New 20kV network concept for an existing distribution network

This paper presents a study of a distribution network of the large city in a former republic of the Soviet Union. The current situation is analyzed and a new network concept is developed. The major part of the current electrical network has been built in the 1960th and 70th using old Russian technology. The economy develops strongly in the last years, and it can be estimated that the total consumption will roughly double within the next 15 years. Today the distribution network is using several voltage levels. A lot of the electrical equipment in the network is reaching the end of its lifetime in the coming years. Therefore and due to the historical developments in the network structure, reliability is low compared to European standards. For these reasons a new network concept has been developed in a consulting project undertaken by Siemens PTI and described in this paper. Especially for the new and optimal network concept for the city, the reduction of the large number of existing voltage levels has been proposed by introducing a new 20 kV level. The Greenfield planning approach is used for this task to achieve the optimal solution for the network. Finally a way is presented to transform the current network step-by-step into the recommended 20 kV solution with future oriented and optimized network structure for the year 2025. The objective of these steps is to achieve a fast improvement of network reliability.