CN105048511A - Inertia comprehensive control method for power generation system comprising controllable inertia wind power generator - Google Patents

Abstract

The invention discloses an inertia comprehensive control method for a power generation system comprising a controllable inertia wind power generator set. The method comprises the steps that whether power gird frequency of a grid-connected point changes is judged, monitoring continues if the judgment result is no, the position of the grid-connected point of the controllable inertia wind power generator set is judged if the judgment result is yes, and active increment deltaP<f> is judged as (the expressions are described in the specification) if the position is at a feed end, or active increment deltaP<f> is judged as (the expressions are described in the specification). Compared with conventional inertia control, the corresponding inertia adjustment method can be adopted according to the geographic position of an area in which a wind power plant is positioned so that two control functions of participating in power grid frequency adjustment and increasing system damping are possessed, and adverse influence caused by introduction of negative damping in frequency modulation of conventional virtual inertia control is eliminated. The size of inertia of the system of the subarea in which the wind power plant is positioned can be flexibly changed by the interconnected power grid with the help of the wind power plant so that inertial support and damping power oscillation capability can be enhanced and dynamic stability of the system can be enhanced.

Description

A kind of electricity generation system inertia integrated control method containing controlled inertia type air generator

Technical field

The present invention relates to a kind of control method of electricity generation system, especially a kind of electricity generation system inertia integrated control method containing controlled inertia type air generating set, belongs to electricity generation system control technology field.

Background technology

In the electricity generation system that Future New Energy Source installation proportion is higher, the virtual inertia that many power supplys possess maintains the customized parameter of power system dynamic stability by becoming, although add the difficulty analyzing grid stability, control method also can be more flexible.For variable-speed wind-power unit, by independent meritorious adjustment, unit can fictionalize controlled inertial response, effectively avoids impair system inertia, the adverse effect that threat frequency is stable.But, different from the built-in inertia of conventional power generation usage unit, variable-speed wind-power unit can by discharging or absorb rotor kinetic energy within the scope of wider rotational speed regulation, and the flexible in size of its virtual inertia is adjustable, and then inertia size and the distribution of system can be changed, system frequency is adjusted and faces many new problems.And multimachine inertia is controlled also can make a significant impact the frequency of power oscillation between regional power grid and attenuation characteristic.After adding this controling parameters of inertia, how to utilize virtual inertia, improve frequency stabilization, inertia is even utilized to regulate dynamic characteristics such as strengthening system damping, to be that can control method have more actual application value, and then improve the another key issue of controlled inertia generating system safety operation level.

Summary of the invention

The technical problem to be solved in the present invention is: the inertia integrated control method providing a kind of electricity generation system containing controlled inertia type air generating set.

The technical solution used in the present invention is:

Containing an inertia integrated control method for the electricity generation system of controlled inertia type air generating set, comprise the following steps:

Step a: judge described controlled inertia type air generating set and whether the mains frequency of site changes, if so, turns to step b; If not, step a is turned to;

Step b: judge controlled inertia type air generating set described in described electricity generation system and the position of site, if be in sending end, then turn to step c, otherwise turn to steps d;

Step c: the power output regulating described controlled inertia type air generating set, meritorious increment Delta P _ffor:

$\left\{\begin{array}{cc}{\mathrm{\&Delta;P}}_f=-T_H\frac{d\mathrm{\&Delta;}f}{dt}& \arctan \frac{d\mathrm{\&Delta;}f/dt}{\mathrm{\&Delta;}f}>0\\ {\mathrm{\&Delta;P}}_f=-T_L\frac{d\mathrm{\&Delta;}f}{dt}& \arctan \frac{d\mathrm{\&Delta;}f/dt}{\mathrm{\&Delta;}f}<0\end{array}\right.---\left(1\right)$

In formula, T _h, T _lbe the first and second derivative control coefficients, and T _h>T _l>0; Δ f is mains frequency deviation, and d Δ f/dt is the rate of change of described mains frequency deviation relative to time t;

Steps d: the power output regulating described controlled inertia type air generating set, meritorious increment Delta P _ffor:

${\mathrm{\&Delta;P}}_f=-T_{vir}\frac{d\mathrm{\&Delta;}f}{dt}---\left(2\right)$

In formula, T _virit is the 3rd derivative control coefficient.

