CN102130442A - Method for determining parameters of faulty forced excitation de-excitation process of power generator - Google Patents

Abstract

The invention provides a method for determining parameters of the faulty forced excitation de-excitation process of a de-excitation system of a power generator, a segmental linear calculation method is provided, the current of a rotor and the voltage of the rotor during the de-excitation process are calculated according to the current of the rotor, the voltage and the parameters of a closed loop at the beginning of de-excitation, and the de-excitation time and the power consumption of a de-excitation resistance during the de-excitation process are calculated according to the current of the rotor and the voltage of the rotor during the de-excitation process, thereby providing a basis for measuring the performances of the de-excitation system and the design of the parameters of the de-excitation resistance; and the power generators in a power plant are equipped with damping windings respectively, according to different time constants of the damping windings of the power generators, the damping windings can be ignored sometimes during the de-excitation dynamic process, and the impacts of the damping windings need to be considered sometimes; as for the two situations, the current and the voltage of the rotor during the de-excitation process when the damping winding is ignored, and the current and the voltage of the rotor during the de-excitation process when considering the impacts of the damping winding can be further obtained, thereby getting the more accurate current and the voltage of the rotor.

Description

The generating chance error is encouraged definite method of demagnetization procedure parameter by force

Technical field

The present invention relates to eliminating magnetism of generator system mistake and encourage definite method of demagnetization procedure parameter by force.

Background technology

When de-excitation system is generator internal short-circuit accident and during the excitation system fault, avoids or reduce unique facility that device damage and restriction accident enlarge, is the important system that is concerning power plant and power system security reliability service in the power plant.

It is the most serious demagnetization operating mode in the various demagnetization operating modes of generator that mistake is encouraged demagnetization by force.It is the excitation system fault accident that causes out of control that the generating chance error is encouraged by force, at this moment the full conducting of thyristor of exciting power rectifier.To generally adopt at present from shunt dynamo, generator excited system has become the voltage positive feedback system by the voltage negative feedback closed loop.Under the effect of positive feedback, generator rotor current increases sharply with the rising of generator terminal voltage, and the increase of rotor current further improves generator terminal voltage again, and this vicious circle one is until generator overvoltage protection would trip demagnetization.Because the effect of voltage positive feedback, de-excitation system will carry out demagnetization under serious overcurrent of rotor and the serious overvoltage of generator end this moment, be the most serious demagnetization operating mode in the various demagnetization operating modes of generator.According to the regulation of China's rules, the eliminating magnetism of generator system needs to encourage by force by satisfying the generating chance error that the demagnetization requirement designs and selection equipment.As the breaking capacity of field circuit breaker, need encourage the best result outage pressure and the maximum breaking current that may occur in the demagnetization process by force by mistake and select, best result outage pressure and maximum breaking current depend on the ceiling voltage and the maximum current of demagnetization process rotor; The de-excitation resistance selection of high drop-out voltage needs to calculate by the maximum current of generator amature in the demagnetization process.So the de-excitation system design must obtain the procedure parameter that the generating chance error is encouraged demagnetization by force.

Because to encourage generator by force be destructive serious accident to the generating chance error, mistake is encouraged the demagnetization procedure parameter by force and can not be encouraged the demagnetization test by force and obtain by missing on actual generator.Generator operation parameter (exciting current, voltage etc.) is in the nonlinear dynamic changing process when encouraging by force owing to mistake again, and its nonlinear characteristic is different with concrete generator, analytical calculation is very complicated, and the chance error that never generates electricity is so far both at home and abroad encouraged definite method of demagnetization procedure parameter by force.So before this, de-excitation system can only adopt the method for estimation to design always, the de-excitation system of design and the equipment of selection, can't affirm whether its parameter can satisfy the requirement that the generating chance error is encouraged demagnetization by force, the accident of burning the demagnetization facility when causing the generating chance error to encourage demagnetization by force happens occasionally, damage the generator and the expansion that causes the accident, have a strong impact on the safety of generator and electric power system.

In addition, demagnetizing time is an important parameter of weighing the de-excitation system performance, and the de-excitation resistance energy consumption is to select the key parameter of de-excitation resistance capacity in the demagnetization process.The generating chance error is encouraged de-excitation resistance energy consumption in the demagnetizing time of demagnetization and the demagnetization process by force, all need be calculated by the attenuation process parameter that mistake is encouraged demagnetization process generator rotor current and voltage by force.

Therefore, for guaranteeing the safety of power plant and electric power system, correct design eliminating magnetism of generator system, one is satisfied the computational methods that the practical generating chance error that requires of engineering is encouraged the demagnetization procedure parameter by force, is to expect the problem that solves for many years always.These parameters mainly comprise the attenuation process parameter of by mistake encouraging maximum current and ceiling voltage, demagnetization process generator rotor current and the voltage of demagnetization process generator amature by force.Because after eliminating magnetism of generator began, generator rotor current and voltage were the attenuation change process,, encourage rotor current and the voltage of demagnetization when beginning by force for missing so mistake is encouraged the maximum current of demagnetization process generator amature and ceiling voltage by force will appear at demagnetization and begin the time.

Summary of the invention

The technical problem to be solved in the present invention is: the definite method that provides a kind of eliminating magnetism of generator system mistake to encourage the demagnetization procedure parameter by force, and for de-excitation system design provides basic parameter.

The present invention solves the problems of the technologies described above the technical scheme of being taked to be: eliminating magnetism of generator system mistake is encouraged definite method of demagnetization procedure parameter by force, and described mistake is encouraged the demagnetization procedure parameter by force and comprised that mistake encourages the maximum current I of demagnetization process generator amature by force _{F (0)}With maximum voltage U _{F (0)}, and mistake is encouraged demagnetization generator rotor current attenuation process value I by force _{F (j)}With rotor voltage attenuation process value U _{F (j)}, it is characterized in that: it may further comprise the steps:

S1) get generator overvoltage t=0 when reaching 1.3 times of rated voltages, generator amature link equation is carried out the processing of piece-wise linearization, the chance error that obtains generating electricity is encouraged the rotor current I of beginning when generator amature reaches maximum current by force _{F (i)}Calculating formula:

$I_{f\left(i\right)}=I_{\mathrm{fc}(i-1)}-(I_{\mathrm{fc}(i-1)}-I_{f(i-1)})e^{-\frac{\mathrm{\Δ}{t}_i}{T_{i-1}}}---\left(1\right)$

I in the formula (1) _{Fc (i-1)}Be t _I-1The steady-state value of the rotor current of moment rotor voltage correspondence; I _{F (i-1)}Be t _I-1Moment rotor current; T _I-1Be t _I-1Moment rotor time constant; Δ t _i=t _i-t _I-1, i is for encouraging the Duan Xu of the time slice of beginning when generator amature reaches maximum current by force to the generating chance error;

