(19)
(11)EP 3 014 759 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
12.01.2022 Bulletin 2022/02

(21)Application number: 14736107.5

(22)Date of filing:  02.06.2014
(51)International Patent Classification (IPC): 
H02P 9/10(2006.01)
(52)Cooperative Patent Classification (CPC):
H02P 9/10; H02P 2101/10
(86)International application number:
PCT/US2014/040435
(87)International publication number:
WO 2014/209542 (31.12.2014 Gazette  2014/53)

(54)

USING STATIC EXCITATION SYSTEM TO REDUCE THE AMPLITUDE OF TORSIONAL OSCILLATIONS DUE TO FLUCTUATING INDUSTRIAL LOADS

VERWENDUNG EINES STATISCHEN ERREGERSYSTEMS ZUR REDUZIERUNG DER AMPLITUDE VON TORSIONSSCHWINGUNGEN AUFGRUND VON VERÄNDERLICHEN INDUSTRIELLEN LASTEN

UTILISATION D'UN SYSTÈME D'EXCITATION STATIQUE SERVANT À RÉDUIRE L'AMPLITUDE D'OSCILLATIONS DE TORSION DUES À DES CHARGES INDUSTRIELLES FLUCTUANTES


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 25.06.2013 US 201313926147

(43)Date of publication of application:
04.05.2016 Bulletin 2016/18

(73)Proprietor: Siemens Energy, Inc.
Orlando, FL 32826 (US)

(72)Inventors:
  • HURLEY, Joseph David
    Casselberry, Florida 32707 (US)
  • CLAYTON, Peter Jon
    Casselberry, Florida 32707 (US)

(74)Representative: Roth, Thomas et al
Siemens Energy Global GmbH & Co. KG Postfach 22 16 34
80506 München
80506 München (DE)


(56)References cited: : 
EP-A2- 2 020 744
EP-A2- 2 325 999
US-A- 3 999 115
EP-A2- 2 216 896
US-A- 3 656 048
US-A- 4 454 428
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    FIELD OF THE INVENTION



    [0001] The present invention relates to the field of power generating equipment and, more particularly to torsional oscillations of power generating equipment.

    BACKGROUND OF THE INVENTION



    [0002] A turbine generator employs a rotating shaft to transform mechanical motion into electrical power. Torsional oscillations may be induced in the shaft by fluctuating loads coupled with the generator. A fluctuating load (e.g., an electrical arc furnace) can cause rapid transients in electrical power on generators, which can act to induce various levels of torsional oscillations in a rotating shaft of the generator. The timing of these transients can at times be such that otherwise small torsional oscillations can be reinforced and built-up into torsional oscillations of considerable amplitude. Attempts to dampen such torsional oscillations have been made in the past. These attempts have involved filtering and leveling the loads powered by the generator in order to lessen an amplitude of any load transients as well as to lessen the repetitive nature of such transients. Relevant prior art can be found in EP 2 020 744 A2, EP 2 216 896 A2, US 3 999 115 A, US 4 454 428 A, EP 2 325 999 A2 and US 3 656 048 A.

    [0003] The problem to be solved for a turbine generator is how to stabilize torsional oscillations induced in the shaft by fluctuating loads coupled with the generator causing rapid transients in electrical power on generators.

    SUMMARY OF THE INVENTION



    [0004] The problem is solved by a system for controlling a shaft of a turbine generator comprising a static exciter with the features of claim 3.

    [0005] The problem is further solved by a method of controlling a shaft of a turbine generator comprising a static exciter with the features of claim 1.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0006] While the specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed that the present invention will be better understood from the following description in conjunction with the accompanying Drawing Figures, in which like reference numerals identify like elements, and wherein:

    FIG. 1A illustrates an example static excitation system for a turbine generator according to the prior art;

    FIG. 1B illustrates a turbine generator in accordance with the principles of the present invention;

    FIG. 1C illustrates a block conceptual diagram of how a supplementary control signal may be injected into a static excitation system in accordance with the principles of the present invention;

    FIG. 2A and 2B depict example signal waveforms of a static excitation control system in accordance with the principles of the present invention; and

    FIG. 3 illustrates a flowchart of an example method for controlling a static excitation system in accordance with the principles of the present invention.


    DETAILED DESCRIPTION OF THE INVENTION



    [0007] In the following detailed description of the preferred embodiment, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, and not by way of limitation, a specific preferred embodiment in which the invention may be practiced.

