WO2019115642A1 - Device and method for measuring power of an electricity generator and computer program - Google Patents

Abstract

The invention relates to a device (1) for measuring the instantaneous electric power supplied by a phase of the stator (4) of an electricity-generating rotating machine (2), including a probe (11) for measuring an instantaneous magnetic flux, located on one of the teeth (D) of the stator (4), and a sensor (12) for measuring the instantaneous electric current supplied by the phase. The invention is characterized by a first module (21) for calculating an instantaneous overall magnetic flux of the phase by summing, performed on its turns and for each turn of the phase on the teeth (D) that are surrounded by this turn, of a plurality of instantaneous fluxes, obtained from the instantaneous flux measured by temporal offsets proportional to the angular offsets of the teeth (D) with respect to the given tooth (Dr), and a second module (22) for calculating the instantaneous electric power supplied by the electricity-generating rotating machine (2) from the electric current measured by the sensor (12) and from the instantaneous overall magnetic flux that has been calculated.

Description

 DEVICE, METHOD FOR MEASURING THE POWER OF A

 GENERATOR OF ELECTRICITY AND COMPUTER PROGRAM

The invention relates to a device for measuring the electric power supplied by a rotating machine generating electricity.

 The field of the invention relates to the diagnosis of rotating machines, called alternators or turboalternators, present in particular in power generation plants.

 One of the objectives of the present invention is to make it possible to make the existing or developing diagnostic techniques more reliable, by allowing the devices carrying out this diagnosis to have, in situ, the level of the load (power delivered) of these alternators in real time and this synchronized with the measurement of a relevant observable magnitude - symptomatic behavioral magnitude of the machine.

 In power plants, the alternator - also called "generator" - is an important component ensuring the conversion of mechanical energy into electrical energy. To increase the availability of the means of production and to better target repairs during periodic shutdowns, the operators of the power plants equip their alternators with sensors to monitor the state of degradation and aging of the latter.

The measurements thus received feed real-time automatic devices that can trigger alarms in case of serious defects or give indications on the need for maintenance and on the priority level of repairs scheduled during periodic stops. It is therefore important for the operator to have reliable detection techniques that reflect at all times the genuine state of wear of its generators. A reliable diagnosis is one that does not anticipate the maintenance program of the rotating machine, otherwise it would have the disadvantage of early mobilization of the resource and equipment generating anticipated expenses. In the same way, this programming for maintenance must not be too late, in which case it could lead to a degradation and destruction of the material. A premature stop of the production plant implies a loss of availability on the electricity distribution network, generating penalizing costs and losses to the operator.

 In particular, the diagnostic boxes are known for recording and analyzing in operation the various parameters characterizing the degradation state of the alternators. The analysis of these magnitudes G individually or in combination provides information on the state of the machine, such as, for example, degraded operation, the occurrence of unbalance (eccentricity of the rotor relative to the stator) and electrical short circuits, aging of components.

 Diagnostic boxes are known that use thresholds or identification techniques.

 In threshold diagnostic techniques, a time signal G (t), representative of a quantity of interest G, comprising one or more electrical periods (cycles), is recovered from the alternator sensors. This signal G (t) is then transformed into a frequency representation (fast Fourier Transform) by applying a harmonic analysis to it. The representation in harmonics makes it possible to be freed from the origin of the times and allows a better classification of the eventual defect whose signature is contained in the signal G (t). The amplitude of one or more frequency lines (harmonics) is then compared to a reference (threshold) representative of the ideal case, in which case the machine is in operation without defects. If the difference (s) between the harmonics of the measured signal G (t) and those of the reference signal exceed the thresholds or thresholds predefined in the housing, then an alarm is triggered to indicate the presence of a fault in the rotating machine. The robustness and reliability of a detection technique is quantified by the ratio between the number of justified alarms (presence of real defect) and the number of false alarms (no apparent real defect).

In identification diagnostic techniques, the signal G (t) is also transposed in the frequency domain, then a frequency signature similar to the frequency representation of the signal G (t) is sought in a database containing a set of signatures describing the healthy and degraded states of the machine. The database is commonly constructed from observations previous, expert judgment or computer by simulating a twin digital model of the alternator.

