WO2023232168A1 - Procédé de détection automatique de frottement synchrone dans une turbine - Google Patents

Procédé de détection automatique de frottement synchrone dans une turbine Download PDF

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Publication number
WO2023232168A1
WO2023232168A1 PCT/CZ2022/050055 CZ2022050055W WO2023232168A1 WO 2023232168 A1 WO2023232168 A1 WO 2023232168A1 CZ 2022050055 W CZ2022050055 W CZ 2022050055W WO 2023232168 A1 WO2023232168 A1 WO 2023232168A1
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WO
WIPO (PCT)
Prior art keywords
rotor
orbit
origin
change
coordinate system
Prior art date
Application number
PCT/CZ2022/050055
Other languages
English (en)
Inventor
Jan JAKL
Jindrich Liska
Original Assignee
Zapadoceska Univerzita V Plzni
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Zapadoceska Univerzita V Plzni filed Critical Zapadoceska Univerzita V Plzni
Priority to EP22744642.4A priority Critical patent/EP4308797B1/fr
Priority to PCT/CZ2022/050055 priority patent/WO2023232168A1/fr
Publication of WO2023232168A1 publication Critical patent/WO2023232168A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
    • F01D21/003—Arrangements for testing or measuring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
    • F01D11/14—Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing
    • F01D11/20—Actively adjusting tip-clearance
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
    • F01D21/04—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for responsive to undesired position of rotor relative to stator or to breaking-off of a part of the rotor, e.g. indicating such position
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2260/00—Function
    • F05D2260/80—Diagnostics
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2270/00—Control
    • F05D2270/30—Control parameters, e.g. input parameters
    • F05D2270/334—Vibration measurements

