Sustainable operation analysis of the mining industry power supply system

Abstract

The paper presents an analysis of operating currents and torques during self-starting of motors with a voltage of 6 kV for cases of short circuit in the head feeders from the main step-down substation and in the feeders to the most distant substations of mining enterprises. For the network under consideration, the characteristic modes are: short circuit on the buses of shop substations. For the mining industry when selfstarting asynchronous motors with a squirrel-cage rotor and synchronous motors with asynchronous startup, the current multiplicity will be determined by the duration of the power failure (run-down duration). It has been established that the acceleration of motors during self-start will be somewhat slower than the usual start, since self-start begins at a speed of 0.89–0.94 of the synchronous speed and a resistance torque is equal to 0.65–0.75 of the maximum motor torque. The self-starting time of the motors is from 9 s to 42 s. To ensure self-starting conditions in the most severe modes in mountain conditions, it is necessary to make changes to the protection settings presented in the work.