Process for detecting degradation of switching device comprising electromagnetic actuator

Abstract

It is proposed a process for detecting degradation of a switching device (30), the switching device (30) comprising an electromagnetic actuator (1) configured to unlock a control mechanism (4), the control mechanism (4) comprising an elastic member (7), the process comprising the steps of: (i) commanding the electromagnetic actuator (1), (ii) measuring a current (C) flowing in the electromagnetic actuator (1), (iii) determining a reaction time (ta) of the electromagnetic actuator (1) from the measured current (C), (iv) determining from the measured current (C) a quantity (i1) representative of the current flowing in the electromagnetic actuator (1), (v) determining a parameter (P) in the form of a polynomial of the determined reaction time (ta) and the determined quantity (i1) representative of the current flowing in the electromagnetic actuator (1), (vi) iterating steps (i) to (v) on a set of consecutive commands of the electromagnetic actuator (1) in order to obtain a set of values (E) of a predetermined parameter (P), (vii) determining a degradation of the electromagnetic actuator (1) from the evolution of the values in the set (E) during successive commands of the electromagnetic actuator (1).

Description

Technical Field

[0001] The present invention relates to the field of switchgear for electrical equipment, such as for low-voltage and medium-voltage electrical equipment. The switchgear may be, for example, a circuit breaker. Background Art

[0002] The low or medium voltage switchgear may include one or more electromagnetic actuators making it possible to unlock a spring-loaded control mechanism, making it possible to move a movable electrical contact, thereby opening or closing an electrical circuit. In the case of a circuit breaker, in the event of a fault in the electrical circuit, the electrical circuit is opened. The fault may be manifestly a short circuit between two phases, or a short circuit between one phase and ground. Closing the electrical circuit makes it possible to energize the load.

[0003] The electromagnetic actuator comprises a movable magnetic core and a control coil. Under the action of the current flowing through the control coil, the magnetic core moves. The magnetic core is mechanically coupled to a control mechanism acting on a movable electrical contact so as to be able to open or close the circuit.

[0004] In order to ensure the safety of the electrical network and personnel, it is important to be able to check whether the switchgear operates correctly throughout its life. To this end, the circuit breaker may include a measurement circuit that makes it possible to diagnose the condition of the electromagnetic actuator in real time. Such an electromagnetic actuator is often subject to the effects of aging, which may gradually reduce its electrical or mechanical functionality and eventually render it inoperative. It is therefore important for the user to be able to track the evolution of the condition of the electromagnetic actuator. It is hoped that the user will be able to intervene at the right moment in the management of the electrical network to repair or replace the electromagnetic actuator. Summary of the invention

[0005] To this end, the invention proposes a process for detecting degradation of a switching device comprising an electromagnetic actuator configured to unlock a control mechanism, the control mechanism comprising an elastic member configured to move a movable electrical contact in order to open or close an electrical circuit, the process comprising the following steps:

[0006] (i) commanding an electromagnetic actuator,

[0007] (ii) measuring the current flowing in the electromagnetic actuator during the command of the electromagnetic actuator,

[0008] (iii) determining the reaction time of the electromagnetic actuator from the measured current,

[0009] (iv) determining from the measured current a quantity representative of the current flowing in the electromagnetic actuator during the command of the electromagnetic actuator,

[0010] (v) determining the determined reaction time and the determined parameters in the form of a polynomial representing the amount of current flowing in the electromagnetic actuator during the command of the electromagnetic actuator,

[0011] (vi) iterating steps (i) to (v) for a set of consecutive commands for the electromagnetic actuator so as to obtain a set of values ​​of a predetermined parameter,

[0012] (vii) determining the degradation of the electromagnetic actuator from the evolution of the values ​​in the set during successive commands of the electromagnetic actuator.

[0013] A process for detecting degradation of a switching device is a process that makes it possible to detect the evolution of the behavior of the switching device due to the aging of its components.

[0014] Aging of components includes, for example, wear, deformation, effects of corrosion, evolution of magnetic properties, evolution of the tribological properties of the components.

[0015] In the case of nominal operation of the electromagnetic actuator, the values ​​in the set do not evolve substantially during continuous actuation. In other words, the various values ​​in the set are substantially constant. In contrast, the gradual degradation of the electromagnetic actuator tends to cause an evolution of the values, in particular fluctuations of these values, during continuous actuation. The values ​​of the set are no longer substantially constant, but show significant fluctuations. This gradual evolution makes it possible to detect the degradation of the magnetic actuator of the switching device.

[0016] The process for detecting switchgear degradation is also a process that makes it possible to predict the occurrence of switchgear failure.

[0017] Specifically, uncorrected degradation of the switching device may eventually lead to the occurrence of a failure.

[0018] The features listed in the following paragraphs can be implemented independently of each other or in any technically possible combination:

[0019] In step (vii), the evolution of the values ​​in the set may be the fluctuation of the values ​​in the set during successive commands of the electromagnetic actuator.

[0020] The set of values ​​of the determined reaction time and of the polynomial of the determined quantity is obtained by a series of consecutive commands of the electromagnetic actuator of the switching device.

[0021] Each value of the set of values ​​of the determined reaction time and the polynomial of the determined quantity corresponds to a different actuation of the electromagnetic actuator of the switching device.

[0022] The switching device may be a circuit breaker.

[0023] As a variant, the switching device may be a switch.

[0024] According to another variant, the switching device may be an isolator.

[0025] The switchgear comprises:

[0026] - electrical contacts movable between a position for opening an electrical circuit and a position for closing an electrical circuit,

[0027] - Control bodies, including:

[0028] a resilient member configured to move the electrical contact from a closed position to an open position or from an open position to a closed position, thereby opening or closing the electrical circuit, respectively,

[0029] an unlocking member configured to move from a locked position, in which the elastic member is held in a tensioned state, to a free position, in which the elastic member is free to relax, thereby moving the electrical contact from the closed position to the open position, or from the open position to the closed position,

[0030] - an electromagnetic actuator configured to move the unlocking member from the locked position to the free position.

[0031] According to one embodiment (which is referred to as the first embodiment):

[0032] - the resilient member is configured to move the electrical contacts from a closed position to an open position so as to open the electrical circuit, and

[0033] The unlocking member is configured to transfer from a locked position, in which the elastic member is kept in a tensioned state, to a free position, in which the elastic member is free to relax, thereby moving the electrical contacts from the closed position to the open position.

[0034] According to another embodiment (which is referred to as the second embodiment):

[0035] - the resilient member is configured to move the electrical contact from an open position to a closed position so as to close the electrical circuit,

[0036] The unlocking member is configured to be transferred from a locked position, in which the elastic member is kept in a tensioned state, to a free position, in which the elastic member is free to relax, thereby moving the electrical contacts from the open position to the closed position.