Diagnostic housings in the industry that do not have access to the instantaneous charge value - ie the instantaneous electrical power delivered by the rotating generator machine do not provide a reliable diagnosis. In fact, threshold methods use valid limit values only over a range of operating speeds of the alternator (generally around the nominal operating speed). However, the harmonic spectrum of the magnitude G (t), having remarkable characteristics, exhibits a different behavior according to the state of charge of the machine. It is therefore difficult to establish threshold criteria (rules of discrimination of the healthy state and the state with default) that remain valid and accurate regardless of the state of charge of the machine. This leads to a diagnosis that is not very robust because it is unreliable. To improve the diagnosis based on the threshold criteria, several threshold criteria must be considered. Each must correspond to a given state of charge. Figures 5A and 5B illustrate this difficulty of establishing a general discriminating rule. FIG. 5A shows the harmonic content H (spectrum obtained with the Lourier analysis) of the observed signal, having the harmonics H1, H2, H3, H4, H5 and H6, obtained at a first state of charge 1, where the discriminating harmonics for the charge Pi, Qi are the harmonics H1 and H3. FIG. 5B shows the harmonic content H of this signal, having the harmonics H1, H2, H3, H4, H5 and H6, at a second state of charge (different from the first state of charge), where the discriminating harmonics for the charge P ₂ , Q are the harmonics H1, H2, H4 and H5. It is observed in this case that the discriminant harmonics chosen to establish the threshold are different in the two states of charge.

 Identification detection methods, even if their databases may contain signatures on all operating points of the alternator, are not reliable because they may present a risk of confusion. Indeed, a default signature obtained at a given load may correspond to a signature without defect for another load.

In the state of the art, in order to be able to perform a reliable diagnosis, it is necessary to have adaptive detection limit criteria according to the level of the load or have databases of references classified by level of load, by nature of the defect and by level of gravity thereof. To do this, you need this information on the load in the diagnostic box simultaneously with the size G (t). Therefore, it is necessary to make connections from the places where this information is available. For example, the charging information may be provided by the electricity distribution network through telecommunication or other means. It can also be obtained directly by wire from the control room.

 However, these solutions pose problems of cost and feasibility. On the one hand, equipping the diagnostic boxes of telecommunications or other means with the electricity distribution network manager is very expensive and requires the authorization of the network operator. On the other hand, recovering the load level of the alternator from the control room requires pulling cables and thus having to make crossings in the walls of the installation. These solutions require administrative permissions and generate additional costs. Indeed, if the connections between the alternator and the control room are generally installed, it is necessary to provide a transmission of the load via a wire means between the control room and the detection box. In addition, these additional connections to the detection box are not possible for the simple reason that these additional connections are not provided during the specification and manufacture of these boxes.

Finally, in the event that the installation of means of communication with the electricity distribution network is possible or that the wire connections from the control room would be possible, then the question of the synchronization of the level of the instantaneous charge with the relevant observable magnitude G (t). Indeed, all these data flows are realized with a shift in time which can be more or less important and more or less penalizing. Having a charge state imposed by the electricity distribution network with a few seconds of delay in the control room can be acceptable for the purposes of general information on the level of production, among others, for an operation. routine of a production center. But on the contrary, do not know this state of charge in the diagnostic boxes or know it with a very small delay, such as for example that observed during a sudden change in the level of the load, depending completely on the specific characteristics of the machine diagnosed (of the order of the second or less) can lead to false alarms and therefore to a stoppage of production.

 The object of the invention is to obtain a device and a method for measuring the electrical power supplied by the generating rotary machine, overcoming the disadvantages mentioned above.

 For this purpose, a first object of the invention is a device for measuring an instantaneous electrical power, supplied by at least one phase of the stator of a rotating machine generating electricity, the device comprising

 a probe for measuring a localized instantaneous magnetic flux, referred to as a measured instantaneous flux, between the stator and the rotor of the rotating machine generating electricity, the stator comprising a determined number of teeth, the measurement probe being fixedly located on one of the teeth of the stator,

 a sensor for measuring the instantaneous electric current, supplied by the phase of the stator of the rotating generator machine.

 According to one embodiment of the invention, the measuring device comprises a first module for calculating an instantaneous global magnetic flux of the phase of the stator by summation, performed on the turns of the phase and for each turn of the phase on the teeth which are surrounded by this turn, of a plurality of instantaneous fluxes, obtained from the instantaneous flux measured by temporal offsets proportional to the angular offsets of the teeth relative to the determined tooth.

According to one embodiment of the invention, the measuring device comprises a second module for calculating said instantaneous electric power supplied by the rotating machine generating electricity from the electric current of the phase measured by the sensor and the magnetic flux. instantaneous total of the phase, having been calculated. The invention thus makes it possible to have, in real time and in a synchronized manner, the level of charge (measurement of the power supplied) of the rotating machine generator, such as for example an alternator, this calculated load level can then be sent into a diagnostic box. This offers the advantage of implementing adaptable diagnostic techniques at the level of the alternator load and thus to achieve a reliable diagnosis regardless of the operating regime of the alternator.

