Effects of harmonic pollution on salient pole synchronous generators and on induction generators operating in parallel in isolated systems.

Abstract

This work presents a study of the disturbances caused by harmonic pollution in salient pole synchronous generators (SPSG) and induction generators, when operating in parallel in isolated systems. SPSG are known to operate with induction generators, since the excitation system of the synchronous generator is responsible for the voltage control on the island system. Due to the increase in the employment of power electronics, the loads take on a nonlinear behavior, where these become responsible for the generation of harmonics, due to the switching of electrical devices. Therefore, the analysis of the disturbances that these loads cause in generators, in this proposed and studied architecture, becomes essential. For the synchronous generator, there is also presented the analyses of the oscillations for voltages and currents on the dq0 model, the currents induced on the damper winding, the disturbances on the load angle and on the field current. In terms of the induction generator, the voltage and current oscillations are also analyzed from the dq0 model on the slip frequency. All the identified and quantified disturbances are oscillations on the electric variables, which possess a pulsating nature of frequencies 6ω, 12ω, and 18ω for the synchronous and induction generators, the oscillations of the sixth order and its multiples, will be given in the harmonic slip frequency of their respective harmonic orders in positive and negative sequence. In this way, verification is made as to the appearance of high slippage on the rotor of the induction generator.