CN104268426A - Calculation method of rotating speed Omega of generator rotor in power system stabilizer (PSS4B) model - Google Patents

Abstract

The invention discloses a calculation method of a rotating speed Omega of a generator rotor in a power system stabilizer (PSS4B) method. With the adoption of the calculation method, the calculation amount in the implementation process is small, the implementation is flexibly and conveniently carried out through an excitation regulator, a simple and effective way is provided to realize PSS4B through a generator excitation regulator, and the calculation method is belongs to the field of control of power systems; the calculation method can be applied to a hydroelectric power station or a thermal power plant, a wind power plant, etc.

Description

The computing method of generator amature rotational speed omega in a kind of power system stabilizer 4B model

Technical field

The present invention discloses a kind of power system stabilizer, PSS (Power System Stabilizer, PSS) computing method of PSS4B model medium speed ω, belong to field of power system control, can be applicable to water-power plant or fuel-burning power plant, wind power plant etc.

Background technology

Along with developing rapidly of power industry, the scale of electric system is increasing, and single-machine capacity is also increasing, and many large and medium generator groups all generally adopt high-speed excitation regulator.High-speed excitation regulator, while raising system response time, but substantially reduces excitation system time constant, reduces system damping, make often to occur underdamping even negative damping in system, and the ability that result in system power oscillation damping declines.Causing system sectionalizing when low-frequency oscillation is serious or lose stable, is one of sixty-four dollar question of the interconnected influential system stability of large-scale power system.At present, solve low-frequency oscillation problem mainly through additional excitation control device, wherein power system stabilizer, PSS is a kind of effective additional excitation control.Power system stabilizer, PSS (PSS) is an optional feature of excitation unit, for improving power system damping ability, suppressing the low-frequency oscillation of system, improving the stability of electric system.

For the low-frequency oscillation of electric system, main automatic excitation adjustor of generator auxiliary power system stabilizer (PSS) that adopts controls to realize suppressing, and main models has PSS1A, PSS2A/PSS2B, PSS4B etc.

There is well-known " instead adjusting " problem in PSS1A, introduces generator speed and active power signal in PSS2A/2B model, through calculating accelerating power as final input signal, avoids " instead adjusting " problem that PSS1A exists.PSS2A/PSS2B only has a wave filter, and after parameter tuning, its frequency response is also fixed, and along with system oscillation frequency shift (FS) or lower, PSS2A/PSS2B power oscillation damping effect also will weaken gradually.

PSS4B is improved and is formed on the basis of PSS2B.Low-frequency oscillation divides in order to high frequency, intermediate frequency, low frequency three frequency ranges by the frequency of vibration by PSS4B, and each channel can be adjusted separately corresponding frequency characteristic, provides suitable positive damping torque, reach better inhibition with more preferably low frequency oscillation.

Summary of the invention

The object of the present invention is to provide the computing method of a kind of PSS4B model medium speed ω, it is complicated that PSS4B model seems comparatively PSS2B, but realize fairly simple to program, in model except the wave filter of two input signals is special, other large multimodes are basic lead-lag module.Lead-lag and low pass link calculate and realize in excitation program, directly call this module.Two-way input signal is had in model, generator active power Pe and generator amature rotational speed omega respectively, power P e calculates in excitation program, rotational speed omega calculates then to be needed to carry out composite calulation according to related electric amount, relative complex, the present invention adopts generator terminal voltage, stator current and generator parameter to calculate built-in potential, carries out calculating rotational speed omega according to using internal potential frequency.

The present invention is concrete by the following technical solutions.

Computing method for generator amature rotational speed omega in power system stabilizer 4B model, is characterized in that: described computing method comprise the following steps:

(1) by each electric signal amount of field regulator Real-time Collection generator, set end voltage is comprised threephase stator electric current

(2) generator terminal voltage step (1) gathered, threephase stator Current calculation positive-sequence component, and according to formula calculating generator built-in potential:

When generator built-in potential represents by A, B phase, can obtain

${\stackrel{\·}{E}}_{\mathrm{aq}}={\stackrel{\·}{U}}_a+j{X_q}^{\′}{\stackrel{\·}{I}}_a={\stackrel{\·}{U}}_a+{X_q}^{\′}\frac{{\stackrel{\·}{I}}_c-{\stackrel{\·}{I}}_b}{\sqrt{3}}$

${\stackrel{\·}{E}}_{\mathrm{bq}}={\stackrel{\·}{U}}_b+j{X_q}^{\′}{\stackrel{\·}{I}}_b={\stackrel{\·}{U}}_b+{X_q}^{\′}\frac{{\stackrel{\·}{I}}_a-{\stackrel{\·}{I}}_c}{\sqrt{3}}$

for generator A phase, B phase built-in potential, for generator A phase, B phase voltage, X _q' be the reactance of generator transient state, for generator threephase stator electric current.

