Recent advances in on-line PDs’detection in power conversion chains used in aeronautics
Résumé
At the dawn of this new millennium, transportations facing a much greener approach, the main aircrafts manufacturers have to change their paradigms: to replace the combination of hydraulic, pneumatic, electrical and mechanical power by a « More » (and “All” in the future) Electrical Aircraft approach consisting in drastically increasing the power density of electrical power systems without compromising on reliability. The increasing demand for more on board electrical power has led to increase the voltage and/or to change its shape. Such an increase may lead, depending on many parameters related to the electrical characteristics of the power chain (power converter, voltage waveform (dV/dt, frequency, …), the cables length, the type of machine driven) or to the environment (pressure, temperature, relative humidity) to the Partial Discharges Ignition in systems which were not supposed (and have not been designed) to endure them. Partial Discharges are voltage-dependent electrical discharges in insulation, which : - do not lead to a direct breakdown of the system, - lead to a gradual deterioration of the insulating material and to its premature failure - is often defined as “the silent enemy One of the main questions to address is the development of an approach for PD detection in type I machines (according to EIC 60034-18-41) ie machines supposed to be PD free allowing the determination of their existence under very different electrical conditions (PWM) due to the wide nature of the embarked equipment and to the different possible natures of the discharges. Recent advances made in the related different topics i.e on line PD detection under PWM voltage, influence of the pressure, influence of the components types…will be presented and discussed regarding their consequences.
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