0000000000135293
AUTHOR
Imburgia A.
Statistical analysis techniques for Partial Discharges measurement under DC voltage
Partial discharges (PD) phenomenon for HVAC (High-Voltage-Alternating-Current) systems has already been widely studied in literature and from this it has been possible to produce a regulatory document that provides indications for description and identification of the different types of discharges. However, the growing diffusion of HVDC (High-Voltage-Direct-Current) systems makes necessary the development of analysis techniques also for DC case. In this paper data obtained from PD measurement under DC voltage were analyzed through the time-frequency map combined with a density-based clustering algorithm. The results show that, with this approach, it's possible to perform a noise rejection a…
Characteristics of partial discharges in an experimental setup reproducing HVDC cable insulation operating conditions
The occurrence of Partial Discharge (PD) inside a cavity subjected to HVDC voltage can be considered as one of the most likely sources of insulation ageing and failure. In practical applications, the recognition of PD under HVDC is more difficult than under AC stress because of the lower repetition rates and the impossibility to obtain a PD pattern synchronized with the waveform of the applied voltage. In this paper, the relationship between conduction phenomena in dielectrics and the occurrence of PD is investigated by means of a novel experimental setup. A couple of dielectric cells connected in series is subjected to various HVDC stress levels. The applied voltage is divided between the …
Effect of Space charge accumulation inside the thermoplastic insulation of a loaded HVDC model cable
The space charge accumulation phenomenon represents one of the main degradation factors for the dielectrics employed in the field of the HVDC transmission. For this reason, the recommendation IEEE Std 1732-2017 has been proposed. In that standard, due to the importance attributed at the space charge phenomenon, the experts suggest the introduction of the space charge measurement in HVDC cables during the prequalification or type tests, by means of the PEA method. However, despite for tests in flat specimens the PEA technique is well consolidated, for cable specimens difficulties are still present. In particular, the PEA cell output signal is strongly conditioned by the arranged measurement …