    [0008] An electric generator that uses field coils rather than permanent magnets requires a current to be present in the field coils for the device to be able to work. If the field coils are not powered, the rotor in a generator can spin without producing any usable electrical energy, while the rotor of a motor may not spin at all. FIG. 1A illustrates an example prior art static exciter system. A generator includes a rotating generator field 102 and a stationary generator stator 104. As is well known, the generator is coupled by a 3-wire bus 106 to provide generated power to a grid 101.

    [0009] The voltage and current of the power produced by the generator can be sampled, or sensed, to provide an indication of current operating conditions of the generator. The voltages and currents generated may not be readily usable by traditional automatic voltage regulator (AVR) circuitry 112 and, thus, current and voltage transformers 108 can be used to step-down the signals from the bus 106 to signals that are more usable by the AVR 112.

    [0010] A static exciter 116 is also coupled with the generator's 3-wire bus 106 through a transformer 110 so that power to the exciter 118 can be provided. In the example circuitry of FIG. 1A, the exciter 116 includes a thyristor bridge with six thyristors 118 coupled to the exciter transformer 110 and the generator field 102. The AVR 112 provides a DC control signal 120 that drives the thyristors 118. Based on the value of the control signal 120, an exciter output voltage 122 is provided to the generator field 102.

    [0011] As is known in the art, the AVR 112 is designed to produce a control signal 120 in such a manner that the operating characteristics of the power generator are changed to more closely replicate ideal operating parameters. One of ordinary skill will recognize that the circuitry of FIG. 1A is simply an example to illustrate the principles of a static exciter, or a "static excitation system" (as used herein) for a turbine generator and that other functionally equivalent circuitry can accomplish similar results.

    [0012] Embodiments relate to a method and apparatus to provide supplementary control of a static excitation system on a turbine-generator. The supplementary control can use a feedback signal from a shaft torsional vibration, or torsional oscillation, measurement of a rotor in order to modulate the static exciter output voltage in such a way as to stabilize torsional oscillations that are induced in the rotor due to fluctuating industrial loads.

    [0013] The feedback signal can come from one or more speed sensors that measure an instantaneous speed of a rotor of a turbine generator. This feedback signal can be demodulated into a torsional velocity or displacement signal, sent through appropriate filters, phase shifting functions, and amplification, in order to generate a supplementary control signal. The supplementary control signal can then be injected into the voltage regulator of the static excitation system to control instantaneous power of the generator field.

    [0014] FIG. 1B illustrates a turbine generator in accordance with the principles of the present invention. A turbine generator employs a rotating shaft to transform mechanical motion into electrical power. Torsional oscillations may be induced in the shaft by fluctuating loads 162 coupled with the generator. In accordance with the principles of the present invention, such torsional oscillations can be detected by measuring the speed at which the shaft is rotating.

    [0015] As described with respect to FIG. 1A, a static excitation system 154 can draw power 152 from the generator 150. The amount of the power 152 that is drawn can be automatically controlled by a voltage regulator 156. The voltage regulator 156 can receive inputs from a voltage transformer (VT) 146 and a current transformer (CT) 148 to determine a voltage control signal for the static excitation system 154 based on current operating conditions of the generator 150.

    [0016] As mentioned above, a speed sensor 158 can be used to determine a rotational speed of the rotating shaft of the generator 150. For example, a toothed or notched wheel can be coupled to the rotating shaft so that as the shaft rotates, the wheel rotates as well. The wheel can be directly coupled with the rotating shaft or various gears and linkages may indirectly couple the wheel with the rotating shaft. Accompanying the wheel can be one or more speed sensors that detect the passing of the teeth or notches of the wheel. Such detection, for example, can be accomplished using an optical sensor that recognizes a visual difference between a notch or tooth and the other portions of the wheel. One of ordinary skill will recognize that many alternative techniques may be used to determine a shaft's rotational speed .

