CN101222133A - Shafting torsional oscillation protecting equipment of steam turbo-generator set - Google Patents

Abstract

The invention discloses a torsional oscillation protective device used for protecting the safety of shafting of a turbo generator set, which comprise: a pulse quantity input module (PI) used for detecting angular velocity change of ends of a machine and performing wave filtering treatment, detecting and demodulating various subsynchronous mode SSO signals and obtaining amplitudes of the various subsynchronous mode signals; a master module (CM) used for calculating endurance range of the shafting according to the various subsynchronous mode signals, and making judgment to the damage of the shafting according to the amplitudes of the various subsynchronous mode signals and obtaining actuating signals; and a digital quantity output module (DO) used for output tripping operations and guard signals. The device acquires the demodulated SSO signals, obtains a fatigue damage value and a fatigue damage tendency value of the shafting through real-time calculation as criterions so as to disconnect the turbo generator set from an electricity grid, thereby preventing torsional oscillation from further damaging the shafting of the turbo generator set.

Description

Shafting torsional oscillation protecting equipment of steam turbo-generator set

Technical field

The present invention relates to electric power system, big power station, need the protection of turbo generator set, hydraulic generator unit sub-synchronous oscillation to use, relate in particular to the shafting torsional oscillation protecting equipment under a kind of subsynchronous oscillation of generator set.

Background technology

Large-scale firepower Steam Turbine technology is one of key equipment of the great equipment of China, the axle cording of high-power unit has the feature of light flexible, multi-support, big span, high power density, generator material use coefficient improves, axle is that the cross section power density increases relatively, the lengthening of axle system descends torsional rigidity, the natural frequency of shafting spectrum is closeer relatively, and the energy of induced vibration is lower; Electrical network also develops in the direction towards the big zone of superhigh pressure simultaneously, and the superhigh pressure long distance power transmission adopts serial compensation capacitance to improve transmitting capacity of the electric wire netting in a large number.

The series capacitor compensation of transmission line, direct current transportation, the improper of power system stabilizer, PSS are installed additional, and sub-synchronous oscillation (SSO) phenomenon all might be brought out, be caused to the feedback effect of generator excited system, thyristor control system, electro-hydraulic control system etc.Steam turbine and generator amature inertia are bigger, and is very responsive to the low order torsion mode of axle system itself, is low all heavily stressed stresses.During the generator electric disturbance, disequilibrium between Steam Turbine Driven torque and the generator electromagnetic braking torque acts on a torsional shear stress of fastening and also will change, and increases the fatigue damage of shaft material, reduces useful life.When torsional stress arrives to a certain degree greatly, will cause shaft system of unit to damage or fracture, have a strong impact on the unit safety reliability service.

The subsynchronous torsional oscillation protecting equipment of generating set is realized under the SSO situation protection to the shaft system of unit torsional oscillation.Domestic present nothing provides the producer of shaft system of unit torsional oscillation protection and control appliance.This patent declaration material is introduced shafting torsional oscillation protecting equipment under a kind of subsynchronous oscillation of generator set.By measuring machine end angular velocity varies amount; it is carried out respectively the mode sampled value being carried out Fatigue Damage Calculation after bandpass filtering separates; the mode amplitude restrained disperse situation analysis; the axle that obtains current operation unit is a degree of impairment, by generator is broken the protection of realization to generating set from electrical network.

Summary of the invention

The present invention relates to the subsynchronous torsional oscillation protecting equipment of a kind of generating set, can be by the subsynchronous dynamo-electric fatigue damage that resonates and cause of calculating generator group, situation is dispersed in the convergence of Analysis Mode amplitude, realizes the protection to generator unit shaft system.The present invention is applicable to main force's large turbo-type generator group of 300MW, 600MW, 1000MW, is applicable to Method of Small Scale Turbo-generator and large capacity motor that 300MW is following too.

The subsynchronous torsional oscillation protecting equipment of generating set comprises: two pulsed quantity input modules (PI), a main control module (CM), four digital quantity output modules (DO), an analog quantity input module (AI), a digital quantity input module (DI) and two power modules (POW), this protective device is externally communicated by letter with the HMI of main website by Ethernet, adopts the communication of DP-NET communication network between described each module of this protective device;

Described pulsed quantity input module (PI) is used for machines end angular velocity varies amount, and obtains subsynchronous mode signal by the filtering link, and the pulse input module is two redundant configuration;

Described main control module (CM) is used for the output signal of received pulse amount input module (PI) and each mode signal is carried out parallel processing respectively, when satisfying the protection operating criterion, to described four digital quantity output modules (DO) output control signal;

Described four digital quantity output modules (DO) are according to the control signal of the main control module (CM) that receives, export trip signal, remote transfer signal, remote motion signal and central signal respectively, be used for alarm, jumping circuit or generator, realize protection generator unit shaft system;

Operational factor temperature, pressure, the exciting current of turbo generator set gathered and monitored to described analog quantity input module (AI); The switching value position of the operation of turbo generator set is gathered and monitored to described digital quantity input module (DI); Described power module (POW) is two redundant configuration, is other module for power supply of device.

