A digital technique for the on-line measurement of dissipation factor and capacitance

This paper reports a computer-aided system for on-line monitoring of dielectric dissipation factor tan /spl delta/, and capacitance of HV apparatus. The method employs the discrete Fourier transform (DFT) which is performed on the scaled down analog voltage and current signals obtained using a digital storage oscilloscope (DSO) board. The results are displayed using the graphic user interface implemented with graphic (G) language, This technique uses optimal values of measurement parameters as indicated by software simulation and laboratory tests. Field tests were conducted at Manitoba Hydro's Dorsey station to evaluate the insulation of a 230 kV current transformer unit using the developed system.