    [0017] A speed sensor signal, produced by the sensor 158, can be demodulated by torsional demodulator 160 to extract a torsional velocity signal 161. Because the shaft is being driven at a known speed (e.g., 3600 RPMs or 1800 RPMs) in a known direction, the detected notches or teeth should produce a known, ideal speed value when there are no torsional oscillations occurring. However, when a torsional oscillation is present and is in a direction opposite of the driven direction, the measured shaft speed will be less than an expected ideal value. Similarly, when the torsional oscillation is in the same direction as the driven direction, the measured shaft speed will be greater than the expected ideal value. Accordingly, based on the measured speed signal from the speed sensor 158, a torsional velocity signal 161 can be calculated that reflects an amplitude of how far the shaft speed diverges from an expected speed value and also a frequency of the oscillation. The torsional velocity signal 161 can then be used to generate a supplementary control signal 165 for the static excitation system 154 of the generator 150. In particular, the static excitation system 154 can be controlled to stabilize operation of the system by counteracting the torsional oscillations.

    [0018] As shown in FIG. 1B, the torsional velocity signal 161 can be sent through a band pass filter 164 to pass only a desired band of frequencies. For example, subsynchronous signals (e.g., 5 Hz - 20Hz) may be an appropriate range of frequencies to pass for a 2-pole 60Hz power generator. These same frequencies or other subsynchronous signal frequencies may be of interest for 4-pole power generation systems. Unwanted noise and other nontorsional components can be filtered or otherwise blocked by the band pass filters 164. The filtered signal 163 may then pass through a phase compensation network and amplifier 166 to produce the supplementary control signal 165. The gain of the amplifier 166 is designed so that a velocity change of a certain amplitude (i.e., the torsional velocity signal 161) will produce a control signal165 of an appropriate amplitude to have a desired effect on the static excitation system 154. The phase compensation network 166 is designed to match a phase of the output control signal 165 to that of the input filtered signal 163. One of ordinary skill will recognize that a variety of different amplifier and compensation circuitry, software, or digital signal processors, can be implemented to achieve these results .

    [0019] The resulting supplementary control signal 165 can then be introduced into the static excitation system 154 by adding it to the normal control signals that are already used to control the static exciter output voltage.

    [0020] FIG. 1C illustrates a block conceptual diagram of how a supplementary control signal may be injected into a static excitation system in accordance with the principles of the present invention. The elements within dashed box 168 from FIG. 1B are abbreviated as a single block element 168 in FIG. 1C. The block 168 produces the supplementary control signal 165 that can be combined by the adder 184 to a control signal 181 from the AVR 156. This combined control signal 186 may then be used to control the behavior of the static excitation system 154 to produce a field voltage 188 to apply to the generator field 190.

    [0021] One of ordinary skill will recognize that many different ways to combine signals 165 and 181 are contemplated within the scope of the present invention. In particular, the control signal may be injected inside the standard generator voltage control loop such that the control signal would not adversely affect the voltage control of the generator or act to bias the generator terminal voltage or reactive power.

    [0022] In operation, raising and lowering the field voltage output by the static excitation system 154 is proportional to increasing or decreasing an amount of power that the static excitation system draws from the generator. In steady state, the static excitation system produces a predetermined operating voltage and draws a predetermined amount of power from the generator. Thus, increasing or decreasing the voltage provided by the static excitation system from its steady-state operating voltage will have the effect of drawing more or less power, respectively, from the generator. When power drawn by the static excitation system from the generator increases, a drag effect is produced on the rotating generator shaft that resists rotation of the shaft in the direction in which it is being driven. When power drawn by the static excitation system decreases, any drag effect is lessened so that shaft rotational speed increases in the direction it is being driven.

    [0023] FIGS. 2A and 2B depict example signal waveforms of a static excitation control system in accordance with the principles of the present invention. In FIG. 2A the vertical axis 202 relates to a difference between the measured speed of the rotating generator shaft and an expected speed of that shaft. The horizontal axis 204 represents time and shows that the signal 163 has a period "t" 206. The signal 163 (referring to FIG. 1B) can be the filtered signal from the band pass filters 164. The signal 163 has a portion 212 that has positive amplitude values, which indicate that the generator shaft is oscillating in a rotational direction that is the same as the direction in which the shaft is being driven. However, in region 214, the signal 163 indicates that the shaft is oscillating in a rotational direction that is opposite to the direction in which the shaft is being driven. The regions 212 and 214 meet at a zero crossing point 216. The frequency and amplitude of these oscillations is captured by the parameters "amplitude" 210 and "Period t" 206.

