Feasibility analysis of reduced‐scale visual corona tests in high‐voltage laboratories

Abstract

Corona is a critical effect that must be considered during the design and optimization stages of high-voltage hardware such as substation connectors, since due to the harmful effects, corona threats power systems reliability. Visual corona tests allow detecting and identifying the critical corona points on the surface of substation connectors, so corrective actions can be applied for product optimization. This paper focuses on reduced-scale visual corona tests intended to verify and optimize the behaviour of such high-voltage hardware. Reduced-scale visual corona tests allow reducing the voltage to be applied, laboratory size, instrumentation requirements, assembly and test times, and finally the overall costs of the tests compared to standard corona tests carried out in large-size high-voltage laboratories. A hybrid approach combining experimental tests and finite element method (FEM) simulations is presented, which allows obtaining the equivalent visual corona onset voltage between reduced-scale and full-scale tests. Although the paper focuses on the analysis of aluminium substation connectors, the proposed approach can be applied to many other hardware intended for high-voltage applications.

Experimental Study of the Corona Performance of Aged Sand-Cast Substation Connectors

“…This section describes the visual corona tests carried out in the AMBER high-voltage laboratory of the Universitat Politècnica de Catalunya (Terrassa, Spain). Similarly to what was undertaken in [20], experimental visual corona tests were carried out by means of a calibrated 130 kV high-voltage generator (BK-130 from Phenix technologies, Accident, Maryland USA), two calibrated 120 kV DC generators (4129-10 model from Phenix technologies, Accident, Maryland USA) with positive and negative outputs, respectively, and a digital camera (Canon EOS-70D resolution incorporating a 20.2 Mpixels CMOS APS-C sensor, 18-135 mm F3.5-5.6 IS STM lenses with super spectra coatings). Visual corona tests were performed in the laboratory in total darkness.…”

“…Experimental corona tests were performed with the connectors placed at a reduced height above the metallic ground plane, as proposed in [20]. This approach allows performing the tests in a small-size high-voltage laboratory, thus drastically simplifying the time required to assemble the experimental setup, reducing the voltage applied and the cost of the high-voltage generators required, while ensuring corona occurrence.…”

Arc Tracking Control in Insulation Systems for Aeronautic Applications: Challenges, Opportunities, and Research Needs

“…Under low pressure environments sound propagates with difficulty, so electromagnetic and UV-visible radiation can be used to detect corona [1,5]. Arcing in short gaps usually is preceded by corona discharges occurring at the region with highest electric field strength [11,78,79]. Corona discharges are key sources of premature failure of insulation systems operating at high altitude [5], occurring earlier at low pressure than at atmospheric conditions [13,80], so surface discharges are among the main causes for early failure of electronic equipment operating in low pressure environments [13].…”

Insulation Failure Quantification Based on the Energy of Digital Images Using Low-Cost Imaging Sensors

“…Whereas PDs are a type of electrical discharges which do not totally bridge the insulation separating two conductive electrodes [ 3 ], corona discharges are a specific type of partial discharges due to the ionization of a gas (insulation medium) surrounding a surface of high electric potential. Arcing and arc tracking in small-size gaps are typically preceded by corona activity generated in the area where the electric field strength is maximum [ 3 , 4 , 5 ]. Surface discharges, which are often responsible of failures in electronic systems intended for low-pressure applications [ 6 ] also generate corona discharges.…”