05/13/15

H. Ahmadi, A. A. Shayegani Akmal, A. Mousavi, H. Mohseni, “Investigation of Rogowski Coil for efficiently monitoring and locating PD faults in high voltage apparatus,” in Proc. IEEE Electrical Insulation Conference (EIC), Montreal, QC, Canada, June 2009. [PDF]

We used this device to measure the current flowing into a surge arrester during its operation. This current has a rise time of 2 us and fall time of 25 us and a peak value of about 10 kA. The Rogowski coil was inserted in the ground path and its output signal was brought to the oscilloscope through a coaxial cable and damping resistor (to cancel any reflection in the cable). A calibration for this current transformer is needed which was done in the HV Lab. Benefits of this instrument are:
Higher accuracy compared to common current transformers.
No core saturation.
Ability to measure very large currents (hundreds of kA).
Very low cost.
Easy to use.

With some modifications, Rogowski coil can be used to measure currents of very low magnitude but high frequency. Partial discharge currents are of such nature and this coil can be used for PD measurements.

Integrator

Rogowski coil.

Lab measurement set-up: air-gap

Lab measurement set-up: transformer.

Lab measurement set-up: surge arrester

Lab measurement set-up: control panel.