Publications resulting from the project
Corona Discharge Characteristics under Variable Frequency and Pressure Environments.
Bas-Calopa, P.; Riba, J.-R.; Moreno-Eguilaz, M. Sensors 2021, 21, 6676. https://doi.org/10.3390/s21196676
Abstract
More electric aircrafts (MEAs) are paving the path to all electric aircrafts (AEAs), which make a much more intensive use of electrical power than conventional aircrafts. Due to the strict weight requirements, both MEA and AEA systems require to increase the distribution voltage in order to limit the required electrical current. Under this paradigm new issues arise, in part due to the voltage rise and in part because of the harsh environments found in aircrafts systems, especially those related to low pressure and high-electric frequency operation. Increased voltage levels, high-operating frequencies, low-pressure environments and reduced distances between wires pose insulation systems at risk, so partial discharges (PDs) and electrical breakdown are more likely to occur. This paper performs an experimental analysis of the effect of low-pressure environments and high-operating frequencies on the visual corona voltage, since corona discharges occurrence is directly related to arc tracking and insulation degradation in wiring systems. To this end, a rod-to-plane electrode configuration is tested in the 20–100 kPa and 50–1000 Hz ranges, these ranges cover most aircraft applications, so that the corona extinction voltage is experimentally determined by using a low-cost high-resolution CMOS imaging sensor which is sensitive to the visible and near ultraviolet (UV) spectra. The imaging sensor locates the discharge points and the intensity of the discharge, offering simplicity and low-cost measurements with high sensitivity. Moreover, to assess the performance of such sensor, the discharges are also acquired by analyzing the leakage current using an inexpensive resistor and a fast oscilloscope. The experimental data presented in this paper can be useful in designing insulation systems for MEA and AEA applications.
Riba, J.-R.; Moreno-Eguilaz, M.; Boizieau, M.; Ibrayemov, T. Sensors 2022, 22, 492. https://doi.org/10.3390/s22020492
Abstract
Unpressurized aircraft circuits facilitate the initiation of electrical discharges in wiring systems, with consequent damage to related insulation materials and safety hazards, that can and have already caused severe incidents and accidents. Specific sensors and solutions must be developed to detect these types of faults at a very incipient stage, before further damage occurs. Electrical discharges in air generate the corona effect, which is characterized by emissions of bluish light, which are found in the ultraviolet (UV) and visible spectra. However, due to sunlight interference, the corona effect is very difficult to detect at the very initial stage, so the use of solar-blind sensors can be a possible solution. This work analyzes the feasibility of using inexpensive non-invasive solar-blind sensors in a range of pressures compatible with aircraft environments to detect the electrical discharges at a very incipient stage. Their behavior and sensitivity compared with other alternatives, i.e., an antenna sensor and a CMOS imaging sensor, is also assessed. Experimental results presented in this paper show that the analyzed solar-blind sensors can be applied for the on-line detection of electrical discharges in unpressurized aircraft environments at the very initial stage, thus facilitating and enabling the application of predictive maintenance strategies. They also offer the possibility to be combined with existing electrical protections to expand their capabilities and improve their sensitivity to detect very early discharges, thus allowing the timely identification of their occurrence.
Riba, J.-R.; Moreno-Eguilaz, M.; Ortega, J.A. IEEE Transactions on Instrumentation and Measurement, 2022, 71. https://doi.org/10.1109/TIM.2022.3141832
Abstract
Arc faults are serious discharges, damaging insulation systems, and triggering electrical fires. This is a transversal topic, affecting from residential to aeronautic applications. Current commercial aircrafts are being progressively equipped with arc fault protections. With the development of MEAs, future airliners will require more electrical power to enhance fuel economy, save weight, and reduce emissions. The ultimate goal of MEAs is electrical propulsion, where fault management devices will have a leading role, because aircraft safety is of utmost importance. Therefore, current fault management devices must evolve to fulfill the safety requirements of electrical propelled aircrafts. To deal with increased electrical power generation, the distribution voltage must be raised, thus leading to new electrical fault types, in particular arc tracking and series arcing, which are further promoted by the harsh environments typical of aircraft systems, i.e., low pressure, extreme humidity, and a wide range of temperatures. Therefore, the development of specific electrical protections which are able to protect against these fault types is a must. This article reviews the state-of-the-art of electrical protections for aeronautic applications, identifying the current status and progress, their drawbacks and limitations, the future challenges, and research needs to fulfill the future requirements of MEAs, with a special emphasis on series arc faults due to arc tracking, because of the difficulty in detecting such low-energy faults in the early stage and the importance and harmful effects of tracking activity in cabling insulation systems. This technological and scientific review is based on a deep analysis of research and conference papers, official reports, white papers, and international regulations.
