Determination of the parameters of voltage variation with voltage fluctuation indices

A set of parameters that describe the quality of power in power grids includes several measures of voltage variation. Among these measures are the voltage fluctuation indices, composed of magnitude, δU, and rate, f, of fluctuations. This paper provides an example of the use of this measure to reconstruct the voltage changes. At the beginning a brief description of discrimination of voltage fluctuations indices is given. Then, on the basis of input data, which include recorded values of Pst indicator, maximum and minimum voltage rms values as well as voltage fluctuation indices, detailed analysis of voltage variation in the power grid is conducted. The results of the analysis are time plots for rates of voltage changes in a selected ranges of the changes' absolute values. A magnituderate characteristics is used to assess the obnoxiousness of voltage fluctuations.