1, PI module machines end angular velocity varies amount

In this device, adopt the input signal of the perunit value of generator shaft speed and rated rotational frequency difference as the subsynchronous torsional oscillation protecting equipment of generating set, be called machine end angular velocity varies amount, ω represents with Δ.

Use the pulse signal of non-contact sensor induction, the pulse signal demodulation is obtained machine end angular velocity varies amount, contain the oscillating component of a plurality of frequencies among the machine end angular velocity varies amount Δ ω with the gear generation of axle rotation.

2, PI module modal filter

Subsynchronous resonance SSO is that the frequency of extrinsic motivated moment of torsion is in step with the intrinsic torsion frequency in certain rank of axle system and is produced resonance, the twisting vibration of main shaft is increased rapidly, thereby cause the fail in shear of main shaft.So in order to realize protection, just need carry out filtering, obtain the corresponding oscillating component of intrinsic torsion frequency with rotor to machine end angular velocity varies amount Δ ω to unit.The filtering link comprises a low pass filter, a high pass filter and the band pass filter that each subsynchronous mode signal is carried out filtering respectively.

The low pass filter function is

$H\left(s\right)=\frac{1}{1+s/{\mathrm{\ω}}_L+{(s/{\mathrm{\ω}}_L)}^2}$

The high pass filter function is

$H\left(s\right)=\frac{{(s/{\mathrm{\ω}}_H)}^2}{1+s/{\mathrm{\ω}}_H+{(s/{\mathrm{\ω}}_H)}^2}$

The band pass filter transfer function is

$H\left(s\right)=\frac{s/{\mathrm{\&omega;}}_{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="S2008100570404E00031.png"\; state="\{\{state\}\}">P</figure-callout>}}}{1+6\mathrm{\&pi;s}/{\mathrm{\&omega;}}_{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="S2008100570404E00031.png"\; state="\{\{state\}\}">P</figure-callout>}}^2+{(s/{\mathrm{\&omega;}}_P)}^2}\frac{1+{(s/{\mathrm{\&omega;}}_{B1})}^2}{1+4\mathrm{\&pi;s}/{\mathrm{\&omega;}}_{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="S2008100570404E00031.png"\; state="\{\{state\}\}">B</figure-callout>}1}^2+{(s/{\mathrm{\&omega;}}_{B1})}^2}\frac{1+{(s/{\mathrm{\&omega;}}_{B2})}^2}{1+4\mathrm{\&pi;s}/{\mathrm{\&omega;}}_{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="S2008100570404E00031.png"\; state="\{\{state\}\}">B</figure-callout>}2}^2+{(s/{\mathrm{\&omega;}}_{B2})}^2}$

After isolating each torsional oscillation mode information, can and then implement independent modal and calculate.

3, the PI module is calculated

Pulsed quantity input module (PI) is realized calculating its amplitude according to each the subsynchronous mode signals sampling value that demodulates simultaneously.Represent with DWi, be called the amplitude of i machine end angular velocity varies component, wherein (i=1,2,3 ..., n).

4, the computing of each mode machine end angular velocity varies amount sampled value

The computing of each mode machine end angular velocity varies amount sampled value is the key link of the subsynchronous torsional oscillation protecting equipment of generating set, and calculation processes is realized by main control module CM.The processing procedure of main control module adopts separates mode computational process; by the generator actual speed is sampled, filtering; after obtaining the tach signal under the corresponding SSO mode, each mode tach signal is carried out computing respectively, with result calculated as the protection criterion one.