[0037] The elastic member is configured to apply a driving force to the movable electrical contact.

[0038] The resilient member is connected to a drive element configured to move the movable electrical contact to open or close an electrical circuit.

[0039] The drive element comprises, for example, a connecting rod.

[0040] According to the first embodiment, the unlocking member can be transferred from a locked position to an unlocked position, in which the elastic member of the control mechanism is elastically pressurized and the movable electrical contact is in a position to close the circuit, and in the unlocked position, the elastic member of the control mechanism is released and moves the movable electrical contact from the position to close the circuit to the position to open the circuit.

[0041] According to a second embodiment, the unlocking member can be transferred from a locked position to an unlocked position, in which the elastic member of the control mechanism is elastically pressurized and the movable electrical contact is in a position for opening the circuit, and in the unlocked position, the elastic member of the control mechanism is released and moves the movable electrical contact from the position for opening the circuit to the position for closing the circuit.

[0042] "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 locked position to the free position.

[0043] An electromagnetic actuator is an electromagnet.

[0044] The electromagnetic actuator includes a control coil and a magnetic core configured to move under the influence of a magnetic field generated by the flow of current in the control coil.

[0045] The magnetic core is, for example, translatable.

[0046] The magnetic core is mechanically coupled to an unlocking member configured to transfer from a locked position, in which the elastic member is held in a tensioned state, to a free position, in which the elastic member is free to relax, thereby moving the electrical contacts from the closed position to the open position.

[0047] “Measuring the current flowing in the electromagnetic actuator” means measuring the intensity of the current flowing in the electromagnetic actuator.

[0048] The current flowing in the electromagnetic actuator is detected by an electronic measuring circuit.

[0049] The current flowing in the electromagnetic actuator is sampled, for example, at a sampling frequency between 1 kHz and 100 kHz.

[0050] The electromagnetic actuator comprises a coupling element mechanically coupling the magnetic core to the unlocking member.

[0051] The control mechanism may include a rotatable element.

[0052] The control mechanism may include a translatable element.

[0053] The elastic member may be a spring, such as a helical spring or a spiral spring.

[0054] The electromagnetic actuator is configured to trigger movement of the movable electrical contact to open the electrical circuit.

[0055] When the switching device is a circuit breaker, the electromagnetic actuator is configured to trigger the opening of the circuit in the event of a fault on the circuit.

[0056] According to one aspect of the proposed detection process, the reaction time of the electromagnetic actuator is determined from the time variation of the measured current.

[0057] Therefore, the proposed process does not require the installation of any additional sensors, such as movement sensors of the electrical contacts or of the elements of the control mechanism.

[0058] The proposed procedure comprises a sub-step of determining the temporal variation of the measurement current.

[0059] According to one example of implementation of the detection process, the reaction time of the electromagnetic actuator is equal to the time elapsed between the moment when the current starts to flow in the electromagnetic actuator and the moment corresponding to the local minimum of the current flowing in the electromagnetic actuator.

[0060] According to one embodiment of the detection process, the quantity representative of the current circulating in the electromagnetic actuator during actuation of the switching device is a local maximum of the current circulating in the electromagnetic actuator.

[0061] In step (v), the parameter is determined by a polynomial with two indeterminates, that is, by the sum of a monomial with two indeterminates. The first indeterminate is the determined reaction time and the second indeterminate is the determined quantity representative of the current circulating in the electromagnetic actuator during its command.

[0062] Each monomial of the polynomial is therefore determined by the product of a determined reaction time given a first power, a determined quantity representative of the current circulating in the electromagnetic actuator during its command given a second power and a constant coefficient.

[0063] Each monomial can be written in the following form:

[0064] [Mathematical formula 2]

[0065]

[0066] Therefore, the polynomial forming the parameter P can be written as:

[0067] [Mathematical formula 3]

[0068]

[0069] in,

[0070] Coefficients k0,…,kH Take rational values,

[0071] Coefficients L0,…,L H takes rational values, and

[0072] Coefficient A i Take a rational value.

[0073] Among a large number of investigated parameters, the applicant concluded that the gradual degradation of the electromagnetic actuator is best explained by a polynomial formed by the reaction time of the electromagnetic actuator and the local maximum of the circuit current in the electromagnetic actuator. The polynomial is therefore a polynomial with two indefinite terms.

[0074] According to one particular embodiment of the proposed detection process, the parameter P is equal to the product of the determined reaction time and the determined quantity representative of the current circulating in the electromagnetic actuator during the command of the electromagnetic actuator.

[0075] In other words, in the particular case in which the process is implemented, the polynomial comprises a single term, in other words a monomial. The first power of a monomial is equal to 1, and the second power of a monomial is also equal to 1.

[0076] The monomial formed is then equal to the product of the determined reaction time and the determined value representing the amount of current flowing in the electromagnetic actuator during the command of the electromagnetic actuator, that is, equal to the product of the value of the determined reaction time and the determined value representing the amount of current flowing in the electromagnetic actuator during the command of the electromagnetic actuator.

[0077] At a time between the time when the current starts to flow in the electromagnetic actuator and the time corresponding to the local minimum value of the current flowing in the electromagnetic actuator, a local maximum value of the current is obtained.

[0078] According to one embodiment, the detection process includes the sub-steps of:

[0079] - calculating the value of a statistical parameter representative of the fluctuations of the values ​​in the set of values ​​of the polynomial of the determined reaction time and the determined quantity,

[0080] - Determining the degradation of the electromagnetic actuator from the calculated values ​​of the statistical parameters.

[0081] According to one example of implementation of the detection process, the statistical parameter representing the fluctuation of the values ​​in the set of values ​​of the polynomial of the determined reaction time and the determined quantity comprises the difference between:

[0082] - the determined reaction time and the current value of the polynomial of the determined quantity determined for the current actuation of the switching device, and

[0083] an average value of the determined reaction time and of the value of the polynomial of the determined quantity obtained for a predetermined number of actuations preceding the current actuation of the switching device.

[0084] The average may be a running average calculated from values ​​corresponding to actuations preceding the current actuation and comprising a number of values ​​equal to a predetermined number of actuations.

[0085] According to an example of an implementation of the detection process, the statistical parameters representing the fluctuations of the values ​​in a set of values ​​of the polynomial of the determined reaction time and the determined quantity include the standard deviation of the values ​​of the polynomial of the determined reaction time and the determined quantity determined for a set of actuations of the switching device performed under reference conditions corresponding to a new condition of the switching device.

[0086] A set of actuations of the switching device performed under reference conditions comprises, for example, 20 consecutive actuations of the switching device.