 The invention makes it possible to obtain a global electrical value (active load P (t), reactive load Q (t)) from a local measurement of gap flux, in a manner synchronized with the measurement of a physical quantity. G (t) forming the observable symptomatic behavior of the rotating machine, and this without additional instrumentation, without intrusion, without cable connections of said machine or resident diagnostic boxes.

 The present invention improves the situation and achieves the stated objectives by means of a solution which overcomes the above-mentioned constraints by advantageously exploiting the measurement of the magnetic flux coming from a sensor residing in the machine.

 According to one embodiment of the invention, said instantaneous electrical power supplied by the rotating machine generating electricity is either the instantaneous electrical power of the phase, or the instantaneous total electrical power of the machine.

According to one embodiment of the invention, the first module is configured to calculate the instantaneous global magnetic flux <D (t) of the stator phase as being equal to

 where i is an index designating each turn of the phase,

Nspire denotes the number of turns of the phase, k and ^> i denote the indices of the teeth which are surrounded by the turn i, cp _r is the instantaneous flux measured by the measuring probe,

w is the rotational angular velocity of the rotor with respect to the stator, dr is the tooth pitch which is the angle between two successive teeth among the teeth,

m is the index of the determined tooth on which the flow measurement probe cp _{r is located} ,

h _{mJ <} is a prescribed time synchronization function, depending on the index k and the index m.

According to one embodiment of the invention, the first module is configured to calculate the prescribed time synchronization function h _{mJ <} as being equal to

 According to one embodiment of the invention, the determined tooth on which the flow measurement probe is located is one of the teeth surrounded by at least one of the turns of the phase.

 According to one embodiment of the invention, the second calculation module comprises a sub-module configured to calculate an instantaneous voltage of the phase at least by time derivative of the instantaneous global magnetic flux of the phase, having been calculated.

 According to one embodiment of the invention, the second calculation module is configured to calculate the instantaneous electric power supplied by the rotating machine generating electricity at least by multiplying the instantaneous voltage of the phase, having been calculated, by the electric current, having been measured by the sensor.

According to one embodiment of the invention, the device comprises a diagnostic module of the operating state of the rotating machine generating electricity, able to calculate at least one diagnostic parameter of the operating state of the machine. rotating generator generating electricity from the instantaneous electrical power, having been calculated by the second calculation module and from an observable quantity and / or from the instantaneous global magnetic flux of the stator phase, having been calculated by the first calculation module. A second object of the invention is an electricity production installation, comprising a rotating machine generating electricity, which comprises a rotor, a stator, an air gap located between the stator and the rotor, the stator comprising at least one phase comprising turns and a determined number of teeth, characterized in that the power generation installation is provided with the device for measuring the instantaneous electric power, supplied by the phase of the stator, as described above.

 A third object of the invention is a method for measuring the instantaneous electrical power, supplied by at least one phase of the stator of a rotating machine generating electricity, the rotating machine comprising a rotor, the stator, an air gap located between the stator and the rotor,

 the at least one phase comprising turns,

 the stator comprising a determined number of teeth,

 the method being characterized in that

 measuring, by a measurement probe located in a fixed manner on a determined one of the stator teeth, a localized and instantaneous magnetic flux of air gap, called measured instantaneous flux,

 the instantaneous electric current supplied by the phase of the stator of the rotating generator machine is measured by a measuring sensor.

 According to one embodiment of the invention, a computation module computes an instantaneous global magnetic flux of the phase of the stator by summation, performed on the turns of the phase and for each turn of the phase on the teeth which are surrounded by this turn, a plurality of instantaneous streams, obtained from the instantaneous flow measured by time offsets proportional to the angular offsets of the teeth relative to the determined tooth.

According to one embodiment of the invention, a second calculation module measures the instantaneous electric power supplied by the rotating machine generating electricity from the electric current measured by the sensor and the instantaneous global magnetic flux of the phase. having been calculated. A third object of the invention is a computer program, comprising code instructions for implementing the measurement method as described above, when it is executed on at least one computer.