Subtracted each other by above two formula and derive

${\stackrel{\·}{E}}_{\mathrm{aq}}-{\stackrel{\·}{E}}_{\mathrm{bq}}={\stackrel{\·}{E}}_{\mathrm{abq}}=\stackrel{\·}{U_{\mathrm{ab}}+{X_q}^{\′}\frac{2{\stackrel{\·}{I}}_c-{\stackrel{\·}{I}}_b-{\stackrel{\·}{I}}_a}{\sqrt{3}}}$

for A, B diphaser built-in potential is poor.Calculate real part E _qrwith imaginary part E _qi:

$E_{\mathrm{qr}}=U_r+\frac{{X_q}^{\′}{I}_r}{\sqrt{3}}$

$E_{\mathrm{qi}}=U_i+\frac{{X_q}^{\′}{I}_i}{\sqrt{3}}$

Wherein, U _rfor set end voltage real part, U _ifor set end voltage imaginary part, I _rfor composite vector real part, I _ifor composite vector imaginary part.

For a sampled signal f is the frequency of U (t), for signal initial phase angle, DFT conversion can be carried out

$U_i=\frac{2}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}{U}_k\cos \frac{2\mathrm{\π}}{N}k$

$U_r=\frac{2}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}{U}_k\cos \frac{2\mathrm{\π}}{N}k$

Wherein U _kfor the sampled point obtained, U _r, U _ifor the real part that obtains and imaginary part after conversion. real part and imaginary part by obtaining each voltage, the real part of the magnitude of current, imaginary part calculate.

(3) calculating generator rotor speed ω:

$\mathrm{\ω}=\frac{{\mathrm{\φ}}_n-{\mathrm{\φ}}_{n-1}}{\mathrm{\ΔT}}=\frac{\arctan \frac{E_{\mathrm{qin}}}{E_{\mathrm{qm}}}-\arctan \frac{E_{\mathrm{qin}-1}}{E_{\mathrm{qm}-1}}}{\mathrm{\ΔT}}$

Wherein E _qinbe the imaginary part of A, B diphaser built-in potential difference in the n-th moment, E _qrnbe the real part of A, B diphaser built-in potential difference in the n-th moment, E _qin-1be the imaginary part of A, B diphaser built-in potential difference in the (n-1)th moment, E _qrn-1be the real part of A, B diphaser built-in potential difference in the (n-1)th moment, Δ T is sampling interval.

The input signal of power system stabilizer 4B is Δ ω and Δ ω=ω-1.0.

The present invention has following Advantageous Effects:

The PSS model used in prior art all becomes master pattern, but its input signal does not provide, need to calculate separately when using a model, active-power P e becomes more readily available, but the sub-rotor speed ω that generates electricity is difficult to accurate Calculation by electric parameters, the present invention gives a kind of comparatively simple and practical computing method, provides a kind of effective way for realizing PSS function in automatic excitation adjustor of generator.

Accompanying drawing explanation

Fig. 1 is PSS4B model schematic;

Fig. 2 is the schematic flow sheet of PSS4B model medium speed ω disclosed by the invention;

Fig. 3 is the realization flow of PSS4B on field regulator.

Embodiment

Be the schematic flow sheet of PSS4B model medium speed ω disclosed by the invention as shown in Figure 2, computing method of the present invention comprise the following steps:

(1) each electric signal amount of Real-time Collection generator, comprises set end voltage threephase stator electric current

(2) according to the three-phase set end voltage gathered threephase stator electric current calculate each phase voltage, stator current positive-sequence component, the reactance of generator transient state and generator built-in potential.

