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

Pau Bas-Calopa,Manuel Moreno-Eguilaz,Jordi-Roger Riba

doi:10.3390/s22051856

Pau Bas-Calopa, Manuel Moreno-Eguilaz + Show 1 more

Open Access

https://doi.org/10.3390/s22051856

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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.

Highlights

To meet strict weight requirements, distribution voltage levels must rise in order to maintain the crosssection of the conductors below certain limits
It is well known that low-pressure operation significantly reduces the dielectric strength of air [3–5], and surface discharges tend to initiate at lower voltages compared to the voltages at which they initiate at sea-level
The respective diameters. (b) Corona image taken with the CMOS imaging sensor to validate the the respective diameters. (b) Corona image taken with the CMOS imaging sensor to validate the location of the corona discharges before Corona Extinction Voltage (CEV) acquisition. (c) Photograph of the sphere-to-plane eleclocation of the corona discharges before CEV acquisition. (c) Photograph of the sphere-to-plane trode setup under an electrical discharge

Summary

Introduction

Aerospace companies are currently designing aircrafts to meet stringent efficiency and performance needs, which are predominately shaped by reducing oil dependency and carbon-dioxide emissions. There is an imperious need to generate useful data to design insulation systems for these generation aircrafts, which can be useful for high-voltage systems operating at high altitude This papers aims at generating useful experimental data for this purpose, so this end the sphere-to-plane geometry is analysed because it is a standard air gap in high-voltage applications [19–22]. To this end, the dependency of the corona extinction voltage (CEV) value on the environmental pressure and operating electrical frequency is studied by means of experimental data. Process overview. (b) Automatic acquisition of corona extinction voltage values using python proProcess cess. overview. (b) Automatic acquisition of corona extinction voltage values using python process

Finite Element Method to Determine the Electric Field Strength

Simulation

Experimental setup including thethe instrumentation

Experiments were consphere electrodes was placed

Summary of experimental values of the measured

Conclusions