Measurement of Corona Discharges under Variable Geometry, Frequency and Pressure Environment

Abstract

Aeronautical industry is evolving towards more electric aircrafts (MEA), which will require much more electrical power compared to conventional models. To satisfy this increasing power demand and stringent weight requirements, distribution voltages must be raised, which jointly with the low-pressure environment and high operating frequencies increase the risk of electrical discharges occurrence. Therefore, it is important to generate data to design insulation systems for these demanding applications. To this end, in this work a sphere-to-plane electrode configuration is tested for several sphere geometries (diameters ranging from 2 mm to 10 mm), frequencies of 50 Hz, 400 Hz and 800 Hz and pressures in the 20–100 kPa range, to cover most aircraft applications. The corona extinction voltage is experimentally determined by using a gas-filled tube solar blind ultraviolet (UV) sensor. In addition, a CMOS imaging sensor is used to locate the discharge points. Next, to gain further insight to the discharge conditions, the electric field strength is calculated using finite element method (FEM) simulations and fitted to equations based on Peek’s law. The results presented in this paper could be especially valuable to design aircraft electrical insulations as well as for high-voltage hardware manufacturers, since the results allow determining the electric field values at which the components can operate free of surface discharges for a wide altitude range.

Analysing the influence of geometry and pressure on corona discharges

“…It is noted that (2) is not a conventional equation found in technical books, but an hypothesis that needs to be verified from experimental data. Rewriting (2), it leads to (3), According to (3), a linear fit of V c /kR as function of 1/(kR) 1/2 should yield the values for E 0 and a.…”

“…This section presents and discusses the experimental values obtained in the laboratory. It is worth noting that further information and a more extensive data set can be found in a previous research paper of the authors [2]. First, to better understand how corona discharges look like, figure 6 shows long exposure photographs of such discharges taken with a high-resolution CMOS imaging sensor (Sony IMX586).…”

“…In uniform electric fields as those generated between two parallel plates separated by atmospheric air, when the voltage between the two plates (electrodes) increases steadily, it will inevitably lead to a complete breakdown of the air gap. However, in the case of non-uniform electric fields, a gradual voltage increase first leads to partial discharges [2] and if the voltage is further increased, finally a complete breakdown of the gap will be produced. Corona is a type of partial discharge occurring in air (or a gas medium), i.e., a self-sustained luminous discharge that produces a conductive area around the electrode but it does not completely bridge the air gap between the two electrodes.…”

Application of Image Sensors to Detect and Locate Electrical Discharges: A Review

“…The results showed that the sensitivity of this camera was similar to other state-of-the art sensors. The same image sensor has been used in [ 45 , 133 , 134 ].…”

Synthesis and Characterization of High‐Quality Ta2O5 Nanoparticles for Highly Selective SAW‐Based DUV Sensor and Corona Detection Application

“…Wide-bandgap materials possess bandgaps that are considerably larger than the 3.4 eV bandgap of gallium nitride (GaN), [1][2][3] making them particularly well-suited for solar-blind DUV photodetection and corona discharge detection. [4][5][6][7][8][9] Meanwhile, most recently DUV photodetectors based on molybdenum sulfide (MoS 2 )/GaN p-n heterojunction, [10] Ga 2 O 3 , [1,[11][12][13] Zn 2 GeO 4 Nanowire, [14] lutetium oxide (Lu 2 O 3 ), [15] p-MnO/n-GaN, [16] indium-galliumzinc-oxide (IGZO) thin film [17] have been extensively studied. But some of the materials have limitations like complex synthesis, high-temperature process requirements, defect states, and stability issues.…”