Group predictive voltage and frequency regulators for small hydro power plant in the context of low power quality

Abstract

The study examines the influence of predictive voltage and frequency regulators of generators of a small hydropower plant (HPP) on the quality indices of electric power and those of the control process in the case of disturbances in the system. The study aimed to determine the performance of the group predictive generator control algorithms. The research has revealed that the use of a DC link and a small HPP with group predictive voltage and frequency controllers has a noticeable effect on the improvement of power quality: the voltage distortion factor decreases by an average of 1.4 times and the voltage unbalance factor is reduced by almost ten times. In all considered conditions, the use of group predictive controllers can significantly improve the quality of electricity and the quality of the voltage and frequency control: the voltage dip depth decreases by 1.7 times and the voltage un-balance factor decreases by almost 4 times when an additional load is connected; the voltage dip depth is reduced by 20%, the frequency overshoot value is reduced by a factor of 1.8, and the transient process time for the frequency under the short-term short-circuit conditions is reduced by a factor of 1.5.