The invention has the beneficial effects as follows:

Compared with controlling with conventional inertia, strategy of the present invention can according to the geographical position in region residing for controlled inertia type air generating set, adopt corresponding inertia control method, make it possess simultaneously and participate in mains frequency adjustment and increase system damping two kinds of controlling functions, eliminate the adverse effect that traditional virtual inertia controls to introduce when frequency modulation negative damping.Under this control strategy, interconnected network can change the inertia size of its place subregion system flexibly by controlled inertia type air generating set, strengthens the ability of inertial supports and power oscillation damping, improves the dynamic stability of system.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the invention will be further described.

Fig. 1 is flow chart of the present invention;

Fig. 2 is the four machine two district system emulation topology diagrams containing wind energy turbine set in the embodiment of the present invention 1;

Fig. 3 is wind-driven generator virtual inertia control structure figure in the embodiment of the present invention 1;

Fig. 4 is four machine two district system frequency dynamic response correlation curves in the embodiment of the present invention 1;

Fig. 5 is four machine two district system power dynamic response correlation curves in the embodiment of the present invention 1;

Fig. 6 is containing controlled inertia two regional generation system construction drawing in the embodiment of the present invention 1;

Fig. 7 is containing controlled inertia two regional generation system equivalent circuit diagram in the embodiment of the present invention 1;

The oscillating characteristic of Δ f when Fig. 8 is two regional generation system undamped in the embodiment of the present invention 1;

Fig. 9 is four machine two district system frequency dynamic response correlation curves in the embodiment of the present invention 2;

Figure 10 is four machine two district system power dynamic response correlation curves in the embodiment of the present invention 2.

Embodiment

Embodiment 1:

As shown in Figure 2, the present embodiment adopts IEEE tetra-machine two district system, and this system comprises 4 thermal power plants, and rated capacity is 900MWA, and 1 capacity is the double-fed fan motor field of 250 × 2WM.Wherein, thermal power plant G ₁, G ₂forming region 1, is sending end; G ₃, G ₄then forming region 2, is receiving end.L ₁and L ₂be respectively the load in region 1 and region 2.In this paper embodiment 1, wind energy turbine set DFIG is through bus B ₅be incorporated to region 1; And in example 2, wind energy turbine set DFIG in region 1 is changed by bus B ₁₁be incorporated to region 2, as shown in phantom in FIG..Wherein, wind energy turbine set is made up of double-fed induction Wind turbines (doublyfedinductiongenerator, DFIG), and its virtual inertia control structure as shown in Figure 3.In emulation, wind speed setting is 11m/s, by arranging following two kinds of control programs, illustrating that the present invention can make the controlled electricity generation system of inertia by inertia adjustment flexibly, improving the ability of system inertia support and power oscillation damping.

Scheme is 1.: noninertia controls;

Scheme is 2.: the first derivative control coefficient T _h=20, second derivative control coefficient T _l=4.

As shown in Figure 4, load L ₁the 2.0s moment uprush 200MW make system frequency occur significantly fall.When controlling without additional inertance, after sudden load increase, fluctuating by a relatively large margin appears in system frequency; After adopting the present embodiment, controlled inertia Wind turbines is by the size of dynamic adjustments virtual inertia, and the amplitude that system frequency is fallen and rate of change are all significantly reduced, and peak frequency deviation is decreased to 0.13Hz by 0.2Hz.

As shown in Figure 5, bus B ₈in the 2.0s moment, it is the three phase short circuit fault of 0.1s that the duration occurs.When controlling without additional inertance, short trouble causes systems stay power oscillation; After adopting the present embodiment, by the inertia of dynamic adjustments sending end electricity generation system, effectively enhance the ability of system damping power oscillation.As shown in the figure, fault occur after the power oscillation of interconnected systems only continue about 10s and namely return to steady operational status.

The present embodiment principle analysis is as follows:

The controlled inertia type air generating set in each region and conventional power generation usage unit in IEEE tetra-machine two district system are equivalent to two Synchronous generator G separately ₁, G ₂, then the two controlled inertia generating systems in region and equivalent electric circuit thereof are as shown in Figure 6 and Figure 7, synchronous generator G in figure ₁be positioned at sending end, G ₂be positioned at receiving end, its equivalent inertia time constant is respectively T _g1, T _g2.Conventional power unit and a wind-powered electricity generation group of planes in two regional power grids are carried out equivalence according to the respective center of inertia by this system, are applicable to the power oscillation characteristic that qualitative analysis interconnected systems is interregional.