    [0024] The phase compensation and gain circuitry 166 can receive signal 163 and produce an appropriate output signal 165 as shown in FIG. 2B. As explained above, when the signal 163 is in region 212, a drag can be placed on the generator shaft by increasing the power being drawn by the static excitation system 154. This increase is denoted by a first portion 222 of the control signal 165. When the shaft is rotating slower than expected (e.g., portion 214), then the power being drawn by the static excitation system voltage may be decreased to effectively increase the shaft's rotational speed.

    [0025] An amplitude 230 of the control signal 165 can be empirically derived through experimentation and/or testing to determine, for any particular static excitation circuitry that is implemented, a correlation between a level of the control signal 165 and a resulting effect on the rotational speed of the generator shaft. Thus, an amplifier's gain can be configured so that the control signal 165 can be produced that has a desired effect on the rotating shaft. The timing of the control signal 165 is based on the frequency of the oscillations that can be calculated from the zero crossing points 216 shown in FIG. 2A. For example, a 10Hz rotational oscillation results in a period of 0.1 seconds for the signal 163 of FIG. 2A. During one half of that period (i.e., 0.05 seconds) the shaft is rotating faster than expected and, thus, the control signal 165 has a positive amplitude. During the other half of that period when the shaft is rotating slower than expected, the control signal 165 has a negative amplitude. The phase compensation circuitry 166 ensures that the phase of the control signal 165 will result in a voltage of the static excitation system 154 that counteracts the rotational oscillation that is occurring.

    [0026] One of ordinary skill will easily recognize that a feedback and control system can be designed in many different ways . For example, the polarities of the control signals can be opposite to that described if the circuitry is designed to still cause rotation of the shaft in a desired direction (i.e., opposing the torsional oscillation).

    [0027] In this way stabilization of torsional oscillations can be achieved in a manner that takes advantage of static excitation system components already present in existing power equipment. Any additional components are low-power sensing and processing equipment. And power equipment operators can act to control torsional oscillations internally within a power plant without relying on industrial load customers to alter their processes or equipment.

    [0028] FIG. 3 illustrates a flowchart of an example method for controlling a static excitation system in accordance with the principles of the present invention. In step 302 an instantaneous rotational speed of a generator shaft is detected. As described above various methods and sensors can be used to determine how fast the shaft is rotating. The rate at which the shaft's speed is sampled depends on the range of frequencies of any torsional oscillations likely to be encountered. That range, for example, can include torsional oscillations in a range of about 5 to 20Hz. For torsional oscillations within that range of frequencies, a speed reading may be determined every millisecond.

    [0029] In step 304, the speed of the shaft is demodulated into a torsional oscillation signal in which the amplitude and a torsional oscillation frequency can be determined. The generator shaft is being driven in a first rotational direction at a predetermined speed. Thus, a difference between the measured speed of the shaft and the predetermined speed provides an indication of how the shaft is torsionally oscillating. During one portion of the oscillation, the shaft is twisting in the direction that the shaft is also being driven, and in the other portion of the oscillation, the shaft is twisting in the direction opposite to how the shaft is being driven. The magnitude of the difference between the measured shaft speed and the predetermined shaft speed indicates an amplitude of the torsional oscillation. How quickly the oscillations change in direction indicates a frequency of the torsional oscillation. Thus, in step 304 these two values (i.e., amplitude and frequency) can be determined. In accordance with at least one embodiment, an amplitude and frequency of the torsional oscillation may not necessarily be explicitly calculated. The control signal could be based on the instantaneous speed deviation from the ideal shaft rotation speed. In this instance, the instantaneous speed deviation value (i.e., signal 161 of FIG. 1B) is sampled and can then be bandpass filtered (or phase-shifted filtered). The filtered signal sample can then be amplified an appropriate amount in order to produce the control signal (i.e., signal 165 of FIG. 1B) that is fed back to the voltage regulator (i.e., 156 of FIG. 1B). In other words, an explicit amplitude of the torsional velocity is not calculated; instead, whatever the filtered signal value happens to be, it is amplified by a predetermined gain. In this manner, the control signal inherently is applied at the right polarity, the correct amplitude, and the appropriate frequency based on the instantaneous speed deviation that is detected.

