METHOD FOR DETECTING A PARTIAL DISCHARGE IN AN ON-BOARD AERONAUTICAL ELECTRICAL SYSTEM

Abstract

The present invention relates to a method for detecting a partial discharge in an on-board aeronautical electrical system (3) comprising a power converter (7) and an electrical machine (5), at least one stator coil (31) housing a resistive measuring sensor (39) and powered by power cables (41) extending through the stator coil (31), the method comprising the following steps: - acquisition of the voltage between the power cables (41) and delivery of a signal representative of the physical quantity as a function of the acquired voltage, - acquisition of the voltage between the power cables (41), filtering by a high-pass filter and delivery of an analysis signal configured to allow the detection of a partial discharge in the electrical machine (5).The present invention also relates to an on-board aeronautical electrical system (3) configured to implement such a method, as well as to an aircraft comprising such an on-board aeronautical electrical system (3). Figure for the abstract: Figure 2.

Description

Title of the invention: METHOD FOR DETECTING A PARTIAL DISCHARGE IN AN ON-BOARD AERONAUTICAL ELECTRICAL SYSTEM FIELD OF THE INVENTION

[0001] The invention relates to the detection of partial discharges in an on-board aeronautical electrical system. STATE OF THE ART

[0002] A partial discharge - or PD - is a localized electrical discharge that only partially short-circuits the insulating gap separating conductors or electrodes. The presence of these discharges leads to accelerated degradation of the insulation, whether liquid, by oxidation, or solid, by erosion, and can lead to significant reliability problems.

[0003] The hybridization and / or electrification of aircraft propulsion systems leads to an increasing demand for electrical energy and therefore to an increase in voltage levels. This increase in voltage is however not without consequences for these propulsion systems because it generates increasingly severe electrical constraints, in particular on the electrical insulation components. Partial discharges represent a significant risk that can lead to the failure of electrical components of these propulsion systems, especially since they are intended for the aeronautical field. Indeed, once mounted on aircraft, these propulsion systems are intended to operate in severe conditions linked to altitude, such as severe conditions of pressure, temperature and cosmic radiation.

[0004] Furthermore, while in the case of a sinusoidal voltage, the detection of partial discharges is relatively simple, in the case of a voltage under pulse control or by pulse width modulation (PWM), the noise generated tends to be superimposed on the partial discharge signals and complicates the detection.

[0005] Partial discharges having very low charge values, complex and robust measuring devices must be implemented. Furthermore, methods for detecting partial discharges exist, but they are difficult to implement. Indeed, they require specific sensors, suitable electronics and high acquisition frequency requirements.

[0006] It is therefore necessary to be able to reliably detect these partial discharges as soon as they appear while reducing the complexity of their detection.

[0007] One objective is to detect the presence of partial discharges in these propulsion systems, during their normal operation, whatever the conditions of use and including at variable altitudes, in particular in flight. Statement of the invention

[0008] The invention aims in particular to detect in a manner that is both reliable and simple the presence of partial discharges in an on-board aeronautical electrical system.

[0009] For this purpose, the invention proposes a method for detecting a partial discharge in an on-board aeronautical electrical system, the on-board aeronautical electrical system comprising a power converter and an electrical machine with N three-phase stars, N being greater than or equal to 1, the electrical machine being supplied with electrical power by the power converter, at least one stator coil of the electrical machine housing a sensor for measuring a physical quantity characteristic of the electrical machine, the measurement sensor being resistive and supplied by power cables extending through the stator coil, the power cables being connected outside the stator coil to an external acquisition unit comprising a first acquisition chain and a second acquisition chain provided with a high-pass filter,the method comprising the following steps: - acquisition of the voltage between the power cables by the first acquisition chain, which delivers a signal representative of the physical quantity as a function of the acquired voltage, - acquisition of the voltage between the power cables by the second acquisition chain and filtering by the high-pass filter, the second acquisition chain delivering an analysis signal configured to allow the detection of a partial discharge in the electrical machine.

