JPS58201030A - Device for supervising twisting oscillation of rotary shaft system - Google Patents

Abstract

PURPOSE:To improve transient response characteristics, by inputting the output of a twisting oscillation detector to an operator through plural band pass filters and phase meters and then inputting the output of the operator to a life and consumption calculator through plural monitoring point stress signal composers to calculate the life and the quantity of consumption. CONSTITUTION:The titled device is provided with the twisting oscillation detector 10, plural band pass filters 11 having center frequency equal to each natural frequency of a rotary shaft system respectively and plural phase meters 12. Phase signals theta1-thetan and a signal (y) from the twisting oscillation detector 10 are applied to an operator 12b for simultaneous equations to calculate the twisting oscillation response of each monitoring point. The outputs y1-yn from the operator 12b are applied to a fatigue life and consumption calculator 14 through the monitoring point stress signal composer 13 and the calculated result is applied to a recording/displaying device 15. Consequently, influences such as noises are removed and the response can be removed.

Description

[Detailed description of the invention] The present invention relates to a rotating shaft system torsional vibration monitoring device.

For example, as shown in the layout diagram of FIG.
．． Medium pressure turbine 02. Low pressure turbine 03, generator 04.
In the turbine generator shaft system in which the exciter 05 is connected in tandem by the shaft 06, Fig. 2), (B),
fcl, (As shown in the DJ diagram, it has multiple torsional natural vibration modes such as primary, secondary, tertiary, and quartic modes determined by the mass and spring stiffness of each part,
When there is a sudden load change such as a power transmission system failure, this causes torsional vibration as an exciting force, and torsional vibration stress is generated in each part of the shaft thread.

MI diagram OA, B, C, D, Fl, F, G are turbine shafts,
These are multiple monitoring points that should be used as checkpoints for fatigue strength due to torsional vibration in couplings, etc., and when the shaft is rotating at a constant rotation, the gear is detected by electromagnetic gear. The period of the 70 rotation zf pulse is constant, but when rotational vibration occurs, it rotates in proportion to the torsional vibration amplitude.) Since the 4 pulse is frequency modulated, conventionally, by detecting this rotation j/f pulse, each According to the knowledge of vibration elevation, which measures the amplitude of torsional vibration at a monitoring point, the torsional vibration of a shaft system can be approximately expressed by equation (1) as a composition of its natural vibration modes.

F(x, t)=a1(t)・g, fxl+a, (t
l・g, fx)+...+an(t)・gn(x)
・・・・・・・・・・・・・・・・・・・・・・・・
...fl) Here, Y(X) is the measurement signal a 1 at the measurement position x, a2'<...an is the response amount g 1 e g of each natural vibration mode component! ...gn is a natural vibration mode as shown in FIG. 2, for example.

Therefore, the rotational pulse signals detected by the gear 07 on the shaft system and the electromagnetic pickup 08 are input to the torsional vibration detector 010 shown in the block diagram of FIG.
A torsional vibration signal as shown in (B) is detected. Here, (B) in the same figure is the frequency spectrum of (A) in the same figure. As shown in Fig. 4 (C1), this is a pantone matrix filter θ11 (third
(see figure), the vibration component of only its eigenvalues yi (xp, t) = at (t) · gi (xp) CO5 as shown in Figure 4
(ωth+θi)・・・・・・・・・・・・・・・・・・
...(2) is obtained.

As shown in FIG. 3, the number of bandpass filters 011 is equal to the number of natural vibrations.

In this way, the response for each natural vibration is known, so by multiplying the vibration mode ratio of the monitoring point obtained from the natural vibration mode in FIG.
The vibration response of the monitoring point for each mode is obtained as shown in Figure (E).

Therefore, for each monitoring point, all modes are summed and synthesized by o1.
s (see Figure 3), the vibration response of the monitoring point is obtained, and the vibration waveform at each point is known. Since stress is proportional to the vibration amplitude, δ (x people, t) = Σyl ( x, t) - α(x)...
If the stress waveform can be estimated as (4) and the stress waveform at each monitoring point is known, then the life consumption can be calculated using Calculator 014 ($
(see Figure 3), and the results are displayed on the record display 015 (
@Refer to Figure 3).

What has been described above is an overview of the conventional torsional vibration monitoring device for the rotating shaft system of a turbine generator.

However, when huge vibrations that consume the fatigue life of the turbine generator shaft system occur, it is when there is a power transmission failure due to a lightning strike etc. in the power transmission system and sudden load changes are applied, and torsional vibration at this time occurs. The response is a transient response oscillation, and the maximum stress occurs at the beginning of the response, so the monitoring device must have a good transient response characteristic and a non-nodal/4' filter to decompose it into each eigenmode. It is necessary to reduce the influence of adjacent eigenvalues, and for this purpose, the cutoff characteristics of the pantone 4-sphere filter must be made large.However, increasing the cutoff characteristics of the filter has the trade-off that the transient response characteristics will deteriorate significantly. A problem arises.

By the way, the cutoff characteristic of a normal bandpass filter is Q-20.
It is said that it is best to choose according to the degree of
As shown in Figure fc), only a response of less than 90% was obtained for the first 15 peaks, making it impossible to reliably monitor vibrations near high stress areas.

