|
Publicación relacionada
| Robles, G., Martínez-Tarifa, J. M., Gómez-de-la-Calle, M., Barroso-de-María, G., & Izquierdo, D. (2021). Detecting Serial Arcs in Aeronautical Applications Using Inductive Sensors. IEEE Transactions on Aerospace and Electronic Systems, 58(3), 2073-2082.doi: 10.1109/TAES.2021.3128868 |
|
Notas
| Description of the project:
There is a clear trend in the aircraft industry to use more electrical systems in propulsion and electromechanical and electrohydraulic actuators to comply with environmental sustainability and to improve reliability and maintenance processes. The increase of electrical consumption requires an increase of the rated voltages to supply power to these so called more electrical aircraft (MEA). Unfortunately, this voltage rise, currently up to 540 Vdc, can lead to ionization processes within the electric wiring due to the lower air density at high altitudes. As a consequence, a degraded insulation can create extremely hazardous events in flight such as arcs between wires (serial) or between wires and fuselage (parallel). Serial arcs in dc bus circuits are specially dangerous for the aircraft operation, so its detection within fractions of seconds is required to ensure a reliable operation. However, during a sustained serial arc the rated current can be passing through air deceiving the protections and avoiding their tripping. In this article, it has been found that arcing introduces high frequency current pulses superimposed to the dc component that can be identified to detect the occurrence of an arc. The frequency components of these pulses depend on the line characteristics and can be detected with inductive sensors. This project also designs and tests a light and inexpensive sensor for arc detection in aircraft applications.
Methodology:
The arc is generated with the opening of a switch consisting on two hemispheric steel electrodes 8 mm in diameter. A high dc voltage source is connected to the electrodes in series with a high power resistive load. The voltage is set to 270 Vdc a standard in the aeronautic industry and the current is set to 10A in the experiments done henceforth To obtain a preliminary characterization of the inductive coupling of signals from the arc phenomenon, a high frequency current transformer (HFCT) with a ferrite core, a gain of 5 V/A and a bandwidth up to 80 MHz is clamped to acquire the current signal during the arc. This sensor is insensitive to low frequency currents so the direct 10 A current will not saturate the core. The output of the HFCT is connected to the 50 ohm input of the oscilloscope. The time window is set to 500 ms and the sampling frequency is 10 MSps. |
