This document describes application of statistical analysis to several diagnostic parameters obtained during on-site measurements on MV power cables. The goal of this analysis is to estimate statistical borders values for different diagnostic parameters related to PD phenomena for cable insulation as well as different cable accessories like joint and termination. Data input introduced to analysis consist of mass, XLPE and mixed (XLPE +PILC) insulated power cables. Investigated parameters were obtained with application of damped AC (DAC) diagnostic system during on-site non-destructive tests. For the purpose of clear distinction between cable components (joints, termination, insulation parts) categories, of different cable accessories were created). For proper interpretation of collected data related to cable insulation condition as well as different accessories condition, categorization based on such diagnostic parameters e.g. PDIV (Partial Discharge Inception Voltage), PD occurrence, and PD mappings was done. Additionally crated in this way measuring criteria based on calculated statistical norms by fitting data to several statistic distributions were employed for overall condition indexing. Later on condition indexing was used to indicate percentage ration how big population of insulation and components are in very good, good and moderate condition.@en

This paper describes important aspects of PD diagnostics of distribution power cables. PD parameter were discussed under consideration of attenuation and dispersive effects of cable characteristics. Field experiences with PD diagnosis on PILC and XLPE cables by energizing with Damped AC Voltage demonstrate relevant demands and the effective outcome for asset management decision support. The main difficulty is to evaluate the risc of PD occurrences on the reliability of the cable system. If an sufficient amount of PD diagnostic data for the cable components is available statistical methods can be used for determing threshold levels and relevant condition indexes for the asset management.@en

For advanced, non-destructive on-site condition monitoring of HV power cables up to 150kV by partial discharge detection and dielectric losses measurement it is necessary to energize the disconnected cable system. One of the methods available for this purpose is based on applying damped AC voltages up to 150kV. In this paper, the use of modern technological solutions in power electronics and signal processing as well as in technical design and production methods will be discussed on the basis of the ultra light system (300kg) which is able to test cables up to 20km lengths.@en

In this contribution statistical analysis were applied to evaluate condition of serviced aged MV power cables systems. Analysis were based on large number of diagnostic data as obtained from the on-site inspections of 89 mass insulated power cables, 26 XLPE insulated power cables and 126 mixed-insulated power cable. Statistical analysis input data was represented with several diagnostic parameters regarding to partial discharges phenomenon (PD). Investigated parameters were obtained with application of damped AC (DAC) diagnostic system during on-site tests. After a survey of all relevant parameters describing condition of the particular cable system components, sub-groups of different cable accessories were created (e.g. joints, termination, insulation types) For proper interpretation of collected data related to cable insulation condition as well as different accessories condition, categorization based on such diagnostic parameters e.g. PDIV (partial discharge inception voltage), PD occurrence, and PD mappings was assumed. Moreover investigated statistically PD parameters were employed to estimate experience norms and measuring criteria. Based on knowledge rules and estimated statistically norms example of so called ldquoexperimental condition indexrdquo was used to indicate overall condition of discussed MV power cables systems.@en