Method for detecting degradation of a switching device comprising an electromagnetic actuator
The method addresses the challenge of detecting degradation in switching devices with electromagnetic actuators by analyzing current and reaction time data using a polynomial parameter, enabling early detection and prevention of faults.
Patent Information
- Application Number
- FR2023007588
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-07-13
- Publication Date
- 2025-06-13
- Estimated Expiration
- 2043-07-13
AI Technical Summary
Existing switching devices with electromagnetic actuators lack effective methods for detecting degradation, which can lead to faults and unsafe electrical network conditions.
A method that involves controlling the electromagnetic actuator, measuring the current flowing through it, determining the reaction time and current quantity, and using a polynomial parameter to detect degradation by analyzing the evolution of these values during successive actuations.
This method allows for the early detection of electromagnetic actuator degradation, enabling timely maintenance or replacement, thereby preventing faults and ensuring electrical safety.
Smart Images
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Abstract
Description
Title of the invention: Method for detecting degradation of a switching device comprising an electromagnetic actuator Technical field
[0001] The present invention relates to the field of switching devices for electrical equipment, for example for low and medium voltage electrical equipment. The switching device may for example be a circuit breaker. Prior art
[0002] A low or medium voltage switching device may comprise one or more electromagnetic actuators for unlocking a spring control mechanism, for moving a movable electrical contact, so as to open or close an electrical circuit. In the case of a circuit breaker, the opening of the electrical circuit is carried out in the event of the appearance of a fault in the electrical circuit. The fault may in particular be a short circuit between two phases, or between a phase and the earth. Closing the circuit allows a load to be energized.
[0003] The electromagnetic actuator comprises a movable magnetic core and a control coil. Under the action of an electric current flowing through the control coil, the magnetic core moves. The magnetic core is mechanically coupled to the control mechanism acting on the movable electrical contacts so as to be able to open or close the electrical circuit.
[0004] In order to ensure the safety of the electrical network and of people, it is important to be able to check the proper functioning of switching devices throughout their lifetime. To this end, circuit breakers may include measuring circuits for diagnosing the state of the electromagnetic actuator in real time. This electromagnetic actuator is generally subject to the effects of aging which can gradually degrade its electrical or mechanical functions, and ultimately render it inoperative. It is therefore important for users to be able to monitor the evolution of the state of the electromagnetic actuator. It is desirable to allow users to intervene to repair or change the electromagnetic actuator at an appropriate time in the management of the electrical network. Summary
[0005] To this end, the invention proposes a method for detecting degradation of a switching device comprising an electromagnetic actuator configured to unlock a control mechanism comprising an elastic member configured to move a movable electrical contact so as to open or close a circuit. electrical, the method comprising the steps: (i) control the electromagnetic actuator, (ii) measuring a current flowing in the electromagnetic actuator when controlling the electromagnetic actuator, (iii) determine from the measured current a reaction time of the electromagnetic actuator, (iv) determine from the measured current a quantity representative of the current flowing in the electromagnetic actuator when controlling the electromagnetic actuator, (v) determining a parameter in the form of a polynomial of the determined reaction time and the determined quantity representative of the current flowing in the electromagnetic actuator when controlling the electromagnetic actuator, (vi) iterating steps (i) to (v) for a set of successive commands of the electromagnetic actuator so as to obtain a set of values of the determined parameter, (vii) determining a degradation of the electromagnetic actuator from the evolution of the values of the assembly during successive commands of the electromagnetic actuator.
[0006] The method for detecting a degradation of the switching device is a method for detecting a change in the behavior of the switching device due to the aging of its components. Aging of components includes, for example, wear, deformation, the effect of corrosion, changes in magnetic performance, changes in tribological properties of the components. In the case where the electromagnetic actuator operates nominally, the values of the assembly do not change significantly during successive actuations. In other words, the different values of the assembly are substantially constant. Conversely, a progressive degradation of the electromagnetic actuator tends to cause a change in the values during successive actuations, in particular a fluctuation of these values. The values of the assembly are no longer substantially constant and exhibit a significant fluctuation. This progressive evolution makes it possible to detect a degradation of the magnetic actuator of the switching device. The method for detecting degradation of the switching device is a method which also makes it possible to anticipate the occurrence of a fault in the switching device. Indeed, uncorrected degradation of the switching device can lead to end to the appearance of a defect.
[0007] The features listed in the following paragraphs can be implemented independently of each other or in any technically possible combination:
[0008] In step (vii), the evolution of the values of the set may be a fluctuation of the values of the set during successive commands of the electromagnetic actuator.
[0009] The set of values of the polynomial of the determined reaction time and of the determined quantity is obtained by a succession of consecutive commands of the electromagnetic actuator of the switching device.
[0010] Each value of the set of values of the polynomial of the determined reaction time and of the determined quantity corresponds to a distinct actuation of the electromagnetic actuator of the switching device.
[0011] The switching device may be a circuit breaker.
[0012] Alternatively, the switching apparatus may be a switch.
[0013] According to another variant, the switching device may be a disconnector.
[0014] The switching apparatus comprises: - a movable electrical contact between an open position of an electrical circuit and a closed position of the electrical circuit, - a control mechanism comprising: — an elastic member configured to move the electrical contact from the closed position to the open position or from the open position to the closed position, so as to respectively open or close the electrical circuit, — an unlocking member configured to move from a locking position in which the elastic member is held in a tensioned state to a release position in which the elastic member is free to relax so as to move the electrical contact from the closed position to the open position or from the open position to the closed position, - an electromagnetic actuator configured to move the unlocking member from the locking position to the release position.
[0015] According to an embodiment, called the first embodiment: - the elastic member is configured to move the electrical contact from the closed position to the open position so as to open the electrical circuit, and - the unlocking member is configured to move from a locking position in which the elastic member is held in a tensioned state to a release position in which the elastic member is free to relax so as to move the electrical contact from the closed position to the open position.
[0016] According to another embodiment, called second embodiment: - the elastic member is configured to move the electrical contact from the open position to the closed position, so as to close the electrical circuit, - the unlocking member is configured to move from a locking position in which the elastic member is held in a tensioned state to a release position in which the elastic member is free to relax so as to move the electrical contact from the open position to the closed position.
[0017] The elastic member is configured to apply a driving force to the movable electrical contact. The elastic member is connected to a drive element configured to move the movable electrical contact so as to open or close an electrical circuit. The drive element comprises, for example, a connecting rod.