Computing among the main control module CM mainly be the calculating of mechanical fatigue of steam turbine generator unit shaft system, be divided into following four steps:

1) according to turbo generator set lumped mass Model Calculation shafting torsional oscillation mode and mode curve

2) torque of reference axis system calculating section part

A) according to the mode curve of each rank mode correspondence, calculate the torsional angle relative value that is subjected to each matter interblock under the different modalities pumping signal,

B) calculate constituent parts mode signal and respectively calculate the torque that section part produces in axle system,

C), calculate in axle system and respectively calculate the torque that section part produces by harvester end angular velocity varies amount;

3) calculate the fatigue damage aggregate-value that under certain disturbance situation each calculating section of shaft system of unit is caused, i.e. mechanical fatigue of steam turbine generator unit shaft system

A) according to 2) each calculates one time of the load course curve of section part to obtain shaft system of unit,

B) the real-time rain stream method of application is searched the Cyclic Stress in the load history,

C) use the equivalent stress width of cloth that the mean stress Reduced Coefficient Method is calculated each Cyclic Stress correspondence,

D) look into the part that calculates the corresponding dangerouse cross-section of section place and reverse the S-N curve, obtain the fatigue damage of single Cyclic Stress determining that dangerouse cross-section causes,

E) the linearity fatigue damage of all circulations that adds up obtains the fatigue damage aggregate-value of each dangerouse cross-section under certain disturbance situation;

4) fatigue data of current calculating is judged, when greater than certain preset value, obtained alarming trip signal

5, the analyzing and processing of each mode machine end angular velocity varies amount amplitude

The analyzing and processing of each mode machine end angular velocity varies amount amplitude is the key link of the subsynchronous torsional oscillation protecting equipment of generating set, and the analyzing and processing process is realized by main control module CM.The processing procedure of main control module adopts separates mode computational process; by the generator actual speed is sampled, filtering; after obtaining the tach signal under the corresponding SSO mode, each mode tach signal amplitude is carried out analyzing and processing respectively, with the result that analyzes as protection criterion two.

Analyzing and processing process among the main control module CM mainly is: the time series of calculating each torsional oscillation mode amplitude in real time, utilize the relative variation tendency of the observation window compute mode amplitude self of different length, differentiating torsional oscillation mode according to the statistics of the mode variation tendency in a period of time disperses, send trip signal generating set disconnected from electrical network, be following four steps:

1) determining the data window length of compute mode amplitude, is example with mode 1=15.1Hz, and the signal period of 15.1Hz correspondence is 1000/15.1=66.2ms, to 66.2 do 4 houses 5 go into 66.Then the corresponding calculated data window length of mode 1 (15.1Hz) is 66ms, and other modal data window is chosen in like manner;

2) according to the time series of following formula compute mode amplitude:

$a\left(y\right)=\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\mathrm{Cos}(\frac{k}{N}\&CenterDot;2\mathrm{\&pi;}{f}_i)\&CenterDot;d{w}_i(x+k)$

$b\left(y\right)=\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\mathrm{Sin}(\frac{k}{N}\&CenterDot;2\mathrm{\&pi;}{f}_i)\&CenterDot;d{w}_i(x+k)$

$A{\mathrm{dw}}_i\left(y\right)=\sqrt{a{\left(y\right)}^2+{b\left(y\right)}^2}$

Wherein, N is a data window length, equals 15.1Hz for mode 1, N=66; π is circumference ratio (3.14159), f _iIt is each model frequency value of axle system; Dw _i(x+k) expression mode i (i=1,2,3 ...) the matter of x+k of seasonal effect in time series point; Adw _i(y) be y point of mode amplitude seasonal effect in time series of the mode i that calculates, Adw _i(y) be dw _i(x+k) (for mode 1=15.1Hz, mode amplitude N=66) is exported through data window N.

3) modality divergence criterion is with Adw _i(y) (i=1,2,3 ...) be identifying object, to Adw _i(y) variation tendency is done differentiation.Because the common time of modality divergence of torsional oscillation protection is one second to tens seconds, this criterion is selected the Adw of constant duration T _iTime series, be labeled as Adw _i(k) (k=1,2,3 ...), definition of T is differentiated the sampling interval for dispersing, and is the integral multiple of sampling time interval.The span of T is (10ms～200ms).By calculating Adw _i(k) relative Changing Pattern determines whether mode occurs dispersing.

4) at Adw _i(k) in the time series, choose the observation window of two unequal lengths, length of window is respectively m, n, and wherein (m＞3n/2).Calculate at window m the Aaw in the n length respectively _i(k) seasonal effect in time series mean value Adw _p(m), Adw _p(n), work as Adw _p(m)＜Adw _p(n) time, mode i (dispersed in the m * T) in time of when observation window m.

6, actuating signal output

Digital quantity output module (DO) output action signal removes tangent line road or generator.