[0087] The proposed process thus comprises a calibration phase making it possible to quantify the nominal variations of the determined reaction times and of the value of the polynomial representing the amount of current circulating 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 exhibits neither manufacturing defects nor wear.

[0088] The reference state corresponds, for example, to a new condition of the switching device.

[0089] The proposed procedure comprises a measurement phase in which the determined reaction time and the variation of the value of a polynomial representing the amount of electric current circulating in the electromagnetic actuator are analyzed.

[0090] The calibration phase is followed by the measurement phase.

[0091] The measuring phases are performed throughout the service life of the switching device.

[0092] According to one embodiment of the detection process, the statistical parameter representing the fluctuation of the polynomial of the determined reaction time and the determined quantity is equal to the following ratio:

[0093] - the difference between the current value of the polynomial determined for the current actuation and the average of the values ​​of the polynomial obtained for a predetermined number of actuations preceding the current actuation, and

[0094] - a determined standard deviation of the determined reaction time and of the value of the polynomial of the determined quantity determined for a set of actuations of the switching device carried out in a reference condition corresponding to a new condition of the switching device.

[0095] The proposed statistical parameters enable a robust detection of possible degradation of the electromagnetic actuator while being easy to implement. In particular, the necessary calculations can be easily performed in real time, which enables a fast detection of possible degradation.

[0096] According to one embodiment of the detection process, the statistical parameter representing the fluctuation of the polynomial of the determined reaction time and the determined quantity is equal to:

[0097] [Mathematical formula 1]

[0098]

[0099] in,

[0100] P i is the determined value of the polynomial (P) for the actuation of position i,

[0101] D i is the calculated value of the statistical parameter (D) for the actuation of position i,

[0102] M is the number of actuations considered to determine the mean value,

[0103] K is the number of actuations performed in the reference condition corresponding to the new condition of the switching device.

[0104] According to one example of implementation of the detection process, degradation of the electromagnetic actuator is determined when the absolute value of a statistical parameter representative of the polynomial of the determined reaction time and of the fluctuation of the determined quantity is above a first positive predetermined threshold value.

[0105] The value chosen for the first positive predetermined threshold makes it possible to adjust the sensitivity of the proposed detection process.

[0106] The first positive predetermined threshold is between 2 and 3, for example.

[0107] Conversely, when the absolute value of the statistical parameter representing the fluctuation of the polynomial of the determined reaction time and the determined quantity is lower than or equal to a first positive predetermined threshold value, it is determined that the electromagnetic actuator is not degraded.

[0108] In other words, when the absolute value of the statistical parameter takes a value higher than a predetermined threshold value, degradation is determined.

[0109] In contrast, when the absolute value of the statistical parameter takes a value lower than a predetermined threshold value, it is determined that there is no degradation.

[0110] According to one example of an embodiment of the detection process, degradation of the electromagnetic actuator is classified as a first type of degradation, called slight degradation, when the absolute value of a statistical parameter representing the fluctuations of the polynomial of the determined reaction time and the determined quantity is above a first positive predetermined threshold and below a second positive predetermined threshold.

[0111] The second positive predetermined threshold is, for example, between 4 and 5.

[0112] According to one example of embodiment of the detection process, degradation of the electromagnetic actuator is classified as a second type of degradation, called significant degradation, when the absolute value of a statistical parameter representing the fluctuations of the polynomial of the determined reaction time and the determined quantity is above a second positive predetermined threshold.

[0113] Thus, the statistical parameters used make it possible to quantify the severity of degradation rather than just the presence or absence of degradation.

[0114] The detection process may include the step of sending an alarm signal in response to a determination that the electromagnetic actuator is degraded.

[0115] The transmitted alarm signal enables the user to plan and perform maintenance or replacement operations of the switchgear when it is in a degraded or even defective condition.

[0116] When it is determined that there is no degradation, no alarm signal is sent. In other words, when the proposed process indicates that the electromagnetic actuator is not degraded, no alarm is sent.

[0117] The present invention also relates to a switch device, comprising:

[0118] - an electromagnetic actuator configured to unlock a control mechanism comprising a resilient member configured to move electrical contacts to open or close an electrical circuit,

[0119] - An electronic control unit configured to implement the process for detecting degradation as described above.

[0120] According to one embodiment, the switch device comprises:

[0121] - a control circuit configured to cause an electric current to flow in the electromagnetic actuator,

[0122] - A sensor for measuring the current flowing in the electromagnetic actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0123] Further features, details and advantages will become apparent from reading the following detailed description and analyzing the accompanying drawings, in which:

[0124] Figure 1 is a schematic diagram of an electric circuit equipped with a switching device, the circuit being in the open position;

[0125] Figure 2 is a schematic diagram of an electric circuit equipped with a switching device, the circuit being in the closed position;

[0126] Figure 3is a time evolution curve of a current in the electromagnetic actuator during actuation of the electromagnetic actuator of the switching device;

[0127] Figure 4 Depicts the aging process of a switchgear Figure 3 The evolution of the curve;

[0128] Figure 5 is a time diagram illustrating a process according to the present invention; and

[0129] Figure 6 is a block diagram illustrating the various steps of a process according to the present invention. DETAILED DESCRIPTION

[0130] In order to make the drawings easier to read, various elements are not necessarily depicted to scale. In these figures, the same elements have the same reference numerals. Certain elements or parameters can be indexed, that is to say, designated as, for example, the first element or the second element, or in fact the first parameter and the second parameter, etc. The purpose of this index is to distinguish similar but not identical elements or parameters. This index does not mean that an element or parameter has a priority relative to another element or parameter, and the names can be interchangeable. When a specified subsystem includes a given element, this does not exclude the presence of other elements in the subsystem. Similarly, when a specified subsystem includes a given element, it should be understood that the subsystem includes at least the element.

[0131] Figure 1 Schematically depicted is an electric circuit 50. The electric circuit 50 comprises three electric conductors 20, 21, 22, each conductor corresponding to a phase of a medium voltage three-phase network.

[0132] The circuit 50 comprises a switching device 30 .

[0133] The switch device 30 may be a circuit breaker.

[0134] According to a variant, the switching device 30 may be a switch.

[0135] According to another example of application, the switch device 30 may be an isolator.

[0136] The switch device 30 comprises:

[0137] an electromagnetic actuator 1 configured to unlock a control mechanism 4 comprising an elastic member 7 configured to move a movable electrical contact 10 in order to open or close an electrical circuit 50,

[0138] An electronic control unit 25 configured to implement a process for detecting degradation which will be described in detail below.

[0139] The electromagnetic actuator 1 is an electromagnet.