I in the formula (1) _{Fc (i-1)}Computing formula be:

$I_{\mathrm{fc}(i-1)}=\frac{U_{f(i-1)}}{R_{f(i-1)}}---\left(2\right)$

U in the formula (2) _{F (i-1)}Equal t _I-1The output voltage of exciting power rectifier constantly, to from shunt dynamo, the excitation transformer secondary side voltage in the time of thus calculates; To separately excited dynamo, U _{F (i-1)}Structural shape according to field power supply calculates; R _{F (i-1)}Be t _I-1Moment rotor resistance;

S2) determine the maximum current I of generator amature _{F (0)}:

The generating chance error is encouraged the totally 0.3 second time of beginning when generator amature reaches maximum current by force, is divided into the n section to 0.3 second, and substitution formula (1) repeated calculation obtains the maximum current of generator amature

I _F(0)＝I _f(i＝n) (4)；

S3) determine the maximum voltage U of generator amature _{F (0)}:

To from shunt dynamo, U _{F (0)}=1.35k ₃U _{G (i=n)}(5)

1.35 is the rectifier coefficient in the formula (5); k ₃Be the excitation transformer no-load voltage ratio; u _{G (i=n)}Be n generator voltage constantly, make on the generator property that factory provides by rotor current I at generator _{F (i=n)}Check in;

To separately excited dynamo, U _{F (0)}Structural shape according to field power supply calculates;

Time t when S4) establishing generator amature and reach maximum current ₀=0, ignore the influence of damping winding, obtain demagnetization process t _jRotor current attenuation process value I constantly _{F (j)}:

$I_{F\left(j\right)}=I_{F(j-1)}{e}^{-\frac{\mathrm{\Δ}{t}_j}{T_{\mathrm{fd}(j-1)}}}---\left(6\right),$

I in the formula (6) _{F (j-1)}Rotor current for a last moment; T _{Fd (j-1)}Be rotor closed-loop path time constant; Δ t _jFor calculating the time interval of j period, i.e. Δ t _j=t _j-t _J-1, j is the Duan Xu to segmentation die-away time;

T _{Fd (j-1)}Calculate by following formula:

T _fd(j-1)＝L _f(j-1)/(R _f+R _r(j-1))＝T _(j-1)·R _f/(R _f+R _r(j-1)) (7)，

L in the formula (7) _{F (j-1)}Be demagnetization process t _J-1Inductor rotor constantly, T _(j-1)Be demagnetization process t _J-1Rotor time constant constantly, R _{R (j-1)}Be t _J-1De-excitation resistance resistance constantly;

R _r(j-1)＝c(I _F(j-1)) ^β-1 (8)

C is a nonlinear resistance performance constant in the formula (8); β is a non linear coefficient, and 0＜β＜1;

S5) according to S4) the rotor current attenuation process value I that obtains _{F (j)}, obtain demagnetization process t _jRotor voltage attenuation process value U constantly _{F (j)}:

Organize on the de-excitation resistance V-A characteristic by I whole _{F (j)}Check in;

Perhaps calculate by following formula:

$U_{F\left(j\right)}=U_{r\left(j\right)}=c{I}_{F\left(j\right)}^{\mathrm{\β}}---\left(9\right)$

U in the formula (9) _{R (j)}Be the voltage on the de-excitation resistance.

Press such scheme, T in the described formula (1) _I-1Try to achieve by following formula (3) or (3 '):

A: when generator is unloaded,, ask for the rotor time constant of generator magnetic circuit when saturated with following formula by the constant and no-load characteristic idle time of concrete generator:

$T_{(i-1)}={\mathrm{<figure-callout\; id="0"\; label="T\; d"\; filenames="HDA0000043548840000013.png,HDA0000043548840000021.png"\; state="\{\{state\}\}">T</figure-callout>}}_d^0\frac{\mathrm{tg\&beta;}}{\mathrm{tg\&alpha;}}---\left(3\right),$

T ' in the formula (3) _D0Constant idle time for generator; Tg β is on the no-load characteristic of generator, corresponding t _I-1Moment rotor current I _{F (i-1)}The angle of contingence; Tg α is on the no-load characteristic of generator, is 0 o'clock the angle of contingence corresponding to rotor current, T ' _D0The no-load characteristic of value and generator all can be provided by generator manufacturing merchant;

B: during generator loading,, ask for generator magnetic circuit rotor time constant when saturated with following formula by the load time constant and the load characteristic of concrete generator:

$T_{(i-1)}=T_d^{\&prime;}\frac{\mathrm{tg}{\mathrm{\&beta;}}^{\&prime;}}{\mathrm{tg}{\mathrm{\&alpha;}}^{\&prime;}}---\left(3^{\&prime;}\right),$

T ' in the formula (3 ') _dLoad time constant for generator; Tg β ' is on the load characteristic of generator, corresponding t _I-1Moment rotor current I _{F (i-1)}The angle of contingence; Tg α ' is on the load characteristic of generator, is 0 o'clock the angle of contingence corresponding to rotor current; T ' _dThe no-load characteristic of value and generator all can be provided by generator manufacturing merchant.

For the part generator, need to consider the influence of damping winding, the computational methods step that is adopted is identical with above-mentioned steps, and its difference is: the time t when described step S4) establishing generator amature and reaching maximum current ₀=0, consider the influence of damping winding, obtain demagnetization process t _jRotor current attenuation process value I constantly _{F (j)}:

$I_{F\left(j\right)}=I_{F\left(0\right)}(\frac{T_{1d0}-T_1}{T_2-T_1}{e}^{-\frac{{\mathrm{<figure-callout\; id="1"\; label="t\; j\; T"\; filenames="HDA0000043548840000011.png,HDA0000043548840000022.png"\; state="\{\{state\}\}">t</figure-callout>}}_j}{T_{}}}+\frac{T_2-T_{1d0}}{T_2-T_1}{e}^{-\frac{t_j}{T_2}})---\left(10\right)$

T in the formula (10) _1d0Generator d-axis damping winding time constant when all opening a way for stator and rotor, I _{F (0)}Encourage the maximum current of demagnetization process generator amature by force for mistake; T ₁, T ₂Be time constant;

T in the formula (10) _1d0Computing formula is:

T _1d0＝X _11d/ωR _1d (11)

X in the formula (11) _11dBe the induction reactance of d-axis damping winding, corresponding to the coefficient of self-inductance L of d-axis damping winding _11dR _1dResistance for the d-axis damping winding; ω is specified angular frequency, ω=2 π f=314.