 The invention will be better understood on reading the description which follows, given solely by way of non-limiting example with reference to the accompanying drawings, in which:

 FIG. 1 schematically represents a generating rotary machine in cross-section along its axis of rotation, on which the measuring device according to the invention can be implemented;

 FIG. 2 diagrammatically represents a modular block diagram of the measuring device according to one embodiment of the invention,

 FIG. 3 diagrammatically represents a modular block diagram of an installation comprising the measuring device according to one embodiment of the invention,

 FIG. 4 diagrammatically shows in a developed view along its circumference the stator of the rotating generator machine of FIG. 1, on which the measuring device according to the invention can be implemented,

 FIG. 5A is a graph showing harmonics of a signal coming from a rotating machine in a first state of charge according to the state of the art; FIG. 5B is a graph showing harmonics of a signal coming from a a rotating machine in a second state of charge according to the state of the art,

 FIG. 6 represents a flowchart of a measurement method according to one embodiment of the invention.

In Figure 1, a rotating machine 2 generating electricity has a stator 4 and a rotor 3 rotatable relative to the stator 4 about an axis 6 of rotation, an air gap 5 being present between the rotor 3 and the stator 4. The rotor 3 comprises a mechanical shaft 7 adapted to be fixed to a source of mechanical rotation, which can be constant and can be for example a turbine T for a rotating machine generator 2 formed by an alternator or turboalternator, to rotate the rotor 3 around the axis 6. The rotation of the rotor 3 induces a field variable magnetic field in the stator 4. The variable magnetic field induces across the winding of the stator 4 a voltage called electromotive force. The stator 4 comprises one or more phases each having one or more connection terminals with the outside, to supply to the outside the electric current produced by the stator 4 when the rotor 3 is rotated about the axis 6. Below is considered the U phase of the stator 4, without this being limiting, the invention being applicable to one or more other phases of the stator 4. The stator 4 may be symmetrical cylindrically about the axis of rotation. For example, the stator may be three-phase, and the measuring device may be provided on one of the three phases, on two of the three phases or on the three phases of the stator 4. For example, the machine 2 may be a synchronous rotating machine, may have smooth poles, may have a stator winding 4 of the nested type and may have one or more channels in parallel on each of its phase or phases. The rotating machine generator 2 may have a nominal output power greater than 1 MW, in particular greater than 10 MW, or greater than 100 MW or greater than 1000 MW.

 The stator 4 comprises a first determined number N of teeth D distributed around the axis 6 towards the gap 5. The phase U comprises a second determined number Nspire of turns i, connected in series with each other and conducting the electricity. Each turn i surrounds one or more determined teeth D of the stator among the N teeth D. The coil winding plane i around the teeth D is predetermined or known in advance.

 For example, FIG. 4 shows a machine 2 formed by a 1300 MW synchronous turboalternator with smooth poles housed in 84 notches. The winding of the stator 4 of this turboalternator is a nested winding with 4 channels in parallel on each of the 3 phases. Each channel is distributed over 7 notches (87 notches / (3 phases x 4 channels)). This turboalternator comprises a stator 4 having N = 32 teeth D, indicated by the references 1 to 32 and N = 7 turns i, of which: a first turn i = 1 surrounding the teeth D referenced 1 to 26, a second turn i = 2 surrounding the teeth D referenced 2 to 27, a third turn i = 3 surrounding the teeth D referenced 3 to 28, a fourth turn i = 4 surrounding the teeth D referenced 4 to

29, a fifth turn i = 5 surrounding the teeth D referenced 5 to 30, a sixth turn i = 6 surrounding the teeth D referenced 6 to 31 and a seventh turn i = 7 surrounding the teeth D referenced 7 to 32. FIG. 4 also shows a geometric axis Al around which is wound the first turn i = 1 and an axis geometric A7 around which is wound the seventh turn i = 7. Of course, any other number Nspire, any other number N and any other winding plane turns i with respect to the teeth D is possible and any other type of rotating machine generator 2 may be provided according to the invention.

 The teeth D can be evenly distributed around the axis 6, being separated from each other by the same angular pitch dr. However, the invention also applies to teeth D distributed unevenly but in known or predetermined manner around the axis 6.

According to one embodiment, the device 1 for measuring the instantaneous electric power, supplied by the phase U of the rotating machine 2 generating electricity comprises a probe 11 for measuring magnetic flux, positioned on a determined tooth Dr of the stator 4 , called the measuring tooth Dr and hereinafter denoted by the index m. The probe 11 measures the localized and instantaneous magnetic flux cp _r of the gap 5, called the instantaneous flux measured cp _r . The magnetic flux measurement probe 11 is positioned and configured so as to measure the magnetic flux cp _r which is radial relative to the axis 6 of rotation, that is to say in the local radial direction R, passing through the determined tooth Dr. for example, the axis normal to the winding of the probe 11 coincides with the radial stator radius, so as to maximize the flux of the magnetic field sensed cp _r. This probe 11 may comprise, for example, one or more windings of an electrically conductive wire wound around the measuring tooth D.sub.r. The probe 11 is connected to the outside by connection means, for example by electrical wires 110. According to one embodiment, the probe 11 is provided on at least one of the teeth D.

