Wavelet-based algorithms for triggering power quality measurement instruments

During the last years, the power quality (PQ) issues have been a subject of major concern. The constraints that must be fulfilled by the voltage wave supplied by utility companies have become more and more exigent. For this reason, the PQ measurement equipment requires new and computational efficient algorithms. This paper presents a Discrete Wavelet Transforms (DWT) based triggering algorithms for PQ measurement instruments. Some typical PQ disturbances (sags, spikes or harmonics) have been considered to define figures of merit that can detect the presence of such disturbances and therefore are suitable to trigger the data recording of the PQ analyzer. All these figures of merit are obtained from the DWT decomposition. The final validations of the triggering algorithms have been done with real measurements.