CN105024601A - Power generator excitation low excitation limit method and device - Google Patents

Abstract

The invention provides a power generator excitation low excitation limit method and device. The method comprises the steps that gain of low excitation limit is adjusted according to a power generator power angle; and excitation low excitation limiting is performed on a power generator according to the adjusted gain. The technical problems in the prior art that system oscillation is liable to occur in actual work due to the fact that low excitation limiting is performed by adopting manufacturer default parameters can be solved so that the technical effects of reducing system oscillation and enhancing system stability can be achieved.

Description

The excitation of generator is low encourages method for limiting and device

Technical field

The present invention relates to technical field of generators, particularly a kind of excitation of generator is low encourages method for limiting and device.

Background technology

Along with the progress of excitation con-trol technology, the exciter control system of Modern Large group generally all has multinomial miscellaneous function, lowly encourage restriction (Under Excitation Limiter, UEL) Main Function be avoid by the excessive winding caused of generator unit stator electric current overheated, and the problem that when avoiding generator to run under underexcitation, static stability is destroyed.For Large Copacity long distance power delivery system, when night load is lighter, system capacitive reactive power is superfluous, and generating set needs leading phase operation, even causes excitation system UEL action.But, if UEL parameter tuning is unreasonable, adverse influence can be caused to excitation system is stable.

Because generator runs under underexcitation, generator internal e.m.f. reduces, and generator's power and angle becomes large, and unit static stability reduces, and damping simultaneously also can reduce, and more easily produces the instability of oscillation mode, therefore lowly encourages restriction and just seems particularly important.At present, low preset parameter of encouraging the factory default of parameter many employings manufacturing firm of limiting element, if the low parameter tuning of encouraging of producer is improper, or control system overall construction design is unreasonable, or even low limit link parameters of encouraging does not mate with the changeable operating condition of reality, all will cause low encourage restriction actual devote oneself to work after there is system oscillation.

Summary of the invention

The excitation embodiments providing a kind of generator is low encourages method for limiting and device, to reach minimizing system oscillation, improves the object of the stability of a system.

The excitation embodiments providing a kind of generator is low encourages method for limiting, and to reach minimizing system oscillation, improve the object of the stability of a system, the method comprises: according to the low gain of encouraging restriction of generator's power and angle adjustment; According to the gain after adjustment described generator carried out to excitation is low encourages restriction.

In one embodiment, according to the low gain of encouraging restriction of generator's power and angle adjustment, comprising:

Gain increases along with generator's power and angle and reduces, and gain reduces along with generator's power and angle and increases.

In one embodiment, according to the low gain of encouraging restriction of following formula adjustment:

${\mathrm{\ΔV}}_{\mathrm{UEL}}=K_{\mathrm{UEL}}\frac{T_{\mathrm{UEL}1}s+1}{T_{\mathrm{UEL}2}s+1}\×\mathrm{\Δz}$

Wherein, Δ V _uELrepresent the low gain of encouraging restriction after adjustment, K _uELrepresent low proportional gain of encouraging restriction, T _uEL1represent low and encourage limit advance time constant, T _uEL2represent low and encourage limit retardation time constant, δ represents generator's power and angle, and s represents complex frequency.

In one embodiment, according to generator's power and angle adjustment is low encourage the gain of restriction before, described method also comprises: according to the reactive power of the active power of generator and the set end voltage calculating generator of generator;

According to the gain after adjustment described generator carried out to excitation is low encourages restriction, comprising: when reactive power is greater than predetermined threshold, described generator is carried out to excitation is low encourages restriction.

In one embodiment, according to the reactive power of following formulae discovery generator:

Q _t＝K _UP _t+pU _t ²

Wherein, P _trepresent the active power of generator, U _trepresent the set end voltage of generator, Q _trepresent the reactive power of generator, K _urepresent proportionality coefficient, p represents voltage correction factor.

The embodiment of the present invention additionally provides that a kind of excitation of generator is low encourages restraint device, and to reach minimizing system oscillation, improve the object of the stability of a system, this device comprises:

Gain regulation module, for adjusting low gain of encouraging restriction according to generator's power and angle;

Lowly encourage limiting module, for carrying out described generator according to the gain after adjustment, excitation is low encourages restriction.

