Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
704732 | Electric Power Systems Research | 2012 | 7 Pages |
Fourier based methods are still popular for calculating power quality indices (PQIs) in the technical community such as IEC and IEEE. They are robust towards noise and can be calculated efficiently using the fast Fourier transform (FFT) method. IEEE Std 1459-2010 provides formulations for calculating important PQI for single and three phase systems. The aim of this paper is to present the theory for estimating PQIs using the Welch spectral and cross spectral analysis techniques, and show experimentally the accuracy of the proposed methods when calculating the PQIs. Further it provides a comparison on the windowing techniques (WTs) that accompany the PQI estimations when using FFT based methods. This information has not been documented extensively in the technical literature when trying to calculate the PQI as specified by IEEE Std 1459-2010. Further we present a virtual instrument (VI) with a Kalman filter (KF) to estimate the PQIs. The KF is used to reduce the variance in measurements for the PQI estimation. We also compare experimentally the accuracy of the VI without the KF with the VI using the KF. Specifically we propose good and bad WTs to estimate such PQIs.
► Designed a new virtual instrument for measuring power quality indices according to IEEE Std 1459-2010. ► Compared many windows for their suitability of estimating power quality indices. ► Compared two virtual instruments with the Kalman filter and without the Kalman filter. ► Kalman filter improved the results. ► The rectangular window was found to be unsuitable for estimating the power quality indices.