The present invention relates to the subsynchronous torsional oscillation protecting equipment of a kind of generating set; can in real time, accurately measure and demodulate the mode torsional vibration signals of turbo generator set; axle by the calculating generator group is that situation is dispersed in mechanical fatigue and the convergence of analyzing shafting torsional oscillation, and actuating signal is protected.Along with large turbo-type generator group and remote large capacity transmission The Application of Technology; the situation that sub-synchronous oscillation (SSO) takes place in unit and electrical network is more and more serious; test unit shafting torsional oscillation fatigue is solve the SSO problem basic, and the subsynchronous torsional oscillation protecting equipment of generating set is the key of the security of operation of power equipment such as protection generating set.This device has been realized the protection to the subsynchronous torsional oscillation of generating set, and the sub-synchronous oscillation problem that solves power plant and electrical network is significant.

Description of drawings

Fig. 1 .1, Fig. 1 .2, Fig. 1 .3 have illustrated pulse signal that the machine end sensor is measured and the machine end angular velocity varies amount Δ ω signal that obtains through demodulation, wherein

Fig. 1 .1 is a rotor when doing uniform rotation, the uniform pulse ripple of transducer output;

Fig. 1 .2 is that rotor exists when vibrating, and transducer is output as the impulse wave of density interphase;

Fig. 1 .3 is for to obtain machine end angular velocity varies amount Δ ω with the pulsed quantity demodulation;

Fig. 2 is a PI module mode filtering schematic diagram;

Fig. 3 .1, Fig. 3 .2 and Fig. 3 .3 have illustrated under certain disturbance, the sampled value of each mode that the machine end angular velocity varies amount Δ ω value analysis that obtains through measurement mechanism obtains, timing statistics 60s, sample frequency 1000HZ.Wherein

Fig. 3 .1 is mode one sampled value;

Fig. 3 .2 is mode two sampled values;

Fig. 3 .3 is mode three sampled values;

The curve of Fig. 3 .4 is that timing statistics 1.6s, sample frequency 1000HZ are amplified in the part of Fig. 3 .2 curve.

Fig. 4 has illustrated under certain disturbance, the amplitude curve of certain mode that the machine end angular velocity varies amount Δ ω value analysis that obtains through measurement mechanism obtains;

What Fig. 5 had illustrated rotor of steam turbo generator reverses the S-N curve, and the S-N curve is the characteristic curve of reflection fatigue of materials intensity;

Fig. 6 is a TSR apparatus structure schematic diagram;

Fig. 7 is the subsynchronous torsional oscillation protecting equipment wiring schematic diagram of generating set.

Embodiment

With embodiment the present invention is described in further details with reference to the accompanying drawings below.

The course of work of this device is: harvester end angular velocity varies amount, access each mode angular velocity varies instantaneous value of machine end by the mode filter solution, and obtain the oscillating component of each torsional oscillation mode, try to achieve the amplitude of each subsynchronous mode signal simultaneously.According to each subsynchronous mode signals sampling value reference axis is tired; simultaneously according to the convergence of the amplitude of each subsynchronous mode signal disperse situation and to axle system degree of impairment judge; tired to cross definite value or exist under the tired situation of a dead axle system shafting torsional oscillation to be divergent trend be criterion with axle system; judge and obtain actuating signal and output; jumping circuit or generator are realized the protection of unit under the subsynchronous resonance conditions takes place.Apparatus structure installs the practical application wiring as shown in Figure 7 as shown in Figure 6.

1, PI module machines end angular velocity varies amount

Use the pulse signal of non-contact sensor induction with the gear generation of axle rotation.During each tooth process transducer, produce a pulse signal.When rotor was done uniform rotation, burst location had reflected the arrangement position of each tooth on circumference of gear.What transducer was exported is uniform impulse wave, and its fundamental frequency is S*N (S is a speed-frequency, is 3000rad/s, and N is the gear number of teeth, is 134 teeth), as Fig. 1 .1.

When there was vibration in rotor, variation had taken place in the position of each pulse, and vibration makes pulse signal that phase shift take place, and is output as the impulse wave of density interphase, as Fig. 1 .2.Extract this phase shift, the one group of sampled value that just obtains vibrating, top pulse train has carried the full detail that axle rotatablely moves.

Use following formula, then the pulsed quantity demodulation can be obtained machine end angular velocity varies amount.

100*π*dt+Δω/3000+Δω*dt＝0

Wherein the pulse period that forms for actual measurement gear two between cog of dt and calibration pulse cycle is poor.

Δ ω is machine end angular velocity varies amount.

Obtain the angular velocity varies amount after the impulse wave demodulation shown in Fig. 1 .3.

If during the simple harmonic quantity torsional oscillation of rotor generation single-frequency, the angular displacement in a certain cross section is:

υ(t)＝Asin(ω _it+θ)

ω in the formula _iBe the angle of throw frequency, A and θ are the amplitude and the initial phase of this section.