In one embodiment, gain increases along with generator's power and angle and reduces, and gain reduces along with generator's power and angle and increases.

In one embodiment, described gain regulation module is used for according to the low gain of encouraging restriction of following formula adjustment:

${\mathrm{\ΔV}}_{\mathrm{UEL}}=K_{\mathrm{UEL}}\frac{T_{\mathrm{UEL}1}s+1}{T_{\mathrm{UEL}2}s+1}\×\mathrm{\Δz}$

Wherein, Δ V _uELrepresent the low gain of encouraging restriction after adjustment, K _uELrepresent low proportional gain of encouraging restriction, T _uEL1represent low and encourage limit advance time constant, T _uEL2represent low and encourage limit retardation time constant, δ represents generator's power and angle, and s represents complex frequency.

In one embodiment, said apparatus also comprises power determination module, for according to generator's power and angle adjustment is low encourage the gain of restriction before, according to the reactive power of the active power of generator and the set end voltage calculating generator of generator;

Describedly lowly encourage limiting module, specifically for when reactive power is greater than predetermined threshold, described generator is carried out to excitation is low encourages restriction.

In one embodiment, described power determination module is specifically for the reactive power according to following formulae discovery generator:

Q _t＝K _UP _t+pU _t ²

Wherein, P _trepresent the active power of generator, U _trepresent the set end voltage of generator, Q _trepresent the reactive power of generator, K _urepresent proportionality coefficient, p represents voltage correction factor.

In embodiments of the present invention, according to the low gain of encouraging restriction of generator's power and angle adjustment, and according to the gain after adjustment described generator carried out to excitation is low encourages restriction, carrying out lowly encouraging in the process of restriction, gain along with generator's power and angle dynamic change, thus solves in prior art, adopts the parameter of producer's acquiescence to carry out low restriction and the technical problem easily occurring system oscillation after actual devoting oneself to work that causes of encouraging, reach minimizing system oscillation, improve the technique effect of the stability of a system.

Accompanying drawing explanation

Accompanying drawing described herein is used to provide a further understanding of the present invention, forms a application's part, does not form limitation of the invention.In the accompanying drawings:

Fig. 1 is that low the encouraging of the excitation of conventional generator limits control mode schematic diagram;

Fig. 2 is the low flow chart of encouraging method for limiting of the excitation of the generator of the embodiment of the present invention;

Fig. 3 is the low structured flowchart of encouraging restraint device of the excitation of the generator of the embodiment of the present invention;

Fig. 4 is that low the encouraging of the excitation of the generator of the embodiment of the present invention limits control mode schematic diagram;

Fig. 5 is that low the encouraging of the excitation of the generator of the embodiment of the present invention limits the concrete schematic diagram of control mode.

Embodiment

For making the object, technical solutions and advantages of the present invention clearly understand, below in conjunction with execution mode and accompanying drawing, the present invention is described in further details.At this, exemplary embodiment of the present invention and illustrating for explaining the present invention, but not as a limitation of the invention.

Inventor finds, the constant voltage mode of PID mode as shown in Figure 1 can be adopted to carry out the low of field regulator and encourage restriction, wherein, and P _trepresent the active power of generator, U _trepresent the set end voltage of generator, Q _trepresent the reactive power of generator, K _urepresent proportionality coefficient, K _uELrepresent low and encourage restriction proportion gain, T _uEL1represent low and encourage limit advance time constant, T _uEL2represent low and encourage limit retardation time constant, Δ S represents idle control deviation amount.

Total transfer function is:

${\mathrm{\ΔV}}_{\mathrm{UEL}}=K_{\mathrm{UEL}}\frac{T_{\mathrm{UEL}1}s+1}{T_{\mathrm{UEL}2}s+1}\×\mathrm{\Δz}$

But in the mode shown in Fig. 1, each gain parameter is also all adopt factory settings good, carries out low encouraging time control is easy to cause actual operation occur that system is shaken according to this parameter.To this, inventors herein propose the low overall gain of encouraging restriction of a kind of field regulator and encourage method for limiting according to the low of size dynamic change of generator's power and angle, thus adopt the low problem of encouraging restriction default parameters and being difficult to adapt to changeable on-the-spot operating condition of manufacturing firm's generator in solution prior art, thus make low encourage be limited in the multiple operational mode of generator under all can obtain quick, stable ideal characterisitics.

