Voltage limiter for urban electric transport traction substations

The article provides information on the current state of the rolling stock of urban electric transport in Eastern Europe. It is shown that, due to available rolling stock with significantly different technical parameters in operation, it is possible for cars with the lowest maximum values ​​of operational parameters to fail due to overvoltages due to braking. Due to the ban by Ukrainian legislation on generation of electricity into the medium-voltage network without coordination of its volumes and due to high cost of accumulators, the only possibility of combating overvoltage remains the dissipative method. With this method, excess braking energy is dissipated on stationary resistors located at the traction substation. Operation of a transistor voltage limiter, which was used in the Oradea and Dnipro urban electric transport, is presented. Oscillograms of its operation are given. The transistor limiter is a chopper that can operate both in the start-stop mode and in the voltage stabilization mode. Using artificial intelligence methods, the assessment of the use of braking energy for heating the premises to increase the energy efficiency of the system was obtained. In this case, irregular braking power is transferred to the energy carrier of the warehouse heating system using the thermal accumulator. The experience of using artificial intelligence tools was generally recognized as satisfactory. Leading companies in the production of electrical equipment for traction substations borrowed the idea and proposed using it to facilitate the ventilation mode of subway tunnels by transferring heat generation outside the substation and tunnels. It was proven that even an inefficient solution at first glance can be used to improve the overall energy efficiency of the system as a whole.