[0010] Such a detection method makes it possible to determine the existence of partial discharges in the different insulation systems of the electrical machine - for example between coils of the same phase, between phases and between a phase and ground -, and this, whether it is supplied with sinusoidal voltage - for example of the order of 50 or 60 Hz - or by a power converter of the voltage inverter type, for example supplied with a voltage obtained by Pulse Width Modulation (PWM). Such detection of partial discharges being necessary to guarantee the reliability of the electrical machine, its implementation carried out simply and reliably by such a detection method is particularly advantageous.The use of an assembly formed by the resistive measuring sensor and its power cables as a capacitive sensor, due to their positioning relative to the stator coil, makes it possible to detect the existence of partial discharges without requiring a specific sensor. Here, the resistive measuring sensor is used both in conventional operation for . measure the physical quantity, and with its power cables, as a capacitive sensor for the detection of partial discharges.

[0011] According to a second aspect, the invention also proposes an on-board aeronautical electrical system configured to implement the method as previously described. Such an on-board aeronautical electrical system comprises a power converter and an electrical machine with N three-phase stars, N being greater than or equal to 1, the electrical machine being supplied with electrical power by the power converter, at least one stator coil of the electrical machine housing a sensor for measuring a physical quantity characteristic of the electrical machine, the measurement sensor being resistive and supplied by power cables extending through the stator coil, the power cables being connected outside the stator coil to an external acquisition unit comprising a first acquisition chain and a second acquisition chain provided with a high-pass filter.

[0012] According to a third aspect, the invention proposes an aircraft comprising at least one propulsion turbine and an on-board aeronautical electrical system as previously described, the propulsion turbine being driven by the on-board aeronautical electrical system.

[0013] The invention is advantageously and optionally supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

[0014] - The measuring sensor is supplied with electrical power separately from the power supply of the electric machine.

[0015] - The measuring sensor is electrically isolated from at least one stator coil housing the measuring sensor.

[0016] - The measuring sensor is supplied with a constant current via the cables power supply.

[0017] - The on-board aeronautical electrical system is such that at least one coil stator housing a measuring sensor houses the measuring sensor in a coil head of the stator coil and / or in a stator notch receiving the stator coil.

[0018] - The physical quantity is temperature. The use of a temperature sensor is thus advantageous, since this type of measuring sensor is generally integrated by default in high-power electrical machines.

[0019] - The measuring sensor is a PtlOO or PtlOOO temperature sensor. These Platinum resistance thermometers are commonly used. The designations Pt100 and Pt1000 refer to the material used for the resistor. In this case, it is platinum Pt with a nominal resistance at a temperature of 0 °C, equal to 100 Ohms for the designation Pt100, and equal to 1000 Ohms for the designation Pt1000.

[0020] - The power converter delivers a maximum voltage greater than or equal to 400 V, preferably greater than or equal to 800 V.

[0021] - The power converter is pulse width modulated controlled (MLI).

[0022] - The power converter has N three-phase outputs.

[0023] - the power converter comprises N three-phase voltage inverters.

[0024] - The electric machine is a drive motor configured to drive a propulsion turbine.

[0025] - The electric machine is a permanent magnet synchronous machine.

[0026] - The on-board aeronautical electrical system is such that the converter of power and the electrical machine form a single component. Thus, the detection of partial discharges using a resistive sensor already present in the electrical machine is particularly advantageous, since the elements of this single component, in particular the power supply of the electrical machine and in particular the conductors supplying each phase, are barely or not at all accessible. Therefore, the integration of a specific sensor dedicated to the detection of partial discharges would be complex and expensive.

[0027] - The high-pass filter comprises a non-inverting operational amplifier. Such an The high-pass filter is thus achieved in a particularly simple manner.