Time constant T ₁Computing formula is:

${\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="HDA0000043548840000011.png,HDA0000043548840000022.png"\; state="\{\{state\}\}">T</figure-callout>}}_1=\frac{1}{2}(T_{\mathrm{fd}}+T_{1d0})(1-q)---\left(12\right);$

Time constant T ₂Computing formula is:

${\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HDA0000043548840000021.png"\; state="\{\{state\}\}">T</figure-callout>}}_2=\frac{1}{2}(T_{\mathrm{fd}}+T_{1d0})(1+q)---\left(13\right);$

T in formula (12), (13) _FdThe closed-loop path time constant that rotor and de-excitation resistance constitute when all opening a way for stator and damping winding, q is a coefficient;

T _FdComputing formula is:

$T_{\mathrm{fd}}=\frac{R_f{\mathrm{<figure-callout\; id="0"\; label="T\; d"\; filenames="HDA0000043548840000013.png,HDA0000043548840000021.png"\; state="\{\{state\}\}">T</figure-callout>}}_d^0}{R_f+R_r}---\left(14\right)$

T ' in the formula (14) _D0The time constant of rotor winding when all opening a way for stator and damping winding; R _fBe generator amature resistance; R _rResistance for de-excitation resistance;

Coefficient q computing formula is:

$q=\sqrt{1-\frac{4\mathrm{\&sigma;}{T}_{\mathrm{fd}}{T}_{1d0}}{{(T_{\mathrm{fd}}+T_{1d0})}^2}}---\left(15\right)$

σ is the magnetic leakage factor between excitation winding and d-axis damping winding in the formula (15), and its computing formula is:

$\mathrm{\&sigma;}=1-\frac{{{\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="HDA0000043548840000021.png"\; state="\{\{state\}\}">X</figure-callout>}}^2}_{\mathrm{ad}}}{X_{\mathrm{ffd}}{X}_{11d}}---\left(16\right)$

X in the formula (16) _AdBe the generator d-axis reactance of armature reaction; X _FfdRotor winding induction reactance during for stator and damping winding open circuit is corresponding to the coefficient of self-inductance L of rotor _f

The principle that the present invention adopts is:

When the generating chance error is encouraged by force, field regulator is out of control, the full conducting of exciting power rectifier thyristor, and rotor current increases unusually, the generator magnetic circuit is saturated, and the variation relation of rotor current and rotor voltage and generator property are non-linear (seeing the generator amature link equation of Fig. 1).The present invention adopts the processing method of piece-wise linearization to non linear system, the calculating formula (1) of rotor current when having proposed to can be used as engineering design and calculating the generating chance error that uses and encourage by force.

The generating chance error is encouraged when beginning by force, existing saturated than the degree of depth of its magnetic circuit, and the generator amature time constant will reduce with the increase of rotor current, the rotor time constant T in the formula (1) _(i-1)Needing employing and this moment (is t _I-1The corresponding numerical value of generator magnetic circuit degree of saturation constantly).The present invention has proposed by the zero load of concrete generator or the zero load or the load characteristic of load time constant and generator according to the basic principle of generator magnetic circuit, asks for computational methods and calculating formula (3) and (3 ') of generator magnetic circuit rotor time constant when saturated.

The generating chance error is encouraged demagnetization by force and is started by generator super-voltage protection usually.Time-delay 0.3s started jumping field circuit breaker demagnetization after generator super-voltage protection generally reached 1.3 times of rated voltages with the generator unit stator overvoltage.Make on the generator characteristics that factory provides at generator, (establish this and be t=0, rotor current value I i=0) constantly in the time of can obtaining the generator unit stator overvoltage and reach 1.3 times of rated voltages _{F (i=0)}The generator rotor current in 1.3 times of rated voltages of overvoltage i moment in the time period when demagnetization begins can be calculated by formula (1).When this dividing time-steps is n period, then can obtain the rotor current I that demagnetization begins _{F (0)}Calculating formula (4).

Have no progeny at generator field circuit breaker branch, the demagnetization process of generator depends on the closed-loop path parameter that generator amature and de-excitation resistance constitute.De-excitation resistance in the loop adopts nonlinear resistance usually, and its resistance value is nonlinear change with the electric current that applies (or voltage); Rotor time constant also is nonlinear change with demagnetization process closed-loop path electric current.The piece-wise linearization computing method that the present invention proposes, the parameter of electric current, voltage and the closed-loop path of rotor in the time of can being begun by demagnetization is calculated demagnetization process rotor current and rotor voltage attenuation process.By demagnetization process rotor current and rotor voltage, calculate the power consumption of demagnetizing time and demagnetization process de-excitation resistance again.

The generator in power plant all is equipped with damping winding, and the calculating of eliminating magnetism of generator process rotor current, voltage need be taken into account the influence of generator damping winding.After taking into account the generator damping winding, it will be more complicated that the electric current of demagnetization process rotor, the attenuation process of voltage are calculated.The present invention proposes the eliminating magnetism of generator process that the reverse voltage addition method is calculated damping winding that adopts.It is incoming end at generator amature and field power supply that this method is regarded eliminating magnetism of generator as, added suddenly one begin with demagnetization to equate on the exciting voltage numerical value, voltage that direction is opposite, two Voltage Series connect, and insert de-excitation resistance in the current circuit of rotor.To the generator of damping winding is arranged, during the stator open circuit behind impact voltage on the unexcited rotor change procedure of rotor current, existing relevant document has provided relevant calculating formula.The present invention utilizes these relevant calculating formulas, and the generator property parameter that provides of generator manufacturing merchant, and the rotor current of eliminating magnetism of generator process that damping winding is arranged is calculated.

Beneficial effect of the present invention is:

1, the present invention proposes the piece-wise linearization computing method, encourage the parameter of demagnetization electric current, voltage and closed-loop path of rotor when beginning by force by mistake, demagnetization process rotor current and rotor voltage are calculated, again by demagnetization process rotor current and rotor voltage, calculate the power consumption of demagnetizing time and demagnetization process de-excitation resistance, for the design of weighing the de-excitation system device parameter provides foundation;

2, the generator in power plant all is equipped with damping winding, big or small different according to generator damping winding time constant, the damping winding ignored that in the demagnetization dynamic process, has, the influence that must consider damping winding that has, the present invention draws demagnetization process t when ignoring damping winding respectively with regard to both of these case _pRotor current voltage constantly and demagnetization process rotor current voltage when considering the influencing of damping winding obtain rotor current voltage parameter value more accurately.

Description of drawings

Fig. 1 is a generator amature link equation.