According to one embodiment, the measuring device 1 comprises a sensor 12 capable of measuring the electric current I (t) supplied by the phase U. This sensor 12 may comprise an ampere-metric clamp positioned on the external connection terminals of the phase U, or others. The current I (t) is an instantaneous current. In FIG. 2, the flow measurement probe 11 and the current sensor 12 are part of a measuring assembly 100 of the measuring device 1. Thus, according to these embodiments, the radial magnetic flux cp _r measured by the probe 11 and the phase current I (t) measured by the sensor 12 are available in real time.

 According to one embodiment, the rotating machine 2 is equipped with another sensor measuring in real time a physical quantity G (t), which may be for example a vibratory signal, a temperature, an electrostatic charge or the like.

The measuring device 1 comprises a set 200 for calculating the instantaneous electrical power supplied by the phase U as a function of the measured electric current I (t) and the measured instantaneous flux cp _r . This set is described below.

 According to one embodiment, the computing assembly 200 comprises a first module 21 configured to calculate an instantaneous global magnetic flux <D (t) of the phase U of the stator 4.

According to one embodiment, the module 21 is configured to calculate the flux <D (t) induced in the phase U as the sum of the instantaneous magnetic flux F _u {t) of the turn gap i on the set of turns i of phase U. So we have

 According to one embodiment, for each turn i of the phase U, the module

où k et {3 · } désignent les indices des dents D qui sont entourées par la spire i, appelées dents k (ou indices k). Suivant un mode de réalisation, pour chaque dent k, le premier module 11 est configuré pour calculer chaque flux magnétique instantané YM) d’entrefer de dent comme étant égal au flux mesuré instantané (p_r, décalé temporellement d’un décalage temporel déterminé, correspondant au décalage angulaire de cette dent k par rapport à la dent déterminée Dr autour de l’axe 6. 21 is configured to calculate each instantaneous magnetic flux F u {t) of turn gap i by summing on those teeth D which are surrounded by this turn i, instant magnetic flux Yi _< (ί) air gap tooth for these teeth. So we have :

where k and {3 ·} denote the indices of the teeth D which are surrounded by the turn i, called teeth k (or indices k). According to one embodiment, for each tooth k, the first module 11 is configured to calculate each instantaneous magnetic flux YM) of the tooth gap as being equal to the instantaneous measured flow (p _r , offset temporally by a given time offset, corresponding to the angular offset of this tooth k relative to the determined tooth Dr around the axis 6.

Thus, according to one embodiment, the module 21 calculates the instantaneous global magnetic flux <D (t) of the phase U of the stator 4 by summation, performed on the turns i of the phase U and for each turn i of the phase U on the teeth D which are surrounded by this turn i, a plurality of instantaneous measured fluxes cp _r , temporally offset time offsets corresponding to the angular offsets of these teeth D relative to the determined tooth Dr. These time offsets are proportional to the angular offsets of the teeth D with respect to the determined tooth Dr.

According to one embodiment, the first module (21) is configured to calculate the instantaneous global magnetic flux <D (t) of the phase U of the stator 4 as being equal to

where w is the rotational angular velocity of the rotor 3 with respect to the stator 4, h _{mi <} is a prescribed time synchronization function, dependent on the index k and the index m.

According to one embodiment, the rotational speed of the rotor 3 is constant. The rotational speed of the rotor 3 can for example be between 60 rpm and 3600 rpm, and can be equal for example to 1500 rpm for a rotary machine delivering electrical power at the frequency f = 50 Hz and whose number of pairs of magnetic poles of the rotor is two, a situation that is found in the electricity generation park of the Applicant. It is well known to those skilled in the art that said rotational speed of the rotor that we will note w is a direct function of the number p of magnetic pole pairs of the rotor of the rotating machine w = 60.f / p. According to one embodiment, the computing assembly 200 comprises a second calculation module 22 configured to calculate the instantaneous electrical power P (t), Q (t) (also called charge P (t), Q (t)) supplied. by the rotating machine 2 generating electricity from the electric current I (t) measured by the sensor 12 and from the instantaneous global magnetic flux <D (t) of the phase U, having been calculated. This instantaneous electrical power P (t), Q (t), calculated by the second calculation module 22, is the instantaneous electrical power P (t), Q (t) provided by the phase U of the stator 4, or by several phases. of the stator 4 or by all the phases of the stator 4 or total instantaneous electrical power supplied by the machine 2.

