CN104701816A - Method and device for matching and setting low-excitation limitation and field loss protection of salient-pole machine - Google Patents

Abstract

The invention provides a method and a device for matching and setting low-excitation limitation and field loss protection of a salient-pole machine, which are used for guaranteeing reasonable matching of the low-excitation limitation and field loss protection of the salient-pole machine. The method comprises the following steps: converting a low-excitation limitation curve to an impedance plane from a power plane, comparing the low-excitation limitation curve converted to the power plane with a static voltage stability limitation curve of the salient-pole machine in an R-axis positive semi-axis area; when the low-excitation limitation curve of the R-axis positive semi-axis area does not include the static voltage stability limitation, re-setting the low-excitation limitation curve. According to the technical scheme adopted by the invention, the reasonable matching between the low-excitation limitation and field loss protection of the salient-pole machine is guaranteed, technical basis is provided for power dispatching production management in a facilitated manner, the control and protection functions of the motor are brought into full play, the network source coordination level is improved, the safe and efficient operation of the energy resources are realized, and the power is guaranteed to safely and economically feed out.

Description

Low fiting tuning method and the device of encouraging restriction and field loss protection of salient-pole machine

Technical field

The present invention relates to technical field of generators, particularly low fiting tuning method and the device of encouraging restriction and field loss protection of a kind of salient-pole machine.

Background technology

Motor loss of excitation refers to that generator suddenly partly or entirely loses excitation, is the common fault of generator excitation circuit.Especially for Generator Set, excitation system link is more, complex structure, and add the probability that loss of excitation fault occurs, statistics shows, loss of excitation fault accounts for more than 60% of generator total failare.After loss of exicitation, will be transitioned into asynchronous operation, there is slip in rotor, and stator current increases, and stator voltage declines, and active power declines, and reactive power oppositely and increase; Difference frequency electric current is there is in rotor loop; The voltage drop of electric power system and some power branch overcurrent.The change of all these electric parameters, all with swing to a certain degree, can destroy the stable operation of electric power system, and threaten the safety of generator itself.Therefore, detect loss of excitation fault in time and take the safe and stable operation of counter-measure to electric power system to be very important.

At present, generator loss-of-excitation protection scheme is mainly characterized as main criterion with stator loop parameter, and impedance plane realizes, and reflects loss of excitation fault with machine end measurement impedance track.Impedance plane detects loss of excitation fault and mainly contain two kinds of criterions, steady state stability limit impedance circle criterion and asynchronous boundary impedance circle criterion.When machine end measurement impedance track enters in steady state stability limit impedance circle, field loss protection may action or transmit.

In addition, the generator coordinated with generator loss-of-excitation protection is low, and to encourage restriction also particularly important.Generator is low encourages restriction and refers to when exciting current drops to a certain limit value, and restriction exciting current declines or increases exciting current, makes unit operationally not cross steady state stability limit.Generator low is encouraged constrain equation and is generally divided into linear pattern or round.

The more important thing is generator loss-of-excitation protection and low reasonable coordination of encouraging restriction; requirement according to power industry Specification fiting tuning therebetween: generator is low encourage with loss of excitation time; low encourage restriction should first action; restriction is encouraged invalid if low; then pass through certain transition allowance; the just action of quiet steady circle, in certain sense, can regard quiet steady circle as low backup protection of encouraging restriction.It is low that to encourage restriction be the protection of excitation system; low restrictive curve of encouraging describes in P-Q plane; generator loss-of-excitation protection impedance operation equation describes at R-X impedance plane; because the two is studied at different coordinate systems respectively; be difficult to carry out matching relationship analysis to the two intuitively, coordinate the unreasonable situation of field loss protection malfunction that causes to happen occasionally.Therefore, be necessary to encourage restriction and field loss protection is done further to study to salient-pole machine is low, seek rational cooperation method therebetween, the setting value order calculating of both guidances.