Fig. 2 is the no-load characteristic of generator.

Fig. 3 is the eliminating magnetism of generator process characteristic.

Fig. 4 is the unloaded demagnetization dynamic process of hydraulic generator characteristic when taking into account damping winding.

Fig. 5 is hydraulic generator machine terminal shortcircuit demagnetization dynamic process characteristic when taking into account damping winding.

Embodiment

Embodiment one:

The eliminating magnetism of generator procedure parameter comprises that mainly demagnetization begins generator rotor current, magnitude of voltage and attenuation process characterisitic parameter.The generating chance error of invention is encouraged the demagnetization procedure parameter by force and is calculated, and has comprised following technology contents:

---mistake is encouraged demagnetization by force and is begun generator rotor current and magnitude of voltage calculating;

---the effect mistiming of ignoring the generator damping winding is encouraged demagnetization process rotor current and the calculating of voltage attenuation process by force;

---when taking into account the generator damping winding, eliminating magnetism of generator process rotor current and voltage attenuation process are calculated.

Concrete implementation step is as follows:

1, mistake is encouraged the calculating that demagnetization begins rotor current, voltage and set end voltage by force

The mistake of invention is encouraged the calculating that demagnetization begins generator rotor current and magnitude of voltage by force, and its content comprises the calculating of rotor current change procedure when the generating chance error is encouraged by force, calculating, the generator overvoltage of rotor time constant protected the calculating that time-delay process generator rotor current and magnitude of voltage are protected in action when consideration generator magnetic circuit was saturated.Mistake is encouraged rotor current and the voltage that demagnetization begins generator by force, can adopt the method for piece-wise linearization to calculate.

The calculating formula of rotor current change procedure when (1) the generating chance error is encouraged by force

When the generating chance error was encouraged by force, field regulator was out of control, full the conducting of exciting power rectifier thyristor, rotor current increases unusually, and rotor time constant T will change generator rotor current i with the full degree of generator magnetic circuit _fWith rotor voltage U _fVariation relation be nonlinear differential equation (seeing the generator amature link equation of Fig. 1).To generally adopt at present from shunt dynamo, when the generating chance error was encouraged by force, excitation system was by generator voltage u _gNegative feedback closed loop has become the voltage positive feedback closed loop, as shown in Figure 1, and U _fBe generator amature voltage, i _fBe generator rotor current, u _gBe generator voltage.k ₁Be exciting power rectifier rectification coefficient, when the full conducting of thyristor, k ₁=1.35; k ₂Be the u on the generator property (see figure 2) _g/ i _f, with i _fMake nonlinear change; k ₃Be excitation transformer no-load voltage ratio u ₂/ u _gK=i _f/ u _f=1/R _f, R _fBe rotor resistance.When mistake is encouraged by force, among Fig. 1, k ₁, k ₂, k ₃Be positive coefficient, generator rotor current i _fWill be with generator voltage U _gRising and increase i _fRising will make U again _gFurther raise.

The present invention adopts the processing method of non linear system piece-wise linearization, the calculating formula of rotor current when having proposed to can be used as engineering design and calculating the generating chance error that uses and encourage by force.Generator amature link equation is carried out piece-wise linearization handle, when the chance error that can obtain generating electricity is encouraged by force, t in the rotor current change procedure _iMoment rotor current I _{F (i)}Calculating formula:

$I_{f\left(i\right)}=I_{\mathrm{fc}(i-1)}-(I_{\mathrm{fc}(i-1)}-I_{f(i-1)})e^{-\frac{\mathrm{\&Delta;}{t}_i}{T_{i-1}}}---\left(1\right)$

In the formula, I _{Fc (i-1)}Be t _I-1The steady-state value of the rotor current of moment rotor voltage correspondence, I _{F (i-1)}Be t _I-1Moment rotor current, T _I-1Be t _I-1Moment rotor time constant, Δ t _i=t _i-t _I-1

Eliminating magnetism of generator is started by the stator overvoltage protection usually; when the generator overvoltage reaches 1.3 times of rated voltages; the field circuit breaker demagnetization is jumped in time-delay 0.3s action; on the generator property that generator manufacturing factory provides; rotor current value in the time of can obtaining the generator overvoltage and reach 1.3 times of rated voltages; so generator overvoltage t=0 when reaching 1.3 times of rated voltages is got in the calculating of formula (1) usually; i=0; on the generator property that generator manufacturing factory provides, the rotor current I in the time of can checking in 1.3 times of rated voltages of corresponding generator _{F (i=0)}, with I _{F (i=0)}And following relevant calculation value substitution formula (1) can be calculated the rotor current I of next period (i=1) _{F (i=1)}Again by I _{F (i=1)}With the rotor current of identical method calculating i=2, until obtaining the rotor current value that demagnetization begins.

I in the formula (1) _{Fc (i-1)}Value can be by t _I-1Moment rotor voltage U _{F (i-1)}And rotor resistance R _{F (i-1)}Calculate with following formula:

$I_{\mathrm{fc}(i-1)}=\frac{U_{f(i-1)}}{R_{f(i-1)}}---\left(2\right)$

R in the formula _{F (i-1)}Be t _I-1Moment generator amature resistance; U _{F (i-1)}Equal t _I-1The output voltage of exciting power rectifier constantly, to from shunt dynamo, the excitation transformer secondary side voltage in the time of thus calculates:

U _f(i-1)＝1.35k ₃·U _g(i-1) (2′)

1.35 is the rectifier rectification coefficient in the formula, k ₃Be the excitation transformer no-load voltage ratio; U _{G (i-1)}Be t _(i-1)Generator voltage constantly can be made on the generator property that factory provides by rotor current I at generator _{F (i-1)}Check in.To separately excited dynamo, U _{F (i-1)}Can calculate according to the structural shape of field power supply, be generally fixed value.

Can not consider the variation of rotor resistance in protection time-delay and the demagnetization process, and get R _{F (i-1)}=R _f

The calculating of rotor time constant when (2) consideration generator magnetic circuit is saturated

The generating chance error is when strong, existing saturated than the degree of depth of its magnetic circuit, and the generator amature time constant will reduce with the increase of rotor current, the rotor time constant T in the formula (1) _(i-1)Need to adopt and (t this moment _I-1The corresponding numerical value of generator magnetic circuit degree of saturation constantly).The present invention is according to the basic principle of generator magnetic circuit, proposed by the zero load of concrete generator or the zero load or the load characteristic of load time constant and generator, ask for the computational methods and the calculating formula of generator magnetic circuit rotor time constant when saturated, Fig. 2 is the no-load characteristic of generator.Calculating formula when the unloaded mistake of generator is strong is:

$T_{(i-1)}={\mathrm{<figure-callout\; id="0"\; label="T\; d"\; filenames="HDA0000043548840000013.png,HDA0000043548840000021.png"\; state="\{\{state\}\}">T</figure-callout>}}_d^0\frac{\mathrm{tg\&beta;}}{\mathrm{tg\&alpha;}}---\left(3\right)$

T in the formula _D0' be constant idle time of generator; Tg β is on the no-load characteristic of generator, corresponding t _I-1Moment rotor current I _{F (i-1)}The angle of contingence, tg α is on the no-load characteristic of generator, is 0 o'clock the angle of contingence corresponding to rotor current.T _D0The no-load characteristic of ' value and generator all can be provided by generator manufacturing merchant.