When built-in potential represents by A, B phase, can obtain

${\stackrel{\·}{E}}_{\mathrm{aq}}={\stackrel{\·}{U}}_a+j{X_q}^{\′}{\stackrel{\·}{I}}_a={\stackrel{\·}{U}}_a+{X_q}^{\′}\frac{{\stackrel{\·}{I}}_c-{\stackrel{\·}{I}}_b}{\sqrt{3}}$

${\stackrel{\·}{E}}_{\mathrm{bq}}={\stackrel{\·}{U}}_b+j{X_q}^{\′}{\stackrel{\·}{I}}_b={\stackrel{\·}{U}}_b+{X_q}^{\′}\frac{{\stackrel{\·}{I}}_a-{\stackrel{\·}{I}}_c}{\sqrt{3}}$

for generator A phase, B phase built-in potential, for generator A phase, B phase voltage, X _q' be the reactance of generator transient state, for generator threephase stator electric current.

Subtracted each other by above two formula and derive

${\stackrel{\·}{E}}_{\mathrm{aq}}-{\stackrel{\·}{E}}_{\mathrm{bq}}={>\stackrel{\·}{E}}_{\mathrm{abq}}=\stackrel{\·}{U_{\mathrm{ab}}+{X_q}^{\′}\frac{2{\stackrel{\·}{I}}_c-{\stackrel{\·}{I}}_b-{\stackrel{\·}{I}}_a}{\sqrt{3}}}$

for A, B diphaser built-in potential is poor, because of with angular frequency identical, so calculate frequency.Derive machine end line voltage easy to use calculates, if E _qrfor electromotive force real part, E _qifor electromotive force imaginary part, U _rfor set end voltage real part, U _ifor set end voltage imaginary part, I _rfor composite vector real part, I _ifor composite vector imaginary part, then

$E_{\mathrm{qr}}=U_r+\frac{{X_q}^{\′}{I}_r}{\sqrt{3}}$

$E_{\mathrm{qi}}=U_i+\frac{{X_q}^{\′}{I}_i}{\sqrt{3}}$

Wherein real part and imaginary part all obtain adopting centralized calculation.

(3) generator amature rotational speed omega calculates according to formula calculate built-in potential angular frequency and obtain, wherein φ _eqfor built-in potential phase place.

$\tan {\mathrm{\φ}}_n=\frac{E_{\mathrm{qin}}}{E_{\mathrm{qrn}}},$ ${\mathrm{\φ}}_n=\arctan \frac{E_{\mathrm{qin}}}{E_{\mathrm{qrn}}}$

$\tan {\mathrm{\φ}}_{n-1}=\frac{E_{\mathrm{qin}-1}}{E_{\mathrm{qrn}-1}},$ ${\mathrm{\φ}}_{n-1}=\arctan \frac{E_{\mathrm{qin}-1}}{E_{\mathrm{qrn}-1}}$

$\mathrm{\ω}=\frac{{\mathrm{\φ}}_n-{\mathrm{\φ}}_{n-1}}{\mathrm{\ΔT}}=\frac{\arctan \frac{E_{\mathrm{qin}}}{E_{\mathrm{qm}}}-\arctan \frac{E_{\mathrm{qin}-1}}{E_{\mathrm{qm}-1}}}{\mathrm{\ΔT}}$

E _qinbe the built-in potential imaginary part of n-hour, E _qrnbe the built-in potential real part of n-hour, E _qin-1be the built-in potential imaginary part in N-1 moment, E _qrn-1be the built-in potential real part in N-1 moment, Δ T is the unit moment.Note using the real part of each of ac positive-sequence component when more than calculating, imaginary part calculates.

Embodiment 1

Implementation process is as follows:

1. each electric signal amount of generator of Real-time Collection generator excitation, PSS4B needs, comprises set end voltage threephase stator electric current pe (calculating).

2. according to the set end voltage gathered, stator current positive-sequence component, the reactance of generator transient state and formula calculating generator built-in potential.If voltage is f is the frequency of U (t), for signal initial phase angle,

If each cycle to be sampled 32 points to alternating voltage U (t), then convert through DFT after discretize

$U_i=\frac{1}{16}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}{U}_k\cos \frac{\mathrm{\π}}{16}k$

$U_r=\frac{1}{16}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}{U}_k\cos \frac{\mathrm{\π}}{16}k$

Wherein U _kfor the sampled point obtained, U _r, U _ifor the real part that obtains and imaginary part after conversion.