[0028] - The high-pass filter has a cutoff frequency greater than or equal to 100 MHz, preferably greater than or equal to 500 MHz. Such a cut-off frequency makes it possible to limit in the analysis signal, or even to eliminate, the parasitic signals - or noise - linked to the electrical components of the on-board aeronautical electrical system, for example linked to the switching of the power converter, in particular in the case where the power converter is controlled by pulse width modulation (PWM). In the case where the power converter forms a sinusoidal power supply for the electrical machine, such a cut-off frequency makes it possible to obtain a good signal-to-noise ratio.

[0029] - The method further comprises the following steps: - comparison of the analysis signal with a signal representative of a partial discharge, and - detection of a partial discharge based on a result of the comparison. Such steps make it possible to conclude in a simple manner on the presence of a partial discharge.

[0030] - The signal representative of a partial discharge is selected from a base of signal data representative of a partial discharge, the database being stored on a storage medium. The detection of a partial discharge is thus simplified.

[0031] - The comparison step is performed by a processor. The detection of a discharge partial is thus simplified.

[0032] - The first acquisition chain is equipped with a low-pass filter. Such a filter allows to optimize the measured value of the physical quantity characteristic of the electrical machine, in particular in the case of a temperature measurement, the time constant generally being of the order of several hundred seconds, for example of the order of 200 seconds, during a rise in temperature of the electrical machine.

[0033] - The low-pass filter has a cut-off frequency of less than 1 Hz, preferably less than 0.5 Hz.

[0034] - The low-pass filter is digital. Such a low-pass filter is thus produced in a particularly simple.

[0035] - The step of acquiring the voltage between the power cables by the first acquisition chain is followed by a filtering step by the low-pass filter, the first acquisition chain delivering a signal representative of the physical quantity as a function of the acquired and filtered voltage. Thus, the signal representative of the physical quantity is particularly easy to use, for example to observe.

[0036] - A multiplexing component connects the power cables to the unit external acquisition. Thus, the transmission of voltage between the power cables to the first acquisition chain and to the second acquisition chain is carried out in a simple manner.

[0037] - The multiplexing component is a bipolar bidirectional switch, the bipolar bidirectional switch being connected at the input to the power cables and being connected at the output alternately to the first acquisition chain and to the second acquisition chain. Thus, the multiplexing component is implemented in a particularly simple manner.

[0038] - N is greater than or equal to 2, preferably N is greater than or equal to 6.

[0039] - At least one stator coil of each star of the electric machine houses a sensor for measuring a physical quantity characteristic of the electrical machine.

[0040] - The method comprises the following steps for each stator coil housing a measuring sensor: - acquisition of the voltage between the power cables by the first acquisition chain, which delivers a signal representative of the physical quantity as a function of the acquired voltage, - acquisition of the voltage between the power cables by the second acquisition chain and filtering by the high-pass filter, the second acquisition chain delivering an analysis signal configured to allow the detection of a partial discharge in the electrical machine, - when a partial discharge is detected from the analysis signal, stopping the electrical power supply to the star comprising the stator coil. Thus, it is possible to keep the electrical machine operating in degraded mode, by stopping the power supply to the star in which a partial discharge is detected. Depending on the number of stars, the impact of such a stoppage can be relatively limited with regard to the mechanical power to be supplied by the electrical machine. The safety of the electrical machine is then improved while allowing use in degraded mode if necessary, for example in a high-altitude flight phase. DESCRIPTION OF FIGURES

[0041] Other characteristics, aims and advantages of the invention will emerge from the detailed description below, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings, given as non-limiting examples and in which: [Fig.l] schematically represents an aircraft comprising an exemplary embodiment of an on-board aeronautical electrical system according to the invention; [Fig.2] schematically represents an exemplary embodiment of an on-board aeronautical electrical system according to the invention; [Fig.3] schematically represents a detail of an on-board aeronautical electrical system according to an alternative embodiment of the invention, according to several views; [Fig.4] schematically represents a detail of an on-board aeronautical electrical system according to an alternative embodiment of the invention, according to several views; [Fig.5] schematically represents a detail of an on-board aeronautical electrical system according to an alternative embodiment of the invention; [Fig.6] schematically represents a detail of an on-board aeronautical electrical system according to an alternative embodiment of the invention; [Fig.7] illustrates the main steps of a detection method according to the invention; [Fig.8] presents two graphs each representing the detection of a partial discharge by means of the detection method according to the invention.