[0140] The electromagnetic actuator 1 includes a control coil 2 and a magnetic core 3 configured to move under the action of a magnetic field generated by the flow of current in the control coil 2 .

[0141] The magnetic core 3 is, for example, translatable.

[0142] The magnetic core 3 is mechanically coupled to an unlocking member 8 configured to transfer from a locking position V, in which the elastic member 7 is maintained in a tensioned state, to a free position L, in which the elastic member 7 is free to relax, thereby moving the electrical contact 10 from the closed position F to the open position O.

[0143] The movable electrical contact 10 is associated with an electrical conductor 20. Likewise, the movable electrical contact 11 is associated with an electrical conductor 21 and the movable electrical contact 12 is associated with an electrical conductor 22.

[0144] exist Figure 1 In FIG. 5 , the movable electrical contact 10 is depicted in an open position, that is to say in a position in which the flow of current in the electrical circuit 50 is interrupted.

[0145] exist Figure 2 In FIG. 5 , the movable electrical contact 10 is shown in a closed position, that is to say in a position in which the flow of electric current in the electrical circuit 50 is possible.

[0146] The electromagnetic actuator 1 comprises a coupling element 13 which mechanically couples the magnetic core 3 to the unlocking member 8 .

[0147] The control mechanism 4 may comprise a rotatable element.

[0148] The control mechanism 4 may comprise a translatable element.

[0149] The control mechanism 4 can move the three movable electrical contacts 10 , 11 , 12 together.

[0150] The electromagnetic actuator 1 is configured to trigger the movement of the movable electrical contact 10 in order to open the electrical circuit 50 .

[0151] When the switching device 30 is a circuit breaker, the electromagnetic actuator 1 is configured to trigger the opening of the electric circuit 50 in the event of a fault on the electric circuit 50 .

[0152] One example of a fault that may occur on the circuit 50 is a short circuit between two different phases. Another type of fault may be a short circuit between a phase and ground.

[0153] The switch device 30 comprises:

[0154] an electrical contact 10 movable between a position O for opening the electrical circuit 50 and a position F for closing the electrical circuit 50 ,

[0155] - Control mechanism 4, comprising:

[0156] a resilient 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, thereby opening or closing the circuit 50, respectively,

[0157] - an unlocking member 8, which is configured to move from a locking position V to a free position L, in which the elastic member 7 is kept in a tensioned state, and in which the elastic member 7 is free to relax, thereby moving 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,

[0158] An electromagnetic actuator 1 configured to move the unlocking member 8 from the locking position V to the free position L.

[0159] according to Figure 1 and Figure 2 The example shown:

[0160] - 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

[0161] The unlocking member 8 is configured to transfer from a locking position V, in which the elastic member 7 is kept in a tensioned state, to a free position L, in which the elastic member 7 is free to relax, thereby moving the electrical contact 10 from the closed position F to the open position O.

[0162] In other words, the control mechanism 4 makes it possible to interrupt the flow of electric current in the electric circuit 50 .

[0163] According to another embodiment not shown:

[0164] 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,

[0165] The unlocking member 8 is configured to transfer from a locking position V, in which the elastic member 7 is kept in a tensioned state, to a free position L, in which the elastic member 7 is free to relax, thereby moving the electrical contact 10 from the open position O to the closed position F.

[0166] In other words, in this case, the control mechanism 4 makes it possible to establish a current flow in the circuit 50 .

[0167] The elastic member 7 is configured to apply a driving force to the movable electrical contact 10 .

[0168] The elastic member 7 may be a spring, such as a helical spring or a spiral spring.

[0169] The resilient member 7 is connected to a drive element 9 which is configured to move the movable electrical contact 10 in order to open or close the electrical circuit 50 .

[0170] The drive element 9 comprises, for example, a connecting rod.

[0171] according to Figure 1 and Figure 2 In the illustrated embodiment, the unlocking member 8 can be transferred from the locked position to the unlocking position V, in which the elastic member 7 of the control mechanism 4 is elastically pressurized and the movable electrical contact 10 is in the position F for closing the circuit 50, and in the unlocking position V, the elastic member 7 of the control mechanism 4 is released and moves the movable electrical contact 10 from the position F for closing the circuit 50 to the position O for opening the circuit 50.

[0172] According to a second embodiment not shown, the unlocking member 8 can be transferred from the locked position to the unlocking position V, in which the elastic member 7 of the control mechanism 4 is elastically pressurized and the movable electrical contact 10 is in the position O for disconnecting the circuit 50, and in the unlocking position V, the elastic member 7 of the control mechanism 4 is released and the movable electrical contact 10 is moved from the position O for disconnecting the circuit 50 to the position F for closing the circuit 50.

[0173] “Unlocking the control mechanism 4 ” means releasing the elastic member 7 of the control mechanism 4 .

[0174] The electromagnet 1 makes it possible to command the movement of the unlocking member 8 , thereby releasing the elastic member 7 .

[0175] The propulsion force that makes it possible to move the movable electric contact 10 is provided by the elastic member 7. The electromagnetic actuator 1 has no direct interaction with the movable electric contact 10. The electromagnetic actuator 1 provides a force of electromagnetic origin, making it possible to move the unlocking member 8 through the coupling element 13. Once the unlocking member 8 is in the unlocking position V, the potential energy stored by the elastic member 7 is released and moves the electric contact 10 through the drive element 9.

[0176] exist Figure 1 In FIG. 1 , the unlocking member 8 is in the locking position V, and the elastic member 7 , schematically depicted as a helical spring, is held in a compressed state. The movable contact 10 is in the closed position, corresponding to the current flowing in the electrical conductor 20 .

[0177] exist Figure 2 , the coupling element 13 has moved the unlocking member 8 to the free position. The elastic member 7 is in a relaxed state, and the drive element 9 has moved the movable electrical contact 10 to its disconnected position, corresponding to the interruption of the current flow in the electrical conductor 20 and thus in the circuit 50.

[0178] The mechanical components of the switch device 30 may degrade during the service life of the switch device, particularly due to wear caused by repeated activation, deformation, and chemical corrosion that may occur.

[0179] Therefore, it is desirable to have a process or method for diagnosing the switching device 30 , that is, a process or method that makes it possible to detect the occurrence of degradation of the switching device 30 .

