A feasibility study of the application of signal processing techniques to corona discharge characterization on HVDC systems

The corona discharge characteristics are key factors affecting the electromagnetic environment on the high-voltage direct-current (HVDC) transmission lines and, consequently, may come in contact with humans and equipment outside of the transmission right-of-way. Therefore, this paper presents an initial and feasibility study of corona discharge characterization on HVDC systems through the application of signal processing techniques. This feasibility study is performed through experimental high-voltage discharge tests conducted under controlled environmental conditions. In the corona discharge test, high voltages varying from ±30 kV to ±80 kV were applied through a DC high-voltage generator and corona discharges around the conductor were measured by means of a data acquisition prototype system equipped with a metal electrode device for the purpose of corona current measurement. Subsequently, the signals collected were subjected to digital signal processing parameters to extract the most relevant features related to corona discharge characteristics. The feature extraction process was conducted on the basis of the following metrics: RMS, peak value, and digital filters in specific frequency bands. The results reveal that the proposed method was able to detect the corona discharge characteristics following the changes in the signal content, especially, for narrow frequency ranges. The results indicate the feasibility of the proposed method to detect and characterize the occurrence of corona discharge in a simple way, which expands the research field in corona discharge characterization in HVDC systems by means of digital processing and feature extraction.