[0042] Throughout the figures, similar elements are designated by identical references. DETAILED DESCRIPTION OF THE INVENTION

[0043] [Fig.l] represents an aircraft 100 comprising at least one propulsion turbine 1, in this example two propulsion turbines 1.

[0044] At least one propulsion turbine 1 is driven by an on-board aeronautical electrical system 3, which is schematically represented in [Fig. 2]. The drive is carried out solely by the aeronautical electrical system. on board 3 or auxiliary by the onboard aeronautical electrical system 3. The propulsion turbine 1 is thus electric or hybrid powered.

[0045] The on-board aeronautical electrical system 3 comprises an electrical machine 5 and a power converter 7. In this example, the on-board aeronautical electrical system 3 is such that the power converter 7 and the electrical machine 5 form a single component 8.

[0046] The electrical machine 5 has N three-phase stars, N being greater than or equal to 1. In this example, the electrical machine 5 is a permanent magnet synchronous machine. According to one variant, N is greater than or equal to 2. According to another variant, N is greater than or equal to 6. In the example shown in [Fig.2], N is equal to 2, and the electrical machine thus comprises two stars E.

[0047] The electrical machine 5 is supplied with electrical power by the power converter 7. The power converter 7 is for example supplied with direct current by a high-voltage battery 9, which delivers for example a maximum voltage greater than or equal to 400 V, preferably greater than or equal to 800 V. The power converter 7 comprises for example a conventional circuit provided with a capacitor 11, switches 13 and diodes 15. In this example, the power converter 7 is controlled by pulse width modulation (PWM), for example at a switching frequency of 10 kHz. The control is delivered by at least one high-voltage control card 17. The control card 17 controls the switching of the switches 13 so that the power converter 7 supplies the electrical machine 3 according to a controlled power profile. The power converter 7 comprises N three-phase outputs, N being for example equal to 2.In this example, two control cards 17 each supply the three phases of a star E. Each control card 17 is itself controlled by a low-voltage control card 19, for example powered by a low-voltage battery 21. The control card 19 is configured to receive a command from a human-machine interface 23, for example a human-machine interface 23 dedicated to the control of the aircraft 100. In this example, the power converter 7 delivers a maximum voltage greater than or equal to 400 V, preferably greater than or equal to 800 V. Thus, the power converter 7 comprises N three-phase voltage inverters.

[0048] The electrical machine 5 comprises a rotor 25, which defines an axis of rotation, and a stator 27. In this example, the electrical machine 5 is a drive motor configured to drive the propulsion turbine 1. Thus, the rotor 25 drives the propulsion turbine 1 in rotation via a shaft 29. Optionally, a reduction mechanism can be interposed between the shaft 29 and the propulsion turbine 1.

[0049] The stator 27 carries stator coils 31, which are partially received in stator notches 33 of the stator 27 and comprise coil heads 35, also called involutes. In this example, coil heads 35 extend axially on either side outside the stator 27, as is shown in particular in FIGS. 3 and 4. The stator 27 also carries a bus bar 37 at one end, which electrically connects the coil heads 35 of this end at least partially to each other, for example the coil heads 35 of each star E.

[0050] At least one stator coil 31 of the electrical machine 5 houses a measurement sensor 39 of a physical quantity characteristic of the electrical machine 5. More precisely in this example, at least one stator coil 31 of each star E of the electrical machine 3 houses a measurement sensor 39 of a physical quantity characteristic of the electrical machine 3. In this example, the physical quantity is the temperature. The onboard aeronautical electrical system 3 is such that the at least one stator coil 31 houses the measurement sensor 39 in a coil head 35 of the stator coil 31 and / or in a stator notch 15 receiving the stator coil 9.