[0180] Therefore, a process or method for detecting degradation of a switching device 30 is proposed, the switching device 30 comprising an electromagnetic actuator 1 configured to unlock a control mechanism 4, the control mechanism 4 comprising an elastic member 7 configured to move a movable electrical contact 10 so as to open or close an electric circuit 50, the process comprising the following steps:

[0181] (i) commanding the electromagnetic actuator 1,

[0182] (ii) measuring the current C flowing in the electromagnetic actuator 1 during the command of the electromagnetic actuator 1,

[0183] (iii) determining the reaction time ta of the electromagnetic actuator 1 from the measured current C,

[0184] (iv) determining, from the measured current C, a quantity i1 representative of the current circulating in the electromagnetic actuator 1 during the command of the electromagnetic actuator 1,

[0185] (v) determining the determined reaction time ta and the determined parameter P in polynomial form representative of the amount i1 of current circulating in the electromagnetic actuator 1 during the command of the electromagnetic actuator 1,

[0186] (vi) iterating steps (i) to (v) for a set of successive commands for the electromagnetic actuator 1 so as to obtain a set E of values ​​of a predetermined parameter P,

[0187] (vii) Determining the degradation of the electromagnetic actuator 1 from the evolution of the values ​​of the set E during successive commands of the electromagnetic actuator 1 .

[0188] In the case of nominal operation of the electromagnetic actuator 1, the values ​​of the set E do not evolve substantially during continuous actuation. In other words, the various values ​​of the set E are substantially constant. On the contrary, the gradual degradation of the electromagnetic actuator 1 has a tendency to cause the values ​​in the set E to evolve during continuous actuation. The values ​​in the set E are no longer substantially constant, but show significant fluctuations. This gradual evolution makes it possible to detect the degradation of the switching device 30 and the presence of a fault.

[0189] The set E of values ​​of the polynomial P of the determined reaction time ta and of the determined quantity i1 is obtained by a series of consecutive commands of the electromagnetic actuator 1 of the switching device 30 .

[0190] Each value in the set E of values ​​of the polynomial P of the determined reaction time ta and of the determined quantity i1 corresponds to a different actuation of the electromagnetic actuator 1 of the switching device 30 .

[0191] In other words, the value of the reaction time ta is associated with each of the various actuations of the switching device 30. Likewise, the value of the predetermined parameter i1 is associated with each of the various actuations of the switching device 30. The value of the polynomial P of ta and i1 is associated with each actuation of the switching device 30.

[0192] The switch device 30 comprises:

[0193] a control circuit 5 configured to cause an electric current to flow in the electromagnetic actuator 1 ,

[0194] A sensor 6 for measuring the current circulating in the electromagnetic actuator 1 .

[0195] “Measuring the current C flowing in the electromagnetic actuator 1 ” means measuring the intensity of the current flowing in the electromagnetic actuator 1 .

[0196] More specifically, the intensity of the current flowing in the control coil 2 is measured.

[0197] For this purpose, the current C circulating in the electromagnetic actuator 1 is detected by an electronic measuring circuit.

[0198] In the example shown, the current C flowing in the electromagnetic actuator 1 is sampled, for example with a sampling frequency between 1 kHz and 100 kHz.

[0199] In other words, during the actuation phase of the electromagnetic actuator 1 , the current value is measured periodically.

[0200] The reaction time ta of the electromagnetic actuator 1 is determined from the time variation of the current C measured.

[0201] The proposed procedure therefore comprises a sub-step of determining the temporal variation of the measurement current C.

[0202] No sensors other than the sensor for measuring the current are needed to determine the reaction time ta of the electromagnetic actuator 1. In particular, no sensors with movement of the elements connecting the movable electrical contact 10 to the control mechanism 4 of the electromagnetic actuator 1 are needed.

[0203] According to one aspect of the proposed detection process, the reaction time ta of the electromagnetic actuator 1 is equal to the time elapsed between the instant t0 when the current starts to flow in the electromagnetic actuator 1 and the instant tmin corresponding to the local minimum of the current flowing in the electromagnetic actuator 1 .

[0204] Figure 3Schematically depicted is the time evolution of the current circulating in the electromagnetic actuator 1 when the electromagnetic actuator 1 is commanded. This intensity curve as a function of time is denoted with the reference symbol G1.

[0205] The time evolution curve G1 of the current in the electromagnetic actuator 1 includes: a first continuously increasing portion p1; a second continuously decreasing portion p2, the second portion p2 is after the first portion p1; a third continuously increasing portion p3, the third portion p3 is after the second portion p2. The time tmin corresponding to the local minimum of the current corresponds to the time separating the third portion p3 from the second portion p2.

[0206] The time t0 at which the current starts to flow in the electromagnetic actuator 1 corresponds to the start of the continuous increase portion p1.

[0207] The first portion p1 comprises a first portion where the current increases linearly.

[0208] Then, as it approaches the instant t1, the increase in current becomes less rapid. At the instant t1, the current reaches its maximum value since the instant t0, and then the current decreases. This decrease in current is associated with the evolution of the gap between the movable part and the fixed part.

[0209] The current decreases until time tmin, when it reaches its minimum value since time t1, and then increases again.

[0210] The instant tmin corresponds to the end of the movement phase of the magnetic core 3 .

[0211] As soon as the gap no longer evolves, the current starts to increase again, which corresponds to part p3 of the G1 curve.

[0212] The time evolution curve of the current in the electromagnetic actuator 1 comprises a fourth substantially constant portion p4 which follows the third portion p3.

[0213] From the time indicated by t2, the constant current is established at a constant value i2.

[0214] Figure 3 Not shown is the drop in current when the command to coil 2 is interrupted.

[0215] According to one embodiment of the detection process, the quantity i1 representative of the current circulating in the electromagnetic actuator 1 during actuation of the switching device 30 is a local maximum of the current circulating in the electromagnetic actuator 1 .

[0216] The parameter i1 corresponds to the maximum value of the current during the command phase during the movement of the core 3 , which extends between the instant t0 and the instant tmin.

[0217] In step (v), parameter P is determined by the sum of a monomial with two uncertainties: a first uncertainty being the determined reaction time ta and a second uncertainty being the determined quantity i1 representative of the current circulating in the electromagnetic actuator 1 during its command.

[0218] therefore:

[0219] [Formula 4]

[0220]

[0221] Therefore, each monomial of the polynomial M i Determined by the product of: Given the first power K i The determined reaction time ta, and the given second power L i The determined value i1 represents the current flowing in the electromagnetic actuator 1 during the command of the electromagnetic actuator 1, and the constant coefficient A i .

[0222] Each monomial M i It can be written as follows:

[0223] [Mathematical formula 2]

[0224]

[0225] Therefore, the polynomial forming the parameter P can be written as:

[0226] [Mathematical formula 3]

[0227]

[0228] in,

[0229] Coefficients k0,…,k H Take rational values,

[0230] Coefficients L0,…,L H takes rational values, and

[0231] Coefficient A i Take a rational value.

