Basic principles of process implementation on voltage level changing in the distribution networks

The increase of storeyedness of dwelling houses and administrative buildings, far of the large point loads and separate regions with high load densities results in the necessity to enter higher level of voltage in the urban power supply system. These tendencies are typical for Riga city - the capital of Latvia and main administrative, industrial, financial, business and cultural centers. Existent 10 kV base voltage in Riga cannot provide increasing requirements to the feed of the large loads in infrastructure of modern cities. The introduction of higher voltage level should be justified by the economical and technical possibilities and advantages in comparison with the existing system of power supply. The paper focuses on the conception of 20 kV voltage introducing in Riga, evaluate the technical and economic possibilities for the progressive or sharp changing of voltage, develop the methodology of management of voltage level changing process in the distribution network of the large city. In the paper the technical economical model of the urban power supply system for the its qualitative and quantitative evaluation is presented. The optimal parameters of the power supply system and its technical economical indices at different load densities in the city and its suburbs are determined.