[0018] According to the first embodiment, the unlocking member can move from a locking position in which the elastic member of the control mechanism is elastically constrained and in which the movable electrical contact is in the position for closing the electrical circuit, to an unlocked position in which the elastic member of the control mechanism is released and moves the movable electrical contact from the position of closing the electrical circuit to a position of opening the electrical circuit.
[0019] According to the second embodiment, the unlocking member can move from a locking position in which the elastic member of the control mechanism is elastically constrained and in which the movable electrical contact is in the opening position of the electrical circuit, to an unlocked position in which the elastic member of the control mechanism is released and moves the movable electrical contact from an open position of the electrical circuit to the closed position of the electrical circuit.
[0020] Unlocking the control mechanism means releasing the elastic member of the control mechanism. In other words, unlocking the control mechanism is equivalent to moving the unlocking member from the locking position to the release position.
[0021] The electromagnetic actuator is an electromagnet.
[0022] The electromagnetic actuator comprises a control coil and a magnetic core configured to move under the action of a magnetic field created by a flow of electric current in the control coil.
[0023] The magnetic core is for example mobile in translation.
[0024] The magnetic core is mechanically coupled to an unlocking member configured to move from a locking position in which the elastic member is held in a tensioned state to a release position in which the elastic member is free to relax so as to move the electrical contact from the position from closing to opening position.
[0025] Measuring a current flowing in the electromagnetic actuator means measuring the intensity of the electric current flowing in the electromagnetic actuator.
[0026] The current flowing in the electromagnetic actuator is detected by an electronic measuring circuit.
[0027] The current flowing in the electromagnetic actuator is sampled, for example with a sampling frequency between 1 kHz and 100 kHz.
[0028] The electromagnetic actuator comprises a coupling element mechanically coupling the magnetic core to the unlocking member.
[0029] The control mechanism may comprise rotating movable elements.
[0030] The control mechanism may comprise elements movable in translation.
[0031] The elastic member may be a spring, for example a spiral spring or a helical spring.
[0032] The electromagnetic actuator is configured to trigger a movement of the movable electrical contact in order to open the electrical circuit. When the switching device is a circuit breaker, the electromagnetic actuator is configured to trigger an opening of the electrical circuit in the event of a fault on the electrical circuit.
[0033] According to one aspect of the proposed detection method, the reaction time of the electromagnetic actuator is determined from the temporal variations of the measured current.
[0034] The proposed method thus does not require the installation of any additional sensor, such as a sensor for the movement of the electrical contact or a sensor for the movement of an element of the control mechanism.
[0035] The proposed method comprises a sub-step of determining the temporal variations of the measured current.
[0036] According to an example of implementation of the detection method, the reaction time of the electromagnetic actuator is equal to a duration elapsed between an instant of start of circulation of the electric current in the electromagnetic actuator and an instant corresponding to a local minimum value of the electric current circulating in the electromagnetic actuator.
[0037] According to one embodiment of the detection method, the quantity representative of the current flowing in the electromagnetic actuator during actuation of the switching device is a local maximum value of the electric current flowing in the electromagnetic actuator.
[0038] In step (v), the parameter is determined by a polynomial with two indeterminates, i.e. a sum of monomials with two indeterminates. A first indeterminate is the determined reaction time, and the second indeterminate is the quantity of terminated representative of the current flowing in the electromagnetic actuator when controlling the electromagnetic actuator. Each monomial of the polynomial is thus determined by the product: of the determined reaction time, raised to a first given power, of the determined quantity representative of the current flowing in the electromagnetic actuator when the electromagnetic actuator is controlled, raised to a second given power, and of a constant coefficient. Each monomial can be written in the form: [Math.2]
[0039] The polynomial forming the parameter P can thus be written: [Math. 3] P = A-^ta)k' 'cs coefficients ko, •••, kH taking values ra tional, the coefficients Lo, ..., LH taking rational values, and the coefficients A; taking rational values.
[0040] Among a multitude of parameters studied, the applicant concluded that the polynomial formed from the reaction time of the electromagnetic actuator and the local maximum value of the circuit current in the electromagnetic actuator best accounts for a progressive degradation of this electromagnetic actuator. The polynomial is thus a polynomial with two indeterminates.
[0041] According to a particular embodiment of the proposed detection method, the parameter P is equal to the product of the determined reaction time and the determined quantity representative of the current flowing in the electromagnetic actuator when controlling the electromagnetic actuator.
[0042] In other words, in this particular case of implementation of the method, the polynomial comprises a single term, in other words is a monomial. The first power of the monomial is equal to 1 and the second power of the monomial is also equal to 1. The monomial formed is then equal to the product of the determined reaction time and the determined quantity representative of the current flowing in the electromagnetic actuator when the electromagnetic actuator is controlled, that is to say the result of multiplying the value of the determined reaction time by the value of the determined quantity representative of the current flowing in the electromagnetic actuator when the electromagnetic actuator is controlled.
[0043] The maximum local value of the current is obtained for an instant between an instant of start of circulation of the electric current in the electromagnetic actuator and an instant corresponding to a local minimum of the electric current. circulating in the electromagnetic actuator.
[0044] According to one embodiment, the detection method comprises the sub-steps: - calculating a value of a statistical parameter representative of a fluctuation of the values of the set of values of the polynomial of the determined reaction time and of the determined quantity, - determine a degradation of the electromagnetic actuator from the calculated value of the statistical parameter.
[0045] According to an example of implementation of the detection method, the statistical parameter representative of a fluctuation of the values of the set of values of the polynomial of the determined reaction time and of the determined quantity comprises a difference between: - a current value of the polynomial of the determined reaction time and of the determined quantity, determined for a current actuation of the switching device, and - an average value of the values of the polynomial of the determined reaction time and of the determined quantity obtained for a predetermined number of actuations preceding the current actuation of the switching device.
[0046] The average value may be a sliding average calculated from the values corresponding to the actuations preceding the current actuation, and comprising a number of values equal to the predetermined number of actuations.
[0047] According to an example of implementation of the detection method, the statistical parameter representative of a fluctuation of the values of the set of values of the polynomial of the determined reaction time and of the determined quantity comprises a standard deviation of the values of the polynomial of the determined reaction time and of the determined quantity determined for a set of actuations of the switching device carried out under reference conditions corresponding to a new state of the switching device.
