Measurement and calculation of surge-arrester residual voltages

This paper presents accurate measurement of residual voltages of surge arresters (SA) by two designed charge meters (D-dot probes) as well as simulation validation in the high-conduction regime. Simultaneous impulse voltage measurements were conducted by using two D-dot probes, two uncompensated commercial mixed resistive-capacitive (RC) probes and an uncompensated damped capacitive voltage divider (CD). Residual voltage measured by two commercial mixed RC probes and the CD showed longer rise time, an initial inductive overshoot superimposed on the waveform and a significant decay even before the current peak instant, contrary to those measured by the two D-dot probes. Theoretical investigations are also introduced for the inductive coupling in the CD loop and analysis of the test circuit. Quantification of measurement errors has shown the superiority of D-dot probe over the other devices used. Finally, good agreement was found between the measured current and voltage waveforms for 33-kV SA and those computed from the test circuit analysis.