Increase in simulation accuracy of self-starting motors used for relay protection and automatic equipment

Abstract

The main and, in real conditions, the only way to protect synchronous motors from voltage losses during a fault is a self-starting method. This method is widely used in industry, in particular, in petrochemical production. In this context, the role of simulation accuracy of the self-starting method for powerful synchronous motors as a part of real power system is considered. In the paper, a three-phase simulation of a large petrochemical enterprise is presented. Interruptions of synchronous motors of water pumps at such enterprises are not allowed; hence, two self-starting methods for powerful synchronous motors applicable in real power system are considered. The first self-starting method is used after a significant decrease or loss of bus voltage due to nearby fault. The second is used after interruption of power supply due to operation of automatic transfer switch or automatic reclosing; at that moment, the synchronous motors are disconnected from the power source for a certain time. This period of time is required for automatic transfer switch or automatic reclosing operation. According to the simulation results, settings of relay protection and emergency automatics of powerful synchronous motors have been changed.