交流配电网与直流配电网的经济性比较

Economic Comparison of AC and DC Distribution System

对目前配电网中的负载进行了定义与分类,并对交、直流配电网的最大传输容量分别进行了推导;对交、直流配电网主要设备的造价与传输效率分别进行了计算与分析,对于直流断路器、直流变压器等尚未实现商业化应用的装置,根据其研发费用对未来的市场价格进行了估算。以典型结构的配电网为例,分别对其采用交流配电网、±7.5 kV及±15 kV直流配电网供电时的投资成本与传输损耗进行计算,进而对其进行经济性比较。研究表明,直流配电网的最大传输容量与投资成本皆大于交流网,且电压等级越高,其最大传输容量与投资成本越大;直流配电网的传输损耗率低于交流网,且随着电压等级的提高而下降;中压直流负载的比例越高,直流配电网的投资成本越低,传输损耗率越小。

The load in the classified and the maximum present distribution network is transmission capacity of AC distribution network and that of DC distribution network are derived respectively. The manufacturing cost and transmission efficiency of main equipments for DC distribution network are calculated and analyzed, as for such equipments as the DC circuit breaker and the DC transformer, whose commercial use is not yet implemented, their market prices in future are estimated according to their research and development expenditure. Taking distribution network with typical structure as example, its investment costs and transmission losses under following three situations, namely supplying power by AC distribution network, ：e7.5kV DC distribution network and ＋15 kV DC distribution network, are calculated respectively, and then the economic comparison among the three situations is performed. Research results show that both maximum transmission capacity and investment cost of DC distribution network is higher than those of AC distribution network, and the higher the voltage class is, the higher the maximum transmission capacity and investment cost will be; the transmission loss DC distribution network is lower than that of AC distribution network, band it will decrease with the increase of voltage class; the higher the proportion of medium-voltage DC load is, the lower the investment cost of DC distribution network and the lower transmission loss will be.