Surface Discharges Performance of ETFE- and PTFE-Insulated Wires for Aircraft Applications
Riba, J.-R.; Moreno-Eguilaz, M.; Ibrayemov, T.; Boizieau, M. Materials 2022, 15, 1677. https://doi.org/10.3390/ma15051677
Abstract
Compared to their predecessors, the next generations of aircrafts will be more electrified, require more electrical power and operate at higher voltage levels to meet strict weight and volume constraints. The combined effect of low-pressure environments, increased voltage levels and compact designs intensifies the risks of premature insulation degradation due to electrical discharge activity. This paper studies the resistance to surface discharges of PTFE (polytetrafluoroethylene) and ETFE (ethylene tetrafluoroethylene), two insulation materials widely used in today’s aircraft wiring systems due to their outstanding properties, such as a wide temperature operation range and a high dielectric strength. The study is carried out in a low-pressure chamber, which was pressurized within the pressure range of 10–100 kPa that includes most aircraft applications. There is a compelling need for experimental data to assess the resistance of insulation materials to surface discharges at a very early stage as a function of the environmental pressure. Data on resistance to surface discharges in low-pressure environments for aeronautical applications are lacking, while most standards for insulation systems are based on tests under standard pressure conditions. The results provided in this work can be useful to design wiring systems for future more electric aircrafts, as well as to design fault detection systems for an early detection and identification of faults related to surface discharges. Therefore, the data and analysis included in this paper could be of great interest to design and develop insulation systems for wiring systems and standard assessment methods, as well as to design fault detection strategies for the early detection and identification of surface discharges for future generations of more electric aircrafts.
Measurement of Corona Discharges under Variable Geometry, Frequency and Pressure Environment
Bas-Calopa, P.; Riba, J.-R.; Moreno-Eguilaz, M. Sensors 2022, 22, 1856. https://doi.org/10.3390/s22051856
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
Riba, J.-R.; Bas-Calopa, P.; Moreno-Eguilaz, M. European Journal of Physics 2022, Vol. 43 (5), pp. 055201. https://doi.org/10.1088/1361-6404/ac78a4
Abstract
In this work, the authors propose an experiment aimed for undergraduate laboratories with the aim of introducing different novelties as a topic for practical sessions or student projects. The topics here investigated are appropriate for students with intermediate physics knowledge. Corona discharges are little studied in regular physics courses despite their practical importance in different areas, such as the distribution and transmission of electrical power, generation of ozone, particulate removal in air conditioning systems, improvement of wettability in polymeric materials, or the removal of electrostatic charges from the surface of airplanes among others. This work analyses the minimum voltage level leading to corona discharges and the influence of geometry and atmospheric pressure because these two factors are the most influential to determine the minimum voltage at which corona discharges appear.
Application of Image Sensors to Detect and Locate Electrical Discharges: A Review
Riba, J.-R. Sensors 2022, 22, 5886. https://doi.org/10.3390/s22155886
Abstract
Today, there are many attempts to introduce the Internet of Things (IoT) in high-voltage systems, where partial discharges are a focus of concern since they degrade the insulation. The idea is to detect such discharges at a very early stage so that corrective actions can be taken before major damage is produced. Electronic image sensors are traditionally based on charge-coupled devices (CCDs) and, next, on complementary metal oxide semiconductor (CMOS) devices. This paper performs a review and analysis of state-of-the-art image sensors for detecting, locating, and quantifying partial discharges in insulation systems and, in particular, corona discharges since it is an area with an important potential for expansion due to the important consequences of discharges and the complexity of their detection. The paper also discusses the recent progress, as well as the research needs and the challenges to be faced, in applying image sensors in this area. Although many of the cited research works focused on high-voltage applications, partial discharges can also occur in medium- and low-voltage applications. Thus, the potential applications that could potentially benefit from the introduction of image sensors to detect electrical discharges include power substations, buried power cables, overhead power lines, and automotive applications, among others.