[0048] The set of actuations of the switching device carried out under reference conditions comprises for example 20 successive actuations of the switching device.
[0049] The proposed method thus comprises a calibration phase making it possible to quantify the nominal variations of the value of the polynomial of the determined reaction time and of the quantity representative of the current flowing in the electromagnetic actuator during actuation of the switching device. These nominal variations correspond to the variations observed in a reference state in which the switching device has neither manufacturing defect nor wear.
[0050] The reference state corresponds for example to a new state of the switching device.
[0051] The proposed method comprises a measurement phase in which the variations of the value of the polynomial of the determined reaction time and of the quantity representative of the current flowing in the electromagnetic actuator are analyzed.
[0052] The measurement phase follows the calibration phase.
[0053] The measurement phase is carried out throughout the duration of use of the device. switching.
[0054] According to one embodiment of the detection method, the statistical parameter representative of a fluctuation of the polynomial of the determined reaction time and of the determined quantity is equal to the ratio of: - the difference between a current value of the polynomial determined for a current actuation and the average value of the values of the polynomial obtained for a predetermined number of actuations preceding the current actuation, and - the determined standard deviation of the values of the polynomial of the determined reaction time and of the determined quantity, determined for a set of actuations of the switching device carried out under reference conditions corresponding to a new state of the switching device.
[0055] The proposed statistical parameter allows robust detection of possible degradation of the electromagnetic actuator, while being simple to implement. In particular, the necessary calculations are easily carried out in real time, which allows rapid detection of possible degradation.
[0056] According to one embodiment of the detection method, the statistical parameter representative of a fluctuation of the polynomial of the determined reaction time and of the determined quantity is equal to:
[0057] [Math.l] * / r - •--< * 2 R" / P l1 ra- IKI With E the determined value of the polynomial for an actuation of rank i, Di the calculated value of the statistical parameter for the actuation of rank i, M a number of actuations taken into account to determine an average value, K a number of actuations carried out under reference conditions corresponding to a new state of the switching device.
[0058] According to an example of implementation of the detection method, a degradation of the electromagnetic actuator is determined when the absolute value of the statistical parameter representative of a fluctuation of the polynomial of the determined reaction time and of the determined quantity is greater than a first positive predetermined threshold.
[0059] The value chosen for the first positive predetermined threshold makes it possible to adjust the sensitivity of the proposed detection method.
[0060] The first predetermined positive threshold is for example between 2 and 3.
[0061] Conversely, an absence of degradation of the electromagnetic actuator is determined when the absolute value of the statistical parameter representative of a fluctuation of the polynomial of the determined reaction time and of the determined quantity is less than or equal to the first positive predetermined threshold.
[0062] In other words, a degradation is determined when the absolute value of the statistical parameter takes a value greater than a predefined threshold value. Conversely, an absence of degradation is determined when the absolute value of the statistical parameter takes a value lower than the predefined threshold value.
[0063] According to an exemplary embodiment of the detection method, the degradation of the electromagnetic actuator is classified into a first type of degradation, called minor degradation, when the absolute value of the statistical parameter representative of a fluctuation of the polynomial of the determined reaction time and of the determined quantity is greater than a first predetermined positive threshold and less than a second predetermined positive threshold.
[0064] The second predetermined positive threshold is for example between 4 and 5.
[0065] According to an exemplary embodiment of the detection method, the degradation of the electromagnetic actuator is classified into a second type of degradation, called major degradation, when the absolute value of the statistical parameter representative of a fluctuation of the polynomial of the determined reaction time and of the determined quantity is greater than the second predetermined positive threshold.
[0066] The statistical parameter used thus allows a quantification of the severity of the degradation, and not only the presence or absence of degradation.
[0067] The detection method may comprise a step of emitting an alert signal in response to a determination of degradation of the electromagnetic actuator.
[0068] The alert signal emitted allows users to plan and carry out a maintenance or replacement operation on the switching device when it is in a degraded or even defective state.
[0069] No alert signal is emitted when no degradation has been determined. In other words, no alert is emitted when the proposed method indicates that the electromagnetic actuator is free from degradation.
[0070] The invention also relates to a switching device30) comprising: - an electromagnetic actuator configured to unlock a control mechanism comprising an elastic member configured to move an electrical contact so as to open or close an electrical circuit, - an electronic control unit configured to implement the degradation detection method as described previously.
[0071] According to one embodiment, the switching device comprises: - a control circuit configured to circulate an electric current in the electromagnetic actuator, - a sensor for measuring the current flowing in the electromagnetic actuator. Brief description of the drawings
[0072] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which:
[0073] [Fig-1] is a schematic view of an electrical circuit equipped with a communication device mutation, the electrical circuit being in the open position,
[0074] [Fig.2] is a schematic view of an electrical circuit equipped with a switching device, the electrical circuit being in the closed position,
[0075] [Fig.3] is a curve of the time evolution of the current in an electromagnetic actuator of a switching device, during its actuation,
[0076] [Fig.4] represents the evolution of the curve of [Fig.2], during the aging of the switching device,
[0077] [Fig.5] is a time diagram illustrating the method according to the invention,
[0078] [Fig.6] is a block diagram illustrating different steps of the method according to the invention. Description of the embodiments
[0079] In order to facilitate reading of the figures, the different elements are not necessarily represented to scale. In these figures, identical elements bear the same references. Certain elements or parameters may be indexed, that is to say designated for example by first element or second element, or even first parameter and second parameter, etc. This indexing is intended to differentiate similar, but not identical, elements or parameters. This indexing does not imply a priority of one element or parameter over another and the names may be interchanged. When it is specified that a subsystem comprises a given element, this does not exclude the presence of other elements in this subsystem. Similarly, when it is specified that a subsystem comprises a given element, it is understood that the subsystem comprises at least this element.
[0080] [Fig.l] shows schematically an electrical circuit 50. The electrical circuit 50 comprises three electrical conductors 20, 21, 22, each conductor corresponding to a phase of a medium voltage three-phase network.
[0081] The electrical circuit 50 comprises a switching device 30. The switching device 30 may be a circuit breaker. According to one variant, the switching device 30 may be a switch. According to another example of application, the switching device 30 can be a disconnector.
