Study on the selection method of economical capacity for MV transformers

An improved TOC method is proposed in this paper, in which the ratio of cost and revenue is set for the TOC value, the affection of the transformers´ economic benefit in return to economic capacity is considered in this way. Moreover, the improved method takes MV/LV distribution network under consideration as a whole, rather than calculates every transformer´s TOC separately, which can also be used as a reference for transformers´ economic capacity choosing. The distribution network of a typical district in Shanghai is analyzed as an example, in which the improved TOC method is used for choosing MV distribution transformers´ economic capacity for the WX and P style substation.