If with the rotor of stabilized (steady-state) speed work, when it was subjected to the periodicity driving torque, the torsional oscillation of rotor comprised the simple harmonic quantity component of different frequency and amplitude, at this moment has:

$\mathrm{\&phi;}\left(t\right)={\mathrm{\&omega;}}_{r}t+\underset{k}{\mathrm{\&Sigma;}}{A}_k\sin ({\mathrm{\&omega;}}_{k}t+{\mathrm{\&theta;}}_k)$

The angular speed that axle rotatablely moves is the mean angular velocity of axle and the superposition of torsional oscillation angular speed:

$\mathrm{\&omega;}={\mathrm{\&omega;}}_r+\underset{k}{\mathrm{\&Sigma;}}{A}_k{\mathrm{\&omega;}}_k\cos ({\mathrm{\&omega;}}_{k}t+{\mathrm{\&theta;}}_k)$

Machine end angular velocity varies amount then $\mathrm{\&Delta;\&omega;}=\underset{k}{\mathrm{\&Sigma;}}{A}_k{\mathrm{\&omega;}}_k\cos ({\mathrm{\&omega;}}_{k}t+{\mathrm{\&theta;}}_k)$

ω in the formula _k, A _k, θ _kThe corresponding parameter of representing K oscillating component respectively.

The oscillating component that contains a plurality of frequencies among the machine end angular velocity varies amount Δ ω.

Subsynchronous resonance SSO is that the frequency of extrinsic motivated moment of torsion is in step with the intrinsic torsion frequency in certain rank of axle system and is produced resonance, the twisting vibration of main shaft is increased rapidly, thereby cause the fail in shear of main shaft.So, just need suppress to the subsynchronous resonance frequency signal in order to suppress the torsional resonance of steam-electric generating set shafting.This needs earlier machine end angular velocity varies amount Δ ω to be carried out filtering, obtains the corresponding oscillating component of intrinsic torsion frequency with rotor.

2, PI module modal filter

Getting a machine end angular velocity varies amount that rotatablely moves by 1 is

$\mathrm{\&Delta;\&omega;}=\underset{k}{\mathrm{\&Sigma;}}{A}_k{\mathrm{\&omega;}}_k\cos ({\mathrm{\&omega;}}_{k}t+{\mathrm{\&theta;}}_k)$

For multi-modal SSO, adopt modal filter from Δ ω signal, to isolate each torsional oscillation mode information, filter is as shown in Figure 2.Wherein

The low pass filter function is

$H\left(s\right)=\frac{1}{1+s/{\mathrm{\&omega;}}_L+{(s/{\mathrm{\&omega;}}_L)}^2}$

The high pass filter function is

$H\left(s\right)=\frac{{(s/{\mathrm{\&omega;}}_H)}^2}{1+s/{\mathrm{\&omega;}}_H+{(s/{\mathrm{\&omega;}}_H)}^2}$

The band pass filter transfer function is

$H\left(s\right)=\frac{s/{\mathrm{\&omega;}}_{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="S2008100570404E00031.png"\; state="\{\{state\}\}">P</figure-callout>}}}{1+6\mathrm{\&pi;s}/{\mathrm{\&omega;}}_{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="S2008100570404E00031.png"\; state="\{\{state\}\}">P</figure-callout>}}^2+{(s/{\mathrm{\&omega;}}_P)}^2}\frac{1+{(s/{\mathrm{\&omega;}}_{B1})}^2}{1+4\mathrm{\&pi;s}/{\mathrm{\&omega;}}_{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="S2008100570404E00031.png"\; state="\{\{state\}\}">B</figure-callout>}1}^2+{(s/{\mathrm{\&omega;}}_{B1})}^2}\frac{1+{(s/{\mathrm{\&omega;}}_{B2})}^2}{1+4\mathrm{\&pi;s}/{\mathrm{\&omega;}}_{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="S2008100570404E00031.png"\; state="\{\{state\}\}">B</figure-callout>}2}^2+{(s/{\mathrm{\&omega;}}_{B2})}^2}$

After isolating each torsional oscillation mode information, can and then implement independent modal control.

Above filter scheme is at model frequency during by certain measuring errors and fluctuation range, can leach the model frequency signal of being paid close attention to preferably, organize other mode signals and the noise of the width of cloth pass through, and the phase deviation of generation suitably and when model frequency fluctuates changes not quite.

3, the PI module is calculated

Pulsed quantity input module (PI) is realized calculating its amplitude according to each the subsynchronous mode signals sampling value that demodulates simultaneously.Represent with DWi, be called the amplitude of i machine end angular velocity varies component, wherein (i=1,2,3 ..., n).