Definitions

  • the present invention relates to a method of automatic detection of a synchronous rotor-stator contact in operation of a turbine and relates to the field of measurement and evaluation of mechanical oscillations and resonances of turbine rotors. It may be applied for use in steam and gas turbines.
  • rotor-stator rub or “rubbing”. Said situations may occur e.g., during run-up of the turbine when vibrations are usually highest while overcoming rotor natural frequencies.
  • seals fitted between the turbine rotor and stator are brushed first due to which the amount of leaking medium increases and the turbine performance reduces.
  • both the rotor and stator may get seriously damaged, or rub may lead to the turbine failure with consequent huge financial loss.
  • Early contact removal may be achieved, for example, by change to the speed during the turbine run-up or run-down, or by change to lifting oil parameters in use of the turbine on a swivelling equipment.
  • the rotor-stator contact may be a partial, which refers to very short but at least several times repeated contact between the rotor and the stator, or a full-annular, which refers to continuous or almost continuous contact between the rotor and the stator. In doing so, the full-annular rotorstator contact is always preceded, at least for a short moment, by the partial rotor-stator contact.
  • detection of the partial rotor-stator contact is based in particular on offline analysis of vibration signals, when the turbine operator monitors total level of the measured vibration, as well as phasor of a first harmonic component in the vibration signal.
  • a phasor refers to visualisation of an amplitude of a harmonic signal and an initial phase with respect to a keyphasor (initiation of the rotor revolution) in a complex plane.
  • the rotor-stator contact is detected, and a detailed data analysis is carried out after finishing the measurement to eliminate a possibility of false-positive detection. Therefore, this approach is inappropriate for the rotor-stator contact detection during real use of the turbine, and may be essentially employed only for laboratory or experimental purposes.
  • EP 1,533,479 discloses a method for detection of the rotor-stator contact where operational parameters of the turbine, such as for example shell temperature, rotor eccentricity, condenser pressure, and generator load are monitored. In doing so, the applicable algorithm evaluates independently the change to individual values and in the case of an abnormal or a jump change of any of them, the change is evaluated as a symptom of the rotor-stator contact.
  • a disadvantage of the method is that a jump change to a monitored value may relate to other phenomena or faults that normally occur in use of the turbine.
  • US 2,008,240,902 discloses a method for the rotor-stator contact detection that consists in monitoring of turbine stator temperature on at least of a part of circumference thereof.
  • a local temperature increase, if any, is attributed to rubbing between the rotor and the stator, and evaluated as presence of the rotor-stator contact.
  • the point of contact on the stator may be roughly localized based on placement of a temperature sensor that senses the temperature increase.
  • a disadvantage of the procedure is that at the moment when sufficiently high heat amount is produced through the rubbing between the rotor and stator for the temperature sensor to detect it, up to order of minutes may lapse since rotor-stator contact origin.
  • US 20090003991 discloses a method for the rotor-stator contact detection that consists in continuous measurement of blade clearance from stator and/or rotor blades height.
  • a disadvantage of the method similarly to previous case, is the necessity of additional installation of special sensors inside the turbine stator and related higher total costs.
  • the contact between a rotor blade and stator may be detected by measuring the change of gap between the rotor blade and seal in the stator.
  • the rotor-stator contact primarily occurs on the turbine shaft. Real likelihood of successful and early detection of the rotor-stator contact in this way is very limited.
  • Another disadvantage is possibility of false-positive detection of the rotor-stator contact in case of change to dimension sensed by the sensors, which may occur also for different reasons, e.g., due to rotor eccentricity, change to rotation speed, and more.
  • the objective of the present invention is to propose a new method for detection of synchronous rotor-stator contact in use of a turbine, which eliminates the disadvantages of the prior art, and allows for the rotor-stator contact detection in real time as earliest as it occurs.
  • the objective is to eliminate installation of new sensors inside the turbine body, or inside flow part of the machine, and use the existing (normally installed) sensors.
  • the present invention discloses a method of automatic detection of a synchronous rubbing in a turbine. It is applicable both for gas as well as steam turbine.
  • at least two sensors of rotor vibrations arranged on the turbine stator, perpendicularly each other within one measurement plane are used.
  • the measurement plane is perpendicular to a rotor rotation axis. It means that the sensors measure one area of the rotor, of which points are at the same distance from ends of the rotor shaft.
  • the described method for automatic detection of synchronous rubbing may be carried out on multiple points of a single rotor at the same time. It means that a plurality of measurement planes with relevant sensors of rotor vibrations are employed, wherein measured data is processed and evaluated separately for each measurement plane. A detection in a single of the employed measurement planes is enough to detect the synchronous rubbing. A plurality of the measurement planes is favourably employed for longer rotors where more accurate detection of the synchronous rubbing is achieved.
  • each sensor continuously measures the relative distance of the rotating rotor and turbine stator in the place of the sensor.
  • a trajectory of eccentric rotor motion in the measurement plane is reconstructed by combination of rotor distances filtered at rotational frequency ( ) in an orthogonal coordinate system.
  • the rotational frequency is denoted IX, and sometimes also referred to as a first harmonic signal component.
  • the trajectory of eccentric rotor motion is divided into individual orbits. Each orbit includes data per one rotor revolution, wherein the data includes information about the orbit origin coordinates in the orthogonal coordinate system for the beginning of the rotor revolution.
  • An initial amplitude defined by the distance of the orbit origin from the origin of the orthogonal coordinate system is determined for each orbit.