    [0030] In step 306, an amplitude of a control signal is determined based on the amplitude of the torsional oscillation. For example, the control signal may be based on the instantaneous speed deviation or may be based on the maximum amplitude measured during one half of a torsional oscillation. As described above, an amplifier (or similar circuitry) is configured to have a gain that produces a control signal that will cause rotation of the generator shaft in a correct direction and at a desired speed. In step 308, the frequency of the torsional oscillation is used to apply the control signal for an appropriate amount of time. As described earlier, if the torsional oscillation had a period of 0.1 seconds, then the control signal can be applied with one polarity for half that period and at the opposite polarity for the other half of the period. When the torsional oscillation causes the shaft to rotate faster than it is being driven, then the control signal causes more power to be drawn by the static excitation system from the generator. This effectively causes the shaft to rotate in a direction opposite to how it is being driven (i.e., slow down). When the torsional oscillation causes the shaft to rotate slower than it is being driven, then the control signal causes less power to be drawn by the static excitation system from the generator. This effectively causes the shaft to rotate in the same direction that it is being driven (i.e., speed up).


    Claims

    1. A method of controlling a shaft of a turbine generator (150) to stabilize torsional oscillations induced in the shaft by fluctuating loads (162) coupled with the generator (150) causing rapid transients in electrical power on generators, wherein a static excitation system (154) provides a field voltage to the turbine generator (150), wherein the shaft is being driven in a first rotational direction at a predetermined speed, the method comprising:

    measuring (302) a rotational speed of the shaft;

    detecting (304), based on the measured rotational speed of the shaft, a torsional oscillation of the shaft;

    calculating (306) a control signal (165) based on the torsional oscillation;

    using (308) the control signal (165), controlling an amount of electrical power drawn by the static excitation system (154) from the turbine generator (150);

    wherein the torsional oscillation comprises a first amplitude (210) corresponding to a difference between the measured rotational speed and the predetermined speed;

    determining a second amplitude (230) of the control signal (165) based on the first amplitude (210);

    wherein the torsional oscillation comprises a first portion (212), lasting a first time period, corresponding to the first rotational direction and a second portion (214),

    lasting a second time period, corresponding to a second rotational direction opposite to the first rotational direction;

    wherein the torsional oscillation comprises a frequency corresponding to the reciprocal of a sum of the first time period and the second time period;

    determining a second amplitude (230) of the control signal (165) based on the first amplitude (210);

    applying the control signal (165), to the static excitation system (154), with the second amplitude (230) and a first polarity (222) during the first time period; and applying the control signal (165), to the static excitation system (154), with the second amplitude (230) and a second polarity (224) during the second time period,

    the second polarity (224) opposite that of the first polarity (222);

    wherein the control signal (165) causes the static excitation system (154) to increase an amount of power being drawn from the turbine generator (150) during the first time period;

    wherein the control signal (165) causes the static excitation system (154) to decrease an amount of power being drawn from the turbine generator (150) during the second time period.


     
    2. The method of claim 1, further comprising:
    injecting the control signal (165) into an automatic voltage regulator (156) of the static excitation system (154).
     
    3. A system for controlling a shaft of a turbine generator (150) to stabilize torsional oscillations induced in the shaft by fluctuating loads (162) coupled with the generator (150) causing rapid transients in electrical power on generators, wherein a static excitation system (154) provides a field voltage to the turbine generator (150), wherein the shaft is being driven in a first rotational direction at a predetermined speed, the system comprising:

    a demodulator (160) configured to receive a speed signal from a speed sensor (158) configured to measure a rotational speed of the shaft, wherein the demodulator (160) is configured to determine, based on the speed signal, a torsional oscillation signal (163) corresponding to a torsional oscillation of the shaft;

    a signal generator (166) having a controllable gain configured to generate a control signal (165) based on the torsional oscillation signal (163);

    an automatic voltage regulator (156) configured to receive the control signal (165) and to control an amount of electrical power drawn by the static excitation system (154) from the turbine generator (150) based on the control signal (165) wherein the torsional oscillation signal (163) comprises a first amplitude (210) corresponding to a difference between the measured rotational speed and the predetermined speed;

    wherein the controllable gain is adjusted to produce a second amplitude (230) for the control signal (165) based on the first amplitude (210);

    wherein the torsional oscillation signal (163) comprises a first portion (212), lasting a first time period, corresponding to the first rotational direction and a second portion (214), lasting a second time period, corresponding to a second rotational direction opposite to the first rotational direction;

    wherein the torsional oscillation signal (163) comprises a frequency corresponding to the reciprocal of a sum of the first time period and the second time period;

    the gain of the signal generator (166) is adjusted to produce a second amplitude (230) for the control signal (165) based on the first amplitude (210);

    the control signal (165) is provided to the automatic voltage regulator (156) with the second amplitude (230) and a first polarity (222) during the first time period;

    the control signal (165) is provided to the automatic voltage regulator (156) with the second amplitude (230)and a second polarity (224) during the second time period,

    the second polarity (224)opposite that of the first polarity (222);

    wherein the control signal (165) causes the static excitation system (154) to increase an amount of power being drawn from the turbine generator (150) during the first time period;

    wherein the control signal (165) causes the static excitation system (154) to decrease an amount of power being drawn from the turbine generator (150) during the second time period.