[0232] The polynomial which makes it possible to determine the parameter P comprises, in its most general form, (H+1) monomials.

[0233] Among a large number of studied parameters, the Applicant has concluded that the polynomial formed by the reaction time ta of the electromagnetic actuator 1 and the local maximum i1 of the current in the electromagnetic actuator 1 is the quantity that best describes the progressive degradation of the electromagnetic actuator.

[0234] A polynomial is a polynomial with two indefinite terms, the first indefinite term being the quantity ta and the second indefinite term being the quantity i1.

[0235] According to one particular embodiment of the proposed detection process, the parameter P is equal to the product of the determined reaction time ta and the determined quantity i1 representative of the current circulating in the electromagnetic actuator 1 during the command of the electromagnetic actuator 1 .

[0236] In other words, in this particular case of process implementation, the polynomial P is a monomial whose first power k1 is equal to 1 and whose second power L1 is also equal to 1.

[0237] The polynomial formed is then equal to the product of the determined reaction time ta and the determined quantity i1 representing the current flowing in the electromagnetic actuator 1 during the command of the electromagnetic actuator 1, that is, equal to the multiplication result ta*i1 of the value of the determined reaction time ta and the determined value i1 representing the current flowing in the electromagnetic actuator 1 during the command of the electromagnetic actuator 1.

[0238] For a time t1 between a time t0 at which the current starts to flow in the electromagnetic actuator 1 and a time tmin corresponding to a local minimum value of the current flowing in the electromagnetic actuator 1 , a local maximum value i1 of the current is obtained.

[0239] The local maximum value i1 of the current is a current value obtained at the passage from the first portion p1 to the second portion p2.

[0240] Figure 4 Schematically depicted is the time evolution of the current circulating in the electromagnetic actuator 1 when the electromagnetic actuator 1 is commanded during an accelerated ageing test of the switching device 30 .

[0241] In particular, Figure 4 The evolution of the parameters ta and i1 during this accelerated ageing test is shown. This type of test is carried out under conditions that are harsh with respect to normal use of the switchgear, such as higher temperatures and more corrosive atmospheres than under normal conditions.

[0242] Curve G2 corresponds to the initial state at the beginning of the test, and curves G3, G4, ..., G7 correspond to the states after the number of tests is increased.

[0243] The time tmin corresponding to the end of the movement of the magnetic core 3 gradually moves towards higher and higher values. The direction of change is highlighted by the arrow fe. This movement reflects that the mechanical parts of the switching device are increasingly difficult to move.

[0244] On curve G7, the current is almost constant, which indicates that the magnetic core is almost blocked in its movement. This state corresponds to a failure of the switching device.

[0245] According to one embodiment of the proposed process, the detection process comprises the sub-steps of:

[0246] - calculating the value of a statistical parameter D of a value in a set E of values ​​of the polynomial representing the determined reaction time ta and the predetermined parameter i1,

[0247] - Determination of the degradation of the electromagnetic actuator 1 from the calculated value of the statistical parameter D

[0248] By means of the statistical parameter D, the evolution of the values ​​in the set E during successive actuations is quantitatively monitored.

[0249] The statistical parameter D representing the fluctuation of the values ​​in the set E of values ​​of the polynomial of the determined reaction time ta and the determined quantity i1 comprises the difference d between:

[0250] the current value of the polynomial P of the determined reaction time ta and the determined quantity i1 determined for the current actuation of the switching device 30, and

[0251] a mean value Moy of the values ​​of the polynomial P of the determined reaction times ta and the determined quantities i1 obtained for a predetermined number M of actuations prior to the current actuation of the switching device 30 .

[0252] The mean value Moy may be a running average calculated from M values ​​corresponding to M actuations before the current actuation and comprising a number of values ​​equal to a predetermined number M of actuations. The current actuation is not included in the subset of values ​​considered for calculating the mean value. The subset comprises M values.

[0253] According to an example of the implementation of the detection process, the statistical parameter D representing the fluctuation of the values ​​of the set E of values ​​of the polynomial of the determined reaction time ta and the determined quantity i1 includes the standard deviation of the values ​​of the polynomial of the determined reaction time ta and the determined quantity i1 determined for a set of actuations of the switching device 30 performed under reference conditions corresponding to a new condition of the switching device 30.

[0254] The "standard deviation of a set of samples" is a quantity equal to the square root of the variance of the set of samples. The variance itself is defined by the expected value of the squared deviations from the mean, or in fact by the root mean square of the deviations of the values ​​of the sample set from the mean of those values.

[0255] A set of actuations of the switching device 30 performed under reference conditions comprises, for example, 20 consecutive actuations of the switching device.

[0256] The proposed procedure thus comprises a calibration phase which makes it possible to quantify the nominal variations of the determined reaction time ta and of the value of the polynomial representing the quantity i1 of the current circulating 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 exhibits no degradation.

[0257] The reference state corresponds, for example, to a new condition of the switching device 30 .

[0258] "New condition" means a time period starting from the first actuation of the switching device, lasting a predetermined maximum time and including a predetermined maximum number of actuations. In other words, a new condition corresponds to a time period.

[0259] The values ​​obtained under these reference conditions make it possible to determine a nominal variability of a quantity equal to the polynomial of the determined reaction time ta and the determined quantity i1. Here, this variability is characterized by a mathematical quantity equal to the standard deviation of the quantity equal to the polynomial of the determined reaction time ta and the determined quantity i1 determined for the actuations corresponding to the calibration phase.

[0260] This variability is characterized by a predetermined number K of values ​​corresponding to a predetermined number of actuations. For example, K=20 consecutive actuations performed in a new condition of the switching device make it possible to characterize an initial variability for determining the amount of degradation of the switching device 30 .

[0261] The proposed procedure comprises a measurement phase in which the determined reaction time ta and the variation of the value of the polynomial representing the quantity i1 of the current circulating in the electromagnetic actuator 1 are analysed.

[0262] The calibration phase is followed by the measurement phase.

[0263] The measuring phase takes place, for example, over the entire service life of the switching device 30 .

[0264] Figure 5 The value of the quantity P which is equal to the polynomial of the determined reaction time ta and the determined quantity i1 is shown for various actuations.

[0265] Part A schematically depicts a measurement performed at a first instant t1. Part B of the figure schematically depicts a measurement performed at a second instant t2 after t1.

[0266] The measurement points framed by J0 are the measurement points produced in a reference condition corresponding to a new condition of the switching device 30. In order to simplify the drawing, only 7 measurement points are depicted. It can be noted that the dispersion of the values ​​of the quantity P is low.

[0267] Reference symbol Ec0 denotes the standard deviation of the values ​​corresponding to a set of actuations of the switching device 30 performed under reference conditions and taken into account for the calibration phase.