As shown in Figure 7, Z ₁and Z ₂be respectively generator G ₁, G ₂to bus B ₄impedance, Z _lfor load impedance.If generator G ₁, G ₂transient potential E ₁', E ₂' constant, then its equation of rotor motion is

$\{\begin{array}{c}\frac{{\mathrm{d\&delta;}}_k}{dt}=({\mathrm{\&omega;}}_k-1){\mathrm{\&omega;}}_0\\ \frac{{\mathrm{d\&omega;}}_k}{dt}=\frac{1}{T_{Gk}}\&lsqb;P_{Tk}-P_{Gk}-D_k({\mathrm{\&omega;}}_k-1)\&rsqb;\end{array}---\left(3\right)$

In formula, k is equivalent synchronous generator group #, and value is 1 or 2; P _gk, P _tk, D _k, δ _k, ω _k, ω ₀be respectively the electromagnetic power of kth equivalent synchronous generator group, mechanical output, damping coefficient, merit angle, angular speed and rated angular velocity.

Star network shown in Fig. 7 is transformed into triangular net, cancellation load bus, synchronous generator G can be tried to achieve ₁and G ₂electromagnetic power expression formula as follows:

$\{\begin{array}{c}{P}_{G1}=E_1^{\&prime;2}{G}_{11}+E_1^{\&prime;}{E}_2^{\&prime;}(G_{12}{\mathrm{cos\&delta;}}_{12}+B_{12}{\mathrm{sin\&delta;}}_{12})\\ P_{G2}=E_{22}^{\&prime;2}{G}_{22}+E_1^{\&prime;}{E}_2^{\&prime;}(G_{12}{\mathrm{cos\&delta;}}_{12}+B_{12}{\mathrm{sin\&delta;}}_{12})\end{array}---\left(4\right)$

In formula, δ ₁₂=δ ₁-δ ₂for G ₁with G ₂between merit angular difference; Wherein

$\left\{\begin{array}{c}{G}_{ii}+{\mathrm{jB}}_{\mathrm{ii}}=\frac{Z_i+Z_L}{Z_1{Z}_2+Z_1{Z}_L+Z_2{Z}_L}\\ G_y+{\mathrm{jB}}_{ij}=\frac{Z_L}{Z_1{Z}_2+Z_1{Z}_L+Z_2{Z}_L}(i\&NotEqual;j)\end{array}\right.$

Formula (4) is substituted into formula (3) linearized, the two machine systems that obtain are with Δ δ ₁₂, Δ ω ₁with Δ ω ₂for the system linear state equation of state variable is

$\frac{{\mathrm{d\&Delta;\&delta;}}_{12}}{dt}={\mathrm{\&omega;}}_0({\mathrm{\&Delta;\&omega;}}_1-{\mathrm{\&Delta;\&omega;}}_2)---\left(5\right)$

$\frac{{\mathrm{d\&Delta;\&omega;}}_1}{dt}=-\frac{1}{T_{G1}}(S_{G1}{\mathrm{\&Delta;\&delta;}}_{12}+D_1{\mathrm{\&Delta;\&omega;}}_1)---\left(6\right)$

$\frac{{\mathrm{d\&Delta;\&omega;}}_2}{dt}=-\frac{1}{T_{G2}}(S_{G2}{\mathrm{\&Delta;\&delta;}}_{12}+D_2{\mathrm{\&Delta;\&omega;}}_2)---\left(7\right)$

Wherein

$\left\{\begin{array}{c}{S}_{G1}=E_1^{\&prime;}{E}_2^{\&prime;}(-G_{12}sin{\mathrm{\&delta;}}_{12}+B_{12}cos{\mathrm{\&delta;}}_{12})\\ S_{G2}=E_1^{\&prime;}{E}_2^{\&prime;}(-G_{12}sin{\mathrm{\&delta;}}_{12}-B_{12}cos{\mathrm{\&delta;}}_{12})\end{array}\right.$

Be rewritten as matrix form:

$\left[\begin{array}{c}\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{\mathrm{\&delta;}}}_{12}\\ \mathrm{\&Delta;}{\stackrel{\&CenterDot;}{\mathrm{\&omega;}}}_1\\ \mathrm{\&Delta;}{\stackrel{\&CenterDot;}{\mathrm{\&omega;}}}_2\end{array}\right]=\left[\begin{array}{ccc}0& {\mathrm{\&omega;}}_0& -{\mathrm{\&omega;}}_0\\ -S_{G1}/T_{G1}& -D_1/T_{G1}& 0\\ -S_{G2}/T_{G2}& 0& -D_2/T_{G2}\end{array}\right]\left[\begin{array}{c}\mathrm{\&Delta;}{\mathrm{\&delta;}}_{12}\\ {\mathrm{\&Delta;\&omega;}}_1\\ {\mathrm{\&Delta;\&omega;}}_2\end{array}\right]---\left(8\right)$