[0082] The switching device 30 comprises: - an electromagnetic actuator 1 configured to unlock a control mechanism 4 comprising an elastic member 7 configured to move a movable electrical contact 10 so as to open or close an electrical circuit 50, - an electronic control unit 25 configured to implement the degradation detection method which will be described in detail below.
[0083] The electromagnetic actuator 1 is an electromagnet. The electromagnetic actuator 1 comprises a control coil 2 and a magnetic core 3 configured to move under the action of a magnetic field created by a flow of electric current in the control coil 2.
[0084] The magnetic core 3 is for example mobile in translation. The magnetic core 3 is mechanically coupled to an unlocking member 8 configured to move from a locking position V in which the elastic member 7 is held in a tensioned state to a release position L in which the elastic member 7 is free to relax so as to move the electrical contact 10 from the closed position F to the open position O.
[0085] The movable electrical contact 10 is associated with the electrical conductor 20. In the same way, a movable electrical contact 11 is associated with the electrical conductor 21, and a movable electrical contact 12 is associated with the electrical conductor 22. In [Fig.l], the movable electrical contact 10 is shown in the open position, that is to say in the position where the flow of electric current in the electrical circuit 50 is interrupted. In [Fig.2], the movable electrical contact 10 is shown in the closed position, that is to say in the position where the circulation of the electric current in the electrical circuit 50 is possible.
[0086] The electromagnetic actuator 1 comprises a coupling element 13 4 coupling mechanically the magnetic core 3 to the unlocking member 8. The control mechanism 4 may comprise rotating movable elements. The control mechanism 4 may comprise elements which can move in translation. The control mechanism 4 may jointly move the three movable electrical contacts 10, 11, 12.
[0087] The electromagnetic actuator 1 is configured to trigger a movement of the movable electrical contact 10 in order to open the electrical circuit 50. When the switching device 30 is a circuit breaker, the electromagnetic actuator 1 is configured to trigger an opening of the electrical circuit 50 in the event of the presence of a fault on the electrical circuit 50. An example of a fault that may be present on the electrical circuit 50 is a short circuit between two separate phases. Another type of fault may be a short circuit between a phase and ground.
[0088] The switching apparatus 30 comprises: - an electrical contact 10 movable between an open position O of an electrical circuit 50 and a closed position F of the electrical circuit 50, - a control mechanism 4 comprising: — an elastic member 7 configured to move the electrical contact 10 from the closed position F to the open position O or from the open position O to the closed position F, so as to respectively open or close the electrical circuit 50, — an unlocking member 8 configured to move from a locking position V in which the elastic member 7 is held in a tensioned state to a release position L in which the elastic member 7 is free to relax so as to move the electrical contact 10 from the closed position F to the open position O or from the open position O to the closed position F, - an electromagnetic actuator 1 configured to move the unlocking member 8 from the locking position V to the release position L.
[0089] According to the embodiment illustrated in [Fig.l] and [Fig.2]: - the elastic member 7 is configured to move the electrical contact 10 from the closed position F to the open position O so as to open the electrical circuit 50, and - the unlocking member 8 is configured to move from a locking position V in which the elastic member 7 is held in a tensioned state to a release position L in which the elastic member 7 is free to relax so as to move the electrical contact 10 from the closed position F to the open position O. In other words, the control mechanism 4 makes it possible to cut off the flow of current in the electrical circuit 50.
[0090] According to another embodiment, not shown: - the elastic member 7 is configured to move the electrical contact 10 from the open position O to the closed position F, so as to close the electrical circuit 50, - the unlocking member 8 is configured to move from a locking position V in which the elastic member 7 is held in a tensioned state to a release position L in which the elastic member 7 is free to relax so as to move the electrical contact 10 from the opening position O to the closing position F. In other words, the control mechanism 4 in this case makes it possible to establish the circulation of current in the electrical circuit 50.
[0091] The elastic member 7 is configured to apply a driving force to the 10 movable electrical contact. The elastic member 7 may be a spring, for example a spiral spring or a helical spring. The elastic member 7 is connected to a drive element 9 configured to move the movable electrical contact 10 so as to open or close an electrical circuit 50. The drive element 9 comprises, for example, a connecting rod.
[0092] According to the embodiment illustrated in [Fig.l] and [Fig.2], the unlocking member 8 can move from a locking position in which the elastic member 7 of the control mechanism 4 is elastically constrained and in which the movable electrical contact 10 is in the closed position F of the electrical circuit 50, to an unlocked position V in which the elastic member 7 of the control mechanism 4 is released and moves the movable electrical contact 10 from the closed position F of the electrical circuit 50 to an open position O of the electrical circuit 50.
[0093] According to the second embodiment, not illustrated, the unlocking member 8 can pass from a locking position in which the elastic member 7 of the control mechanism 4 is elastically constrained and in which the movable electrical contact 10 is in the open position O of the electrical circuit 50, to an unlocked position V in which the elastic member 7 of the control mechanism 4 is released and moves the movable electrical contact 10 from an open position O of the electrical circuit 50 to the closed position F of the electrical circuit 50.
[0094] Unlocking the control mechanism 4 means releasing the elastic member 7 from the control mechanism 4. The electromagnet 1 makes it possible to control the movement of the unlocking member 8 so as to release the elastic member 7.
[0095] The propulsive force for moving the movable electrical contact 10 is provided by the elastic member 7. The electromagnetic actuator 1 has no direct interaction with the movable electrical contact 10. The electromagnetic actuator 1 provides a force of electromagnetic origin allowing the movement of the unlocking member 8, via the coupling element 13. Once the unlocking member 8 is in the unlocked position V, the potential energy stored by the elastic member 7 is released and ensures the movement of the electrical contact 10 via the drive element 9. In [Fig.l], the unlocking member 8 is in the locking position V and the elastic member 7, represented schematically as a helical spring, is maintained in the compressed state. The movable contact 10 is in the closed position, corresponding to a circulation of the electric current in the electric conductor 20. In [Fig. 2], the coupling element 13 has moved the unlocking member 8 to the release position. The elastic member 7 is in the relaxed state, and the drive element 9 has moved the movable electrical contact 10 to its open position, corresponding to an interruption of the flow of current in the electrical conductor 20 and therefore in the electrical circuit 50.
[0096] The mechanical components of the switching device 30 may deteriorate over the lifetime of use of the switching device, in particular due to wear resulting from repeated triggering, deformations and chemical corrosion which may occur. It is therefore desirable to be able to have a method for diagnosing the switching device 30, that is to say a method making it possible to detect the appearance of degradation of the switching device 30.