Positive-sequence component for voltage, its positive sequence ${\stackrel{\·}{U}}_{+}=1/3*({\stackrel{\·}{U}}_A+\mathrm{\α}{\stackrel{\·}{U}}_B+{\mathrm{\α}}^2{\stackrel{\·}{U}}_C)$ (α＝e ^j120°)

${\stackrel{\·}{\mathrm{Ur}}}_{+}=1/3*({\stackrel{\·}{\mathrm{Ur}}}_A+\mathrm{\α}{\stackrel{\·}{U}r}_B+{\mathrm{\α}}^2{\stackrel{\·}{\mathrm{Ur}}}_C)$

${\stackrel{\·}{U}i}_{+}=1/3*({\stackrel{\·}{U}i}_A+\mathrm{\α}{\stackrel{\·}{\mathrm{Ui}}}_B+{\mathrm{\α}}^2{\stackrel{\·}{U}i}_C)$

Wherein for generator A, B, C phase voltage.

Electric current positive sequence calculates in like manner: i ₊=1/3* (i _a+ α i _b+ α ²i _c) (α=e ^{j120 °})

i _r+＝1/3*(i _rA+αi _rB+α ²i _rC)

i _i+＝1/3*(i _iA+αi _iB+α ²i _iC)

Wherein i _a, i _b, i _cfor generator A, B, C phase current.

When built-in potential represents by A, B phase, can obtain

${\stackrel{\·}{E}}_{\mathrm{aq}}={\stackrel{\·}{U}}_a+j{X_q}^{\′}{\stackrel{\·}{I}}_a={\stackrel{\·}{U}}_a+{X_q}^{\′}\frac{{\stackrel{\·}{I}}_c-{\stackrel{\·}{I}}_b}{\sqrt{3}}$

${\stackrel{\·}{E}}_{\mathrm{bq}}={\stackrel{\·}{U}}_b+j{X_q}^{\′}{\stackrel{\·}{I}}_b={\stackrel{\·}{U}}_b+{X_q}^{\′}\frac{{\stackrel{\·}{I}}_a-{\stackrel{\·}{I}}_c}{\sqrt{3}}$

Subtracted each other by above two formula and derive

${\stackrel{\·}{E}}_{\mathrm{aq}}-{\stackrel{\·}{E}}_{\mathrm{bq}}={>\stackrel{\·}{E}}_{\mathrm{abq}}=\stackrel{\·}{U_{\mathrm{ab}}+{X_q}^{\′}\frac{2{\stackrel{\·}{I}}_c-{\stackrel{\·}{I}}_b-{\stackrel{\·}{I}}_a}{\sqrt{3}}}$

Cause with angular frequency identical, so calculate frequency.Derive machine end line voltage easy to use calculates, if E _qrfor electromotive force real part, E _qifor electromotive force imaginary part, U _rfor set end voltage real part, U _ifor set end voltage imaginary part, I _rfor composite vector real part, I _ifor composite vector imaginary part, then

$E_{\mathrm{qr}}=U_r+\frac{{X_q}^{\′}{I}_r}{\sqrt{3}}$

$E_{\mathrm{qi}}=U_i+\frac{{X_q}^{\′}{I}_i}{\sqrt{3}}$

Wherein real part and imaginary part all obtain adopting centralized calculation.

3. generator amature rotational speed omega calculates according to formula calculate built-in potential angular frequency and obtain, wherein φ _eqfor built-in potential phase place.

$\tan {\mathrm{\φ}}_n=\frac{E_{\mathrm{qin}}}{E_{\mathrm{qrn}}},$ ${\mathrm{\φ}}_n=\arctan \frac{E_{\mathrm{qin}}}{E_{\mathrm{qrn}}}$

$\tan {\mathrm{\φ}}_{n-1}=\frac{E_{\mathrm{qin}-1}}{E_{\mathrm{qrn}-1}},$ ${\mathrm{\φ}}_{n-1}=\arctan \frac{E_{\mathrm{qin}-1}}{E_{\mathrm{qrn}-1}}$

$\mathrm{\ω}=\frac{{\mathrm{\φ}}_n-{\mathrm{\φ}}_{n-1}}{\mathrm{\ΔT}}=\frac{\arctan \frac{E_{\mathrm{qin}}}{E_{\mathrm{qm}}}-\arctan \frac{E_{\mathrm{qin}-1}}{E_{\mathrm{qm}-1}}}{\mathrm{\ΔT}}$

The input signal of PSS is Δ ω and Δ ω=ω-1.0.

Note using the real part of each of ac positive-sequence component when more than calculating, imaginary part calculates.