     
    4. The system of claim 3, further comprising:
    a combiner (184) configured to combine the control signal (165) with other, separately generated voltage control signals (181).
     


    Ansprüche

    1. Verfahren zum Steuern einer Welle eines Turbinengenerators (150) zwecks Stabilisierung von Torsionsschwingungen, die durch an den Generator (150) gekoppelte schwankende Lasten (162) in der Welle induziert werden, welche schnelle Transienten bei der elektrischen Leistung von Generatoren verursachen, wobei ein statisches Erregungssystem (154) eine Feldspannung für den Turbinengenerator (150) liefert, wobei die Welle mit einer vorgegebenen Drehzahl in einer ersten Rotationsrichtung angetrieben wird, wobei das Verfahren Folgendes umfasst:

    Messen (302) einer Drehzahl der Welle,

    Erkennen (304) einer Torsionsschwingung der Welle auf der Grundlage der gemessenen Drehzahl der Welle,

    Berechnen (306) eines Steuersignals (165) auf der Grundlage der Torsionsschwingung,

    Regeln eines Betrags der von dem statischen Erregungssystem (154) aus dem Turbinengenerator (150) bezogenen elektrischen Leistung unter Verwendung (308) des Steuersignals (165),

    wobei die Torsionsschwingung eine erste Amplitude (210) umfasst, die einer Differenz zwischen der gemessenen Drehzahl und der vorgegebenen Drehzahl entspricht,

    Ermitteln einer zweiten Amplitude (230) des Steuersignals (165) auf der Grundlage der ersten Amplitude (210),

    wobei die Torsionsschwingung einen ersten Abschnitt (212) umfasst, der einen ersten Zeitraum andauert und der ersten Rotationsrichtung entspricht, und einen zweiten Abschnitt (214), der einen zweiten Zeitraum andauert und einer der ersten Rotationsrichtung entgegengesetzten zweiten Rotationsrichtung entspricht,

    wobei die Torsionsschwingung eine Frequenz aufweist, die dem Kehrwert einer Summe des ersten und des zweiten Zeitraums entspricht,

    Ermitteln einer zweiten Amplitude (230) des Steuersignals (165) auf der Grundlage der ersten Amplitude (210),

    Anlegen des Steuersignals (165) mit der zweiten Amplitude (230) und einer ersten Polarität (222) in dem ersten Zeitraum an das statische Erregungssystem (154) und

    Anlegen des Steuersignals (165) mit der zweiten Amplitude (230) und einer zweiten Polarität (224) in dem zweiten Zeitraum an das statische Erregungssystem (154), wobei die zweite Polarität (224) der ersten Polarität (222) entgegengesetzt ist,

    wobei das Steuersignal (165) bewirkt, dass das statische Erregungssystem (154) einen Betrag der in dem ersten Zeitraum aus dem Turbinengenerator (150) bezogenen Leistung erhöht,

    wobei das Steuersignal (165) bewirkt, dass das statische Erregungssystem (154) einen Betrag der in dem zweiten Zeitraum aus dem Turbinengenerator (150) bezogenen Leistung verringert.


     
    2. Verfahren nach Anspruch 1, das ferner Folgendes umfasst:
    Einspeisen des Steuersignals (165) in einen automatischen Spannungsregler (156) des statischen Erregungssystems (154).
     