[0097] A method is thus proposed for detecting a degradation of a switching device 30 comprising an electromagnetic actuator 1 configured to unlock a control mechanism 4 comprising an elastic member 7 configured to move a movable electrical contact 10 so as to open or close an electrical circuit 50, the method comprising the steps: (i) control the electromagnetic actuator 1, (ii) measuring a current C flowing in the electromagnetic actuator 1 when controlling the electromagnetic actuator 1, (iii) determine from the measured current C a reaction time ta of the electromagnetic actuator 1, (iv) determine from the measured current C a quantity il representative of the current flowing in the electromagnetic actuator 1 when controlling the electromagnetic actuator 1, (v) determining a parameter P in the form of a polynomial of the determined reaction time ta and of the determined quantity il representative of the current flowing in the electromagnetic actuator 1 when controlling the electromagnetic actuator 1, (vi) iterating steps (i) to (v) for a set of successive commands of the electromagnetic actuator 1 so as to obtain a set E of values of the determined parameter P, (vii) determining a degradation of the electromagnetic actuator 1 from the evolution of the values of the set E during successive commands of the electromagnetic actuator 1.
[0098] In the case where the electromagnetic actuator 1 operates nominally, the values of the set E do not change significantly during successive actuations. In other words, the different values of the set E are substantially constants. Conversely, a progressive degradation of the electromagnetic actuator 1 tends to cause a change in the values of the set E during successive actuations. The values of the set E are no longer substantially constant and show a significant change. This progressive change makes it possible to detect a degradation of the switching device 30, as well as the presence of a fault.
[0099] The set E of values of the polynomial P of the determined reaction time ta and of the determined quantity il is obtained by a succession of consecutive commands of the electromagnetic actuator 1 of the switching device 30.
[0100] Each value of the set E of values of the polynomial P of the determined reaction time ta and of the determined quantity il corresponds to a distinct actuation of the electromagnetic actuator 1 of the switching device 30. In other words, a value of the reaction time ta is associated with each of the different actuations of the switching device 30. In the same way, a value of the determined parameter il is associated with each of the different actuations of the switching device 30. A value of the polynomial P of ta and il is associated with each of the actuations of the switching device 30.
[0101] The switching device 30 comprises: - a control circuit 5 configured to circulate an electric current in the electromagnetic actuator 1, - a sensor 6 for measuring the current flowing in the electromagnetic actuator 1.
[0102] By measuring a current C flowing in the electromagnetic actuator 1 is meant the fact of measuring the intensity of the electric current flowing in the electromagnetic actuator 1. More precisely, the intensity of the electric current flowing in the control coil 2 is measured.
[0103] For this, the current C flowing in the electromagnetic actuator 1 is detected by an electronic measuring circuit. In the illustrated example, the current C flowing in the electromagnetic actuator 1 is sampled, for example with a sampling frequency between 1 kHz and 100 kHz. In other words, the current value is measured periodically during an actuation phase of the electromagnetic actuator 1.
[0104] The reaction time ta of the electromagnetic actuator 1 is determined from the temporal variations of the measured current C. The proposed method thus includes a sub-step of determining the temporal variations of the measured current C.
[0105] No sensor other than the current measuring sensor is required to detect terminate the reaction time ta of the electromagnetic actuator 1. In particular, it is not necessary to have a displacement sensor of an element of the control mechanism 4 connecting the movable electrical contact 10 to the electromagnetic actuator 1.
[0106] According to one aspect of the proposed detection method, the reaction time ta of the electromagnetic actuator 1 is equal to a duration elapsed between an instant t0 of start of circulation of the electric current in the electromagnetic actuator 1 and an instant tmin corresponding to a local minimum value of the electric current circulating in the electromagnetic actuator 1.
[0107] [Fig. 3] schematically represents a curve of the time evolution of the electric current flowing in the electromagnetic actuator 1 when the latter is controlled. This curve of the intensity as a function of time is designated by the sign Gl.
[0108] The curve Gl of the time evolution of the electric current in the electromagnetic actuator 1 comprises a first portion pl continuously increasing, a second portion p2 continuously decreasing, the second portion p2 following the first portion pl, a third portion p3 continuously increasing, the third portion p3 following the second portion p2. The instant tmin corresponding to the local minimum of the current corresponds to the instant separating the third portion p3 from the second portion p2. The instant tO of start of circulation of the electric current in the electromagnetic actuator 1 corresponds to the start of the continuously increasing portion pl. The first portion pl includes a first part in which the current increases linearly. Then, as we approach time tl, the increase in current becomes less rapid. At time tl, the current reaches its maximum value since time t0, then the current decreases. This decrease in current is linked to the change in the air gap between the moving parts and the fixed parts. The current decreases until time tmin, where it reaches its minimum value since time tl, then increases again.
[0109] The instant tmin corresponds to the end of the displacement phase of the magnetic core 3. Once the air gap stops changing, the current starts to increase again, which corresponds to the p3 portion of the GL curve
[0110] The time evolution curve of the electric current in the electromagnetic actuator 1 comprises a fourth portion p4 which is substantially constant, the fourth portion P4 following the third portion p3. The permanent current is established, from the instant indicated by t2, at a value permanent i2. The current drop when the control of coil 2 is interrupted is not shown in [Fig.3].
[0111] According to one embodiment of the detection method, the quantity il representative of the current flowing in the electromagnetic actuator 1 during actuation of the switching device 30 is a local maximum value of the electric current flowing in the electromagnetic actuator 1.
[0112] The parameter it corresponds to the maximum value of the current during the control phase during which the magnetic core 3 is in motion, which extends between the instant t0 and the instant tmin.
[0113] In step (v), the parameter P is determined by a sum of monomials with two indeterminates. A first indeterminate is the determined reaction time ta, and the second indeterminate is the determined quantity il representative of the current flowing in the electromagnetic actuator 1 when controlling the electromagnetic actuator 1. We thus have:
[0114] P^M
[0115] The polynomial forming the parameter P can thus be written: [Math.3] [Math.4]EachmonomialMiofthepolynomialisthusdeterminedbytheproductof:thedeterminedreactiontimeta,raisedtoafirstgivenpowerKi,and:thedeterminedmagnitudeilrepresentingthecurrentflowingintheelectromagneticactuatorwhentheelectromagneticactuator1iscontrolled,raisedtoasecondgivenpowerLi,andaconstantcoefficientAi.EachmonomialMicanbewrittenintheform:[Math.2] P = ïZoAi*^^ with the coefficients k0, ..., kH taking rational values, the coefficients Lo, ..., LH taking rational values, and the coefficients A; taking rational values. The polynomial used to determine the parameter P comprises, in its most general form, (H+l) monomials.