Too low matching problem of encouraging between restriction and field loss protection once discussed by existing document; but research to coordinate be carry out under circular prerequisite according to non-salient pole machine steady state stability limit; Fig. 1 is non-salient pole machine static stability boundary and lowly encourages restriction fiting relation figure; as shown in Figure 1; 1 is quiet steady circle; 2 is asynchronous circle, and 3 encourage restriction circle for low.Prior art research be the method that non-salient pole machine encourages restriction and the fiting tuning of field loss protection, concrete step is as follows:

1), calculate with generator base impedance be benchmark generator and system impedance perunit value, P-Q plane calculates the perunit value with the generator apparent power quiet steady circle coordinates of generator that are benchmark and radius.

2), consider the static stability reserve coefficient of 10% ~ 20%, the parameter error of 5% ~ 10% and certain safety factor, namely the perunit value of quiet steady circle coordinates and radius is divided by the quiet steady circle obtaining nargin after 1.2 ~ 1.5.

3), calculate have the quiet steady circle of nargin and negative Q axle and just P axle (during P<Pn) or the crossing coordinate of P=Pn straight line (during P>Pn) to determine low 2 points of encouraging restraining line, the top of other Ying Yuan.

4) field loss protection of, adjusting impedance circle; field loss protection impedance circle is mapped to P-Q plane; maybe low restrictive curve of encouraging is mapped to R-X plane, respectively when set end voltage is specified and minimum permission voltage, checks the matching relationship with field loss protection impedance circle according to matching principle.

As can be seen here; although too low matching problem of encouraging between restriction and field loss protection once discussed by existing document; but general is analyze concrete test; lack general method; and research concentrates on non-salient pole machine field loss protection and low relation of encouraging restriction, do not consider that salient-pole machine steady state stability limit curve is this particularity of drop-wise curve.

Summary of the invention

The invention provides a kind of low fiting tuning method of encouraging restriction and field loss protection of salient-pole machine, in order to ensure the low reasonable coordination of encouraging restriction and field loss protection of salient-pole machine, the method comprises:

Low restrictive curve of encouraging is transformed to impedance plane by power planes, lowly encourages restrictive curve and salient-pole machine steady state stability limit curve contrasts in R axle positive axis region by what transform to impedance plane;

When R axle positive axis low encourages restrictive curve non-envelope steady state stability limit curve, low restrictive curve of encouraging is adjusted again.

In one embodiment, when low to encourage restrictive curve be linear pattern time, get U=0.9pu and U=1.0pu respectively, according to following formula, low restrictive curve of encouraging transformed to impedance plane by power planes:

${(R+\frac{{\mathrm{kU}}^2}{2({\mathrm{aU}}^2+b)})}^2+{(X-\frac{U^2}{2({\mathrm{aU}}^2+b)})}^2<\frac{(k^2+1)U^4}{4{({\mathrm{aU}}^2+b)}^2};$

Wherein, R is the resistance of salient-pole machine machine end, and X is the reactance of salient-pole machine machine end; U is the voltage of salient-pole machine machine end; A and b is constant; K is slope.

In one embodiment, when low to encourage restrictive curve be round time, according to following formula, low restrictive curve of encouraging is transformed to impedance plane by power planes:

$R^2+{(X-\frac{a}{b-a^2})}^2<\frac{b}{{(b-a^2)}^2};$

Wherein, R is the resistance of salient-pole machine machine end, and X is the reactance of salient-pole machine machine end; A and b is constant.

Present invention also offers the low fiting tuning device of encouraging restriction and field loss protection of a kind of salient-pole machine, in order to ensure the low reasonable coordination of encouraging restriction and field loss protection of salient-pole machine, this device comprises:

Lowly encourage restrictive curve modular converter, for low restrictive curve of encouraging is transformed to impedance plane by power planes, lowly encourage restrictive curve and salient-pole machine steady state stability limit curve contrasts in R axle positive axis region by what transform to impedance plane;

Low restrictive curve of encouraging is adjusted module again, for when R axle positive axis low encourages restrictive curve non-envelope steady state stability limit curve, again adjusts to low restrictive curve of encouraging.