The excitation of the generator that the embodiment of the present invention provides is low encourages method for limiting as shown in Figure 2, comprises the following steps:

Step 201: according to the low gain of encouraging restriction of generator's power and angle adjustment;

Step 202: according to the gain after adjustment described generator carried out to excitation is low encourages restriction.

In the above-described embodiments, according to the low gain of encouraging restriction of generator's power and angle adjustment, and according to the gain after adjustment described generator carried out to excitation is low encourages restriction, carrying out lowly encouraging in the process of restriction, gain along with generator's power and angle dynamic change, thus solves in prior art, adopts the parameter of producer's acquiescence to carry out low restriction and the technical problem easily occurring system oscillation after actual devoting oneself to work that causes of encouraging, reach minimizing system oscillation, improve the technique effect of the stability of a system.

In order to ensure that low encouraging can fast by the restriction of the reactive power of generator in the reasonable scope after limit movement, the simultaneously more conventional constant low dynamic stability of encouraging limiting gain and comparing and unit can be improved, in this example, gain increases along with generator's power and angle and reduces, and gain reduces along with generator's power and angle and increases.

Concrete, low gain of encouraging restriction can be determined according to following formula:

${\mathrm{\ΔV}}_{\mathrm{UEL}}=K_{\mathrm{UEL}}\frac{T_{\mathrm{UEL}1}s+1}{T_{\mathrm{UEL}2}s+1}\×\mathrm{\Δz}$

Wherein, Δ V _uELrepresent the low gain of encouraging restriction after adjustment, K _uELrepresent low proportional gain of encouraging restriction, T _uEL1represent low and encourage limit advance time constant, T _uEL2represent low and encourage limit retardation time constant, δ represents generator's power and angle, and s represents complex frequency.

Excitation is low, and to encourage restriction be what to carry out when system capacitive reactive power surplus, therefore the process determining reactive power can first be performed before carrying out, namely, according to the adjustment of motor merit angle is low encourage the gain of restriction before, said method also comprises: according to the reactive power of the active power of generator and the set end voltage calculating generator of generator; When reactive power is greater than predetermined threshold, just triggers and generator carried out to excitation is low encourages restriction.

Concrete, can according to the reactive power of following formulae discovery generator:

Q _t＝K _UP _t+pU _t ²

Wherein, P _trepresent the active power of generator, U _trepresent the set end voltage of generator, Q _trepresent the reactive power of generator, K _urepresent proportionality coefficient, p represents voltage correction factor.

Based on same inventive concept, the excitation additionally providing a kind of generator in the embodiment of the present invention is low encourages restraint device, as described in the following examples.Excitation due to generator is low, and to encourage the principle that restraint device deals with problems similar to the low method for limiting of encouraging of the excitation of generator, therefore the low enforcement of encouraging restraint device of the excitation of generator see the low enforcement of encouraging method for limiting of the excitation of generator, can repeat part and repeats no more.Following used, term " unit " or " module " can realize the software of predetermined function and/or the combination of hardware.Although the device described by following examples preferably realizes with software, hardware, or the realization of the combination of software and hardware also may and conceived.Fig. 3 is the low a kind of structured flowchart of encouraging restraint device of the excitation of the generator of the embodiment of the present invention, as shown in Figure 3, comprising: gain regulation module 301 and lowly encourage limiting module 302, is described below to this structure.

Gain regulation module 301, for adjusting low gain of encouraging restriction according to generator's power and angle;

Lowly encourage limiting module 302, for carrying out described generator according to the gain after adjustment, excitation is low encourages restriction.

In one embodiment, gain reduces along with the increase of generator's power and angle, and gain increases along with the reduction of generator's power and angle.