[0051] [Fig. 3] schematically represents three views of a variant in which a stator coil 31 houses a measurement sensor 39 in a coil head 35. For simplicity, only the position of the measurement sensor 39 is indicated there, the power supply cables 41 not being shown.

[0052] [Fig.4] schematically represents two views of another variant in which a stator coil 31 houses a measurement sensor 39 in a stator notch 33 receiving the stator coil 31. For simplicity, only the position of the measurement sensor 39 is indicated there, the power supply cables 41 not being shown.

[0053] The variants shown in Figures 3 and 4 can be combined such that a stator coil 31 houses a measurement sensor 39 in a coil head 35, and a stator coil 31 houses a measurement sensor 39 in a stator notch 33 receiving the stator coil 31.

[0054] The measuring sensor 39 is resistive and powered by power supply cables 4L. Thus, the power supply cables extend through the winding of the stator 27, more precisely through the stator coil 31. In this example, the measuring sensor 39 is powered with electrical power separately from the power supply of the electrical machine 3. Furthermore, the measuring sensor 39 is electrically isolated from at least one stator coil 31 housing the measuring sensor 39. In this example, the measuring sensor 39 is powered with a constant current via the power supply cables 4L. For example, the measuring sensor 39 is a PtlOO or PtlOOO temperature sensor. In this example, the measuring sensor 39 is a PtlOOO temperature sensor.

[0055] The power cables 41 are connected outside the stator coil 31 to an external acquisition unit 43.

[0056] As shown in [Fig.5], in this example, a multiplexing component 44 connects the power cables 41 to the external acquisition unit 43. The external acquisition unit 43 comprises a first acquisition chain 45 and a second acquisition chain 47.

[0057] The multiplexing component 44 is for example a bipolar bidirectional switch, the bipolar bidirectional switch being connected at the input to the power supply cables 41 and being connected at the output alternately to the first acquisition chain 45 and to the second acquisition chain 47.

[0058] In this example, the first acquisition chain 43 is provided with a low-pass filter. For example, the low-pass filter is digital and has a cutoff frequency of less than 1 Hz, preferably less than 0.5 Hz. The second acquisition chain 47 is provided with a high-pass filter. The high-pass filter comprises, for example, a non-inverting operational amplifier. In this example, the high-pass filter has a cutoff frequency greater than or equal to 100 MHz, preferably greater than or equal to 500 MHz. For example, the second acquisition chain 47 comprises a processor and a storage medium, which contains a database. For example, the database is a database of signals representative of a partial discharge.

[0059] [Fig.6] schematically represents a stator 27' according to an alternative embodiment. For simplicity, the stator 27' is schematically represented flat. This stator 27' according to this alternative embodiment is similar to the stator 27 previously described, the analogous elements being designated by the same references, but differs from the stator 27 mainly in that N is equal to 3. Thus, the stator 27' comprises three stars E of three phases. Furthermore, in this example, the first phase of each star E comprises a measurement sensor 39, which is housed in a coil head 35 of a stator coil 31.

[0060] [Fig.7] represents the main steps of a method for detecting a partial discharge in an on-board aeronautical electrical system, which in this example is the on-board aeronautical electrical system 3 previously described. Thus, the on-board aeronautical electrical system 3 previously described is configured to implement the detection method described below.

[0061] Such a detection method comprises, for example, the following steps: - acquisition P10 of the voltage between the power cables 41 by the first acquisition chain 45, which delivers P12 a signal representative of the physical quantity as a function of the acquired voltage, - acquisition P20 of the voltage between the power cables 41 by the second acquisition chain 47 and filtering P21 by the high-pass filter, the second acquisition chain 47 delivering P22 an analysis signal configured to allow the detection of a partial discharge in the electrical machine 3.