In one embodiment, described low encourage restrictive curve modular converter specifically for when low to encourage restrictive curve be linear pattern time, get U=0.9pu and U=1.0pu respectively, according to following formula, low restrictive curve of encouraging transformed to impedance plane by power planes:

${(R+\frac{{\mathrm{kU}}^2}{2({\mathrm{aU}}^2+b)})}^2+{(X-\frac{U^2}{2({\mathrm{aU}}^2+b)})}^2<\frac{(k^2+1)U^4}{4{({\mathrm{aU}}^2+b)}^2};$

Wherein, R is the resistance of salient-pole machine machine end, and X is the reactance of salient-pole machine machine end; U is the voltage of salient-pole machine machine end; A and b is constant; K is slope.

In one embodiment, described low encourage restrictive curve modular converter specifically for when low to encourage restrictive curve be round time, according to following formula, low restrictive curve of encouraging is transformed to impedance plane by power planes:

$R^2+{(X-\frac{a}{b-a^2})}^2<\frac{b}{{(b-a^2)}^2};$

Wherein, R is the resistance of salient-pole machine machine end, and X is the reactance of salient-pole machine machine end; A and b is constant.

Technical solution of the present invention; by extremely low for salient pole restrictive curve of encouraging is transformed to impedance plane by power planes; under the same coordinate system, compare with steady state stability limit curve, calculate to instruct the fiting tuning of the two; when R axle positive axis low encourages restrictive curve envelope steady state stability limit curve; proof meets low encouraging and limits prior to field loss protection action, and matching relationship is correct, otherwise; prove matching relationship mistake, low restrictive curve of encouraging is adjusted again.Technique scheme ensure that the low reasonable coordination of encouraging restriction and field loss protection of salient-pole machine; solving salient-pole machine steady state stability limit curve is that a drop-wise curve cannot transform to power planes; and then cause carrying out field loss protection and lowly encourage the problem limiting fiting tuning and calculate; be conducive to for power scheduling production management provides technical basis; give full play to generator control and defencive function; improve net source and coordinate level, realize energy security Effec-tive Function, ensure that electric power safety economy is sent.

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 non-salient pole machine steady state stability limit curve in background technology of the present invention and lowly encourages restrictive curve fiting relation figure;

Fig. 2 is the low fiting tuning method flow schematic diagram of encouraging restriction and field loss protection of salient-pole machine in the embodiment of the present invention;

Fig. 3 lowly in the embodiment of the present invention encourages restrictive curve and salient-pole machine drop-wise steady state stability limit curve fitting graph of a relation;

Fig. 4 lowly in the embodiment of the present invention encourages restrictive curve and salient-pole machine apple circle steady state stability limit curve fitting graph of a relation;

Fig. 5 is the low fiting tuning apparatus structure schematic diagram of encouraging restriction and field loss protection of salient-pole machine in the embodiment of the present invention.

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.

Low to encourage restriction be the protection of excitation system, and low restrictive curve of encouraging describes in P-Q plane.But generator loss-of-excitation protection impedance operation equation describes at R-X impedance plane.Because low restrictive curve of encouraging is studied at different coordinate systems respectively from field loss protection impedance operation equation curve, be difficult to carry out matching relationship analysis to the two intuitively, coordinate the unreasonable situation of field loss protection malfunction that causes to happen occasionally.In addition; although there is document that too low matching problem of encouraging between restriction and field loss protection was once discussed; but general is analyze concrete test; lack general method; and research concentrates on non-salient pole machine field loss protection and low relation of encouraging restriction, do not consider that salient-pole machine steady state stability limit is this particularity of drop-wise curve.

