Comparative measurement of surge arrester residual voltages by D-dot probes and dividers

This paper presents the design and testing of coaxial D-dot probes with three different designs, namely, totally closed, totally open and semi-open designs. The latter design gives a good response and has an easy-access assembly for fixing and replacing the surge arresters (SA) under test. Simultaneous measurements of residual voltage for 9-kV SA are conducted by the designed probes, and resistive and universal dividers (RD and MRCD). The divider compensation principle is also introduced and implemented for both dividers. Both perfectly compensated dividers and the designed D-dot probes have an error of about 2.5% in the SA residual voltage due to the unavoidable resistance of connecting leads. SA residual voltages measured by uncompensated short MCRD divider give good agreement with that measured by the D-dot probe. The former has small inductive overshoot which can be neglected as the residual voltage crests before the discharge current by a few microseconds.

► Measurement errors in surge-arrester residual voltage using high-voltage dividers.
► Explain the principle and design of D-dot probes.
► Check response of different D-dot probe designs against uncompensated resistive divider.
► Demonstrate and apply the voltage divider compensation principle.
► Investigate divider response of long and short universal ones.