In one embodiment, gain regulation module 301 is for adjusting low gain of encouraging restriction according to following formula:

${\mathrm{\ΔV}}_{\mathrm{UEL}}=K_{\mathrm{UEL}}\frac{T_{\mathrm{UEL}1}s+1}{T_{\mathrm{UEL}2}s+1}\×\mathrm{\Δz}$

Wherein, Δ V _uELrepresent the low gain of encouraging restriction after adjustment, K _uELrepresent low proportional gain of encouraging restriction, T _uEL1represent low and encourage limit advance time constant, T _uEL2represent low and encourage limit retardation time constant, δ represents generator's power and angle, and s represents complex frequency.

In one embodiment, said apparatus also comprises power determination module, for according to generator's power and angle adjustment is low encourage the gain of restriction before, according to the reactive power of the active power of generator and the set end voltage calculating generator of generator; Lowly encourage limiting module 302, specifically for when reactive power is greater than predetermined threshold, described generator is carried out to excitation is low encourages restriction.

In one embodiment, power determination module is specifically for the reactive power according to following formulae discovery generator:

Q _t＝K _UP _t+pU _t ²

Wherein, P _trepresent the active power of generator, U _trepresent the set end voltage of generator, Q _trepresent the reactive power of generator, K _urepresent proportionality coefficient, p represents voltage correction factor.

Be specifically described below in conjunction with the low method for limiting of encouraging of the excitation of a specific embodiment to above-mentioned generator, but it should be noted that this specific embodiment is only to describe the present invention better, do not form inappropriate limitation of the present invention.

Propose low gain of encouraging restriction in this example according to the size dynamic change at current generator merit angle, namely as shown in Figure 4, after the lead-lag link shown in Fig. 1, increase a dynamic gain link.The excitation of generator of the present invention is low encourages adaptive gain concrete methods of realizing that method for limiting adopts as shown in Figure 5.

5, δ represent that the generator's power and angle of gained measured by field regulator in the drawings, and it is as follows that adaptation module exports concrete computing formula:

$\mathrm{\Δz}=(\frac{\mathrm{\π}}{2}-|\mathrm{\δ}\left|\right)\÷\frac{\mathrm{\π}}{2}$

Wherein, the output of Δ z is doubly limited in the scope of 0.1-1.

By this example propose according to the low gain of encouraging restriction of the size dynamic change of generator's power and angle, when generator's power and angle is larger, low encouraging limits the less gain coefficient of employing, larger gain coefficient is then adopted when generator's power and angle is less, can ensure so lowly to encourage after limit movement fast by generator reactive restriction in the reasonable scope, the dynamic stability of encouraging limiting gain comparing and can improve unit low compared with conventional constant simultaneously, also enhances the ability of the interference such as anti-reflective tune simultaneously.Test show with the low contrast test be limited under identical disturbance of encouraging of conventional fixed gain, the low dynamic response of encouraging restriction of the adaptive gain that this example proposes reaches rapidly steady through 10 swings, and adopts the dynamic response of fixed gain controller to need just to recover steady through vibration for a long time.

In another embodiment, additionally provide a kind of software, this software is for performing the technical scheme described in above-described embodiment and preferred implementation.

In another embodiment, additionally provide a kind of storage medium, store above-mentioned software in this storage medium, this storage medium includes but not limited to: CD, floppy disk, hard disk, scratch pad memory etc.

From above description, can find out, the embodiment of the present invention achieves following technique effect: according to the low gain of encouraging restriction of generator's power and angle adjustment, and according to the gain after adjustment described generator carried out to excitation is low encourages restriction, carrying out lowly encouraging in the process of restriction, gain is along with generator's power and angle dynamic change, thus solve in prior art, the parameter of producer's acquiescence is adopted to carry out low restriction and the technical problem easily occurring system oscillation after actual devoting oneself to work that causes of encouraging, reach minimizing system oscillation, improve the technique effect of the stability of a system.