According to one embodiment, the first module 21 is configured to calculate the prescribed time synchronization function h _mk as being equal to

We therefore have in this embodiment:

, dr et h_{m. k} sont caractérisés de manière unique pour chaque machine tournante génératrice 2. Suivant un mode de réalisation, l’ensemble est l’ensemble des indices des dents internes à la spire i, non polaires. The parameters m,

, dr and h _{m. k} are uniquely characterized for each rotating machine generating 2. According to one embodiment, the set is the set of indices of internal teeth to the turn i, nonpolar.

 In the case where the teeth D are regularly distributed around the axis 6, the index k is an integer, and the index m is an integer, the angular offset of the teeth D being equal to (mk) dr by relative to the determined tooth Dr of index m. Of course, the indices k may not be integer in the case where the teeth D are evenly distributed around the axis 6 and where thus the angular offset of the teeth D relative to the determined tooth Dr of index m n ' is not an integer multiple of the angular step dr.

According to one embodiment, the phase U surrounds the flow measurement probe 11. According to one embodiment, the determined tooth Dr, of index m, on which is the flow measurement probe 11 cp _r is one of the teeth D, k surrounded by one of the turns i of the phase U, or by several turns i of the phase U or by all the turns i of the phase U.

According to one embodiment, the second calculation module 22 comprises a first submodule 221 configured to calculate an instantaneous voltage V (t) of the at least one phase U by time derivative of the instantaneous global magnetic flux <D (t) of the phase U, having been calculated. Thus, according to this embodiment determining the voltage V (t) by calculation, the invention dispenses with an expensive instrumentation measuring the voltage V (t). For example, this calculation also takes into account the ohmic losses of the phase U of the stator 4, by subtracting a predetermined internal resistance R _eS from the phase U of the stator 4, multiplied by the measured current I (t) of the phase U of the stator 4. We have

 The submodule 221 or 222 may also calculate an angular phase shift a (or a corresponding power factor cos (a)) between the reactive power portion Q (t) of the instantaneous electric power P (t), Q (t) provided by the rotating machine 2 generating electricity and the part P (t) of active power of the instantaneous electric power P (t), Q (t) provided by the rotating machine 2 generating electricity.

According to one embodiment, the second calculation module 22 comprises a second sub-module 222 configured to calculate the instantaneous electric power P (t), Q (t) supplied by the rotating machine 2 generating electricity at least by multiplication of the instantaneous voltage V (t) of the phase U, having been calculated by the first sub-module 221, by the electric current I (t), having been measured by the sensor 12. Thus, the load P (t), Q (t) can be calculated according to the invention using neither the torque (V (t), I (t)) but rather the torque (cp _r (t),

I (t)).

 According to one embodiment,

 P (t) = 3. V (t) .I (t) .cos (a)

and Q (t) = 3. V (t) .I (t) .sin (a)

 According to one embodiment, the device 1 comprises a module 23 for diagnosing the operating state of the rotating machine 2 generating electricity as a function of the instantaneous electrical power P (t), Q (t), having been calculated by the second calculation module 22 and / or as a function of the instantaneous global magnetic flux <D (t) of the phase U of the stator 4, which has been calculated by the first calculation module 21. For example, the diagnostic module 23 is able to calculate at least one diagnostic parameter of the operating state of the rotating machine 2 generating electricity from the instantaneous electric power P (t), Q (t), having been calculated by the second calculation module 22 and / or from the instantaneous global magnetic flux <D (t) of the phase U of the stator 4, having been calculated by the first calculation module 21. The diagnostic module 23 may also take into account one or more observable variables G (t), such as for example one or more of those mentioned, for calculating the diagnostic parameter.

The modules 21 and 22 may for example be implemented in a computer, a computer or the like, contained for example in a housing 201 and comprising a processor for performing the calculations automatically according to the values of the flow cp _r and current values I (t) sent to respectively a first input 210 of the first module 21 and a second input 220 of the second module 22 respectively the probe 11 and the sensor 12. The computer or computer or processor is programmed by a program computer having code instructions executing the calculations mentioned above.

 According to one embodiment, the power generation installation is provided with the device 1 for measuring the electrical power as described above.