Consider above-mentioned technical problem; inventor for salient-pole machine low encourage restriction with field loss protection between fiting tuning calculate the deficiency existed; low restrictive curve of encouraging is proposed to transform to impedance plane by power planes first; disclose a kind of low fiting tuning method of encouraging restriction and field loss protection of salient-pole machine; this method solving salient-pole machine static stability boundary is that a drop-wise curve is difficult to transform to power planes; cause carrying out field loss protection and lowly encourage the problem limiting fiting tuning and calculate, there is good practical meaning in engineering.Be described in detail below.

Fig. 2 is the low fiting tuning method flow schematic diagram of encouraging restriction and field loss protection of salient-pole machine in the embodiment of the present invention, and as shown in Figure 2, the method comprises the steps:

Step 10: low restrictive curve of encouraging is transformed to impedance plane by power planes, lowly encourages restrictive curve and salient-pole machine steady state stability limit curve contrasts in R axle positive axis region by what transform to impedance plane;

Step 20: when R axle positive axis low encourages restrictive curve non-envelope steady state stability limit curve, low restrictive curve of encouraging is adjusted again.

Technical solution of the present invention; by extremely low for salient pole restrictive curve of encouraging is transformed to impedance plane by power planes; under the same coordinate system, compare with steady state stability limit curve, calculate to instruct the fiting tuning of the two; when R axle positive axis low encourages restrictive curve envelope steady state stability limit curve; proof meets low encouraging and limits prior to field loss protection action, proves that matching relationship is correct, otherwise; prove matching relationship mistake, low restrictive curve of encouraging is adjusted again.Technique scheme ensure that the low reasonable coordination of encouraging restriction and field loss protection of salient-pole machine; solving salient-pole machine steady state stability limit curve is that a drop-wise curve cannot transform to power planes; and then cause carrying out field loss protection and lowly encourage the problem limiting fiting tuning and calculate; be conducive to for power scheduling production management provides technical basis; give full play to generator control and defencive function; improve net source and coordinate level, realize energy security Effec-tive Function, ensure that electric power safety economy is sent.

In above-mentioned steps 10, the present invention adopt generator low restrictive curve of encouraging be generally linear pattern or round, analyze for both of these case respectively:

In one embodiment, when low to encourage restrictive curve be linear pattern time, get U=0.9pu and U=1.0pu respectively, according to following formula, low restrictive curve of encouraging transformed to impedance plane by power planes:

${(R+\frac{{\mathrm{kU}}^2}{2({\mathrm{aU}}^2+b)})}^2+{(X-\frac{U^2}{2({\mathrm{aU}}^2+b)})}^2<\frac{(k^2+1)U^4}{4{({\mathrm{aU}}^2+b)}^2};$

Wherein, R and X is resistance and the reactance of salient-pole machine machine end; U is the voltage of salient-pole machine machine end; A and b is constant; K is slope.

During concrete enforcement, the concrete derivation of above-mentioned formula is as follows:

The low limit movement equation of encouraging of generator is:

Q<kP+aU ²+b； (1)

According to Electrical Motor knowledge, there is formula:

$P=I^{2}R=\frac{U^2}{R^2+X^2}R$

$Q=I^{2}X=\frac{U^2}{R^2+X^2}X;---\left(2\right)$

Formula (2) is substituted in formula (1), can obtain:

$\frac{U^2}{R^2+X^2}X<\frac{{\mathrm{kU}}^2}{R^2+X^2}R+a{U}^2+b;---\left(3\right)$

By formula (1), as P=0, Q<aU ²+ b.Encourage restriction engineering practice in conjunction with low, have relational expression aU ²+ b<0.Therefore, formula (3) can be transformed to:

$R^2+\frac{{\mathrm{kU}}^2}{{\mathrm{aU}}^2+b}R+X^2-\frac{U^2}{{\mathrm{aU}}^2+b}X<0;---\left(4\right)$

To formula (4) conversion, obtain:

${(R+\frac{{\mathrm{kU}}^2}{2({\mathrm{aU}}^2+b)})}^2+{(X-\frac{U^2}{2({\mathrm{aU}}^2+b)})}^2<\frac{(k^2+1)U^4}{4{({\mathrm{aU}}^2+b)}^2}.---\left(5\right)$

