A novel converter for optical pd measurement with output as electrical charge proportional to light intensity

Summary

Measurements of Partial Discharges (PD) are frequently disturbed by noise from electromagnetic sources. Therefore sensitive PD measurements are often hardly possible, especially under on-site conditions and for on-line monitoring purposes. Electromagnetic noise can not disturb PD measurements if the PD light emission is recorded instead of the apparent electrical charge (in accordance to IEC 60270). Hence the optical measurement of PD has clear advantages that are far too seldom utilized. However, one task is the recording of the light impulses. Preferably one would use a commercially available PD measurement system for this task. That means the light impulses have to be converted into electrical impulses. Photon counters were already successfully applied for sensitive detection of the light emission of PD impulses. However, since the output of photon counters are binary TTL-impulses, the light intensity (optical magnitude) of single PD impulses is lost during the optical-electrical conversion process. Furthermore, photon counters have the disadvantage of a dark count rate that cannot be distinguished from PD impulses. This is why the development of a new optical to electrical converter was carried out. This novel converter generates output impulses with (electric) charges proportional to the light intensities of the optical input impulses. In this paper properties like sensitivity and linearity are investigated and characterized with the aim to verify the suitability of the novel converter for the optical measurement of PD.

Additional informations

Authors

ŠKUNDRI, VIZIREANU, VAN DEN BOOGAARD

Keywords

Partial Discharge, electric power cable system, optical PD measurement, on-site testing, monitoring