After active-power P e and tach signal ω possesses, PSS4B more easily calculates other, due to PSS4B model time-frequency domain representation, needs to be converted into time domain to calculate when calculating, the following method of each link computing method in PSS4B:

(1) tach signal wave filter

$G\left(s\right)=\frac{1+T_{1}S}{T_2{S}^2+T_{3}S+1}$

After conversion $\mathrm{Yn}=$

$\frac{\mathrm{\Δ}{t}^2+T_1\mathrm{\Δt}}{T_2+T_3\mathrm{\Δt}+{\mathrm{\Δt}}^2}{X}_n-\frac{T_1\mathrm{\Δt}}{T_2+T_3\mathrm{\Δt}+{\mathrm{\Δt}}^2}{X}_{n-1}+\frac{2T_2+T_3\mathrm{\Δt}}{T_2+T_3\mathrm{\Δt}+{\mathrm{\Δt}}^2}{Y}_{n-1}-\frac{T_2}{T_2+T_3\mathrm{\ΔT}+{\mathrm{\Δt}}^2}{Y}_{n-2}$

Bring filter time constant T1=-0.0017590, T2=0.00012739, T3=0.017823 into above formula, Δ T is module computation period for this reason, with in lower module in like manner.

(2) power signal input filter

$\begin{array}{c}G\left(s\right)=\frac{{80S}^2}{S^3+82S^2+161S+80}\\ =\frac{1}{0.0125S+1}\frac{S}{S+1}\frac{S}{S+1}\end{array}$

Obtain an inertial element and two after conversion every straight link, can following module (4), (5) that directly calling program has realized can realize.

(3) lead-lag link

$G\left(S\right)=K*\left(\frac{1+\mathrm{sT}1}{1+\mathrm{sT}2}\right)$

Above formula can be expressed as with X (s) for input, with Y (s) for exporting, namely

$Y\left(s\right)=K\frac{1+T_{1}S}{1+T_{2}S}X\left(S\right)$

Be transformed to Y (s)+T ₂y (s) s=kX (s)+kT ₁x (s) s, changing into forms of time and space is

x in formula _n-1, y _n-1represent moment input, output valve in interval of delta t, below in like manner (T ₂+ Δ t) y _n=K (T ₁+ Δ t) x _n-KT ₁x _n-1+ T ₂y _n-1

∴y _n＝K _ax _n-K _bx _n-1+K _Cy _n-1

Wherein: $K_a=\frac{K(T_1+\mathrm{\Δt})}{T_2+\mathrm{\Δt}},$ $K_b=\frac{{\mathrm{KT}}_1}{T_2+\mathrm{\Δt}},$ $K_C=\frac{T_2}{T_2+\mathrm{\Δt}}$

(4) every straight link

$G\left(S\right)=K*\left(\frac{\mathrm{sT}}{1+\mathrm{sT}}\right)$

＝K _a(x _n-x _n-1)+K _by _n-1

Wherein: $K_a=\frac{\mathrm{KT}}{\mathrm{\Δt}},$ $K_b=\frac{T}{\mathrm{\Δt}}$

(5) inertial element

$G\left(S\right)=K*\left(\frac{1}{1+\mathrm{sT}2}\right)$

In like manner=>y _n=K _ax _n+ K _by _n-1

Wherein: $K_a=\frac{\mathrm{K\Δt}}{T_2+\mathrm{\Δt}},$ $K_b=\frac{T_2}{T_2+\mathrm{\Δt}}$

As shown in Figure 1 in PSS4B model, two-way input signal is rotational speed omega and active-power P e, respectively through low, bandpass filter for rear class provides input.Low-frequency oscillation divides in order to 3 branches by centre frequency difference by model, each branch is the difference filter be made up of two wave filters, transport function is identical, just setting parameter is different, in fig. 1 except ratio is directly multiplied and except simple amplitude limit, other models directly call above-mentioned module (3) and can realize.

4. judge the entry condition of PSS4B function, entry condition is 0.9<Ut<1.1 and Pe>0.32, does not meet entry condition and is then reset by final for PSS4B model calculated value Urpss.

5. PSS4B the model calculation Urpss is additional on field regulator voltage given to come in add control.

Now 3 explanations by reference to the accompanying drawings

Accompanying drawing 3 model is a kind of field voltage Controlling model, and Ur is that set end voltage is given, and Ut is set end voltage, and Output rusults Urpss to be added on Ur by fling-cut switch and to participate in controlling by PSS4B.Meet entry condition then selector switch 1 position, be added to PSS4B result of calculation Ur, otherwise switching over is to 2 positions, and namely input value is 0.

