Conductivity measurement on thick insulating plaque samples

The conductivity is one of the main properties of HVDC cable insulation materials and needs to beevaluated carefully. Since measurement on cables is time consuming, often thin specimens and normalconductivity measurement cells are used to compare the materials. In this way however, the bulk effectswill be less represented in the measurement and the results will be less representative. Instead, one needsto perform the measurements on thick plate samples and with higher voltage levels. This work focuseson the conductivity measurements on thick HVDC insulation plate samples subject to a high electricfield and carefully controlled conditions. In the literature, there are many different methods of measuringthe leakage current such as dielectric spectroscopy, PD, IV and PEA measurements. In this thesis a threeelectrode setup is used to measure the leakage current where the electrodes are placed inside the oven.This is to be able to control both temperature and high voltage under similar and different conditionswhere it is possible to change these two parameters during measurement. This was made by two Labviewprograms; one for creating a schedule and one control program which controls the equipment in the cell.The task was to make sure that the cell functioned by obtaining repeatable and reasonable measurements.The results that were obtained were reasonable and verified that the cell functioned. The executedmeasurements were performed in order to achieve a better understanding of error factors in themeasurement system, ranging from preparing the sample to measuring the leakage current. The purposewith the cell is it to investigate the quality of the HVDC insulation by conductivity measurements onmillimetre thick plate samples.