Formula (8) is the state equation on three rank, is difficult to direct qualitative analytic systems inertia to the impact of power oscillation, therefore needs to carry out depression of order process to model.For this reason, herein by integral manifold method, by state variable Δ ω ₂the corresponding differential equation represents with a rational integral manifold, thus simplifies Mathematical Modeling, and the method can ensure that before and after depression of order, the stability of a system is constant.

Get singular perturbation parameter ε=T _g2/ (mT _g1), wherein, m>2, formula (7) both sides obtain with being multiplied by ε

$\mathrm{\&epsiv;}\frac{{\mathrm{d\&Delta;\&omega;}}_2}{dt}=-\frac{1}{{\mathrm{mT}}_{G1}}(S_{G2}{\mathrm{\&Delta;\&delta;}}_{12}+D_2{\mathrm{\&Delta;\&omega;}}_2)---\left(9\right)$

If integral manifold

Δω ₂＝h(Δδ ₁₂,Δω ₁,ε)(10)

When m value meets ε abundant hour, formula (10) can expand into power series at ε=0 place

Δω ₂＝h＝h ₀+εh ₁+ε ²h ₂+…(11)

Function h must meet formula (9), then

$\mathrm{\&epsiv;}\frac{\&part;h}{\&part;{\mathrm{\&Delta;\&delta;}}_{12}}\frac{{\mathrm{d\&Delta;\&delta;}}_{12}}{dt}+\mathrm{\&epsiv;}\frac{\&part;h}{\&part;{\mathrm{\&Delta;\&omega;}}_1}\frac{{\mathrm{d\&Delta;\&omega;}}_1}{dt}=-\frac{1}{{\mathrm{mT}}_{G1}}(S_{G2}{\mathrm{\&Delta;\&delta;}}_{12}+D_{2}h)---\left(12\right)$

Wherein

$\left\{\begin{array}{c}\frac{\&part;h}{\&part;{\mathrm{\&Delta;\&delta;}}_{12}}=\frac{\&part;h_0}{\&part;{\mathrm{\&Delta;\&delta;}}_{12}}+\mathrm{\&epsiv;}\frac{\&part;h_1}{\&part;{\mathrm{\&Delta;\&delta;}}_{12}}{\mathrm{\&epsiv;}}^2\frac{\&part;h_2}{\&part;{\mathrm{\&Delta;\&delta;}}_{12}}+\mathrm{...}\\ \frac{\&part;{\mathrm{\&Delta;\&delta;}}_{12}}{dt}=({\mathrm{\&Delta;\&omega;}}_1-h_0-{\mathrm{\&epsiv;h}}_1-{\mathrm{\&epsiv;}}^2{h}_2-\mathrm{...}){\mathrm{\&omega;}}_0\\ \frac{\&part;h}{\&part;{\mathrm{\&Delta;\&omega;}}_1}=\frac{\&part;h_0}{\&part;{\mathrm{\&Delta;\&omega;}}_1}+\mathrm{\&epsiv;}\frac{\&part;h_1}{\&part;{\mathrm{\&Delta;\&omega;}}_1}+{\mathrm{\&epsiv;}}^2\frac{\&part;h_2}{\&part;{\mathrm{\&Delta;\&omega;}}_1}+\mathrm{...}\end{array}\right.$

Formula (12) left and right sides is about ε ⁰, ε ¹, ε ²... each term coefficient should be equal, can obtain

$\left\{\begin{array}{c}{h}_0=\frac{S_{G2}}{D_2}{\mathrm{\&Delta;\&delta;}}_{12}\\ h_1=\frac{{\mathrm{m\&omega;}}_0{T}_{G1}{S}_{G2}^2}{D_2^3}{\mathrm{\&Delta;\&delta;}}_{12}+\frac{{\mathrm{m\&omega;}}_0{T}_{G1}{S}_{G2}}{D_2^2}{\mathrm{\&Delta;\&omega;}}_1\\ .\\ .\\ .\end{array}\right.---\left(13\right)$