  • an initial angle is defined by angle between straight line defined by the origin of the orthogonal coordinate system and the orbit origin and any axis having a known position in the orthogonal coordinate system. It is favourable if an axis having known position is the X axis or Y axis of the orthogonal coordinate system.
  • the origin of the coordinate system lies in axis of non-vibrating rotor, or lies in the centre of a circle inscribed to the rotor journal bearing inside the stator.
  • the development of change to coordinates of the orbit origin over time is monitored by monitoring the changes of the initial amplitude and the initial angle between consecutive orbits. Of the measured values, the synchronous rubbing is detected by cumulative meeting of these indicators for a unit of time:
  • the primary excitation force acting on the rotating rotor is the centrifugal force which acts in the point of a residual unbalance of the rotor.
  • the centrifugal excitation force is a harmonic function of time with frequency equal to the rotor rotational frequency.
  • the point where the centrifugal force acts is known as Heavy Spot.
  • Vibration response of the rotor to acting centrifugal force is the harmonic function of time that is phase-delayed with respect to the excitation force.
  • a place on the rotor surface being steadily farthest from non-deflected (ideal) rotor centre, or from the origin of the orthogonal coordinate system, is referred to as High Spot.
  • This place is angle-shifted counter the rotation direction when compared to the point of the centrifugal force.
  • the shift angle size between High Spot and Heavy Spot depends on rotational speed of the rotor, and is defined by phase characteristics of a mechanical system. In the case when rub occurs due to excessive vibrations, it usually occurs in High Spot. In the case of the synchronous rubbing, which occurs periodically with each rotor revolution, there is transient temperature rotor bending caused by rubbing the stator and by local rotor temperature increase. The rotor bending may be interpreted as another unbalance, and a point of another centrifugal force is formed in the High Spot direction.
  • the amplitude of the resultant of the centrifugal forces will be higher or lower than the amplitude of original centrifugal force acting in Heavy Spot considering the mutual angle between the original centrifugal force and the centrifugal force with its point in High Spot.
  • Change of the excitation force amplitude invokes corresponding change to the IX amplitude of rotor vibration response.
  • the method described in the present invention assumes measurement of relative rotor vibrations in two mutually perpendicular directions.
  • the angular position of the first of the sensors in the rotation direction with respect to the horizontal axis may be arbitrary (p m (Fig. 1).
  • a rotor key-phasor signal measurement is assumed.
  • the rotor key-phasor is one specific point of the rotor in the measurement plane.
  • Rotor key-phasor measurement is an assumption for dividing the measured signals into individual rotor revolutions. It is usually carried out by an induction sensor located on the turbine stator.
  • the initial amplitude and the initial angle of the IX orbit origin is evaluated for signals of the relative rotor vibrations, e.g., by applying the order spectrum calculation from said signals, or by estimation using the least squares method.
  • the initial amplitude and the initial angle of the IX orbit are monitored (Fig. 2).
  • the initial amplitude and the initial angle of the IX orbit origin are evaluated from the amplitudes and the initial IX phases of both signals of the relative rotor vibrations:
  • the threshold values for each criterion are determined as 400% of standard deviation of said quantity from a sufficiently long data line (at least 1 hour) in use without rubbing present.
  • the determined time unit may be different for each criterion.
  • the assumptions for use of the described method include turbine operation at constant speed and knowledge of phase characteristic of the system.
  • Fig. 1 is a scheme of possible position of sensors of the rotor vibrations against the rotor with indication of the sense of rotor rotation while measuring the relative rotor vibrations;
  • Fig. 2 filtered IX orbit with the illustrated origin of the orbit
  • Fig. 3 characteristics for development of quantities for detection of the synchronous rubbing
  • Fig. 4 course of the initial amplitude and of the initial angle of the IX orbit origin in the presence of the synchronous rubbing;
  • Fig. 5 detection criteria of synchronous rubbing with indicated threshold values
  • Fig. 6 the detected presence of synchronous rubbing identified, marked in bold (exceeding of all three threshold values and development of change to the initial angle counter the rotor rotation direction).
  • Two sensors of the rotor vibrations are used in this exemplary method of the automatic detection of synchronous rubbing in the steam turbine.
  • the sensors are arranged on the steam turbine stator perpendicularly each other within a single measurement plane perpendicular to the steam turbine rotor axis of rotation.
  • Each sensor continuously measures the relative distance of the rotating rotor and the steam turbine stator in the place of the sensor.
  • the rotor rotates counter clockwise.
  • a trajectory of eccentric rotor motion in the measurement plane is reconstructed by combination of rotor distances filtered at rotational frequency IX in an orthogonal coordinate system.
  • the trajectory of rotor motion is divided into individual orbits.
  • Each orbit includes data per one rotor revolution, wherein the data includes information about orbit origin coordinates in an orthogonal coordinate system.
  • An initial amplitude defined by distance of the orbit origin from the origin of the orthogonal coordinate system is determined for each orbit. Furthermore, an initial angle is defined for each orbit by angle between a straight line defined by the origin of the orthogonal coordinate system and the orbit origin and any axis having a known position in the orthogonal coordinate system. In this case, the X axis of the orthogonal coordinate system is the axis.
  • the development of change of the orbit origin coordinates over time is monitored so that the change of the initial amplitude value and change of the initial angle between the consecutive orbits are monitored.
  • the synchronous rubbing is detected by the development of change to the initial angle counter the rotor rotation direction (counter clockwise in this example - the area of positive values) and by exceeding of the threshold values of derivation of the initial amplitude, initial angle, and area under curve being defined by the coordinates of the origins of the consecutive orbits.
  • the threshold values are: initial amplitude: 0.12 [pm/min] initial angle: -0.0168 [rad/min] area under curve: 0.1 [pm 2 ] while assuming the orbit initial point curve in 1 minute.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Testing Of Devices, Machine Parts, Or Other Structures Thereof (AREA)

