Analysis of circuit solutions for the modernization of distribution networks for housing and communal services
The article presents the results of the analysis of the main stages of the development of electric networks for housing and communal services (HCS) since the 50s of the last century and ending with the latest innovative developments, which are both at the stage of theoretical research and experimental tests in pilot projects implemented in existing networks. It is noted that the traditional 10(6)/0.4 kV structure with a dead-earth neutral on the low-voltage side, which is used both in industrial and utility networks, has disadvantages associated with increased power losses, as well as the need to use special technical means to ensure the required quality of electricity. It is shown that with the average value of the reverse sequence current coefficient equal to 0.3, the relative value of additional power losses in the low-voltage line from the presence of current in the neutral wire can reach 36% of the total amount of additional losses. The review and analysis of the four most promising areas of modern research, innovative developments and experiments on the structural optimization of utility networks is given: a network with an increased voltage of 6(10; 35) kV and a reduced voltage of 0.4 kV with an isolated neutral; a network with an increased voltage of 6 (10; 35) kV and a reduced voltage of 0.4 kV with an isolated neutral; 0,95/0,4 /0,23 A network with two levels of high voltage of 1.14 (0.66) kV and a reduced line voltage of 0.23 kV with a grounded neutral of transformers; Fundamentally new methods of transmitting electricity over a single wire at alternating and direct current of increased voltage are described. The necessity of choosing the most rational integrated circuit solution for the structure and schemes of utility networks, which will reduce the loss of electricity in the networks, improve the quality of electricity and electrical safety, is justified