    3. System zum Steuern einer Welle eines Turbinengenerators (150) zwecks Stabilisierung von Torsionsschwingungen, die durch an den Generator (150) gekoppelte schwankende Lasten (162) in der Welle induziert werden, welche schnelle Transienten bei der elektrischen Leistung von Generatoren verursachen, wobei ein statisches Erregungssystem (154) eine Feldspannung für den Turbinengenerator (150) liefert, wobei die Welle mit einer vorgegebenen Drehzahl in einer ersten Rotationsrichtung angetrieben wird, wobei das System Folgendes umfasst:

    einen Demodulator (160), der so konfiguriert ist, dass er ein Drehzahlsignal aus einem Drehzahlsensor (158) empfängt, der so konfiguriert ist, dass er eine Drehzahl der Welle misst, wobei der Demodulator (160) so konfiguriert ist, dass er auf der Grundlage des Drehzahlsignals ein Torsionsschwingungssignal (163) ermittelt, das einer Torsionsschwingung der Welle entspricht,

    einen Signalgenerator (166) mit einer regelbaren Verstärkung,

    der so konfiguriert ist, dass er auf der Grundlage des Torsionsschwingungssignals (163) ein Steuersignal (165) erzeugt,

    einen automatischen Spannungsregler (156), der so konfiguriert ist, dass er das Steuersignal (165) empfängt und einen Betrag der von dem statischen Erregungssystem (154) aus dem Turbinengenerator (150) bezogenen elektrischen Leistung auf der Grundlage des Steuersignals (165) regelt,

    wobei das Torsionsschwingungssignal (163) eine erste Amplitude (210) umfasst, die einer Differenz zwischen der gemessenen Drehzahl und der vorgegebenen Drehzahl entspricht,

    wobei die regelbare Verstärkung so angepasst wird, dass auf der Grundlage der ersten Amplitude (210) eine zweite Amplitude (230) für das Steuersignal (165) erzeugt wird,

    wobei das Torsionsschwingungssignal (163) einen ersten Abschnitt (212) umfasst, der einen ersten Zeitraum andauert und der ersten Rotationsrichtung entspricht, und einen zweiten Abschnitt (214), der einen zweiten Zeitraum andauert und einer der ersten Rotationsrichtung entgegengesetzten zweiten Rotationsrichtung entspricht,

    wobei das Torsionsschwingungssignal (163) eine Frequenz umfasst, die dem Kehrwert einer Summe des ersten und des zweiten Zeitraums entspricht,

    wobei die Verstärkung des Signalgenerators (166) so angepasst wird, dass auf der Grundlage der ersten Amplitude (210) eine zweite Amplitude (230) für das Steuersignal (165) erzeugt wird,

    wobei das Steuersignal (165) in dem ersten Zeitraum mit der zweiten Amplitude (230) und einer ersten Polarität (222) an den automatischen Spannungsregler (156) geliefert wird,

    wobei das Steuersignal (165) in dem zweiten Zeitraum mit der zweiten Amplitude (230) und einer zweiten Polarität (224) an den automatischen Spannungsregler (156) geliefert wird, wobei die zweite Polarität (224) der ersten Polarität (222) entgegengesetzt ist,

    wobei das Steuersignal (165) bewirkt, dass das statische Erregungssystem (154) einen Betrag der in dem ersten Zeitraum aus dem Turbinengenerator (150) bezogenen Leistung erhöht,

    wobei das Steuersignal (165) bewirkt, dass das statische Erregungssystem (154) einen Betrag der in dem zweiten Zeitraum aus dem Turbinengenerator (150) bezogenen Leistung verringert.


     
    4. System nach Anspruch 3, das ferner Folgendes umfasst:
    einen Kombinierer (184), der so konfiguriert ist, dass er das Steuersignal (165) mit anderen, getrennt erzeugten Spannungsregelsignalen (181) kombiniert.
     


    Revendications

    1. Procédé pour contrôler l'arbre d'une éolienne (150) afin de stabiliser les oscillations de torsion sur l'arbre dues à des charges fluctuantes (162) couplées au générateur (150) causant des transitoires rapides dans la puissance électrique sur les générateurs, dans lequel un système d'excitation statique (154) fournit une tension en champ au générateur de l'éolienne (150), dans lequel l'arbre est entraîné dans une première direction rotationnelle à une vitesse prédéterminée, le procédé comprenant :

    la mesure (302) d'une vitesse rotationnelle sur l'arbre ;

    la détection (304), basée sur la vitesse rotationnelle mesurée de l'arbre, une oscillation de torsion de l'arbre ;

    le calcul (306) d'un signal de contrôle (165) basé sur l'oscillation de torsion ;

    l'utilisation (308) d'un signal de contrôle (165), contrôlant une quantité de puissance électrique générée par le système d'excitation statique (154) depuis l'éolienne (150) ;