[0116] Among a multitude of parameters studied, the applicant concluded that the polynomial formed from the reaction time ta of the electromagnetic actuator 1 and the local maximum value il of the current in the electromagnetic actuator 1 is the quantity which best accounts for a progressive degradation of this electromagnetic actuator. The polynomial is a polynomial with two indeterminates, the first indeterminate being the quantity ta and the second indeterminate being the quantity il.
[0117] According to a particular embodiment of the proposed detection method, the parameter P is equal to the product of the determined reaction time ta and the determined quantity il representative of the current flowing in the electromagnetic actuator 1 when controlling the electromagnetic actuator 1.
[0118] In other words, in this particular case of implementation of the method, the polynomial P is a monomial, the first power ki of which is equal to 1 and the second power Li of which is also equal to 1. The polynomial formed is then equal to the product of the determined reaction time ta and the determined quantity il representative of the current flowing in the electromagnetic actuator 1 when the electromagnetic actuator 1 is controlled, that is to say the result of the multiplication ta * il of the value of the determined reaction time ta by the value of the determined quantity il representative of the current flowing in the electromagnetic actuator 1 when the electromagnetic actuator 1 is controlled.
[0119] The maximum local value il of the current is obtained for an instant tl between an instant t0 of start of circulation of the electric current in the electromagnetic actuator 1 and an instant tmin corresponding to a local minimum of the electric current circulating in the electromagnetic actuator 1. The maximum local value il of the current is the value of the current obtained when passing from the first portion pl to the second portion p2.
[0120] [Fig.4] schematically represents the temporal evolution of the electric current circulating in the electromagnetic actuator 1 when the latter is controlled, during an accelerated aging test of a switching device 30. In particular, [Fig.4] illustrates the evolution of the parameters ta and il during this accelerated aging test. Such a type of test is carried out under conditions that are more severe than normal use of the switching device, for example with a higher temperature and a more corrosive atmosphere than under normal conditions.
[0121] Curve G2 corresponds to the initial state at the start of the test, and curves G3, G4, ..., G7 correspond to the state after increasing test durations. The time tmin, corresponding to the end of movement of the magnetic core 3, gradually shifts towards increasingly higher values. The direction of variation is highlighted by the arrow fe. This shift reflects an increasingly difficult movement of the mechanical parts of the switching device. On curve G7, the current is almost constant, which shows that the magnetic core is almost blocked in its movement. Such a state corresponds to a failure of the switching device.
[0122] According to one embodiment of the proposed method, the detection method comprises the sub-steps: - calculate a value of a statistical parameter D representative of a fluctuation of the values of the set E of values of the polynomial of the determined reaction time ta and of the determined parameter il, - determine a degradation of the electromagnetic actuator 1 from the calculated value of the statistical parameter D.
[0123] The evolution of the values of the set E during successive actuations is followed quantitatively using the statistical parameter D.
[0124] The statistical parameter D representative of a fluctuation of the values of the set E of values of the polynomial of the determined reaction time ta and of the determined quantity it includes a difference d between: - a current value of the polynomial P of the determined reaction time ta and of the determined quantity il, determined for a current actuation of the switching device 30, and - an average value Moy of the values of the polynomial P of the determined reaction time ta and of the determined quantity il obtained for a predetermined number M of actuations preceding the current actuation of the switching device 30.
[0125] The average value Moy may be a sliding average calculated from the M values corresponding to the M actuations preceding the current actuation, and comprising a number of values equal to the predetermined number M of actuations. The current actuation is not included in the subset of values taken into account for the calculation of the average value. This subset comprises M values.
[0126] According to an example of implementation of the detection method, the statistical parameter D representative of a fluctuation of the values of the set E of values of the polynomial of the determined reaction time ta and of the determined quantity il comprises a standard deviation of the values of the polynomial of the determined reaction time ta and of the determined quantity il determined for a set of actuations of the switching device 30 carried out under reference conditions corresponding to a new state of the switching device 30. The standard deviation of a set of samples is defined as the magnitude equal to the square root of the variance of that set of samples. The variance is itself defined by the mathematical expectation of the square of the deviations from the mean, or the quadratic mean of the deviations between the values of the set of samples and the mean of those values.
[0127] The set of actuations of the switching device 30 carried out under reference conditions comprises for example 20 successive actuations of the switching device.
[0128] The proposed method thus includes a calibration phase making it possible to quantify the nominal variations of the value of the polynomial of the determined reaction time ta and of the quantity il representative of the current flowing in the electromagnetic actuator 1 during the actuation of the switching device 30. These nominal variations correspond to the variations observed in a reference state in which the switching device 30 does not exhibit any degradation.
[0129] The reference state corresponds for example to a new state of the switching device 30. The new state is understood to mean a period starting from the first actuation of the switching device, lasting a predetermined maximum duration and comprising a predetermined maximum number of actuations. In other words, the new state corresponds to a period of time.
[0130] The values acquired under these reference conditions make it possible to determine the nominal variability of the quantity equal to the polynomial of the determined reaction time ta and of the determined quantity il. This variability is here characterized by the mathematical quantity equal to the standard deviation of the quantity equal to the polynomial of the determined reaction time ta and of the determined quantity il, determined for the actuations corresponding to the calibration phase. This variability is characterized from a predetermined number K of values corresponding to a predetermined number of actuations. For example, K=20 successive actuations carried out in the new state of the switching device can make it possible to characterize the initial variability of the quantity used to determine a degradation of the switching device 30.
[0131] The proposed method comprises a measurement phase in which the variations of the value of the polynomial of the determined reaction time ta and of the quantity il representative of the current flowing in the electromagnetic actuator 1 are analyzed. The measurement phase follows the calibration phase. The measuring phase is, for example, carried out throughout the duration of use of the switching device 30.