Riba, J.-R.; Bas-Calopa, P.; Aziz-Qolla, Y.; Pourraz, M.; Ozsahin, B. Applied Sciences 2022, 12(17), 8595. https://doi.org/10.3390/app12178595
Abstract
The development of more electric aircrafts (MEA) and all electric aircrafts (AEA) inevitably implies an increase in electric power and a consequent increase in distribution voltage levels. Increased operating voltages coupled with low pressure in some areas of the aircraft greatly increase the chances of premature insulation failure. Insulation failure manifests itself as surface discharges, arc tracking, arcing, and disruptive or breakdown discharges, in order of increasing severity. Unfortunately, on-board electrical protections cannot detect discharges at an early stage, so other strategies must be explored. In their early stage, insulation faults manifest as surface and corona discharges. They generate optical radiation, mainly in the near-ultraviolet (UV) and visible spectral regions. This paper focuses on a method to detect the discharges, locate the discharge sites, and determine their intensity to facilitate predictive maintenance tasks. It is shown that by using small size and low-cost image sensors, it is possible to detect, locate, and quantify the intensity of the discharges. This paper also proposes and evaluates the behavior of a discharge severity indicator, which is based on determining the intensity of digital images of the discharges, so it can be useful to apply predictive maintenance tasks. The behavior and accuracy of this indicator has been tested in the laboratory using a low-pressure chamber operating in the pressure range of 10–100 kPa, which is characteristic of aircraft applications, analyzing a needle-plane air gap geometry and using an image sensor. The proposed method can be extended to other applications where electrical discharges are an issue.
Spectrum of Corona Discharges and Electric Arcs in Air under Aeronautical Pressure Conditions
Riba, J.-R. Aerospace, 2022, 9, 524. https://doi.org/10.3390/aerospace9090524
Abstract
Due to the increase in electrical power demand, future more electric and all-electric aircraft designs will operate at higher voltage levels compared to current aircraft. Due to higher voltage levels and reduced operating pressure, insulation systems will be at risk. Air is the main insulating medium, and it is well known that its dielectric strength decreases considerably with operating pressure. Although electrical discharges can be detected by different techniques, optical methods are very attractive due to their sensitivity and immunity to acoustic and electromagnetic noise typical of aeronautical environments. This work analyzes the UV-visible spectrum of corona discharges and electric arcs in the 10–100 kPa pressure range, which covers most of the aeronautical applications, due to the lack of experimental data for this pressure range. The data presented in this work are important to select the most suitable optical sensors to detect electrical discharges at an early stage, before significant damage occurs. This approach will help implement preventive maintenance plans and increase aircraft safety. The results presented in this paper can also be applied to other areas, such as monitoring of discharges in power lines, particularly those located in high-altitude regions.
Use of DSLR and Sonic Cameras to Detect and Locate High-Voltage Corona Discharges
Riba, J.-R.; Bas-Calopa, P. Sensors 2022, 22, 7250. https://doi.org/10.3390/s22197250
Abstract
Corona discharges are a concern in high-voltage applications. It is of utmost importance to detect and locate the discharges at an early stage using simple methods for this purpose. This paper evaluates and compares the sensitivity of two methods for detecting and locating the source of discharges, which are based on a digital single-lens reflex (DSLR) camera and a portable wideband sonic camera incorporating a matrix of micro-electromechanical systems (MEMS) microphones. Both cameras can generate an image of the studied area where the discharge sites are identified. The study is carried out with different electrode geometries, 50 Hz alternating current (ac) and positive and negative direct current (dc) supplies, and the effect of the distance between the sensor and the discharge sites is also analyzed. The presented results show that the sonic camera enables fast, simple, and sensitive detection and localization of the source of corona discharges even at a very early stage in daylight conditions, regardless of the type of power supply, that is, ac or positive/negative dc, and at distance of several meters from the discharge source.