Fig. 3 lowly in the embodiment of the present invention encourages restrictive curve and salient-pole machine drop-wise steady state stability limit curve fitting graph of a relation, known with formula (5) as shown in Figure 3, linear pattern is low encourages restrictive curve to transform to impedance plane is a circular curve, when machine end measurement impedance track enters in circle, show lowly to encourage limit movement, otherwise, be failure to actuate.Therefore; the requirement of restriction prior to field loss protection action is encouraged according to low; if this circular curve envelope steady state stability limit curve; proof meets low encouraging and limits prior to field loss protection action; then coordinate correct; otherwise, low restrictive curve of encouraging is adjusted again, to ensure lowly to encourage restrictive curve and the curve fitting of salient-pole machine drop-wise steady state stability limit is correct.

In addition, hold measurement impedance trail change rule opportunity by loss of exicitation, low matching relationship of encouraging restriction and field loss protection only needs to consider the positive axis part of R axle in impedance plane.Particularly, as shown in Figure 3, low encourage restrictive curve 1. envelope salient-pole machine steady state stability limit drop-wise curve 3., this kind of mated condition shows, low restrictive curve and the salient-pole machine steady state stability limit drop-wise curve fitting relation of encouraging is correct, and namely salient-pole machine is low encourages restriction and coordinate correctly with field loss protection; Lowly encourage restrictive curve 2. non-envelope salient-pole machine steady state stability limit drop-wise curve; so prove lowly to encourage restrictive curve and salient-pole machine steady state stability limit drop-wise curve fitting relation mistake; need low restrictive curve of encouraging is adjusted again, with ensure salient-pole machine low encourage restriction coordinate correctly with field loss protection.

From above-mentioned formula (5), the low restriction circular curve of encouraging transforming to impedance plane is relevant to set end voltage, under accidental conditions, generator terminal voltage excursion is (0.9pu, 1.0pu), U=0.9pu and U=1.0pu can be got respectively draw and lowly encourage restriction circular curve, under ensureing two kinds of operating modes, lowly encourage restrictive curve and salient-pole machine steady state stability limit drop-wise curve fitting relation is all correct.

In one embodiment, when low to encourage restrictive curve be round time, according to following formula, low restrictive curve of encouraging is transformed to impedance plane by power planes:

$R^2+{(X-\frac{a}{b-a^2})}^2<\frac{b}{{(b-a^2)}^2};$

Wherein, R and X is resistance and the reactance of salient-pole machine machine end; A and b is constant.

The process of specifically shifting onto of above-mentioned formula is as follows:

Low limit movement equation of encouraging is:

P ²+(Q+aU ²) ²>bU ⁴； (6)

According to formula (2), conversion is carried out to formula (6) and obtains:

$\frac{U^4}{R^2+X^2}+\frac{2a{U}^{4}X}{R^2+X^2}>{\mathrm{bU}}^4-a^2{U}^4;---\left(7\right)$

Carry out conversion to formula (7) can obtain:

$R^2+X^2-\frac{2\mathrm{aX}}{b-a^2}<\frac{1}{b-a^2};---\left(8\right)$

By formula (8), can obtain:

$R^2+{(X-\frac{a}{b-a^2})}^2<\frac{b}{{(b-a^2)}^2}.---\left(9\right)$

From above-mentioned formula (9), round low encourage restrictive curve transform to impedance plane be still one circle equation curve, therefore, can at grade to low encourage restriction and field loss protection be analyzed.The two matching relationship and above-mentioned linear pattern be low encourages restrictive curve to transform to impedance plane similar to steady state stability limit drop-wise curve comparison, repeats no more herein.Roundly be parameter a in round equation with the low difference of encouraging constrain equation curve of linear pattern; the value of b is different; final derivation formula may be caused; namely on impedance plane, equation of a circle (9) inequality both sides magnitude relationship changes; but low encourage restriction and the matching relationship of field loss protection and fiting tuning computational methods still constant; therefore; round low restrictive curve of encouraging is transformed to impedance plane by power planes, and the method comparing to instruct the fiting tuning of the two to calculate with steady state stability limit curve is generally suitable for.