The present invention was proposed in view of the above circumstances, and aims to provide a high-performance rotating shaft system torsional vibration monitoring device based on a mode decomposition method with excellent transient response characteristics. , a plurality of backbone filters each having a center frequency equal to each natural frequency of the rotating shaft system and inputting the output of the torsional vibration detector, and a plurality of backplane filters inputting the output of each band/mother filter, respectively. a phase meter, a simultaneous equation calculator that inputs the outputs of the plurality of phase hands and calculates the torsional vibration response of each monitoring point of the rotating shaft system; The present invention is characterized by comprising a plurality of monitoring point stress signal synthesizers for calculating stress.

An embodiment of the present invention will be described with reference to the drawings.

FIG. 6 is a block diagram showing the circuit configuration.

In the above figure, 10 is the torsional vibration detector, 11 is the detector 1
12a is a phase meter that inputs the output of the bandpass filter 11, 12a is a simultaneous equation calculator that inputs the outputs of the phase meter 12a and the detector 10, and 13 is the output of the calculator 12b. 14 is a fatigue life consumption calculator that inputs the output of the synthesizer 13; 15 is a fatigue life consumption amount calculator 1
This is a recording/displaying device that inputs the output of 4.

In such a device, the torsional vibration signal detected by the torsional vibration detector 10 is passed through a bandpass filter 1 which is matched to the central river wave number at each natural frequency, and decomposed into signals for each natural mode. The phase information of each signal is obtained using a phase meter 12m.

This phase can be determined, for example, by the following method. That is, the maximum value of the output waveform of the pantone filter 11,
Detect the minimum value and zero crossing timing, and these timings are 0 degrees.

Since this corresponds to phases of 180 degrees, 90 degrees, and 270 degrees, the phase angle θ1 at each timing can be found by approximating this.

Once the phase angle for each mode is known in this way, the measurement signal can be calculated using equation (5) based on equation (1): y(x,t)=Σa
1(t), g 1(x) ・cosθ width)...
...(5) Expressed in the east, and at a point with a slightly different time, Equation (6) (6
), the only unknown quantity is al, and the number of modes (1
) It is also easy to create a larger number of equations, and by solving these simultaneous equations, the response amount of each mode can be calculated using the calculator 1.
Obtained in 2b. Thereafter, fatigue life consumption is monitored using the same circuit as in conventional equipment.

Such a device provides the following effects.

(1) Since the output of the bandpass filter is used only as phase information, increasing the cut-off characteristics and lowering the transient characteristics does not affect the device performance, and the overall performance of the device improves the transient characteristics.

(2) When torsional vibration is determined from the rotation base, noise of the shaft rotational speed component is always mixed in, but this can also be removed in the same manner as mode decomposition.

In short, according to the present invention, a torsional vibration detector, a plurality of pantone filters each having a center wave number equal to each natural frequency of the rotating shaft system and inputting the output of the torsional vibration detector, and each of the above-mentioned a plurality of phase meters that input the output of each bandpass filter; a simultaneous equation calculator that inputs the output of the plurality of phase meters and calculates the torsional vibration response of each monitoring point of the rotating shaft system; and a simultaneous equation calculator that inputs the output of each of the bandpass filters; The present invention is industrially extremely useful because it provides a high-performance rotating shaft system torsional vibration monitoring device by including a plurality of monitoring point stress signal synthesizers that input the output of the device and calculate the stress at each of the monitoring points. It is something.

[Brief explanation of the drawing]

Figure 1 shows a well-known turbine generator [arrangement diagram of the machine shaft system, in the 2nd section, (B), fc), and (D) are in the '1st section, respectively.
Figure 3 is a block diagram of a known rotary shaft system assisted vibration monitoring device, Figure 4 (N is an output diagram of the electromagnetic pickup in Figure 1, Figure 4 is B) is the wavenumber spectrum diagram of Figure 4 (N), Figure 4 (C) is the characteristic diagram of the pantone quantity filter of Figure 3, and the peak of Figure 4 is the output diagram of the bandpass filter of Figure 3. , Figure 4 (Unit is the vibration response diagram of the monitoring point in Figure 1, Figure 5 (A) is the standard input waveform diagram to the bandpass filter, Figure 5 (Bl, (C1, ()
Dl is shown in Figure 5 (each output waveform diagram for the input waveform of ~ shows each case of Q = 10, 20, 40, respectively,
FIG. 6 is a block diagram of one embodiment of the present invention. DESCRIPTION OF SYMBOLS 10... Torsional vibration detector, 11... Band pass filter, 12a... Phase meter, 12b... Simultaneous equation calculator, 13... Monitoring point stress signal synthesizer, 14... Fatigue life Consumption calculator, 15...recording display device. Representative Patent Attorney Suzue Takehiko Figure 2 Figure 4 □J CJJI va! -8 3

Claims (1)

[Claims] a torsional vibration detector, a plurality of pantone 4-sphere filters each having a center frequency equal to each natural frequency of the rotating shaft system and each inputting the output of the torsional vibration detector, and each inputting the output of each of the pantone gusset filters; a simultaneous equation calculator that inputs the outputs of the plurality of phase meters and calculates the torsional vibration response of each monitoring point of the rotating shaft system; A rotating shaft system torsional vibration monitoring device comprising a plurality of monitoring point stress signal synthesizers for calculating stress at monitoring points.