    dans lequel l'oscillation de torsion comprend une première amplitude (210) correspondant à une différence entre la vitesse rotationnelle mesurée et la vitesse prédéterminée ; la détermination d'une seconde amplitude (230) du signal de contrôle (165) basée sur la première amplitude (210) ;

    dans lequel l'oscillation de torsion comprend une première portion (212) durant une première période de temps,

    correspondant à la première direction rotationnelle et une seconde portion (214) durant une seconde durée de temps,

    correspondant à une seconde direction rotationnelle opposée à la première direction rotationnelle ;

    dans lequel l'oscillation de torsion comprend une fréquence correspondant à la réciproque de la somme de la première période de temps et de la seconde période de temps ;

    la détermination d'une seconde amplitude (230) du signal de contrôle (165) basée sur la première amplitude (210) ;

    l'application du signal de contrôle (165) au système d'excitation statique (154), avec la seconde amplitude (230) et

    la première polarité (222) durant la première période de temps ;

    et l'application du signal de contrôle (165) au système d'excitation statique (154) avec la seconde amplitude (230) et

    la première polarité (224) durant la seconde période de temps,

    la seconde polarité (224) opposée à la première polarité (222) ;

    dans lequel le signal de contrôle (165) fait augmenter au système d'excitation statique (154) une quantité de puissance générée depuis l'éolienne (150) durant la première période de temps ;

    dans lequel le signal de contrôle (165) fait réduire au système d'excitation statique (154) une quantité de puissance générée depuis l'éolienne (150) durant la seconde période de temps.


     
    2. Procédé selon la revendication 1 comprenant également :
    l'injection du signal de contrôle (165) dans un régulateur de tension automatique (156) du système d'excitation statique (154) .
     
    3. Système pour le contrôle de l'arbre d'une éolienne (150) afin de stabiliser les oscillations de torsion sur l'arbre dues à des charges fluctuantes (162) couplées au générateur (150) causant des transitoires rapides dans la puissance électrique sur les générateurs, dans lequel un système d'excitation statique (154) fournit une tension en champ au générateur de l'éolienne (150),
    dans lequel l'arbre est entraîné dans une première direction rotationnelle à une vitesse prédéterminée, le système comprenant :

    un démodulateur (160) configuré pour recevoir un signal de vitesse depuis un capteur de vitesse (158) configuré pour mesurer une vitesse rotationnelle de l'arbre, dans lequel le démodulateur (160) est configuré pour déterminer, sur la base du signal de vitesse, un signal d'oscillation de torsion (163) correspondant à l'oscillation de torsion de l'arbre ;

    un générateur de signal (166) doté d'un gain contrôlable configuré pour générer un signal de contrôle (165) basé sur le signal d'oscillation de torsion (163) ;

    un régulateur de tension automatique (156) configuré pour recevoir le signal de contrôle (165) dans lequel le signal d'oscillation de torsion et pour contrôler une quantité de puissance électrique générée par le système d'excitation statique (154) depuis l'éolienne (150) sur la base du signal de contrôle (165) dans lequel le signal d'oscillation de torsion (163) comprend une première amplitude (210) correspondant à la différence entre la vitesse rotationnelle mesurée et la vitesse prédéterminée ;

    dans lequel le gain contrôlable est ajusté pour produire une seconde amplitude (230) pour le signal de contrôle (165) sur la base de la première amplitude (210) ;

    le signal de contrôle (165) est délivré au régulateur automatique de tension (156) avec la seconde amplitude (230) et une première polarité (222) durant la première période de temps ;

    le signal de contrôle (165) est délivré au régulateur automatique de tension (156) avec la seconde amplitude (230) et une seconde polarité (222) durant la seconde période de temps ;

    la seconde polarité (224) opposée à la première polarité (222) ;

    dans lequel le signal de contrôle (165) fait augmenter au système d'excitation statique (154) la quantité de puissance générée depuis l'éolienne (150) durant la première période de temps ;

    dans lequel le signal de contrôle (165) fait diminuer au système d'excitation statique (154) la quantité de puissance générée depuis l'éolienne (150) durant la seconde période de temps.


     
    4. Système selon la revendication 3, comprenant également :
    un combineur (184) configuré pour combiner le signal de contrôle (165) avec d'autres signaux de contrôle de tension (181) générés séparément.
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description