A Novel Stratified Sampling Technique and Its Application in Power Quality Indices Estimation

The growing concern about the power quality im-provement associates with the recent increase in the loads which produce high PQ disturbances as well as the increase in the loads which are sensitive to PQ disturbances. One important aspect of PQ enhancement is to monitor and measure PQ of the system in an effi-cient and suitable way. Considering the financial and technical diffi-culties of measuring the PQ of all system’s buses, this paper focuses on clustering as an important area of data mining which is frequent-ly used in power system studies. In this regard, a novel sampling technique is developed which integrates grid-based clustering with stratified sampling and provides a more sophisticated and accurate approach for estimating the system power quality using the PQ of the sample points. Moreover, new methods are proposed for esti-mating the system indices for harmonics, voltage unbalance and flickering using the sample data. This method is suitable for power quality assessment of subdistribution and transmission systems.

Keywords:

power quality , clustering , sampling , system indices , flickering , harmonics , voltage unbalance ,