Calculation of Short-Circuit Currents of an Electrical Complex with its Own Generation in the Presence of Synchronous and Asynchronous Drives

The presence of own sources of electricity in the conditions of joint operation of autonomous and centralized power sources of power supply systems imposes the need to use a special mathematical apparatus for the study of short-circuit modes. The mathematical model of the power supply system with autonomous and centralized sources proposed by us takes into account the closed electric network of sewage treatment plants. Computational studies of various types of short circuits in a combined circuit with autonomous and centralized power sources have been carried out, which confirm an increase in the accuracy of calculations of currents and residual voltages of the network by taking into account the EMF angles of generators, synchronous and asynchronous motors relative to the EMF of the balancing unit.Computational studies have confirmed that the short-circuit currents in the VTE Wassertechnik GmbH division (APVSH-682510.003-PZ project from 2008), with the assumptions adopted there, are overestimated by 15-24%. This led to the choice of switches with a high cut-off current, and also required changes in the relay protection and automation settings. Short-Circuit currents in the supply power system on 110 buses, as well as the 10 and 6 kV distribution network of the electrotechnical complex of sewage treatment plants are compared. The nodes are identified, with a three-phase short circuit, in which dynamic stability is disrupted.