 The invention also relates to a method for measuring the instantaneous electric power, supplied by the rotating machine 2 generating electricity, which performs the following steps using the measuring device 1 described above. This method comprises, with reference to FIG. 6, the following steps:

first step El: measurement, by the probe 11, of the magnetic flux cp _r located and instantaneous gap, second step E2: measurement, by the sensor 12, of the instantaneous electric current I (t), supplied by the phase U of the stator 4 of the rotating generator machine 2,

third step E3: calculation, by the first calculation module 21, of the instantaneous global magnetic flux <D (t) of the phase U of the stator 4 by summation, performed on the turns i of the phase U and for each turn i of the phase U on the teeth (D) which are surrounded by this turn i, of a plurality of instantaneous measured fluxes cp _r , temporally offset by time offsets corresponding to the angular offsets of these teeth D relative to the determined tooth Dr,

 fourth step E4: calculation, by the second calculation module 22, of the instantaneous electrical power P (t), Q (t) supplied by the rotating machine 2 generating electricity from the electric current I (t) measured by the sensor 12 and the instantaneous global magnetic flux <D (t) of the phase U, having been calculated.

According to one embodiment, the first step E1 is executed simultaneously with the second step E2, for measuring the magnetic flux cp _r at the same instant t as the current I (t).

 The invention also relates to a computer program for implementing this method.

 The diagnostic module 23 may for example be implemented in a computer, a computer or the like, contained for example in a diagnostic box 202 and comprising a processor for performing calculations in an automatic manner. The computer or computer or processor is programmed by a computer program having code instructions executing these calculations. According to one embodiment, the diagnostic module or diagnostic box takes as input the measurement of the observed magnitude G (t), the charge level P (t), Q (t) calculated by the module 22 and the measurement of the current I (t) provided by the sensor 12.

An alternative is to take as observed value G (t) the measurement of the radial flow cp _r (t), that is to say G (t) = cp _r (t). In this case, the module 21 and / or 22 and / or 221 and / or 222 for calculating the load can be implanted directly inside the diagnostic box. In this case, the diagnostic box 2 requires only two inputs: the measurement of the magnitude cp _r (t) supplied by the probe 11 and the measurement of the current I (t) supplied by the sensor 12. The measuring device 1 can be installed in a power generation installation 300, represented in FIG. 1. An embodiment of this installation 300 is described below. The electricity generating installation 300 comprises one or more several alternators 2 (each forming a generator rotating machine as described above), mechanically driven by one or more turbines 301 so that the stator 4 of the alternators 2 provide electrical power P (t), Q (t) to meet the load (demand) imposed by a distribution network 302 of electricity to electricity consumers. The alternator 2 is instrumented and equipped with sensors, including the probe 11 and the sensor 12, which send real-time or sequenced measurement data to the control room 303, generally distant from the alternator 2 and sometimes from the production itself. The data of the alternator 2 are all or partly returned to diagnostic housings 23, also often distant from the alternator 2 and the room 303 control. In some installations, there may be connections returning the outgoing data streams from the sensors of the alternators 2 to the control room 303. The information delivered by these boxes can also be routed to remote platforms, centralizing the information of several power plants. Finally, it is often possible to find direct or indirect communication between the network 302 and the control room 303.

 By using the measuring device as described above, the diagnostic boxes can deploy better diagnostics by choosing the right limit criteria, for so-called threshold methods, or reduce the signature base of references where the we seek to identify a signal G (t) in the case of the so-called identification methods. In both cases, the operator of these rotating generators will perform a more efficient diagnostic, without additional connections between the control room and the diagnostic boxes to transmit information on the level of load of these machines.

 Of course, the above embodiments, features, possibilties, and examples can be combined with one another or be selected independently of one another.

Claims

1. Device (1) for measuring an instantaneous electric power, provided by at least one phase (U) of the stator (4) of a rotating machine (2) generating electricity, the device comprising a probe (11) for measuring a localized and instantaneous gap magnetic flux (cp _r ), called a measured instantaneous flux, between the stator (4) and the rotor (3) of the rotating machine (2) generating electricity, the stator (4) comprising a determined number of teeth (D), the measurement probe (11) being located in a fixed manner on a determined one (Dr) of the teeth (D) of the stator (4),  a sensor (12) for measuring the instantaneous electric current (I (t)) supplied by the phase (U) of the stator (4) of the rotating generator machine (2),  characterized in that it comprises a first module (21) for calculating an instantaneous global magnetic flux (F (ί)) of the phase (U) of the stator (4) by summation, performed on the turns (i) of the phase (U) and for each turn (i) of the phase (U) on the teeth (D) which are surrounded by this turn (i), of a plurality of instantaneous fluxes, obtained from the instantaneous flux measured (cp _r ) by time offsets proportional to the angular offsets of the teeth (D) relative to the determined tooth (Dr),  a second module (22) for calculating said instantaneous electrical power (P (t), Q (t)) supplied by the rotating machine (2) generating electricity from the electric current (I (t)) of the phase (U) measured by the sensor (12) and the instantaneous global magnetic flux (F (ί)) of the phase (U), having been calculated.  2. Device according to claim 1, characterized in that said instantaneous electrical power (P (t), Q (t)) provided by the rotating machine (2) generating electricity is either the instantaneous electrical power of the phase (U ), or the total instantaneous electric power of the machine.  3. Device according to claim 1 or 2, characterized in that the first module (21) is configured to calculate the instantaneous global magnetic flux F (ί) of the phase (U) of the stator (4) as being equal to