More than that applicant has done detailed description and description in conjunction with the embodiment of Figure of description to the application; but those skilled in the art should understand that; above embodiment is only the preferred embodiment of the application; detailed explanation is just in order to help reader to understand spirit of the present invention better; and the restriction not to the application's protection domain; on the contrary, any based on the present application any improvement of doing of spirit or modify all should drop on the application protection domain within.

Claims (2)

1. the computing method of generator amature rotational speed omega in power system stabilizer 4B model, is characterized in that: adopt generator unit stator voltage, stator current and generator parameter to calculate built-in potential, carry out calculating rotational speed omega according to using internal potential frequency.

2. the computing method of generator amature rotational speed omega in power system stabilizer 4B model, is characterized in that: described computing method comprise the following steps:

(1) by each electric signal amount of field regulator Real-time Collection generator, machine end line voltage is comprised threephase stator electric current

(2) the generator three-phase voltage, the Current calculation positive-sequence component that step (1) are gathered, calculating generator built-in potential:

When generator built-in potential represents by A, B phase, can obtain

${\stackrel{\&CenterDot;}{E}}_{\mathrm{aq}}={\stackrel{\&CenterDot;}{U}}_a+j{X_q}^{\&prime;}{\stackrel{\&CenterDot;}{I}}_a={\stackrel{\&CenterDot;}{U}}_a+{X_q}^{\&prime;}\frac{{\stackrel{\&CenterDot;}{I}}_c-{\stackrel{\&CenterDot;}{I}}_b}{\sqrt{3}}$

${\stackrel{\&CenterDot;}{E}}_{\mathrm{bq}}={\stackrel{\&CenterDot;}{U}}_b+j{X_q}^{\&prime;}{\stackrel{\&CenterDot;}{I}}_b={\stackrel{\&CenterDot;}{U}}_b+{X_q}^{\&prime;}\frac{{\stackrel{\&CenterDot;}{I}}_a-{\stackrel{\&CenterDot;}{I}}_c}{\sqrt{3}}$

for generator A phase, B phase built-in potential, for generator A phase, B phase voltage, X _q' be the reactance of generator transient state, for generator threephase stator electric current;

Subtracted each other by above two formula and derive

${\stackrel{\&CenterDot;}{E}}_{\mathrm{aq}}-{\stackrel{\&CenterDot;}{E}}_{\mathrm{bq}}={\stackrel{\&CenterDot;}{E}}_{\mathrm{abq}}={\stackrel{\&CenterDot;}{U}}_{\mathrm{ab}}+{X_q}^{\&prime;}\frac{2{\stackrel{\&CenterDot;}{I}}_c-{\stackrel{\&CenterDot;}{I}}_b-{\stackrel{\&CenterDot;}{I}}_a}{\sqrt{3}}$

for A, B diphaser built-in potential is poor, with angular frequency identical;

Calculate again real part E _qrwith imaginary part E _qi:

$E_{\mathrm{qr}}=U_r+\frac{{X_q}^{\&prime;}{I}_r}{\sqrt{3}}$

$E_{\mathrm{qi}}=U_i+\frac{{X_q}^{\&prime;}{I}_i}{\sqrt{3}}$

Wherein, U _rfor set end voltage real part, U _ifor set end voltage imaginary part, I _rfor composite vector real part, I _ifor composite vector imaginary part;

(3) calculating generator rotor speed ω:

$\mathrm{\&omega;}=\frac{\arctan \frac{E_{\mathrm{qin}}}{E_{\mathrm{qrn}}}-\arctan \frac{E_{\mathrm{qin}-1}}{E_{\mathrm{qrn}-1}}}{\mathrm{\&Delta;T}}$

Wherein E _qinbe the imaginary part of A, B diphaser built-in potential difference in the n-th moment, E _qrnbe the real part of A, B diphaser built-in potential difference in the n-th moment, E _qin-1be the imaginary part of A, B diphaser built-in potential difference in the (n-1)th moment, E _qrn-1be the real part of A, B diphaser built-in potential difference in the (n-1)th moment, Δ T is sampling interval;

Power system stabilizer 4B input signal is Δ ω, and Δ ω=ω-1.0.