Riba, J.-R.; Bas-Calopa, P.; Ortega, J.A. Aerospace 2023, 10(1), 3. https://doi.org/10.3390/aerospace10010003
Abstract
Strict regulations issued by international administrative bodies limit the CO2 equivalent emissions for new aircraft, while increasing efficiency requirements. To reach this goal, next generations of aircraft will use more electrical power than their predecessors, so distribution voltage levels will inevitably increase to limit the weight of the electrical wiring interconnect system (EWIS). However, such increased voltage levels generate higher electric stresses in insulation materials as well as in electric and electronic components; thus new failure modes triggered by electrical discharges will appear, their effects being aggravated by harsh environments typical of aircraft systems. The combined effect of higher electrical stresses, compact designs, and low-pressure operating conditions greatly intensifies the risks of premature insulation failure due to electrical discharge activity. This paper shows that by using image sensors, it is possible to detect, localize, and quantify the intensity of electrical discharges occurring in aircraft environments. Through experiments carried out in a low-pressure chamber using an image sensor, this work detects and determines the intensity of electrical discharges generated in electrical wires in their initial stage, long before major faults develop. This paper also shows that the intensity of the discharges calculated from the digital images obtained with the image sensor is directly proportional to the electrical energy involved in the discharge process and increases linearly with the applied voltage. Due to the difficulty of detecting these failure modes at a very early stage, this strategy could potentially facilitate predictive maintenance tasks while contributing to increased levels of aircraft safety.
Analyzing the effect of dynamic pressure drop on corona discharges for aircraft applications
Bas-Calopa, P.; Riba, J.-R.; Moreno-Eguilaz, M. Aerospace 2023, 10, 320. https://doi.org/10.3390/aerospace10030320
Abstract
The combination of the low-pressure environment found in aircraft systems and the gradual electrification of aircraft increases the risk of electrical discharges occurrence. This is an undesirable situation that compromises aircraft safety and complicates maintenance operations. Experimental data are needed to understand this problem. However, most of the published studies are based on static pressure conditions, but aircraft systems are exposed to dynamic pressure conditions, especially during the climb and descent phases of flight. This paper analyzes the effect of dynamic pressure during the climb phase on the corona inception voltage because this phase experiences the worst pressure drop rate. The experimental evidence presented in this paper shows that within the analyzed pressure drop rate range, the dynamic pressure conditions do not have a significant effect on the corona inception value under typical conditions found in aircraft systems during the climb phase.
Experimental Validation of the Adiabatic Assumption of Short-Circuit Tests on Bare Conductors
Riba, J.-R.; González, D.; Bas-Calopa, P.; Moreno-Eguilaz, M. IEEE Transactions on Power Delivery 2023, 38(5), 3594-3601. https://doi.org/10.1109/TPWRD.2023.3281599
Abstract
According to various international standards, many high-voltage devices must withstand short-circuit tests. Due to the enormous power and current requirements, they have to be tested in very specialized and expensive power laboratories, which are scarce and not affordable for the vast majority of electrical product manufacturers. It is proposed to break the time limit of about one second imposed by the standards by using a lower current to heat for a longer time, requiring more affordable equipment and thus reducing the cost for testing. This work analyzes the limits of the adiabatic assumption in short-circuit tests in order to quantify how the duration of these tests can be extended to reduce the power required and the current applied, while obtaining almost the same results, i.e., the same temperature at the end of the heating phase of the tests. For this purpose, bare cylindrical conductors are analyzed and the temperature dependence of the properties of the conductor material is considered. Experimental and simulation results presented in this paper suggest that by applying this approach, short-circuit tests intended for product design, verification and quality control can be performed in much less demanding and affordable laboratory facilities.
Linking digital image intensity to carrier density in low-pressure corona discharges
Riba, J.-R. Sensors and Actuators A: Physical 2023, 359, 114474. https://doi.org/10.1016/j.sna.2023.114474
Abstract
The electrification of transportation, and aircraft electrification in particular, is experiencing rapid development due to the more efficient use of energy. Since the dielectric strength of air decreases at the cruising altitudes of commercial aircraft due to the reduced pressure environment, there is a need to control and minimize the risks associated with electrical discharges. This paper shows from experimental and computational data that there is a relationship between the electrical and optical phenomena involved in the discharge process. To this end, this paper analyzes corona discharges generated using different electrode geometries under a wide range of pressures from 100 kPa to 10 kPa. It is shown that the densities of charged particles or charge carriers generated during the discharge process are positively correlated with the intensity of corona images acquired with a digital imaging sensor sensitive to the near UV and visible wavelength ranges. Therefore, the intensity of the images can be used as a reliable and accurate indicator of the corona activity, the values of which are related to the ionization processes involved in the discharges. The results presented in this paper can be applied in various physical and engineering fields, such as high voltage engineering, power line monitoring, or ozone generation, among others.