 where i is an index designating each turn of the phase (U), Nspire denotes the number of turns of the phase (U), k and ^> i denote the indices of the teeth (D) which are surrounded by the turn i, cp _r is the instantaneous flux measured by the measuring probe (11),  w is the rotational angular velocity of the rotor (3) relative to the stator (4), dr is the tooth pitch which is the angle between two successive teeth among the teeth (D), m is the index of the determined tooth (Dr) on which is located the flow measurement probe (11) f _G , h _{mJ <} is a prescribed time synchronization function, depending on the index k and the index m. 4. Device according to claim 3, characterized in that the first module (21) is configured to calculate the prescribed time synchronization function h _{mJ <} as being equal to

5. Device according to any one of the preceding claims, characterized in that the determined tooth (Dr) on which is the probe (11) for measuring the flow (cp _r ) is one of the teeth surrounded by at least one turns of the phase (U).  6. Device according to any one of the preceding claims, characterized in that the second module (22) comprises a calculation sub-module (221) configured to calculate an instantaneous voltage (V (t)) phase (U) at least by time derivation of the instantaneous global magnetic flux (<(t)) of the phase (U), having been calculated. 7. Device according to claim 6, characterized in that the second module (22) for calculating is configured to calculate the instantaneous electrical power (P (t), Q (t)) provided by the rotating machine (2) generating electricity at least by multiplying the instantaneous voltage (V (t)) of the phase (U) calculated by the electric current (I (t)) measured by the sensor (12).  8. Device according to any one of the preceding claims, characterized in that it comprises a module (23) for diagnosing the operating state of the rotating machine (2) generating electricity, able to calculate at least one diagnostic parameter of the operating state of the rotating machine (2) generating electricity from the instantaneous electrical power (P (t), Q (t)), having been calculated by the second module (22) of calculation and from an observable quantity (G (t)) and / or from the instantaneous global magnetic flux (F (ί)) of the phase (U) of the stator (4), having been calculated by the first module (21) calculation.  9. Electricity production plant, comprising a rotating machine (2) generating electricity, which comprises a rotor (3), a stator (4), an air gap (5) located between the stator (4) and the rotor (3), the stator (4) comprising at least one phase (U) comprising turns (i) and a predetermined number of teeth (D), characterized in that the power generation installation is provided with the device ( 1) for measuring the instantaneous electric power, provided by the phase (U) of the stator (4), according to any one of the preceding claims.  10. A method for measuring the instantaneous electric power, supplied by at least one phase (U) of the stator (4) of a rotating machine (2) generating electricity,  the rotating machine (2) comprising a rotor (3), the stator (4), an air gap (5) located between the stator (4) and the rotor (3),  the at least one phase (U) comprising turns (i),  the stator (4) comprising a determined number of teeth (D),  the method being characterized in that measuring, by means of a measurement probe (11) located in a fixed manner on a determined one (Dr) of the teeth (D) of the stator (4), a magnetic flux (cp _r ) located and instantaneous of air gap, called flux measured snapshot, the instantaneous electric current (I (t)) supplied by the phase (U) of the stator (4) of the rotating generator machine (2) is measured by a measuring sensor (12), a global instantaneous magnetic flux (F (ί)) of the phase (U) of the stator (4) is calculated by a first calculation module (21) by summation, performed on the turns (i) of the phase (U) and for each turn (i) of the phase (U) on the teeth (D) which are surrounded by this turn (i), of a plurality of instantaneous fluxes, obtained from the measured instantaneous flux (cp _r ) by offsets time proportional to the angular offsets of the teeth (D) relative to the determined tooth (Dr),  the instantaneous electrical power (P (t), Q (t)) supplied by the rotating machine (2) generating electricity from the measured electric current (I (t)) is measured by a second module (22) for calculation by the sensor (12) and the instantaneous global magnetic flux (F (ί)) of the phase (U) having been calculated.  11. Computer program, comprising code instructions for implementing the measurement method according to claim 10, when it is executed on at least one computer.