio between feeders and main transformers in a distribution network is proposed. Firstly, two indices including the average load rates of feeder and main transformer under the total supply capability(TSC)are defined. Then, the law of variation of the two indices with the capacity ratio between feeders and main transformers is analyzed. It is revealed that the two indices cannot reach the maximum value at the same time. Secondly, according to the construction cost differences between feeders and main transformers, the optimal capacity ratio between feeders and main transformers is calculated. At this ratio, the total construction investment in the unit power supply capability is minimum. Finally, the optimal capacity ratio of multiple cases in different situations is obtained, which declines with an increase in the cost ratio between feeders and substations and rises with the increase in tie-line balance degrees. The optimal ratio is suggested to be 1. 0-1. 6 in current cost level of an urban network, which is obviously lower than the range of 1. 5-2. 0 for the conventional distribution network and the planning empirical value. This work is supported by National Natural Science Foundation of China(No. 51277129)and Program for New Century Excellent Talents in University(No. NCET-10-0624).