Energy Reports (Nov 2022)
Control of electric power quality indicators in distribution networks comprising a high share of solar photovoltaic and wind power stations
Abstract
Mass-scale integration of renewable power stations into distribution power networks is a main trend of power industry development aimed at its decarbonation. All solar photovoltaic (SPVS) and wind power (WPS) stations are connected to the existing medium- and high-voltage distribution networks, excluding large capacity wind power and photoelectric fields. Modern SPVS and WPS are integrated into energy systems with the use of inverters/converters into which control algorithms for output power and protection have to be included. Critical deviations of electric power quality indicator (EPQI) from their normal operation values may occur, in networks, in these inverters/converters low-load conditions. Such deviation appears in low irradiance conditions in SPVS and low wind speed in WPS. It has to be noted that various electric loads of industrial consumers can be connected to the distribution networks for which such EPQI deviations are critical. This article deals with the newly developed method and device for EPQI sampling control enabling to automatically detect EPQI deviations including short-term ones. Results of preliminary simulation modeling, in various operation conditions, of distribution network including SPVS and WPS are used in the newly developed device. Besides, the device implements automatic Wald’s sequential analysis procedure on the basis of a multiple-choice indicator distributed in accordance with the binomial law. The effectiveness of EPQI sampling control based on the mathematical statistics methods has been demonstrated. It has been proposed to apply an integrated indicator, i.e. the absolute value of intercorrelation coefficient, for current and voltage signals, in order to take account of the complex effect of EPQI on the electric loads. Implementing the developed method and device for sample-based EPQI control makes it possible to prevent considerable and long-term EPQI deviations, in order to ensure reliable operation of consumers’ electric receivers, in distribution networks comprising a high share of SPVS and WPS.