During generator loading,, ask for generator magnetic circuit rotor time constant when saturated with following formula by the load time constant and the load characteristic of concrete generator:

$T_{(i-1)}=T_d^{\&prime;}\frac{\mathrm{tg}{\mathrm{\&beta;}}^{\&prime;}}{\mathrm{tg}{\mathrm{\&alpha;}}^{\&prime;}}---\left(3^{\&prime;}\right),$

T in the formula _d' be the load time constant of generator; Tg β ' is on the load characteristic of generator, corresponding t _I-1Moment rotor current I _{F (i-1)}The angle of contingence; Tg α ' is on the load characteristic of generator, is 0 o'clock the angle of contingence corresponding to rotor current; T _dThe no-load characteristic of ' value and generator all can be provided by generator manufacturing merchant.

(3) mistake is encouraged the calculating that demagnetization begins the generator amature voltage and current by force

The generating chance error is encouraged demagnetization by force and is started by generator super-voltage protection usually.Time-delay 0.3s started demagnetization (sending out the jumping field circuit breaker makes) after generator super-voltage protection generally reached 1.3 times of rated voltages with the generator unit stator overvoltage, had no progeny at the field circuit breaker branch, and generator amature and de-excitation resistance constitute the closed-loop path, and mistake is encouraged demagnetization by force and begun.

Make on the generator property that factory provides the rotor current value I of (establish this and be t=0 constantly) in the time of to obtain the generator unit stator overvoltage and reach 1.3 times of rated voltages at generator _{F (i=0)}The generator overvoltage reaches 1.3 times of mistakes after the rated voltage and encourages the rotor current constantly of i in the process by force and can be calculated T in the formula by formula (1) _I-1Calculate by formula (3) or (3 ').Encourage the time period of demagnetization when beginning by force when being divided into n period, the rotor current I when then demagnetization begins when the generator unit stator overvoltage being reached 1.3 times to mistake _{F (0)}Rotor current I for n period of calculating by formula (1) _{F (i=n)}That is:

I _F(0)＝I _f(i＝n) (4)

To from shunt dynamo, mistake is encouraged demagnetization by force and is begun rotor voltage U _{F (0)}Equal the output voltage of n period exciting power rectifier, the excitation transformer secondary side voltage in the time of thus calculates:

U _F(0)＝1.35k ₃·u _g(i＝n) (5)

1.35 is the rectifier rectification coefficient in the formula, k ₃Be the excitation transformer no-load voltage ratio; u _{G (i=n)}Be t _nGenerator voltage constantly can be made on the generator property that factory provides by rotor current I at generator _{F (i=n)}Check in.

To separately excited dynamo, U _{F (0)}Can calculate according to the structural shape of field power supply, be generally fixed value after mistake is encouraged by force.

2, ignore damping winding, mistake is encouraged the calculating of demagnetization generator rotor current and voltage attenuation process values by force

Have no progeny at generator field circuit breaker branch, the demagnetization process of generator depends on the closed-loop path parameter that generator amature and de-excitation resistance constitute.De-excitation resistance in the loop adopts nonlinear resistance usually, and its resistance value is nonlinear change with the electric current that applies (or voltage); Rotor time constant also is nonlinear change with demagnetization process closed-loop path electric current.So the equation that rotor current in the demagnetization process and rotor voltage change is a nonlinear differential equation.The piece-wise linearization computing method that the present invention proposes, the parameter of electric current, voltage and the closed-loop path of rotor is calculated demagnetization process rotor current and rotor voltage in the time of can being begun by demagnetization.By demagnetization process rotor current and rotor voltage, calculate the power consumption of demagnetizing time and demagnetization process de-excitation resistance again, for the design alternative of weighing de-excitation system performance and de-excitation resistance parameter provides foundation.

Demagnetization attenuation process t _jRotor current I constantly _{F (j)}Can adopt the rotor current and the rotor closed-loop path time constant in a moment to calculate:

$I_{F\left(j\right)}=I_{F(j-1)}{e}^{-\frac{\mathrm{\&Delta;}{t}_j}{T_{\mathrm{fd}(j-1)}}}---\left(6\right)$

T in the formula _{Fd (j-1)}Be rotor closed-loop path t _J-1Time constant is constantly calculated by formula (7); Δ t _jBe the time interval of calculation interval j period, Δ t _j=t _j-t _J-1When demagnetization begins, t ₀=0, j=0.T _{Fd (p-1)}Calculate by following formula:

T _fd(j-1)＝L _f(j-1)/(R _f+R _r(j-1))＝T _(j-1)·R _f/(R _f+R _r(j-1)) (7)

Wherein, L _{F (j-1)}, T _(j-1)Be respectively demagnetization process t _J-1Inductor rotor, rotor time constant constantly, R _{R (j-1)}Be t _J-1De-excitation resistance resistance constantly.R when adopting non-linear de-excitation resistance _{R (j-1)}Calculate by following formula:

R _r(j-1)＝c(I _F(j-1)) ^β-1 (8)

C is a nonlinear resistance performance constant in the formula, and β is non linear coefficient (0＜β＜1).

Demagnetization process j rotor voltage U constantly _{F (j)}(this voltage also is the voltage U on the de-excitation resistance _{R (j)}) can be by I on whole group de-excitation resistance V-A characteristic _{F (j)}Check in.When adopting non-linear de-excitation resistance, also can calculate by following formula:

$U_{F\left(j\right)}=U_{r\left(j\right)}=c{I}_{F\left(j\right)}^{\mathrm{\&beta;}}---\left(9\right)$

The demagnetization procedure parameter that the aforementioned calculation method also can be used under other demagnetization operating modes of generator calculates.

Fig. 3,4, the 5th utilizes the result of calculation of computational methods to calculating from shunt dynamo demagnetization process of inventing, wherein Fig. 4,5 has provided the influence of hydraulic generator damping winding to unloaded demagnetization and the calculating of machine terminal shortcircuit demagnetization process, and the demagnetization process all adopts linear de-excitation resistance.As seen, to hydraulic generator, can ignore the effect of generator damping winding the demagnetization process is calculated.

