Защита электрогенераторов объектов распределенной генерации от аварийных режимов

Abstract

Distributed generation is a good solution for areas remote from centralized power supply sources as it helps increase the reliability of consumer operation. Distributed generation power supply systems use renewable sources of electricity, diesel generators and gasoline generators in the form of mobile power stations, which in most cases are not equipped with modern means of protection. This study presents an analysis of existing means of protecting electric generators from abnormal and emergency operating conditions, including voltage asymmetry, which is one of the factors reducing the service life of generators and is typical for rural electrical networks. During the analysis, the authors determined the main types of generator protection against emergency operation modes: protection of stator windings, protection against underfrequency and overfrequency, protection against undervoltage and overvoltage, protection against voltage (current) asymmetry. It is noted that the main cause of voltage asymmetry leading to mechanical vibration and rapid overheating of the rotor is single-phase loads in the system, which are unevenly distributed over three phases. The problem of voltage asymmetry is mainly solved by redistributing loads in transmission lines and/or installing compensating devices. However, in rural power supply systems, unbalanced load distribution is rarely corrected. The voltage asymmetry can be compensated through the use of hybrid active power filters of series compensation and improved control methods of these filters. Voltage converters that are effective in equalizing voltage asymmetry in PV systems can effectively protect small capacity diesel power generators provided that the use of additional equipment is economically viable.