Riba, J.-R.; Moreno-Eguilaz, M.; Bogarra, S. Polymers 2023, 15(18), 3717. https://doi.org/10.3390/polym15183717
Abstract
With the increasing electrification of the transportation and mobility sectors, polymer insulation materials are inevitably exposed to harsher environments, including exposure to contamination, wide temperature ranges, operation at higher voltages and switching frequencies, and low-pressure environments. This paper reviews the tests to characterize the polymeric materials used in insulation systems for electric mobility applications, focusing on resistance to tracking. This paper also reports on the limitations of existing standard test methods and identifies the challenges and research needs to meet the increasing demands of the electric mobility industry. To this end, an evaluation of the scientific and technological state of the art is carried out through the analysis of theses, research articles, technical reports, manufacturers’ datasheets, international standards, and white papers.
Radial Thermoelectric Model for Stranded Transmission Line Conductors
Riba, J.-R. Sensors 2023, 23, 9205. https://doi.org/10.3390/s23229205
Abstract
Bare-stranded conductors play a critical role in the efficiency and safe operation of transmission lines. The heat generated in the interior of the conductor is conducted radially to the outer surface, creating a radial thermal gradient. The radial temperature gradient between the core and the surface depends on multiple factors, such as stranding, number of layers, current level, electrical resistance and the effective radial thermal conductivity. Therefore, the radial temperature model must be considered when developing accurate conductor models. Such models are particularly important in the development of dynamic line rating (DLR) approaches to allow the full current carrying capacity of the conductor to be utilized while ensuring safe operation. This paper develops a radial one-dimensional thermoelectric model for bare-stranded conductors used in transmission lines. The accuracy of the proposed model is determined by experimental tests performed on three conductors.
Studying the Breakdown Electric Field in Uniform and Non-uniform Air Gaps
Riba, J.-R. European Journal of Physics 2024, 45 045205. https://doi.org/10.1088/1361-6404/ad5392
Abstract
High voltage is essential in power grids, but it inevitably leads to high electrical stress and the associated risk of electrical discharges. Due to the complexity of the phenomena involved in electrical discharges, there are no analytical formulas for predicting the electric field strength at which they initiate, so experimental data and numerical methods are required for this purpose. According to many sources, electrical discharges can occur in air at normal pressure and temperature when the electric field strength is approximately 3 kV mm−1 or greater. This paper analyzes and discusses this threshold in detail by examining relevant electrode geometries used in high voltage applications from experimental data found in the scientific literature and using 2D finite element analysis simulations. Uniform, quasi-uniform, and non-uniform field gaps are analyzed to help students draw conclusions and gain insight into the nature of gas breakdown and the applicability of the 3 kV mm−1 threshold. The approach proposed in this paper is well suited for a practical session or group project for undergraduate or even graduate courses. Despite the important effects and design implications of electrical discharges on high voltage equipment, apparatus and systems, this topic is often not covered in sufficient detail in regular courses.
Gupta. P.K.; Riba, J.-R.; Casals, P.; Talens, J.; Tuttelberg, K.; Kilter, J. IEEE Sensors Letters 2024, 8(12), 6015704. https://doi.org/10.1109/LSENS.2024.3504551
Abstract
Corona discharge testing is critical to ensuring the safety, performance and reliability of high-voltage (HV) equipment and systems. Due to the high cost of shielded laboratories, many manufacturers test their components in unshielded laboratories for applications, such as product research and development or quality control. This letter compares the sensitivity of two corona detection instruments in an unshielded laboratory. The sensitivity of an electrical detector according to IEC 60270 in combination with a measuring impedance and a coupling capacitor is compared with that of a digital single lens reflex (DSLR) camera. In addition, needle-to-plane and sphere-to-plane electrode geometries are studied under different types of high-voltage power supplies, i.e., 50 Hz ac, positive dc, and negative dc. Experimental results performed in an unshielded high-voltage laboratory show that although the DSLR camera is not a standard method for partial discharge (PD) detection, it has similar sensitivity to the conventional electrical method according to IEC 60270 in all cases analyzed, and that the digital camera behaves much better in pulseless glow corona mode.