4, the computing of each mode machine end angular velocity varies amount sampled value

The computing of each mode machine end angular velocity varies amount sampled value is the key link of the subsynchronous torsional oscillation protecting equipment of generating set, and calculation processes is realized by main control module CM.The processing procedure of main control module adopts separates mode computational process; by the generator actual speed is sampled, filtering; after obtaining the tach signal under the corresponding SSO mode, each mode tach signal is carried out computing respectively, with result calculated as the protection criterion one.

Computing among the main control module CM mainly be the calculating of mechanical fatigue of steam turbine generator unit shaft system, be divided into following four steps:

1) according to turbo generator set lumped mass Model Calculation shafting torsional oscillation mode and mode curve.

2) torque of reference axis system calculating section part.

A) according to the mode curve of each rank mode correspondence, calculate the torsional angle relative value that is subjected to each matter interblock under the different modalities pumping signal;

B) calculate constituent parts mode signal and respectively calculate the torque that section part produces in axle system;

C), calculate in axle system and respectively calculate the torque that section part produces by harvester end angular velocity varies amount;

3) calculate the fatigue damage aggregate-value that under certain disturbance situation each calculating section of shaft system of unit is caused, i.e. mechanical fatigue of steam turbine generator unit shaft system.

A) according to 2) each calculates the load-time history curve of section part to obtain shaft system of unit;

B) the real-time rain stream method of application is searched the Cyclic Stress in the load history;

C) use the equivalent stress width of cloth that the mean stress Reduced Coefficient Method is calculated each Cyclic Stress correspondence;

D) look into the part that calculates the corresponding dangerouse cross-section of section place and reverse the S-N curve, obtain the fatigue damage of single Cyclic Stress determining that dangerouse cross-section causes;

E) the linearity fatigue damage of all circulations that adds up obtains the fatigue damage aggregate-value of each dangerouse cross-section under certain disturbance situation;

4) fatigue data of current calculating is judged obtained alarming trip signal.

5, the analyzing and processing of each mode machine end angular velocity varies amount amplitude

The analyzing and processing of each mode machine end angular velocity varies amount amplitude is the key link of the subsynchronous torsional oscillation protecting equipment of generating set, and the analyzing and processing process is realized by main control module CM.The processing procedure of main control module adopts separates mode computational process; by the generator actual speed is sampled, filtering; after obtaining the tach signal under the corresponding SSO mode, each mode tach signal amplitude is carried out analyzing and processing respectively, with the result that analyzes as protection criterion two.

Analyzing and processing process among the main control module CM mainly is: the time series of calculating each torsional oscillation mode amplitude in real time, utilize the relative variation tendency of the observation window compute mode amplitude self of different length, differentiating torsional oscillation mode according to the statistics of the mode variation tendency in a period of time disperses, send trip signal generating set disconnected from electrical network, be following four steps:

1) determining the data window length of compute mode amplitude, is example with mode 1=15.1Hz, and the signal period of 15.1Hz correspondence is 1000/15.1=66.2ms, to 66.2 do 4 houses 5 go into 66.Then the corresponding calculated data window length of mode 1 (15.1Hz) is 66, and other modal data window is chosen in like manner;

2) according to the time series of following formula compute mode amplitude:

$a\left(y\right)=\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\mathrm{Cos}(\frac{k}{N}\&CenterDot;2\mathrm{\&pi;}{f}_i)\&CenterDot;d{w}_i(x+k)$

$b\left(y\right)=\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\mathrm{Sin}(\frac{k}{N}\&CenterDot;2\mathrm{\&pi;}{f}_i)\&CenterDot;d{w}_i(x+k)$

$\mathrm{Ad}{w}_i\left(y\right)=\sqrt{{a\left(y\right)}^2+b{\left(y\right)}^2}$

Wherein, N is a data window length, equals 15.1Hz for mode 1, N=66; π is circumference ratio (3.14159), f _iIt is each model frequency value of axle system; Dw _i(x+k) expression mode i (i=1,2,3 ...) the matter of x+k of seasonal effect in time series point; Adw _i(y) be y point of mode amplitude seasonal effect in time series of the mode i that calculates, Adw _i(y) be dw _i(x+k) (for mode 1=15.1Hz, mode amplitude N=66) is exported through data window N.

3) modality divergence criterion is with Adw _i(y) (i=1,2,3 ...) be identifying object, to Adw _i(y) variation tendency is done differentiation.

