A Stochastic Programming to Volt/VAR/Total Harmonic Distortion Control in Distribution Networks Including Wind Turbines

Abstract

—This article presents a stochastic methodology for volt/VAR/total harmonic distortion control to reduce power losses while satisfying the main recommended power quality standards and optimizing dispatch schedules for the switchable shunt capacitor and on-load tap-changer in distribution networks. The main aim is to find proper dispatch schedules for on-load tap-changer tap positions, substation capacitors, and along feeder capacitors. For this purpose, distribution network uncertainties, including load demand and wind power generation, are considered to provide a robust control scheme. A new scenario reduction method based on the highest potential cluster center is used to decrease the huge number of probable states. A new scenario-based probabilistic time-interval division framework, over a 24-hr period on both load curve and wind power output, is introduced to reduce effects of forecast plan uncertainty and switching operations in the on-load tap-changer. A genetic algorithm solution method is applied to find the best solution corresponding to various scenarios. To improve search ability, a method guaranteeing the suppression of maximum allowable daily substation capacitors switching and effectively correcting the convergence process is utilized. The proposed stochastic approach is tested on an IEEE 123-bus distribution network containing a number of non-linear loads and wind energy generation systems.