On the Existing and New Potential Methods for Partial Discharge Source Monitoring in Electrical Power Grids
Résumé
Power transmission and distribution networks currently face an intensive use and climate change challenges. In such networks, the occurrence of defaults (caused by the cable aging process, the structure and network capacity, voltage levels, and related environmental conditions) is inevitable. The difficulties of predictive maintenance of power grids are related to the large spread of electrical infrastructures and the definition of early warning indicators. Such indicators are the partial discharge activities which are very informative about the rising insulation problems of electrical materials. The monitoring of such phenomena is nowadays an important field in the power transmission and distribution systems. The purpose of this paper is to study different techniques for the detection of transient signals in the context of monitoring partial discharges in electrical networks. Among the various techniques developed and used for the detection of partial discharges, we will focus here on four classes of methods; two of them are encountered in existing products, whereas two new techniques are based on recent concepts: compressive sensing and phase-diagram based analysis. The comparative study concerns the evaluation of the probability of detection versus false alarm ratio of real signals measured on a reduced scale experimental facility. Thanks to this experimental facility typical for real life configurations, we are able to add to the partial discharge signals perturbations such as load signals, reflections but also the effect of propagation effects in a real electrical cable which allow us to highlight the performances of each method.