Following table is that the calculating and the actual tests recorder data of the unloaded demagnetization process of hydraulic generator compares.

Computational analysis shows: the generating chance error is encouraged rotor current, the voltage that demagnetization begins by force, can calculate by the effect of ignoring the generator damping winding; Because hydraulic generator damping winding time constant is less, the effect that its demagnetization procedure parameter can be ignored the generator damping winding is calculated.

Embodiment two:

The feature of present embodiment and embodiment one is basic identical, and its difference is:

When taking into account the generator damping winding, the generating chance error is encouraged the calculating of demagnetization process rotor current and voltage attenuation process by force

The generator in power plant all is equipped with damping winding, and the calculating of eliminating magnetism of generator process rotor current, voltage need be taken into account the influence of generator damping winding.After taking into account the generator damping winding, the electric current of demagnetization process rotor, the calculating of voltage will be more complicated.The present invention proposes the eliminating magnetism of generator process that the reverse voltage addition method is calculated damping winding that adopts.It is incoming end at generator amature and field power supply that this method is regarded eliminating magnetism of generator as, added suddenly one begin with demagnetization to equate on the exciting voltage numerical value, voltage that direction is opposite, two Voltage Series connect, and insert de-excitation resistance in the current circuit of rotor.To the generator of damping winding is arranged, during the stator open circuit behind impact voltage on the unexcited rotor change procedure of rotor current, existing relevant document has provided relevant calculating formula.The present invention provides how to utilize these relevant calculating formulas, and the generator property parameter that provides of generator manufacturing merchant, and the rotor current of eliminating magnetism of generator attenuation process that damping winding is arranged is calculated.

The eliminating magnetism of generator process all generator tripped with the electric power system off-the-line under carry out i.e. demagnetization under the generator idle condition.

After taking into account the generator damping winding, the unloaded demagnetization attenuation process of generator rotor current I _{F (j)}Change procedure can be expressed as:

$I_{F\left(j\right)}=I_{F\left(0\right)}(\frac{T_{1d0}-T_1}{T_2-T_1}{e}^{-\frac{{\mathrm{<figure-callout\; id="1"\; label="t\; j\; T"\; filenames="HDA0000043548840000011.png,HDA0000043548840000022.png"\; state="\{\{state\}\}">t</figure-callout>}}_j}{T_{}}}+\frac{T_2-T_{1d0}}{T_2-T_1}{e}^{-\frac{t_j}{T_2}})---\left(10\right)$

T in the formula _1d0Generator d-axis damping winding time constant when all opening a way for stator and rotor, I _{F (0)}The rotor current (A) that begins for demagnetization.T _1d0And time constant T ₁, T ₂Calculate by following calculating formula respectively:

T _1d0＝X _11d/ωR _1d (11)

X in the formula _11dFor the induction reactance (standard value) of d-axis damping winding, corresponding to the coefficient of self-inductance L of d-axis damping winding _11dR _1dResistance for the d-axis damping winding; ω is specified angular frequency, ω=2 π f=314.

${\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="HDA0000043548840000011.png,HDA0000043548840000022.png"\; state="\{\{state\}\}">T</figure-callout>}}_1=\frac{1}{2}(T_{\mathrm{fd}}+T_{1d0})(1-q)---\left(12\right)$

${\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HDA0000043548840000021.png"\; state="\{\{state\}\}">T</figure-callout>}}_2=\frac{1}{2}(T_{\mathrm{fd}}+T_{1d0})(1+q)---\left(13\right)$

T in the formula _FdWhen all opening a way for stator and damping winding, the closed-loop path time constant that rotor and de-excitation resistance constitute, calculate by following formula:

$T_{\mathrm{fd}}=\frac{R_{\mathrm{<figure-callout\; id="0"\; label="f\; T\; d"\; filenames="HDA0000043548840000013.png,HDA0000043548840000021.png"\; state="\{\{state\}\}">f</figure-callout>}}{T}_d^{}{0}_{\&prime;}^{}}{R_f+R_r}---\left(14\right)$

T ' in the formula _D0The time constant (claiming generator d-axis transient state open circuit time constant again) of rotor winding when all opening a way for stator and damping winding.R _f, R _rBe respectively the resistance of generator amature, de-excitation resistance.

Coefficient q is calculated by following formula:

$q=\sqrt{1-\frac{4\mathrm{\&sigma;}{T}_{\mathrm{fd}}{T}_{1d0}}{{(T_{\mathrm{fd}}+T_{1d0})}^2}}---\left(15\right)$

σ is the magnetic leakage factor between excitation winding and d-axis damping winding, is calculated by following formula:

$\mathrm{\&sigma;}=1-\frac{{{\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="HDA0000043548840000021.png"\; state="\{\{state\}\}">X</figure-callout>}}^2}_{\mathrm{ad}}}{X_{\mathrm{ffd}}{X}_{11d}}---\left(16\right)$

X in the formula _AdBe the generator d-axis reactance of armature reaction (standard value); X _FfdRotor winding induction reactance (standard value) during for stator and damping winding open circuit is corresponding to the coefficient of self-inductance L of rotor _f

T ' _D0, T ' _D0, R _f, R _1d, X _AdBut parameter generator manufacturing producer usually provides.

To turbo generator, because its damping winding time constant is bigger, need consider the effect of generator damping winding, the calculating formula of utilizing the present invention to provide is encouraged the demagnetization procedure parameter by force to mistake and is calculated.

Claims (4)

1. eliminating magnetism of generator system mistake is encouraged definite method of demagnetization procedure parameter by force, and described mistake is encouraged the demagnetization procedure parameter by force and comprised that mistake encourages the maximum current I of demagnetization process generator amature by force _{F (0)}With maximum voltage U _{F (0)}, and mistake is encouraged demagnetization generator rotor current attenuation process value I by force _{F (j)}With rotor voltage attenuation process value U _{F (j)}, it is characterized in that: it may further comprise the steps:

S1) get generator overvoltage t=0 when reaching 1.3 times of rated voltages, generator amature link equation is carried out the processing of piece-wise linearization, the chance error that obtains generating electricity is encouraged the rotor current I of beginning when generator amature reaches maximum current by force _{F (i)}Calculating formula:

$I_{f\left(i\right)}=I_{\mathrm{fc}(i-1)}-(I_{\mathrm{fc}(i-1)}-I_{f(i-1)})e^{-\frac{\mathrm{\&Delta;}{t}_i}{T_{i-1}}}---\left(1\right)$