In practical engineering application, salient-pole machine field loss protection steady state stability limit curve is reduced to apple circular curve by some producer, and as shown in Figure 4, apple circular curve is also irregular curve, and it is still more difficult to be transformed to power planes.Therefore, what the present invention should be adopted equally to propose encourages low constrain equation to be transformed to impedance plane method by power planes.Now the low matching relationship of encouraging restriction and field loss protection of salient-pole machine is also embodied in the diagram; namely bently lowly encourage restraining line 1. envelope salient-pole machine static stability boundary apple circular curve is 3.; prove that the low matching relationship limited with field loss protection of encouraging is correct; low encourage restrictive curve 2. non-envelope salient-pole machine static stability boundary apple circular curve 3., prove lowly to encourage restriction and the matching relationship mistake of field loss protection.

In sum; no matter low restrictive curve of encouraging is linear pattern or round; transformed to impedance plane and be a circular curve, can in positive axis region to this low encourage restriction circular curve and steady state stability limit curve be analyzed, thus determine low encourage restriction with field loss protection matching relationship whether correct.

Based on same inventive concept, additionally provide the low fiting tuning device of encouraging restriction and field loss protection of a kind of salient-pole machine in the embodiment of the present invention, as described in the following examples.Restriction is encouraged similar to the low fiting tuning method limited to field loss protection of encouraging of the principle that the fiting tuning device of field loss protection is dealt with problems and salient-pole machine because salient-pole machine is low; therefore the low enforcement of encouraging the fiting tuning device of restriction and field loss protection of salient-pole machine can encourage see salient-pole machine is low the enforcement limited with the fiting tuning method of field loss protection, repeats 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. 5 is the low structural representation of encouraging the fiting tuning device of restriction and field loss protection of salient-pole machine in the embodiment of the present invention, and as shown in Figure 5, this device comprises:

Lowly encourage restrictive curve modular converter 02, for low restrictive curve of encouraging is transformed to impedance plane by power planes, lowly encourage restrictive curve and salient-pole machine steady state stability limit curve contrasts in R axle positive axis region by what transform to impedance plane;

Low restrictive curve of encouraging is adjusted module 04 again, for when R axle positive axis low encourages restrictive curve non-envelope steady state stability limit curve, again adjusts to low restrictive curve of encouraging.

In one embodiment, described low encourage restrictive curve modular converter 02 specifically for when low to encourage restrictive curve be linear pattern time, get U=0.9pu and U=1.0pu respectively, according to following formula, low restrictive curve of encouraging transformed to impedance plane by power planes:

${(R+\frac{{\mathrm{kU}}^2}{2({\mathrm{aU}}^2+b)})}^2+{(X-\frac{U^2}{2({\mathrm{aU}}^2+b)})}^2<\frac{(k^2+1)U^4}{4{({\mathrm{aU}}^2+b)}^2};$

Wherein, R is the resistance of salient-pole machine machine end, and X is the reactance of salient-pole machine machine end; U is the voltage of salient-pole machine machine end; A and b is constant; K is slope.

In one embodiment, described low encourage restrictive curve modular converter 02 specifically for when low to encourage restrictive curve be round time, according to following formula, low restrictive curve of encouraging is transformed to impedance plane by power planes:

$R^2+{(X-\frac{a}{b-a^2})}^2<\frac{b}{{(b-a^2)}^2};$

Wherein, R is the resistance of salient-pole machine machine end, and X is the reactance of salient-pole machine machine end; A and b is constant.