[0268] In the example depicted, the values ​​considered for determining the reference standard deviation correspond to continuous actuations of the electromagnetic actuator 1. It is also possible that these values ​​do not correspond to continuous actuations, that is to say that certain actuations may not be taken into account.

[0269] exist Figure 5 In part A of FIG. 1 , the measurement points framed by J1 are the points used for the measurement phase at time t1. As mentioned above, only 10 measurement points of the quantity P are depicted in order to simplify the drawing.

[0270] The value P determined at time t1 n is the current value at time t1 , ie the most recent value, corresponding to the most recent command to the electromagnetic actuator 1 .

[0271] The dashed horizontal line represents the mean value moy1 of the values ​​considered, ie those occurring in frame J1.

[0272] The arrow indicated by d1 shows the current value P n and in Figure 5 In the example of , the deviation d1 between the mean values ​​moy1 calculated at the 10 measuring points before the current measurement.

[0273] exist Figure 5 In part B of FIG. 1 , the measurement points framed by the frame designated by J2 are the points used for the measurement phase at time t2. As mentioned above, 10 measurement points are used in the figure.

[0274] The value determined at time t2 is the current value at time t2, that is to say the most recent value. With respect to time t1 , 4 new measurements have been acquired and the 4 oldest values ​​from frame J1 are not used at time t2 and do not form part of frame J2.

[0275] The dashed horizontal line represents the mean value moy2 of the values ​​considered, that is to say those occurring in frame J2.

[0276] The arrow indicated by d2 shows the current value P n+4 The deviation d2 from the mean value moy2.

[0277] According to one embodiment of the detection process, the statistical parameter D representing the fluctuation of the polynomial of the determined reaction time ta and the determined quantity i1 is equal to the following ratio:

[0278] the difference d between the current value of the polynomial P determined for the current actuation and the mean value Moy of the values ​​of the polynomial P obtained for a predetermined number M of actuations prior to the current actuation, and

[0279] - the determined standard deviation of the determined reaction time ta and the value of the polynomial of the determined quantity i1 determined for a set of actuations of the switching device 30 carried out in a reference condition corresponding to a new condition of the switching device 30 .

[0280] The proposed statistical parameter D enables a robust detection of degradation of the electromagnetic actuator 1 while being easy to implement. In particular, the necessary calculations can easily be performed in real time, which makes it possible to detect the presence of degradation also in real time.

[0281] Thus, for the measurement of rank i, the statistical parameter D representing the fluctuation of the polynomial of the determined reaction time ta and the determined quantity i1 is equal to:

[0282] [Mathematical formula 1]

[0283]

[0284] in,

[0285] P i is the determined value of the polynomial P for the actuation of rank i,

[0286] D i is the calculated value of the statistical parameter D for the actuation of rank i,

[0287] M is the number of actuations considered to determine the mean value,

[0288] K is the number of actuations performed in a reference condition corresponding to a new condition of the switching device 30. In other words, K is the number of actuations considered for the initial calibration.

[0289] Degradation of the electromagnetic actuator 1 is determined when the absolute value of the statistical parameter D representing the polynomial fluctuations of the determined reaction time ta and of the determined quantity i1 is above a first positive predetermined threshold value S1 .

[0290] By definition, the absolute value of a given number is its numerical value, regardless of its sign.

[0291] If the number is positive, its absolute value is equal to this number.

[0292] If the number is negative, its absolute value is equal to the opposite of the number.

[0293] When degradation is detected, it can be said that the degradation is determined.

[0294] The value chosen for the first positive predetermined threshold S1 makes it possible to adjust the sensitivity of the proposed detection process.

[0295] The first positive predetermined threshold S1 is between 2 and 3, for example.

[0296] The closer the threshold is chosen to 1, the more sensitive the fault detection will be, that is, small deviations from the reference condition will be interpreted as the presence of degradation.

[0297] Conversely, when the absolute value of the statistical parameter D representing the fluctuations of the polynomial of the determined reaction time ta and the determined quantity i1 is lower than or equal to the first positive predetermined threshold value S1 , it is determined that the electromagnetic actuator 1 is not degraded.

[0298] A small value of the absolute value of the statistical parameter D indicates a small deviation between the current behavior of the electromagnetic actuator 1 and its behavior in a new condition, indicating an operating state close to the new condition. It can therefore be confirmed that there is no degradation.

[0299] According to one example of an embodiment of the detection process, the degradation of the electromagnetic actuator 1 is classified as a first type of degradation, called slight degradation, when the absolute value of the statistical parameter D of the polynomial representing the fluctuations of the determined reaction time ta and the determined quantity i1 is higher than a first positive predetermined threshold S1 and lower than a second positive predetermined threshold S2.

[0300] The second positive predetermined threshold S2 is between 4 and 5, for example.

[0301] According to one example of embodiment of the detection process, the degradation of the electromagnetic actuator 1 is classified as a second type of degradation, called significant degradation, when the absolute value of the statistical parameter D representing the fluctuations of the polynomial of the determined reaction time ta and the determined quantity i1 is higher than a second positive predetermined threshold S2.

[0302] It should be noted that the proposed procedure can be implemented without directly calculating the absolute value of the statistical parameter D. In particular, the determined value of the statistical parameter D can be compared with positive thresholds S1, S2 on the one hand and with the opposite values ​​of these thresholds -S1, -S2 on the other hand. Based on this double comparison, a possible degradation can be determined.

[0303] The statistical parameter D used thus makes it possible to quantify the severity of the degradation, rather than just determine the presence or absence of degradation. An operator of a circuit 50 using a switching device can thus monitor the evolution of the device over the course of time and react accordingly.

[0304] The detection process may include the step of sending an alarm signal in response to the determination of degradation of the electromagnetic actuator 1 .

[0305] The warning signal may be, for example, a code stored in the electronic control unit.

[0306] As an alternative or in addition, the warning signal may be the activation of a warning light.

[0307] As another alternative or supplement, the warning signal may be the display of a message on a monitor.

[0308] Other types of alerts are of course possible.

[0309] The alarm signal sent may be different when the detected degradation is what is called a minor degradation and when the detected degradation is what is called a major degradation.

[0310] The transmitted alarm signal enables the user to plan and execute maintenance or replacement operations of the degraded switchgear in order to correct the diagnosed problem.

[0311] When it is determined that there is no degradation, no alarm signal is sent. In other words, when the proposed process indicates that the electromagnetic actuator 1 is not degraded, no alarm is sent.

