Partial discharges in transformers can lead to corrosion on solid insulating materials and thus cause a breakdown of the concerned operating component in the long term. PO processes can also lead to decomposition and pollution of the insulating oil as a result of which the insulation properties of the oil cannot be guaranteed.
This is why measuring partial discharges is mandatory for new transformers and sometimes even in case of major repairs. PO measurement can also provide information about the ageing condition of service-aged transformers and thus enable conclusions about their remaining lifetime. In such cases, specific phase-related representations (PARD, fingerprints) can assist the identification of the fault type and, if necessary, a more precise localization of the fault [1].
The digital PO measurement system MPO 600 from OMICRON [2] is suitable for test facility measurements as well as for measurements in the field under strongly interfering environmental conditions and thus provides an estimable contribution to the maintenance of quality and value of expensive transformers.