I in the formula (1) _{Fc (i-1)}Be t _I-1The steady-state value of the rotor current of moment rotor voltage correspondence; I _{F (i-1)}Be t _I-1Moment rotor current; T _I-1Be t _I-1Moment rotor time constant; Δ t _i=t _i-t _I-1, i is for encouraging the Duan Xu of the time slice of beginning when generator amature reaches maximum current by force to the generating chance error;

I in the formula (1) _{Fc (i-1)}Computing formula be:

$I_{\mathrm{fc}(i-1)}=\frac{U_{f(i-1)}}{R_{f(i-1)}}---\left(2\right)$

U in the formula (2) _{F (i-1)}Equal t _I-1The output voltage of exciting power rectifier constantly, to from shunt dynamo, the excitation transformer secondary side voltage in the time of thus calculates; To separately excited dynamo, U _{F (i-1)}Structural shape according to field power supply calculates; R _{F (i-1)}Be t _I-1Moment rotor resistance;

S2) determine the maximum current I of generator amature _{F (0)}:

The generating chance error is encouraged the totally 0.3 second time of beginning when generator amature reaches maximum current by force, is divided into the n section to 0.3 second, and substitution formula (1) repeated calculation obtains the maximum current of generator amature

I _F(0)＝I _f(i＝n) (4)；

S3) determine the maximum voltage U of generator amature _{F (0)}:

To from shunt dynamo, U _{F (0)}=1.35k ₃U _{G (i=n)}(5)

1.35 is the rectifier coefficient in the formula (5); k ₃Be the excitation transformer no-load voltage ratio; u _{G (i=n)}Be n generator voltage constantly, make on the generator property that factory provides by rotor current I at generator _{F (i=n)}Check in;

To separately excited dynamo, U _{F (0)}Structural shape according to field power supply calculates;

Time t when S4) establishing generator amature and reach maximum current ₀=0, ignore the influence of damping winding, obtain demagnetization process t _jRotor current attenuation process value I constantly _{F (j)}:

$I_{F\left(j\right)}=I_{F(j-1)}{e}^{-\frac{\mathrm{\&Delta;}{t}_j}{T_{\mathrm{fd}(j-1)}}}---\left(6\right),$

I in the formula (6) _{F (j-1)}Rotor current for a last moment; T _{Fd (j-1)}Be rotor closed-loop path time constant; Δ t _jFor calculating the time interval of j period, i.e. Δ t _j=t _j-t _J-1, j is the Duan Xu to segmentation die-away time;

T _{Fd (j-1)}Calculate by following formula:

T _fd(j-1)＝L _f(j-1)/(R _f+R _r(j-1))＝T _(j-1)·R _f/(R _f+R _r(j-1)) (7)，

L in the formula (7) _{F (j-1)}Be demagnetization process t _J-1Inductor rotor constantly, T _(j-1)Be demagnetization process t _J-1Rotor time constant constantly, R _{R (j-1)}Be t _J-1De-excitation resistance resistance constantly;

R _r(j-1)＝c(I _F(j-1)) ^β-1 (8)

C is a nonlinear resistance performance constant in the formula (8); β is a non linear coefficient, and 0＜β＜1;

S5) according to S4) the rotor current attenuation process value I that obtains _{F (j)}, obtain demagnetization process t _jRotor voltage attenuation process value U constantly _{F (j)}:

Organize on the de-excitation resistance V-A characteristic by I whole _{F (j)}Check in;

Perhaps calculate by following formula:

$U_{F\left(j\right)}=U_{r\left(j\right)}=c{I}_{F\left(j\right)}^{\mathrm{\&beta;}}---\left(9\right)$

U in the formula (9) _{R (j)}Be the voltage on the de-excitation resistance.

2. eliminating magnetism of generator according to claim 1 system mistake is encouraged definite method of demagnetization procedure parameter by force, it is characterized in that: T in the described formula (1) _I-1Try to achieve by following formula (3) or (3 '):

A: when generator is unloaded,, ask for the rotor time constant of generator magnetic circuit when saturated with following formula by the constant and no-load characteristic idle time of concrete generator:

$T_{(i-1)}=T_{d0}^{\&prime;}\frac{\mathrm{tg\&beta;}}{\mathrm{tg\&alpha;}}---\left(3\right),$

T ' in the formula (3) _D0Constant idle time for generator; Tg β is on the no-load characteristic of generator, corresponding t _I-1Moment rotor current I _{F (i-1)}The angle of contingence; Tg α is on the no-load characteristic of generator, is 0 o'clock the angle of contingence corresponding to rotor current, T ' _D0The no-load characteristic of value and generator all can be provided by generator manufacturing merchant;

B: during generator loading,, ask for generator magnetic circuit rotor time constant when saturated with following formula by the load time constant and the load characteristic of concrete generator:

$T_{(i-1)}=T_d^{\&prime;}\frac{\mathrm{tg}{\mathrm{\&beta;}}^{\&prime;}}{\mathrm{tg}{\mathrm{\&alpha;}}^{\&prime;}}---\left(3^{\&prime;}\right),$

T ' in the formula (3 ') _dLoad time constant for generator; Tg β ' is on the load characteristic of generator, corresponding t _I-1Moment rotor current I _{F (i-1)}The angle of contingence; Tg α ' is on the load characteristic of generator, is 0 o'clock the angle of contingence corresponding to rotor current; T ' _dThe no-load characteristic of value and generator all can be provided by generator manufacturing merchant.

3. eliminating magnetism of generator system mistake is encouraged definite method of demagnetization procedure parameter by force, and described mistake is encouraged the demagnetization procedure parameter by force and comprised that mistake encourages the maximum current I of demagnetization process generator amature by force _{F (0)}With maximum voltage U _{F (0)}, and mistake is encouraged demagnetization generator rotor current attenuation process value I by force _{F (j)}With rotor voltage attenuation process value U _{F (j)}, it is characterized in that: it may further comprise the steps:

S1) get generator overvoltage t=0 when reaching 1.3 times of rated voltages, generator amature link equation is carried out the processing of piece-wise linearization, the chance error that obtains generating electricity is encouraged the rotor current I of beginning when generator amature reaches maximum current by force _{F (i)}Calculating formula:

$I_{f\left(i\right)}=I_{\mathrm{fc}(i-1)}-(I_{\mathrm{fc}(i-1)}-I_{f(i-1)})e^{-\frac{\mathrm{\&Delta;}{t}_i}{T_{i-1}}}---\left(1\right)$