The salient-pole machine that the embodiment of the present invention provides is low encourages restriction and with the fiting tuning method of field loss protection and the Advantageous Effects of device is: low constrain equation of encouraging is transformed to impedance plane by power planes by technical solution of the present invention, under the same coordinate system, the method compared with steady state stability limit border, the fiting tuning directing the two calculates, and be deduced transformation equation, avoid the two unreasonable situation causing field loss protection malfunction of fiting tuning, solving salient-pole machine static stability boundary is that a drop-wise curve cannot transform to power planes, and then cause carrying out field loss protection and lowly encourage the problem limiting fiting tuning and calculate, be conducive to for power scheduling production management provides technical basis, give full play to generator control and defencive function, improve net source and coordinate level, realize energy security Effec-tive Function, ensure that electric power safety economy is sent.

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 (6)

1. salient-pole machine is low encourages restriction and a fiting tuning method for field loss protection, it is characterized in that, comprising:

Low restrictive curve of encouraging is transformed to impedance plane by power planes, lowly encourages restrictive curve and salient-pole machine steady state stability limit curve contrasts in R axle positive axis region by what transform to impedance plane;

When R axle positive axis low encourages restrictive curve non-envelope steady state stability limit curve, low restrictive curve of encouraging is adjusted again.

2. the method for claim 1, is characterized in that, when low to encourage restrictive curve be linear pattern time, get U=0.9pu and U=1.0pu respectively, according to following formula, low restrictive curve of encouraging transformed to impedance plane by power planes:

${(R+\frac{{\mathrm{kU}}^2}{2({\mathrm{aU}}^2+b)})}^2+{(X-\frac{U^2}{2({\mathrm{aU}}^2+b)})}^2<\frac{(k^2+1)U^4}{4{({\mathrm{aU}}^2+b)}^2};$

Wherein, R is the resistance of salient-pole machine machine end, and X is the reactance of salient-pole machine machine end; U is the voltage of salient-pole machine machine end; A and b is constant; K is slope.

3. the method for claim 1, is characterized in that, when low to encourage restrictive curve be round time, according to following formula, low restrictive curve of encouraging is transformed to impedance plane by power planes:

$R^2+{(X-\frac{a}{b-a^2})}^2<\frac{b}{{(b-a^2)}^2};$

Wherein, R is the resistance of salient-pole machine machine end, and X is the reactance of salient-pole machine machine end; A and b is constant.

4. salient-pole machine is low encourages restriction and a fiting tuning device for field loss protection, it is characterized in that, comprising:

Lowly encourage restrictive curve modular converter, for low restrictive curve of encouraging is transformed to impedance plane by power planes, lowly encourage restrictive curve and salient-pole machine steady state stability limit curve contrasts in R axle positive axis region by what transform to impedance plane;

Low restrictive curve of encouraging is adjusted module again, for when R axle positive axis low encourages restrictive curve non-envelope steady state stability limit curve, again adjusts to low restrictive curve of encouraging.

5. device as claimed in claim 4, it is characterized in that, described low encourage restrictive curve modular converter specifically for when low to encourage restrictive curve be linear pattern time, get U=0.9pu and U=1.0pu respectively, according to following formula, low restrictive curve of encouraging transformed to impedance plane by power planes:

${(R+\frac{{\mathrm{kU}}^2}{2({\mathrm{aU}}^2+b)})}^2+{(X-\frac{U^2}{2({\mathrm{aU}}^2+b)})}^2<\frac{(k^2+1)U^4}{4{({\mathrm{aU}}^2+b)}^2};$

Wherein, R is the resistance of salient-pole machine machine end, and X is the reactance of salient-pole machine machine end; U is the voltage of salient-pole machine machine end; A and b is constant; K is slope.

6. device as claimed in claim 4, is characterized in that, described low encourage restrictive curve modular converter specifically for when low to encourage restrictive curve be round time, according to following formula, low restrictive curve of encouraging is transformed to impedance plane by power planes:

$R^2+{(X-\frac{a}{b-a^2})}^2<\frac{b}{{(b-a^2)}^2};$

Wherein, R is the resistance of salient-pole machine machine end, and X is the reactance of salient-pole machine machine end; A and b is constant.