Detecting and Locating Corona Discharges in Low-Pressure Aircraft Environments Using Optical Sensors
Bas-Calopa, P.; Riba, J.-R.; Moreno-Eguilaz, M. Renewable energy and power quality journal 2024, 22(6), pp. 94–98. http://hdl.handle.net/2117/415048
Abstract
Today, there is a clear trend toward electrification of transportation systems, including aircraft. Due to the enormous power requirements, they must operate at high voltages. However, the combined effect of higher voltage levels and low pressure environments is conducive to the occurrence of electrical discharges in electrical systems. Therefore, there is an urgent need to develop cost-effective systems to detect the discharges in the early stages before major failures can occur. This paper compares two optical sensors for early discharge detection in a simulated aircraft environment. The experimental study is performed in a low pressure chamber using a needle plane electrode. The pressure is changed from that corresponding to ground level to that corresponding to flight altitude, i.e., from 100 kPa to 20 kPa. The effect of the supply frequency is also studied, since modern aircraft operate in a wide range of frequencies up to about 800 Hz. Both variables, especially pressure, have shown significant effects on the corona inception voltage (CIV) value. The results have also shown a similar sensitivity of both sensors for all the experimental conditions analysed, allowing a fast and sensitive detection and localization of incipient electrical discharge activity.
Bogarra, S.; Moreno-Eguilaz, M.; Ortega, J.A.; Riba, J.-R. Renewable energy and power quality journal 2024, 22(2), pp. 121–126. http://hdl.handle.net/2117/415050
Abstract
The More Electric Aircraft (MEA) paradigm advocates weight reduction by transitioning to electrical components, resulting in increased system voltage and higher arc fault risk. This paper presents a methodology for creating a database of nearly one thousand tests simulating parallel arc faults, using Andrea's arc model for accurate representation. Objectives include the creation of a robust experimental database and the use of a simplified model to analyze arcing behavior. The setup follows the UL 746A standard and considers various pressure and electrode separation conditions. The database includes 960 experiments with PVC and PTFE materials, and model fitting ensures accurate representation of arc currents and voltages. Error analysis shows consistent model performance across materials and highlights sensitivity to electrode spacing, pressure, and source voltage. The paper concludes with a clear 30% error threshold for model validity, enhancing the understanding of the applicability of Andrea's model under various experimental scenarios in aircraft environments.
Accelerated Aging Quantification of XL-ETFE Wires in Low Pressure Aircraft Environments
Bas-Calopa, P.; Riba, J.-R.; Moreno-Eguilaz, M. 2024 IEEE International Instrumentation and Measurement Technology Conference (I2MTC). https://doi.org/10.1109/I2MTC60896.2024.10561022
Abstract
Most international standards for the qualification of insulated wires for aerospace applications are based on degradation tests performed under standard pressure conditions. However, some wires must withstand low pressure conditions in unpressurized areas, and there is a lack of data and experience in the literature on this subject. This paper proposes a method to test the wires and evaluate their performance under low pressure conditions. In addition, two optical methods are evaluated to quantify the degree of degradation of the insulation. By analyzing the relationship between the electrical degradation of the insulation and the light emitted by the surface discharges, this study contributes to a better understanding of how commercially available optical sensors can be used for this purpose and how the light emitted by the surface discharges can be used to determine the condition of the insulation. Specifically, the change in corona inception voltage and light intensity detected by two optical sensors was used to evaluate the degradation of the insulated wire samples analyzed. The results presented in the pressure range of 100 - 16 kPa indicate a potential application of optical sensors for inspection and predictive maintenance of insulation systems in the aerospace industry and other sectors where insulation integrity is critical.
Analysis of the Relationship between Light Intensity and Electrical Power of Corona Discharges
Riba, J.-R. European Journal of Physics 2025, 46 015202. https://doi.org/10.1088/1361-6404/ad955a
Abstract
This work analyzes the intensity of the light emitted by corona discharges using a smartphone camera, which is compared to the electrical power associated with the corona discharges. The raw images from the camera provide essential information for the experiment. Data at different atmospheric pressures are also provided to help students understand that at lower pressures, due to the increased mean free path of the electrons, they are more efficient at ionizing neutral air molecules. An analysis of the data obtained also makes it possible to estimate the values of the energy of the electrons involved in the discharge process, the mean free path of the electrons and the cross section for electron collision, using much simpler equipment compared to other studies. The data and approach presented in this paper can be adapted for a group project or a guided practical session for both undergraduate and graduate courses.