A. C. Power Losses in MOV Surge Arrestors

It was the objective of this study to measure power losses occurring in MOV surge arrestors as they were subjected to various voltage Excitations. In particular, power losses were observed in two MOV devices as sinusoidal voltages of different magnitudes were applied, at various frequencies in the range of typical power frequencies and common harmonics. Power losses were also observed in an MOV device for applied voltages consisting of the sum of 60 Hertz sinusoids and a single harmonic. The measurement procedure consisted of obtaining digital records representing the waveforms of voltage across and current through the MOV device during operation; power was calculated as the mean of the product of these digitally represented waveforms; This report contains a detailed description of the implementation of this procedure, as well as a discussion of some of its limitations when making measurements on highly reactive devices. Experimental results indicate that power losses in the MOV devices studied were primarily dependent upon frequency of operation, and peak amplitude of applied voltage. The results indicate that 60 Hertz specifications given for a particular device do not, in general, apply for other frequencies or non-sinusoidal excitation