Showing papers by "Roberto Candela published in 2016"
16 Oct 2016
TL;DR: In this article, the authors verify a possibility to measure simultaneously the space charge and the PDs under DC stress in order to evaluate the correlation between both phenomena, using a modified PEA cell and using a novel wireless sensor system.
Abstract: In the field of HVDC, the main causes of insulation aging are due to the space charge and PD phenomena. In particular, the purpose of the present work is to verify a possibility to measure simultaneously the space charge and the PDs under DC stress in order to evaluate the correlation between both phenomena. The space charge was measured by using a modified PEA cell and PDs were measured by using a novel wireless sensor system. The space charge profile and the PD pulses carried out simultaneously have been reported and discussed.
22 citations
03 Jul 2016
TL;DR: In this paper, the exact phase angle displacement of each Partial Discharge, PD, pulse with respect to the voltage reference waveform is estimated using a customized electronic device, the "phase check", consisting of a server to collect remote measurements and a Look up table to provide corrections to the measured phase shift values.
Abstract: The main objective of this paper is the assessment of the exact phase angle displacement of each Partial Discharge, PD, pulse with respect to the voltage reference waveform. Such problem also referred to as ‘synchronization’ is relevant when the cable is not accessible and the PD measure is carried out in wireless mode. It is well known, that the angle phase shift, due to the propagation phenomenon on the transmission line, can be calculated knowing the line type and length and typical operating conditions of the transmission line. The setup comprises a customized electronic device, the “Phase check”, a server to collect remote measurements and a Look up table to provide corrections to the measured phase shift values. To evaluate the voltage phase shift introduced by a transmission line, different simulations have been carried out in PSCAD. Then, to prove the correctness of simulated results and verify the “Phase check” precision, experimental measurements have been carries out on three transmission lines in Sicily, Italy. The experimental measurements prove that the proposed setup is effective and quite useful to provide precise assessment of voltage phase shift for PD wireless diagnosis.
4 citations
07 Jun 2016
TL;DR: In this article, the authors investigated the possibility to use remotely measured reference voltage at the closest accessible substation to create a reliable reference, thus reducing the time and associated costs required for performing field wireless measurements.
Abstract: In this paper, several aspects of the fundamentals of wireless Partial Discharge (PD) measurements are first discussed. Then, the relevance of the problem of voltage synchronization in PD wireless diagnosis is outlined. When portable instruments are used for PD detection, the main issue is the voltage measurement at the site where the PD detection is carried out. When such analysis is carried out over shielded cables, the AC (50/60 Hz) voltage reference signal is not easily detectable, while one of the basic parameters for PD diagnosis, the displacement of the inception voltage of the PD as compared to the reference voltage, is not available. Even if highperformance sensors are readily available on the market, the authors are investigating the possibility to use remotely measured reference voltage at the closest accessible substation to create a reliable reference, thus reducing the time and associated costs required for performing field wireless measurements.
1 citations