Abstract

L'invention concerne les capteurs de vibrations de rotor qui mesurent la distance relative entre le rotor d'une turbine en rotation et le stator. Une trajectoire du mouvement du rotor excentrique est reconstruite en combinant les distances mesurées dans un système de coordonnées orthogonales. La trajectoire du mouvement du rotor est divisée en orbites individuelles. Chaque orbite comprend des informations sur les coordonnées d'origine de l'orbite dans un système de coordonnées orthogonales au début de la révolution du rotor. Une amplitude initiale et un angle initial par rapport à l'origine du système de coordonnées orthogonales sont déterminés pour chaque orbite. L'évolution des coordonnées de l'origine de l'orbite dans le temps est surveillée en contrôlant la valeur de changement des valeurs d'amplitude initiales et le changement de l'angle initial entre les orbites consécutives. Le frottement synchrone est détecté par l'évolution de l'angle initial contre le sens de rotation du rotor et par le dépassement des valeurs seuils de l'amplitude initiale, de l'angle initial et de l'aire sous la courbe définie par les coordonnées des origines des orbites consécutives, dans une unité de temps déterminée.
PCT/CZ2022/050055 2022-06-02 2022-06-02 Procédé de détection automatique de frottement synchrone dans une turbine WO2023232168A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP22744642.4A EP4308797B1 (fr) 2022-06-02 2022-06-02 Procédé de détection automatique de frottement synchrone dans une turbine
PCT/CZ2022/050055 WO2023232168A1 (fr) 2022-06-02 2022-06-02 Procédé de détection automatique de frottement synchrone dans une turbine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CZ2022/050055 WO2023232168A1 (fr) 2022-06-02 2022-06-02 Procédé de détection automatique de frottement synchrone dans une turbine

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WO2023232168A1 true WO2023232168A1 (fr) 2023-12-07

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4478082A (en) * 1981-08-26 1984-10-23 Hitachi, Ltd. Method and apparatus for detecting rubbing in a rotary machine
EP2746541A2 (fr) * 2012-12-20 2014-06-25 Doosan Skoda Power S.r.o. Procédé de détection et de localisation de frottement de rotor-stator partiel pendant le fonctionnement d'une turbine
US20210140851A1 (en) * 2017-05-12 2021-05-13 Korea Electric Power Corporation System and method for automatic diagnosis of power generation facility

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4478082A (en) * 1981-08-26 1984-10-23 Hitachi, Ltd. Method and apparatus for detecting rubbing in a rotary machine
EP2746541A2 (fr) * 2012-12-20 2014-06-25 Doosan Skoda Power S.r.o. Procédé de détection et de localisation de frottement de rotor-stator partiel pendant le fonctionnement d'une turbine
US20210140851A1 (en) * 2017-05-12 2021-05-13 Korea Electric Power Corporation System and method for automatic diagnosis of power generation facility

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EP4308797B1 (fr) 2024-02-28
EP4308797A1 (fr) 2024-01-24

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