4) at Adw _i(k) in the time series, choose the observation window of two unequal lengths, length of window is respectively m=10 and n=5 execution cycle.Calculate the Adw in length of window respectively _i(k) seasonal effect in time series mean value Adw _p(m), Adw _p(n), work as Adw _p(m)＜Adw _p(n) time, mode i (dispersed in the m * T) in time of m=10 execution cycle of when observation window.

6, actuating signal output

Digital quantity output module (DO) output action signal removes tangent line road or generator.

With domestic certain 600MW of power plant turbo generator set is example.

Known turbo generator set Mechatronic Systems characteristic frequency is as shown in table 1:

Mode 1	Mode 2	Mode 3
			15.2HZ	26.1HZ	30.2HZ

Table 1, turbo generator set characteristic frequency

Generating set lumped mass model modelling data are as shown in table 2;

The lumped mass module	Equivalence inertia M (kg*m 2)	Equivalent stiffness K (N*m/rad)
			High pressure rotor HIP	2851
0.76882E+08

A low pressure rotor ALP	15542
			0.13316 E+09
		B low pressure rotor BLP		15235
0.13232 E+09
	Generator amature GEN		9732

Table 2, axle are the modelling data

PI module harvester end angular velocity varies value Δ ω through mode filtering, obtains three subsynchronous mode Δ ω 1, Δ ω 2, Δ ω 3.The mode filtering as shown in Figure 2,

The low pass filter parameter is set to: ω _y=2 π 40

The high pass filter parameter is set to: ω _H=2 π 10

The parameter of band pass filter 1 is set to: ω _P=2 π 16, ω _B1=2 π 26, ω _B2=2 π 30

The parameter of band pass filter 2 is set to: ω _P=2 π 26, ω _B1=2 π 16, ω _B2=2 π 30

The parameter of band pass filter 3 is set to: ω _P=2 π 30, ω _B1=2 π 16, ω _B2=2 π 26

Fig. 3 .1, Fig. 3 .2 and Fig. 3 .3 have illustrated under certain disturbance, the sampled value of each mode that the machine end angular velocity varies amount Δ ω value analysis that obtains through the PI module filtered obtains, and abscissa is the time, timing statistics 60s, sample frequency 1000HZ.Ordinate is the perunit value of angular velocity varies value.Wherein

Fig. 3 .1 is mode one sampled value;

Fig. 3 .2 is mode two sampled values;

Fig. 3 .3 is mode three sampled values;

The curve of Fig. 3 .4 is that timing statistics 1.6s, sample frequency 1000HZ are amplified in the part of Fig. 3 .2 curve.

Fig. 4 has illustrated under certain disturbance, the amplitude of the mode two that the machine end angular velocity varies amount Δ ω value demodulation that obtains through the PI module filtered calculates;

Under the disturbance this time, the torsional angle relative value of matter interblock calculating section part is as shown in table 3;

Mode	Frequency (HZ)	The matter interblock calculates the torsional angle relative value of section part
					(between the matter piece one, two)	(between the matter piece two, three)	(between the matter piece three, four)
		Mode one	15.2	θ11＝-0.35176				θ12＝-0.92079	θ13＝-0.62897
Mode two	26.1				θ21＝-0.98820	θ22＝-0.60771	θ23＝1.21629.93
		Mode three	30.2	θ31＝-1.31161				θ32＝0.52913	θ33＝-0.35334

Concentrate torsional angle relative value between quality module under table 3, certain disturbance situation

Each mode unit strength single stress circulates in each matter interblock, and to calculate the torque of section part as shown in table 4;

Mode	Frequency (HZ)	Each matter interblock calculates the torque of section part
			(between the matter piece one, two)	(between the matter piece two, three)	(between the matter piece three, four)

Mode one	15.2	t11＝-1.44211	t12＝-6.53824	t13＝-4.43794
					Mode two	26.1	t21＝--2.43477	t22＝-2.59333	t23＝5.15.5767
Mode three	30.2	t31＝--2.82900	t32＝1.97669	t33＝-1.31166

Table 4, each mode unit strength single stress circulate in the torque that each matter interblock calculates section part

According to torque curve, that looks into as shown in Figure 5 2# bearing shell place reverses the S-N curve, can obtain the fatigue loss that under given fault this time axle journal place, this 600MW steam-electric generating set shafting 2# bearing shell position is produced.The fatigue loss that under the given fault axle journal place, 2# bearing shell position is produced in this example is 0.03548%.Axle is that the Fatigue Damage Calculation method of other positions is identical with 2# bearing shell position.