[0132] [Fig.5] illustrates the values of the quantity P equal to the polynomial of the determined reaction time ta and of the determined quantity il, for different actuations. Part A shows the measurements taken at a first time tl. Part B of the figure shows the measurements taken at a second time t2, which is later than tl.
[0133] The measurement points framed by the box designated by J0 are those carried out under reference conditions corresponding to a new state of the switching device 30. To simplify the figure, only 7 measurement points have been shown. It can be noted that the dispersion of the values of the quantity P is low. The sign EcO denotes the standard deviation of the values corresponding to the set of actuations of the switching device 30 carried out under conditions of reference, and taken into account for the calibration phase. In the example shown, the values taken into account for determining the reference standard deviation correspond to consecutive actuations of the electromagnetic actuator 1. It is also possible that the values do not correspond to consecutive actuations, i.e. some actuations may not be taken into account.
[0134] In part A of [Fig.5], the measurement points framed by the box designated by J1 are the points used at time t1 for the measurement phase. As previously, to simplify the figure only 10 measurement points of the quantity P have been represented. The value Pn, determined at time tl, is the current value at time tl, i.e. the most recent value, corresponding to the most recent command of the electromagnetic actuator 1. The dotted horizontal line indicates the average mean value of the values taken into account, i.e. those present in the JL frame The arrow designated by dl illustrates the difference dl between the current value Pnet and the average value avg calculated on the example of [Fig.5] on the 10 measurement points preceding the current measurement.
[0135] In part B of [Fig.5], the measurement points framed by the box designated by J2 are the points used at time t2 for the measurement phase. As previously, 10 measurement points are used in the figure. The value determined at time t2 is the current value at time t2, i.e. the most recent value. Compared to time t1, 4 new measurements have been acquired, and the 4 oldest values of frame J1 are not used at time t2 and are not part of frame J2. The dotted horizontal line indicates the average value avg2 of the values taken into account, i.e. those present in the J2 frame. The arrow designated by d2 illustrates the difference d2 between the current value Pn+4 and the average value avg2.
[0136] According to one embodiment of the detection method, the statistical parameter D representative of a fluctuation of the polynomial of the determined reaction time ta and of the determined quantity il is equal to the ratio of: - the difference d between a current value of the polynomial P determined for a current actuation and the average value Moy of the values of the polynomial P obtained for a predetermined number M of actuations preceding the current actuation, and - the determined standard deviation of the values of the polynomial of the determined reaction time ta and of the determined quantity il, determined for a set of actuations of the switching device 30 carried out under reference conditions corresponding to a new condition of the switching device 30.
[0137] The proposed statistical parameter D allows robust detection of degradation of the electromagnetic actuator 1, while being simple to implement. In particular, the necessary calculations are easily carried out in real time, which also allows detection in real time of the presence of degradation.
[0138] The statistical parameter D representative of a fluctuation of the polynomial of the determined reaction time ta and of the determined quantity il is thus equal, for a measurement of rank i, to:
[0139] [Math.l]
[0140] With P; the determined value of the polynomial P for an actuation of rank i, D; the calculated value of the statistical parameter D for the actuation of rank i, M the number of actuations taken into account for the determination of the average value, K is a number of actuations carried out under reference conditions corresponding to a new state of the switching device 30. That is to say that K is the number of actuations taken into account for the initial calibration
[0141] A degradation of the electromagnetic actuator 1 is determined when the absolute value of the statistical parameter D representative of a fluctuation of the polynomial of the determined reaction time ta and of the determined quantity il is greater than a first predetermined positive threshold SL By definition, the absolute value of a given number is its numerical value without regard to its sign. If a number is positive, its absolute value is thus equal to that number. If a number is negative, its absolute value is equal to the opposite of that number.
[0142] A degradation is said to be determined when a degradation is detected.
[0143] The value chosen for the first positive predetermined threshold SI makes it possible to adjust the sensitivity of the proposed detection method. The first predetermined positive threshold SI is for example between 2 and 3. The closer the chosen threshold is to 1, the more sensitive the fault detection will be, i.e. a small deviation from the reference conditions will be interpreted as the appearance of degradation.
[0144] Conversely, an absence of degradation of the electromagnetic actuator 1 is determined when the absolute value of the statistical parameter D representative of a fluctuation of the polynomial of the determined reaction time ta and of the quantity de- completed it is less than or equal to the first predetermined positive threshold SI.
[0145] A low value of the absolute value of the statistical parameter D, indicating a small deviation between the current behavior of the electromagnetic actuator 1 and its behavior in the new state, indicates an operating state close to the new state. An absence of degradation can thus be confirmed.
[0146] According to an exemplary embodiment of the detection method, the degradation of the electromagnetic actuator 1 is classified into a first type of degradation, called minor degradation, when the absolute value of the statistical parameter D representative of a fluctuation of the polynomial of the determined reaction time ta and of the determined quantity il is greater than a first predetermined positive threshold SI and less than a second predetermined positive threshold S2. The second predetermined positive threshold S2 is for example between 4 and 5.
[0147] According to an exemplary embodiment of the detection method, the degradation of the electromagnetic actuator 1 is classified into a second type of degradation, called major degradation, when the absolute value of the statistical parameter D representative of a fluctuation of the polynomial of the determined reaction time ta and of the determined quantity il is greater than the second predetermined positive threshold S2.
[0148] It will be noted that the proposed method can be implemented without performing a direct calculation of the absolute value of the statistical parameter D. Indeed, the determined value of the statistical parameter D can be compared on the one hand with the threshold values SI, S2, which are positive, and on the other hand with the opposite -SI, -S2 of these threshold values. A possible degradation can be determined on the basis of this double comparison.
[0149] The statistical parameter D used thus allows a quantification of the severity of the degradation, and not only a determination of the presence or absence of a degradation. The operators of the electrical circuit 50 on which the switching device is used can thus follow the evolution of the device over time, and react accordingly.
[0150] The detection method may comprise a step of emitting an alert signal in response to a determination of degradation of the electromagnetic actuator 1.
[0151] The alert signal may be, for example, a code stored in an electronic control unit. Alternatively or additionally, the alert signal may be the lighting of a warning light.
[0152] As a further variant or in addition, the alert signal may be a display of a message on a control screen. Other types of alert are of course possible. The alert signal issued may be different when the detected degradation is a so-called minor degradation and when the detected degradation is a so-called serious degradation. major.