[0062] For example, the detection method further comprises the following steps: - comparison P23 of the analysis signal with a signal representative of a partial discharge, and - detection P24 of a partial discharge as a function of a result of the comparison P23. As previously described, the signal representative of a partial discharge is selected from a database of signals representative of a partial discharge. In this example, the comparison step P23 is carried out by a processor, for example the processor of the second acquisition chain 47.

[0063] For example, the acquisition step P10 of the voltage between the power cables 41 by the first acquisition chain 45 is followed by a filtering step P10 by the low-pass filter, the first acquisition chain 45 delivering P12 a signal representative of the physical quantity as a function of the acquired and filtered voltage.

[0064] In this example, the acquisition steps P10 and P20 are carried out alternately using the multiplexing component 44.

[0065] Furthermore, when N is greater than or equal to 2, at least one stator coil 31 of each star of the electrical machine 3 housing a measurement sensor 39 of a physical quantity characteristic of the electrical machine 3, for example according to the variant shown in [Fig.2] in which N is equal to 2 or according to the variant shown in [Fig.3] in which N is equal to 3, the method comprises the following steps for each stator coil 31 housing a measurement sensor 39: - acquisition P10 of the voltage between the power cables 41 by the first acquisition chain 45, which delivers a signal representative of the physical quantity as a function of the acquired voltage, - acquisition P20 of the voltage between the power cables 41 by the second acquisition chain 47 and filtering P21 by the high-pass filter, the second acquisition chain 47 delivering P22 an analysis signal configured to allow the detection of a partial discharge in the electrical machine 3, - when a partial discharge is detected P24 from the analysis signal, stop P25 of the electrical power supply to the star E comprising the stator coil 31.

[0066] [Fig. 8] shows two graphs each representing the detection of a partial discharge by means of the detection method previously described. These graphs represent results obtained using Pt1000 temperature measuring sensors present in an electrical machine of the ENGINeUS type (registered trademark) 50A, non-integrated, in which the power converter and the electric machine form separate components. The detected and filtered signals from the measuring sensors are compared to those obtained with partial discharge detection sensors of the same type as those described for example in the document "Partial Discharge in Electric Motor Fed by a PVVM Inverter: Off-line and On-line Detection, T. Billard and T. Lebey, IEEE Transactions on Dielectrics and Electrical Insulation Vol. 21, No. 3, June 2014". An excellent correlation is observed, which thus validates the principle of using a resistive measuring sensor and diverting it from its classic use to detect a partial discharge. On each of these graphs, viewed from top to bottom and in an inter: - the first curve Cl represents the voltage between two phases of a star of the electrical machine 3; - the second curve C2 represents a reference signal of a partial discharge, for example obtained via a partial discharge detection method as disclosed in the aforementioned document; - the third curve C3 represents the analysis signal coming from a first star E of the electric machine; - the fourth curve C4 represents the analysis signal coming from a second star E of the electric machine.

[0067] On the left graph, the comparison between the reference signal and each of the analysis signals allows us to conclude the presence of a partial discharge, which is visible on the analysis signal of each of the two E stars.

[0068] On the graph on the right, the comparison between the reference signal and each of the analysis signals allows us to conclude that there is a partial discharge, which is visible on the analysis signal of the first star E.

