Entropy and coefficient of variation CV as tools to power quality assessment
We´ll present in this paper several concepts and techniques to quantify electric signal entropy and variability in order to assess power quality, showing their irregularities , such as the electrical sine wave, which delivers power to industry and homes.. We will review these concepts and present some magnetic radiated waves measurements taken below 115 KV electric lines circuits of the city of Manizales (Colombia) through a non invasive and indirect measurement of the complexity of the current transported by the supply.
Entropy, as an accepted indicator of the complexity of physical realities, is proportional to the logarithm of the number of states in a thermodynamic system. Some writers identify entropy as a disorder of a system, but this is not completely true. Entropy of the information was first defined by Shannon in 1949 , and it is applied to multiple physical events. In this context, entropy describes the complexity of the magnetic wave radiated by the line.
Furthermore, we obtained the spectral and amplitude coefficient of variation CV of the magnetic waves with a multi resolution wavelet algorithm, which permits the measurement of dispersion of the data distribution .It is a dimensionless number that allows comparison of the variation of magnetic radiated data ,that have significantly different mean values, against a 60 Hz magnetic pure wave as a reference