This time under the disturbance situation, as shown in table 5 to the fatigue damage that each dangerouse cross-section causes;

Dangerouse cross-section	Fatigue damage (%)
		2# watt of position	0.03548
3# watt of position	0.0
		4# watt of position	0.00611
5# watt of position	0.00692
		6# watt of position	0.05248

The fatigue damage that under table 5, certain disturbance situation each dangerouse cross-section is caused

Fig. 6 is the shafting torsional oscillation protecting equipment of steam turbo-generator set structural representation;

Device assembly comprises two power modules (POW), two pulse input modules (PI) redundant configuration, a controller module (CM), an analog quantity input module (AI), a digital quantity input module (DI), four digital quantity output modules (DO).

Device is externally communicated by letter with HMI by Ethernet, adopts the DP-NET communication network between inner each assembly of device.

Power module (POW) is a redundant configuration, is other module for power supply of device.

The operational factor temperature of analog quantity input module (AI) collection turbo generator set, pressure, exciting current etc., digital quantity input module (DI) is gathered switching value position etc., monitors.

Device is finished the calculating of mechanical fatigue by PI harvester end pulse signal in CM, and puts the DO outlet according to certain criterion and alarm or the jumping machine.

Fig. 7 is the shafting torsional oscillation protecting equipment of steam turbo-generator set wiring schematic diagram.Device has only simply been illustrated the major function of TSR device.From the head end of high pressure cylinder the speed probe that a pair of axle is is installed.Device is gathered the tach signal that the redundant speed probe of axle system sends, and the axle by CM calculating generator group is that situation is dispersed in mechanical fatigue and the convergence of analyzing shafting torsional oscillation, the actuating signal that is protected, and output DO signal is alarmed or is tripped.

Claims (5)

1. shafting torsional oscillation protecting equipment of steam turbo-generator set; comprise; two pulsed quantity input modules (PI); a main control module (CM), four digital quantity output modules (DO), an analog quantity input module (AI); a digital quantity input module (DI) and two power modules (POW); this protective device is externally communicated by letter with the HMI of main website by Ethernet, adopts communication network communication between described each module of this protective device, it is characterized by:

Described pulsed quantity input module (PI) is used for machines end angular velocity varies amount, and obtains subsynchronous mode signal by the filtering link, and the pulse input module is two redundant configuration;

Described main control module (CM) is used for the output signal of received pulse amount input module (PI) and each mode signal is carried out parallel processing respectively, when satisfying the protection operating criterion, to described four digital quantity output modules (DO) output control signal;

Described four digital quantity output modules (DO) are according to the control signal of the main control module (CM) that receives, export trip signal, remote transfer signal, remote motion signal and central signal respectively, be used for alarm, jumping circuit or generator, realize protection generator unit shaft system;

Operational factor temperature, pressure, the exciting current of turbo generator set gathered and monitored to described analog quantity input module (AI);

The switching value position of the operation of turbo generator set is gathered and monitored to described digital quantity input module (DI);

Described power module (POW) is two redundant configuration, is other module for power supply of device.

2. shafting torsional oscillation protecting equipment of steam turbo-generator set according to claim 1; it is characterized by; described machine end angular velocity varies amount is as the input signal of generator unit shaft system protective device; ω represents with Δ; it is the perunit value of motor shaft speed and rated rotational frequency difference; the process of described pulsed quantity input module (PI) machines end angular velocity varies amount Δ ω adopts noncontact to survey the tooth principle, and the pulse signal of transducer is demodulated into the torsional angle displacement signal.

3. shafting torsional oscillation protecting equipment of steam turbo-generator set according to claim 1, the filtering link of said pulsed quantity input module (PI) comprise a low pass filter, a high pass filter and the band pass filter that each subsynchronous mode signal is carried out filtering respectively.

4. according to the described shafting torsional oscillation protecting equipment of steam turbo-generator set of claim 1 to 3, said pulsed quantity input module (PI) is realized the calculating to each subsynchronous mode signal amplitude simultaneously.

5. shafting torsional oscillation protecting equipment of steam turbo-generator set according to claim 1, master control module (CM) are realized each subsynchronous mode signal is handled, and described protection operating criterion comprises criterion one and criterion two, it is characterized by:

Calculate according to each mode signals sampling value, the fatigue damage that the accumulative total torsional vibration signals causes axle system, with the fatigue damage aggregate-value of gained whether greater than the criterion one of set point as the protection action;

Amplitude according to each mode signal is analyzed, and situation is dispersed in the convergence that obtains torsional vibration signals, disperses the criterion two of moving as protection with torsional vibration signals;

When aforementioned any protection operating criterion satisfied, master control module (CM) made generator or line tripping to digital quantity output module (DO) output control signal.

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