Evaluating the benefit of voltage comprehensive planning of high and medium voltage networks

The cost pressure on distribution system operators has significantly increased due to the liberalization of the electricity markets and the setting up of regulatory authorities. Therefore, the reduction of network costs to improve the efficiency of distribution networks gains in importance. In the general planning process, each network is separately planned from adjacent networks in the same or upper/lower voltage level. Thus, the planning process concentrates exclusively on a single network of one voltage level while neglecting interactions with adjacent networks. As a result, it is possible to determine long- term cost-efficient networks, so called reference networks, which represent a long-term objective for existing networks. The benefit of voltage comprehensive network planning by consideration of adjacent networks in the same or adjacent voltage levels has not been estimated yet. It is expected that this approach yields to lower costs of voltage comprehensively planned networks compared to separately planned networks while still providing the same level of power quality. Therefore, in this paper the benefit of voltage comprehensive planning of distribution networks is evaluated in respect of the network costs as well as power quality. For this purpose, it is necessary to develop a voltage comprehensive network planning methodology.