Abstract: A temperature compensated current measurement device comprises a Rogowski coil having a terminating impedance arranged to adjust the attenuation of the coil to balance changes in coil sensitivity so that the output voltage indicative of measured current remains substantially unchanged, the terminating impedance having different values above and below a threshold frequency.
Type:
Grant
Filed:
February 1, 2013
Date of Patent:
May 15, 2018
Assignee:
Power Electronic Measurements Limited
Inventors:
William Frederick Ray, Christopher Rene Hewson, Joanne Marie Aberdeen
Abstract: A current measuring device comprising a Rogowski coil (30). Connected across ends of the coil (30) is a passive integrator in two parts (34, 36), the parts being connected by a coaxial cable (32). Connected to the output of the passive integrator (34, 36), is an electronic integrator (38). At low frequencies the passive integrator (34, 36) has a substantially constant gain and the electronic integrator (38) integrates the signal from the coil (30). At high frequencies, the electronic integrator (38) has substantially constant gain and the passive integrator (34, 36) integrates the signal from the coil (30). In order to reduce high frequency voltage oscillations, the Rogowski coil (30) is terminated with a coil damping resistor that has a value that is approximately the same as a characteristic impedance of the coil.