Claims

1. A process for detecting degradation of a switching device (30), the switching device (30) comprising an electromagnetic actuator (1) configured to unlock a control mechanism (4), the 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 process comprising the following steps: (i) commanding the electromagnetic actuator (1), (ii) measuring the current (C) flowing in the electromagnetic actuator (1) during the command of the electromagnetic actuator (1), (iii) determining the reaction time (ta) of the electromagnetic actuator (1) from the measured current (C), (iv) determining from the measured current (C) a quantity (i1) representative of the current flowing in the electromagnetic actuator (1) during the command of the electromagnetic actuator (1), (v) determining the determined reaction time (ta) and the determined parameter (P) in the form of a polynomial representing the amount of current (i1) flowing in the electromagnetic actuator (1) during the command of the electromagnetic actuator (1), the parameter (P) being written as: in, Coefficients k0,…,k H Take rational values, Coefficients L0,…,L H takes rational values, and Coefficient A i Take rational values, (vi) iterating steps (i) to (v) for a set of successive commands to the electromagnetic actuator (1) so as to obtain a set (E) of values ​​of a predetermined parameter (P), (vii) determining the degradation of the electromagnetic actuator (1) from the evolution of the values ​​in the set (E) during successive commands of the electromagnetic actuator (1).

2. The detection process according to claim 1, wherein: The switch device (30) comprises: - an electrical contact (10) movable between a position (O) for opening the electric circuit (50) and a position (F) for closing the electric circuit (50), - a control mechanism (4), comprising: - a resilient member (7) configured to move the electrical contact (10) from a closed position (F) to an open position (O) or from an open position (O) to a closed position (F) in order to open or close the circuit (50), respectively, - an unlocking member (8) configured to be transferred from a locked position (V) in which the elastic member (7) is kept in a tensioned state to a free position (L) in which the elastic member (7) is free to relax in order 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 free position (L).

3. The detection process according to claim 1 or 2, wherein: The parameter (P) is equal to the product of the determined reaction time (ta) and a determined quantity (i1) representative of the current circulating in the electromagnetic actuator (1) during the command of the electromagnetic actuator (1).

4. A detection process according to any one of the preceding claims, wherein: The reaction time (ta) of the electromagnetic actuator (1) is determined from the measured time variation of the current (C).

5. A detection process according to any one of the preceding claims, wherein: The reaction time (ta) of the electromagnetic actuator is equal to the time elapsed between the time (t0) when the current starts to flow in the electromagnetic actuator (1) and the time (tmin) corresponding to the local minimum value of the current flowing in the electromagnetic actuator (1).

6. A detection process according to any one of the preceding claims, wherein: The quantity (i1) representing the current flowing in the electromagnetic actuator (1) during actuation of the switching device (30) is a local maximum value of the current flowing in the electromagnetic actuator (1).

7. The detection process according to any one of the preceding claims, comprising the following sub-steps: - calculating the value of a statistical parameter (D) representing the fluctuations in the values ​​of the set (E) of values ​​of the polynomial (P) for the determined reaction time (ta) and the determined quantity (i1), - Determining the degradation of the electromagnetic actuator (1) from the calculated value of the statistical parameter (D).

8. Detection process according to the preceding claim, wherein: The statistical parameter (D) representing the fluctuation of the values ​​in the set (E) of values ​​of the polynomial of the determined reaction time (ta) and the determined quantity (i1) comprises the difference (d) between: - the current value of the polynomial (P) of the determined reaction time (ta) and the determined quantity (i1) determined for the current actuation of the switching device (30), and a mean value (Moy) of the values ​​of the polynomial (P) of the determined reaction time (ta) and the determined quantity (i1) obtained for a predetermined number (M) of actuations prior to the current actuation of the switching device (30).

9. The detection process according to claim 7 or 8, wherein: A statistical parameter (D) representing the fluctuation of the values ​​in a set (E) of values ​​of a polynomial (P) for a determined reaction time (ta) and a determined quantity (i1) comprises a standard deviation of the values ​​of the polynomial (P) for a determined reaction time (ta) and a determined quantity (i1) determined for a set of actuations of the switching device (30) performed under reference conditions corresponding to a new condition of the switching device (30).

10. The detection process according to any one of claims 7 to 9, wherein: The statistical parameter (D) of the fluctuation of the polynomial (P) representing the determined reaction time (ta) and the determined quantity (i1) is equal to the following ratio: - the difference (d) between the current value of the polynomial (P) determined for the current actuation and the mean (Moy) of the values ​​of the polynomial (P) obtained for a predetermined number (M) of actuations prior to the current actuation, and - a determined standard deviation of the values ​​of the polynomial (P) of the determined reaction times (ta) and the determined quantities (i1) determined for a set of actuations of the switching device (30) performed under reference conditions corresponding to new conditions of said switching device (30).

11. The detection process according to any one of claims 7 to 10, wherein: The statistical parameter (D) of the fluctuation of the polynomial (P) representing the determined reaction time (ta) and the determined quantity (i1) is equal to: [Mathematical formula 1] in, P i is the determined value of the polynomial (P) for the actuation of position i, D i is the calculated value of the statistical parameter (D) for the actuation of position i, M is the number of actuations considered to determine the mean value, K is the number of actuations performed in a reference condition corresponding to a new condition of the switching device (30).

12. The detection process according to any one of claims 7 to 11, wherein: Degradation of the electromagnetic actuator (1) is determined when the absolute value of a statistical parameter (D) representing the fluctuations of the polynomial (P) of the determined reaction time (ta) and the determined quantity (i1) is above a first positive predetermined threshold (S1).

13. Detection process according to the preceding claim, wherein: When the absolute value of a statistical parameter (D) representing the fluctuations of the polynomial (P) of the determined reaction time (ta) and the determined quantity (i1) is above a first positive predetermined threshold (S1) and below a second positive predetermined threshold (S2), the degradation of the electromagnetic actuator (1) is classified as a first type of degradation, called slight degradation.

14. The detection process according to claim 12 or 13, wherein: When the absolute value of a statistical parameter (D) representing the fluctuations of the polynomial (P) of the determined reaction time (ta) and the determined quantity (i1) is above a second positive predetermined threshold (S2), the degradation of the electromagnetic actuator (1) is classified as a second type of fault, called major degradation.

15. A detection process according to any one of the preceding claims, comprising the step of sending an alarm signal in response to a determination of degradation of the electromagnetic actuator (1).

16. A switch device (30), comprising: - an electromagnetic actuator (1) configured to unlock a control mechanism (4), the control mechanism (4) comprising an elastic member (7) configured to move a movable electrical contact (10) in order to open or close an electrical circuit (50), - an electronic control unit (15) configured to implement a process for detecting degradation according to any one of the preceding claims, The switch device (30) is a circuit breaker, a switch or an isolator.

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