<atl>An HTS SQUID picovoltmeter used as preamplifier for Rogowski coil sensors

In the design and development of high voltage insulation systems, partial discharge measurements are often used for system characterization and evaluation. One commonly used sensor for such measurements is the Rogowski sensor, which is a type of induction coil. Since the sensor itself has low resistance it produces very little voltage noise. Hence, the noise limit of the measurement is often set by the preamplifier. Recent development of SQUID picovoltmeters shows excellent noise performance, especially for sensors with low source impedances. We have evaluated the possibility to use the SQUID picovoltmeter as preamplifier for Rogowski type sensors. The designed voltmeter has a voltage noise of 110 pV/<f>√ of <RCD><rm>Hz</rm></RCD></f> and a bandwidth of 250 kHz. Measurements of sensors with inductances between 0.5 and 40 <f>μ</f>H have been performed. [Copyright &y& Elsevier]