I in the formula (1) _{Fc (i-1)}Be t _I-1The steady-state value of the rotor current of moment rotor voltage correspondence; I _{F (i-1)}Be t _I-1Moment rotor current; T _I-1Be t _I-1Moment rotor time constant; Δ t _i=t _i-t _I-1, i is for encouraging the Duan Xu of the time slice of beginning when generator amature reaches maximum current by force to the generating chance error;

I in the formula (1) _{Fc (i-1)}Computing formula be:

$I_{\mathrm{fc}(i-1)}=\frac{U_{f(i-1)}}{R_{f(i-1)}}---\left(2\right)$

U in the formula (2) _{F (i-1)}Equal t _I-1The output voltage of exciting power rectifier constantly, to from shunt dynamo, the excitation transformer secondary side voltage in the time of thus calculates; To separately excited dynamo, U _{F (i-1)}Structural shape according to field power supply calculates; R _{F (i-1)}Be t _I-1Moment rotor resistance;

S2) determine the maximum current I of generator amature _{F (0)}:

The generating chance error is encouraged the totally 0.3 second time of beginning when generator amature reaches maximum current by force, is divided into the n section to 0.3 second, and substitution formula (1) repeated calculation obtains the maximum current of generator amature

I _F(0)＝I _f(i＝n) (4)；

S3) determine the maximum voltage U of generator amature _{F (0)}:

To from shunt dynamo, U _{F (0)}=1.35k ₃U _{G (i=n)}(5)

1.35 is the rectifier coefficient in the formula (5); k ₃Be the excitation transformer no-load voltage ratio; u _{G (i=n)}Be n generator voltage constantly, make on the generator property that factory provides by rotor current I at generator _{F (i=n)}Check in;

To separately excited dynamo, U _{F (0)}Structural shape according to field power supply calculates;

Time t when S4) establishing generator amature and reach maximum current ₀=0, consider the influence of damping winding, obtain demagnetization process t _jRotor current attenuation process value I constantly _{F (j)}:

$I_{F\left(j\right)}=I_{F\left(0\right)}(\frac{T_{1d0}-T_1}{T_2-T_1}{e}^{-\frac{t_j}{T_1}}+\frac{T_2-T_{1d0}}{T_2-T_1}{e}^{-\frac{t_j}{T_2}})---\left(10\right)$

T in the formula (10) _1d0Generator d-axis damping winding time constant when all opening a way for stator and rotor, I _{F (0)}Encourage the maximum current of demagnetization process generator amature by force for mistake; T ₁, T ₂Be time constant;

T in the formula (10) _1d0Computing formula is:

T _1d0＝X _11d/ωR _1d (11)

X in the formula (11) _11dBe the induction reactance of d-axis damping winding, corresponding to the coefficient of self-inductance L of d-axis damping winding _11dR _1dResistance for the d-axis damping winding; ω is specified angular frequency, ω=2 π f=314.

Time constant T ₁Computing formula is:

$T_1=\frac{1}{2}(T_{\mathrm{fd}}+T_{1d0})(1-q)---\left(12\right);$

Time constant T ₂Computing formula is:

$T_2=\frac{1}{2}(T_{\mathrm{fd}}+T_{1d0})(1+q)---\left(13\right);$

T in formula (12), (13) _FdThe closed-loop path time constant that rotor and de-excitation resistance constitute when all opening a way for stator and damping winding, q is a coefficient;

T _FdComputing formula is:

$T_{\mathrm{fd}}=\frac{R_f{T}_{d0}^{\&prime;}}{R_f+R_r}---\left(14\right)$

T ' in the formula (14) _D0The time constant of rotor winding when all opening a way for stator and damping winding; R _fBe generator amature resistance; R _rResistance for de-excitation resistance;

Coefficient q computing formula is:

$q=\sqrt{1-\frac{4\mathrm{\&sigma;}{T}_{\mathrm{fd}}{T}_{1d0}}{{(T_{\mathrm{fd}}+T_{1d0})}^2}}---\left(15\right)$

σ is the magnetic leakage factor between excitation winding and d-axis damping winding in the formula (15), and its computing formula is:

$\mathrm{\&sigma;}=1-\frac{{X^2}_{\mathrm{ad}}}{X_{\mathrm{ffd}}{X}_{11d}}---\left(16\right)$

X in the formula (16) _AdBe the generator d-axis reactance of armature reaction; X _FfdRotor winding induction reactance during for stator and damping winding open circuit is corresponding to the coefficient of self-inductance L of rotor _f

S5) according to S4) the rotor current attenuation process value I that obtains _{F (j)}, obtain demagnetization process t _jRotor voltage attenuation process value U constantly _{F (j)}:

Organize on the de-excitation resistance V-A characteristic by I whole _{F (j)}Check in;

Perhaps calculate by following formula:

$U_{F\left(j\right)}=U_{r\left(j\right)}=c{I}_{F\left(j\right)}^{\mathrm{\&beta;}}---\left(9\right)$

U in the formula (9) _{R (j)}Be the voltage on the de-excitation resistance.

4. eliminating magnetism of generator according to claim 3 system mistake is encouraged definite method of demagnetization procedure parameter by force, it is characterized in that: T in the described formula (1) _I-1Try to achieve by following formula (3) or (3 '):

A: when generator is unloaded,, ask for the rotor time constant of generator magnetic circuit when saturated with following formula by the constant and no-load characteristic idle time of concrete generator:

$T_{(i-1)}=T_{d0}^{\&prime;}\frac{\mathrm{tg\&beta;}}{\mathrm{tg\&alpha;}}---\left(3\right),$

T ' in the formula (3) _D0Constant idle time for generator; Tg β is on the no-load characteristic of generator, corresponding t _I-1Moment rotor current I _{F (i-1)}The angle of contingence; Tg α is on the no-load characteristic of generator, is 0 o'clock the angle of contingence corresponding to rotor current, T ' _D0The no-load characteristic of value and generator all can be provided by generator manufacturing merchant;

B: during generator loading,, ask for generator magnetic circuit rotor time constant when saturated with following formula by the load time constant and the load characteristic of concrete generator:

$T_{(i-1)}=T_d^{\&prime;}\frac{\mathrm{tg}{\mathrm{\&beta;}}^{\&prime;}}{\mathrm{tg}{\mathrm{\&alpha;}}^{\&prime;}}---\left(3^{\&prime;}\right),$

T ' in the formula (3 ') _dLoad time constant for generator; Tg β ' is on the load characteristic of generator, corresponding t _I-1Moment rotor current I _{F (i-1)}The angle of contingence; Tg α ' is on the load characteristic of generator, is 0 o'clock the angle of contingence corresponding to rotor current; T ' _dThe no-load characteristic of value and generator all can be provided by generator manufacturing merchant.

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