Formula (13) is substituted into formula (11), obtains state variable Δ ω ₂for

$\begin{array}{c}{\mathrm{\&Delta;\&omega;}}_2=h_0+{\mathrm{\&epsiv;h}}_1+o\left({\mathrm{\&epsiv;}}^2\right)\mathrm{...}\\ \&ap;(\frac{{\mathrm{\&omega;}}_0{T}_{G2}{S}_{G2}^2}{D_2^2}-\frac{S_{G2}}{D_2}){\mathrm{\&Delta;\&delta;}}_{12}+\frac{{\mathrm{\&omega;}}_0{T}_{G2}{S}_{G2}}{D_2^2}{\mathrm{\&Delta;\&omega;}}_1\\ =K_4{\mathrm{\&Delta;\&delta;}}_{12}+K_B{\mathrm{\&Delta;\&omega;}}_1\end{array}---\left(14\right)$

Known according to formula (14), by the method for integral manifold, state variable Δ ω ₂can approximate representation be Δ δ ₁₂, Δ ω ₁function, formula (14) is substituted into formula (5)

$\frac{{\mathrm{d\&Delta;\&delta;}}_{12}}{dt}=-{\mathrm{\&omega;}}_0{K}_A{\mathrm{\&Delta;\&delta;}}_{12}+{\mathrm{\&omega;}}_0(1-K_B){\mathrm{\&Delta;\&omega;}}_1---\left(15\right)$

The state equation depression of order of system is formula (6), (15), namely

$\left[\begin{array}{c}\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{\mathrm{\&delta;}}}_{12}\\ \mathrm{\&Delta;}{\stackrel{\&CenterDot;}{\mathrm{\&omega;}}}_1\end{array}\right]=\left[\begin{array}{cc}-{\mathrm{\&omega;}}_0{K}_A& {\mathrm{\&omega;}}_0(1-K_B)\\ -\frac{S_{G1}}{T_{G1}}& -\frac{D_1}{T_{G1}}\end{array}\right]\left[\begin{array}{c}\mathrm{\&Delta;}{\mathrm{\&delta;}}_{12}\\ {\mathrm{\&Delta;\&omega;}}_1\end{array}\right]---\left(16\right)$

The characteristic equation of equation (16) can be expressed as

$p^2+p({\mathrm{\&omega;}}_0{K}_A+\frac{D_1}{T_{G1}})+\frac{{\mathrm{\&omega;}}_0}{T_{G1}}\&lsqb;K_A{D}_1+(1-K_B)S_{G1}\&rsqb;=0---\left(17\right)$

In formula, p is differential operator.

Formulation character root is asked to be by formula (17)

p＝λ±jω(18)

Wherein

$\mathrm{\&lambda;}=-\frac{1}{2}({\mathrm{\&omega;}}_0{K}_A+\frac{D_1}{T_{G1}})=-\frac{1}{2}(\frac{{\mathrm{\&omega;}}_0^2{S}_{G2}^2}{D_2^3}{T}_{G2}+\frac{D_1}{T_{G1}}-\frac{{\mathrm{\&omega;}}_0{S}_{G2}}{D_2})---\left(19\right)$

Because λ has reacted the damping characteristic of system, and λ absolute value is larger, stronger to the damping capacity of system power vibration.Can as drawn a conclusion by (19):

1) in above-mentioned two machine power generating systems, sending end system G is increased ₁inertia T _g1, system damping will reduce, even this regional power grid of wind power integration, stablize, be unfavorable for damping system power oscillation although larger virtual inertia can improve frequency dynamic;

2) receiving end system G is increased ₂inertia T _g2, system damping is enhanced, and namely in this regional power grid, the virtual inertia of Wind turbines controls to have raising frequency dynamic simultaneously and stablizes and system damping two kinds of controlling functions, more effectively improves the stability of electricity generation system.

As the above analysis, in system frequency change procedure, the inertia that receiving end is larger effectively can strengthen system dynamic stability; And at sending end, wind energy turbine set but reduces system damping, easily brings out low-frequency oscillation, make the application of conventional inertia control program be restricted while providing inertia to support.For this problem, propose the Dynamic Inertia Comprehensive Control Technology of variable-speed wind-power unit, this control technology is passed through inertia flexibly and is regulated, even if make wind energy turbine set be in sending end still have inertia and damping two ore control function concurrently.