[0153] The alert signal emitted allows users to plan and carry out a maintenance operation or replacement of the degraded switching device, in order to correct the diagnosed problem.
[0154] No alert signal is issued when no degradation has been determined. In other words, no alert is issued when the proposed method indicates that the electromagnetic actuator 1 is free from degradation.
Claims
Claims
1. Method for detecting a degradation of a switching device (30) comprising an electromagnetic actuator (1) configured to unlock a control mechanism (4) comprising an elastic member (7) configured to move a movable electrical contact (10) so as to open or close an electrical circuit (50), the method comprising the steps: (i) controlling the electromagnetic actuator (1), (ii) measuring a current (C) flowing in the electromagnetic actuator (1) when controlling the electromagnetic actuator (1), (iii) determining from the measured current (C) a reaction time (ta) of the electromagnetic actuator (1), (iv) determining from the measured current (C) a quantity (il) representative of the current flowing in the electromagnetic actuator (1) when controlling the electromagnetic actuator (1), (v) determining a parameter (P) in the form of a polynomial of the determined reaction time (ta) and of the determined quantity (il) representative of the current flowing in the electromagnetic actuator (1) when controlling the electromagnetic actuator (1), (vi) iterating steps (i) to (v) for a set of successive controls of the electromagnetic actuator (1) so as to obtain a set (E) of values of the determined parameter (P), (vii) determining a degradation of the electromagnetic actuator (1) from the evolution of the values of the assembly (E) during successive commands of the electromagnetic actuator (1).
2. A detection method according to claim 1, wherein the switching apparatus (30) comprises: - an electrical contact (10) movable between an open position (O) of an electrical circuit (50) and a closed position (F) of the electrical circuit (50), - a control mechanism (4) comprising: — an elastic member (7) configured to move the electrical contact (10) from the closed position (F) to the open position (O) or from the open position (O) to the closed position (F), so as to respectively open or close the electrical circuit (50), — an unlocking member (8) configured to move from a locking position (V) in which the elastic member (7) is held in a tensioned state at a release position (L) in which the elastic member (7) is free to relax so as to move the electrical contact (10) from the closed position (F) to the open position (0) or from the open position (0) to the closed position (F), - an electromagnetic actuator (1) configured to move the unlocking member (8) from the locking position (V) to the release position (L).
3. Detection method according to claim 1 or 2, in which the parameter (P) is equal to the product of the determined reaction time (ta) and the determined quantity (il) representative of the current flowing in the electromagnetic actuator (1) when controlling the electromagnetic actuator (1).
4. Detection method according to one of the preceding claims, in which the reaction time (ta) of the electromagnetic actuator (1) is determined from the temporal variations of the measured current (C).
5. Detection method according to one of the preceding claims, in which the reaction time (ta) of the electromagnetic actuator is equal to a time elapsed between an instant (tO) of start of circulation of the electric current in the electromagnetic actuator (1) and an instant (tmin) corresponding to a local minimum value of the electric current circulating in the electromagnetic actuator (1).
6. Detection method according to one of the preceding claims, in which the quantity (il) representative of the current flowing in the electromagnetic actuator (1) during actuation of the switching device (30) is a local maximum value of the electric current flowing in the electromagnetic actuator (1).
7. Detection method according to one of the preceding claims, comprising the sub-steps: - calculating a value of a statistical parameter (D) representative of a fluctuation of the values of the set (E) of values of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (il), - determining a degradation of the electromagnetic actuator (1) from the calculated value of the statistical parameter (D).
8. Detection method according to the preceding claim, in which the statistical parameter (D) representative of a fluctuation of the values of the set (E) of values of the polynomial of the determined reaction time (ta) and of the determined quantity (il) comprises a difference (d) between: - a current value of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (il), determined for a current actuation of the switching device (30), and - an average value (Avg) of the values of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (il) obtained for a predetermined number (M) of actuations preceding the current actuation of the switching device (30).
9. Detection method according to claim 7 or 8, in which the statistical parameter (D) representative of a fluctuation of the values of the set (E) of values of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (il) comprises a standard deviation of the values of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (il), determined for a set of actuations of the switching device (30) carried out under reference conditions corresponding to a new state of the switching device (30).
10. Detection method according to one of claims 7 to 9, in which the statistical parameter (D) representative of a fluctuation of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (il) is equal to the ratio of: - the difference (d) between a current value of the polynomial (P) determined for a current actuation and the average value (Moy) of the values of the polynomial (P) obtained for a predetermined number (M) of actuations preceding the current actuation, and of - the determined standard deviation of the values of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (il) determined for a set of actuations of the switching device (30) carried out under reference conditions corresponding to a new state of the switching device (30).
11. Detection method according to one of claims 7 to 10, in which the statistical parameter (D) representative of a fluctuation of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (il) is equal to: [Math.l] i 1 With P; the determined value of the polynomial (P) for an actuation of rank i, Di the calculated value of the statistical parameter (D) for the actuation of rank i, M a number of actuations taken into account to determine an average value, K a number of actuations carried out under reference conditions corresponding to a new state of the switching device (30).
12. Detection method according to one of claims 7 to 11, in which a degradation of the electromagnetic actuator (1) is determined when the absolute value of the statistical parameter (D) representative of a fluctuation of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (il) is greater than a first predetermined positive threshold (SI).
13. Detection method according to the preceding claim, in which the degradation of the electromagnetic actuator (1) is classified into a first type of degradation, called minor degradation, when the absolute value of the statistical parameter (D) representative of a fluctuation of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (il) is greater than a first predetermined positive threshold (SI) and less than a second predetermined positive threshold (S2).
14. Detection method according to claim 12 or 13, in which the degradation of the electromagnetic actuator (1) is classified into a second type of fault, called major degradation, when the absolute value of the statistical parameter (D) representative of a fluctuation of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (il) is greater than the second predetermined positive threshold (S2).
15. Detection method according to one of the preceding claims, comprising a step of emitting an alert signal in response to a determination of a degradation of the electromagnetic actuator (1).
16. Switching apparatus (30) comprising: - an electromagnetic actuator (1) configured to unlock a control mechanism (4) comprising an elastic member (7) configured to move a movable electrical contact (10) so as to open or close an electrical circuit (50), - an electronic control unit (15) configured to implement the degradation detection method according to one of the preceding claims, wherein the switching apparatus (30) is a circuit breaker, or a switch, or a disconnector.