Obviously, those skilled in the art should be understood that, each module of the above-mentioned embodiment of the present invention or each step can realize with general calculation element, they can concentrate on single calculation element, or be distributed on network that multiple calculation element forms, alternatively, they can realize with the executable program code of calculation element, thus, they can be stored and be performed by calculation element in the storage device, and in some cases, step shown or described by can performing with the order be different from herein, or they are made into each integrated circuit modules respectively, or the multiple module in them or step are made into single integrated circuit module to realize.Like this, the embodiment of the present invention is not restricted to any specific hardware and software combination.

The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the embodiment of the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (10)

1. the excitation of generator is low encourages a method for limiting, it is characterized in that, comprising:

According to the low gain of encouraging restriction of generator's power and angle adjustment;

According to the gain after adjustment described generator carried out to excitation is low encourages restriction.

2. the method for claim 1, is characterized in that, according to the low gain of encouraging restriction of generator's power and angle adjustment, comprising:

Gain increases along with generator's power and angle and reduces, and gain reduces along with generator's power and angle and increases.

3. method as claimed in claim 2, is characterized in that, according to the low gain of encouraging restriction of following formula adjustment:

${\mathrm{\ΔV}}_{\mathrm{UEL}}=K_{\mathrm{UEL}}\frac{T_{\mathrm{UEL}1}s+1}{T_{\mathrm{UEL}2}s+1}\×\mathrm{\Δz}$

Wherein, Δ V _uELrepresent the low gain of encouraging restriction after adjustment, K _uELrepresent low proportional gain of encouraging restriction, T _uEL1represent low and encourage limit advance time constant, T _uEL2represent low and encourage limit retardation time constant, δ represents generator's power and angle, and s represents complex frequency.

4. method as claimed any one in claims 1 to 3, is characterized in that:

According to generator's power and angle adjustment is low encourage the gain of restriction before, described method also comprises: according to the reactive power of the active power of generator and the set end voltage calculating generator of generator;

According to the gain after adjustment described generator carried out to excitation is low encourages restriction, comprising: when reactive power is greater than predetermined threshold, described generator is carried out to excitation is low encourages restriction.

5. method as claimed in claim 4, is characterized in that, the reactive power according to following formulae discovery generator:

Q _t＝K _UP _t+pU _t ²

Wherein, P _trepresent the active power of generator, U _trepresent the set end voltage of generator, Q _trepresent the reactive power of generator, K _urepresent proportionality coefficient, p represents voltage correction factor.

6. the excitation of generator is low encourages a restraint device, it is characterized in that, comprising:

Gain regulation module, for adjusting low gain of encouraging restriction according to generator's power and angle;

Lowly encourage limiting module, for carrying out described generator according to the gain after adjustment, excitation is low encourages restriction.

7. device as claimed in claim 6, is characterized in that, gain increases along with generator's power and angle and reduces, and gain reduces along with generator's power and angle and increases.

8. device as claimed in claim 7, is characterized in that, described gain regulation module is used for according to the low gain of encouraging restriction of following formula adjustment:

${\mathrm{\ΔV}}_{\mathrm{UEL}}=K_{\mathrm{UEL}}\frac{T_{\mathrm{UEL}1}s+1}{T_{\mathrm{UEL}2}s+1}\×\mathrm{\Δz}$

Wherein, Δ V _uELrepresent the low gain of encouraging restriction after adjustment, K _uELrepresent low proportional gain of encouraging restriction, T _uEL1represent low and encourage limit advance time constant, T _uEL2represent low and encourage limit retardation time constant, δ represents generator's power and angle, and s represents complex frequency.

9. the device according to any one of claim 6 to 8, is characterized in that:

Also comprise power determination module, for according to generator's power and angle adjustment is low encourage the gain of restriction before, according to the reactive power of the active power of generator and the set end voltage calculating generator of generator;

Describedly lowly encourage limiting module, specifically for when reactive power is greater than predetermined threshold, described generator is carried out to excitation is low encourages restriction.

10. device as claimed in claim 9, is characterized in that:

Described power determination module is specifically for the reactive power according to following formulae discovery generator:

Q _t＝K _UP _t+pU _t ²

Wherein, P _trepresent the active power of generator, U _trepresent the set end voltage of generator, Q _trepresent the reactive power of generator, K _urepresent proportionality coefficient, p represents voltage correction factor.