Figure 8 shows that the oscillating characteristic of two regional generation system Δ f during undamped, by converting Δ f and rate of change thereof, using θ as judging signal, can by its point of four-stage.

$\mathrm{\&theta;}=arctan\frac{d\mathrm{\&Delta;}f/dt}{\mathrm{\&Delta;}f},\mathrm{\&theta;}\&Element;\&lsqb;-\mathrm{\&pi;}/2\mathrm{\&pi;}/2\&rsqb;---\left(20\right)$

According to the judgement signal of θ, the Dynamic Inertia of the controlled inertia type air generating set of sending end controls to be described below:

1) if θ is >0, show that 1., 3. Δ f is in oscillation phase, amplitude increases gradually, and now larger system inertia contributes to reducing oscillation amplitude, and namely Wind turbines possesses the increase that larger virtual inertia effectively can suppress oscillation amplitude.

2) if θ is <0, show that 2., 4. Δ f is in oscillation phase, Δ f will be decreased to 0 gradually by peak swing, and now less system inertia can accelerate the reduction of oscillation amplitude, namely Wind turbines should reduce virtual inertia in this stage, accelerates oscillation amplitude decay.

To sum up, the Dynamic Inertia integrated control strategy of controlled inertia type air generating set by detection signal θ, oscillation phase 1. and 3. in, larger parameter T is set _h, and the stage 2. and 4. in, controling parameters is reduced to T _l, can realize the control objectives suppressing system power vibration, control program is in table 1.

Table 1

Embodiment 2:

Be with the difference of embodiment 1, in embodiment 2, change controlled inertia type air generating set into receiving end, by bus B ₁₁be incorporated to region 2, as shown in phantom in Figure 2.In emulation, wind speed setting is 11m/s, arranges control program 3., the 3rd derivative control coefficient T _vir=20.

As shown in Figure 9, load L ₁the 2.0s moment uprush 200MW make system frequency occur significantly fall.When controlling without additional inertance, after sudden load increase, fluctuating by a relatively large margin appears in system frequency; After adopting the present embodiment, the larger and constant inertia that controlled inertia Wind turbines utilizes it to fictionalize, the amplitude that system frequency is fallen and rate of change are all significantly reduced, and have same frequency modulation effect compared with embodiment 1.

As shown in Figure 10, bus B ₈in the 2.0s moment, it is the three phase short circuit fault of 0.1s that the duration occurs.When controlling without additional inertance, short trouble causes systems stay power oscillation; After adopting the present embodiment, according to the analysis in embodiment 1, Wind turbines utilizes it to fictionalize larger inertia, can increase interregional damping of power oscillation, accelerates oscillatory extinction.

Above-described embodiment is only for explaining explanation the present invention, but not the restriction to rights protection of the present invention, the change of every any unsubstantiality carried out on the basis of the present invention's essence scheme, all should fall within the scope of protection of the present invention.

Claims (1)

1., containing an inertia integrated control method for the electricity generation system of controlled inertia type air generating set, it is characterized in that: comprise the following steps:

Step a: judge described controlled inertia type air generating set and whether the mains frequency of site changes, if so, turns to step b; If not, step a is turned to;

Step b: judge controlled inertia type air generating set described in described electricity generation system and the position of site, if be in sending end, then turn to step c, otherwise turn to steps d;

Step c: the power output regulating described controlled inertia type air generating set, meritorious increment Delta P _ffor:

$\left\{\begin{array}{cc}{\mathrm{\&Delta;P}}_f=-T_H\frac{d\mathrm{\&Delta;}f}{dt}& \arctan \frac{d\mathrm{\&Delta;}f/dt}{\mathrm{\&Delta;}f}>0\\ {\mathrm{\&Delta;P}}_f=-T_L\frac{d\mathrm{\&Delta;}f}{dt}& \arctan \frac{d\mathrm{\&Delta;}f/dt}{\mathrm{\&Delta;}f}<0\end{array}\right.---\left(1\right)$

In formula, T _h, T _lbe the first and second derivative control coefficients, and T _h>T _l>0; Δ f is mains frequency deviation, and d Δ f/dt is the rate of change of described mains frequency deviation relative to time t;

Steps d: the power output regulating described controlled inertia type air generating set, meritorious increment Delta P _ffor:

${\mathrm{\&Delta;P}}_f=-T_{vir}\frac{d\mathrm{\&Delta;}f}{dt}---\left(2\right)$

In formula, T _virit is the 3rd derivative control coefficient.