Fibre optics in board arrangements with respect to partial discharge

Monitoring systems for condition evaluation are essential tools in the modern operation of high voltage equipment. Several new developments of insulation diagnostic are currently under discussion. Fibre optic technique was mainly used in the past as a galvanic separated, EMI-resistant data transmission. Today new developments in the area of signal acquisition offer an interesting possibility for temperature or force measurement by using fibre optic cable. These indicators represent significant parameters for a condition evaluation of electrical insulations and equipment. A potential free measurement inside the housing of the equipment is possible. Special point of interest is the condition evaluation of transformers. For example the temperature monitoring of high voltage power transformer is the key factor for an optimal operation (load limit, thermal rating). Therefore it must be guaranteed that the installation of these special fibre optic cables causes no additional disturbance like partial discharge inside the insulation system. In the paper, basic investigations of the PD behaviour of a test arrangement with implementation of fibre optic cables will be presented. Different materials like transformer board or plastics under air or oil test setup will be examined with different types of fibre optical sensor. The aim of these investigations will be the evaluation of the usability of fibre optical cables inside high voltage insulation systems.