Claims

Claims

1. Method for detecting a partial discharge in an on-board aeronautical electrical system (3), the on-board aeronautical electrical system (3) comprising a power converter (7) and an electrical machine (5) with N three-phase E stars, N being greater than or equal to 1, the electrical machine (5) being supplied with electrical power by the power converter (7), at least one stator coil (31) of the electrical machine (5) housing a measuring sensor (39) of a physical quantity characteristic of the electrical machine (5), the measuring sensor (39) being resistive and supplied by power cables (41) extending through the stator coil (31), the power cables (41) being connected outside the stator coil (31) to an external acquisition unit (43) comprising a first acquisition chain (45) and a second acquisition chain (47) provided with a high-pass filter,the method comprising the following steps: - acquisition (P 10) of the voltage between the power cables (41) by the first acquisition chain (45), which delivers (P12) a signal representative of the physical quantity as a function of the acquired voltage, - acquisition (P20) of the voltage between the power cables (41) by the second acquisition chain (47) and filtering (P21) by the high-pass filter, the second acquisition chain (47) delivering (P22) an analysis signal configured to allow the detection of a partial discharge in the electrical machine (5) characterized in that it comprises the following step: - comparison (P23) of the analysis signal with a signal representative of a partial discharge, the signal representative of a partial discharge being selected from a database of signals representative of a partial discharge, the comparison step (P23) being carried out by a processor,and detection (P24) of a partial discharge based on a result of the comparison.,

2. Method according to claim 1, in which the on-board aeronautical electrical system (3) is such that the at least one stator coil (31) housing a measurement sensor (39) houses the measurement sensor (39) in a coil head (35) of the stator coil (31) and / or in a stator notch (33) receiving the stator coil (31).

3. A method according to any one of claims 1 to 2, wherein the physical quantity is temperature.

4. A method according to any one of claims 1 to 3, wherein the high-pass filter has a cutoff frequency greater than or equal to 100 MHz.

5. Method according to any one of claims 1 to 4, in which the first acquisition chain (45) is provided with a low-pass filter, and in which the step of acquisition (P10) of the voltage between the power cables (41) by the first acquisition chain (45) is followed by a step of filtering (Pli) by the low-pass filter, the first acquisition chain (45) delivering (P12) a signal representative of the physical quantity as a function of the acquired and filtered voltage.

6. A method according to any one of claims 1 to 5, wherein a multiplexing component (44) connects the power cables (41) to the external acquisition unit (43).

7. Method according to claim 6, in which the multiplexing component is a bipolar bidirectional switch, the bipolar bidirectional switch being connected at the input to the power cables (41) and being connected at the output alternately to the first acquisition chain (45) and to the second acquisition chain (47).

8. Method according to any one of claims 1 to 7, in which N is greater than or equal to 2, at least one stator coil (31) of each star of the electrical machine (5) housing a measurement sensor (39) of a physical quantity characteristic of the electrical machine (5), the method comprising the following steps for each stator coil (31) housing a measurement sensor (39): - acquisition (P 10) of the voltage between the power supply cables (41) by the first acquisition chain (45), which delivers (P12) a signal representative of the physical quantity as a function of the acquired voltage, - acquisition (P20) of the voltage between the power supply cables (41) by the second acquisition chain (47) and filtering (P21) by the high-pass filter, the second acquisition chain (47) delivering (P22) an analysis signal configured to allow the detection of a partial discharge in the electrical machine (5), - when a partial discharge is detected (P24) from the analysis signal, stopping (P25) the electrical power supply to the star comprising the stator coil (31).

9. On-board aeronautical electrical system (3) configured to implement the method according to any one of claims 1 to 8, characterized in that it comprises a power converter (7) and a three-phase star electrical machine (5), N being greater than or equal to 1, the electrical machine (5) being supplied with electrical power by the power converter (7), at least one stator coil (31) of the electrical machine (5) housing a measurement sensor (39) of a physical quantity characteristic of the electrical machine (5), the measurement sensor (39) being resistive and supplied by power cables (41) extending through the stator coil (31), the power cables (41) being connected outside the stator coil (31) to an external acquisition unit (43) comprising a first acquisition chain (45) and a second acquisition chain (47) provided with a high-pass filter.

10. Aircraft (100) comprising at least one propulsion turbine (1), characterized in that it comprises an on-board aeronautical electrical system (3) according to claim 9, the propulsion turbine (1) being driven by the on-board aeronautical electrical system (3).

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