CN103217904A - Control method of wide-area measurement power system limited in communication - Google Patents

Abstract

Provided is a control method of a wide-area measurement power system limited in communication. The steps of the control method includes that (1) a communication limit problem is considered in a power system model, and a traditional power system model is changed into a power system switching system model limited in the communication; and (2) stability analysis is carried out on the obtained power switching system model by means of Lyapunov stability theories and a linear matrix inequality method so that inequalities of (3), (4) and (5) are satisfied, and obtained controller gain is analyzed and verified. On the condition that stability of the power system with the communication limit problem is guaranteed, communication network congestion is effectively avoided, building consumption in a communication network is reduced, and economic efficiency is improved.

Description

A kind of have a limited wide area measurement electric power system control method of communication

Technical field

The present invention relates to the wide area field of power system control, be specifically related to a kind of control method that is applicable to wide area measurement electric system with the limited problem of communication.

Background technology

Along with the Da Qu of electrical networks such as northeast, North China, south is interconnected, China has realized the power system development strategy of " transferring electricity from the west to the east, north and south supply mutually, the whole nation interconnected " substantially.The interconnected of electrical network can improve power supply reliability effectively, optimizes allocation of resources, and saves cost of electricity-generating, produces bigger economic benefit.Yet also make the structure and the running environment more sophisticated of whole electrical network, the power system security problem is also more and more between extensive area, and simultaneously, the various extreme disaster that takes place frequently has also brought some uncertain factors for the operation of electric system.Undoubtedly, electric system is its top priority with dynamic security and stable operation all, and the operating analysis of electric system and control, all based on state measurement.

Utilization synchronous phasor measurement (PMU, Phasor Measurement Unit) WAMS of technology (WAMS, Wide-Area Measurement System) can satisfy two development new demands of electric system: the temporal wide area that reaches synchronously on the space.The real-time effectiveness of WAMS is brought up to dynamic level to the monitoring level of electric system by quiescent levels, for the safe and stable operation of electric system has been created good condition.At present, layouting and the construction of WAMS on a large scale of PMU all stepped up in countries in the world, and some areas have embodied the advantage of its dynamic real-time.Be the effective operation of guarantee WAMS and the safety and stability of whole electric power networks, it is prerequisite that Wide-area Measurement Information is transmitted in communication network in real time effectively.Yet, WAMS is a baroque network system of being made up of multiple telecommunication media (as line of electric force, optical fiber, microwave and satellite etc.), inevitably has some information transmission problems, as propagation delay time, data-bag lost, problems such as traffic congestion.For traffic congestion problem in the WAMS, domestic and international research is also fewer, concentrates on the communication protocol aspect mostly, and all requires wide-area communication network to adopt the mode of asynchronous transmission (ATM, Asynchronous Transfer Mode).But, it is key switching technology with ATM that the at present domestic data communication network that has only small part to economize has adopted in wide area network, and most laboratories does not adopt, and the ATM transfer efficiency has only 90.6%, efficient is lower, and this just makes the scheme of utilizing the ATM mode be difficult for promoting.

Summary of the invention

The objective of the invention is to solve the traffic congestion problem in the wide area measurement electric system, can under the situation that part wide area measurement information can not send in real time, guarantee the stability of whole electric system simultaneously.The present invention proposes a kind of limited wide area measurement electric power system control method of communication that has.

The technical solution adopted for the present invention to solve the technical problems is:

A kind of have a limited wide area measurement electric power system control method of communication, comprises the steps:

1) in the middle of WAMS, the collection of information is finished by PMU, PMU measured electric system state quantity with the fixing sampling period, under the situation of the limited problem of not communicating by letter, was that the closed loop electric system discretize state-space model in sampling period is with T:

$\left\{\begin{array}{c}x(k+1)={\hat{A}}_{i}x\left(k\right)+{\hat{B}}_{i}u\left(k\right)\\ u\left(k\right)=K_{i}x\left(k\right)\end{array}\right.----\left(1\right)$

Wherein,

K represents k transmission cycle kT;

The constant matrices of representing i platform motor;

The electric system of x (k+1) expression wide area is in the state variable in k+1 cycle;

The feedback variable of u (k) expression system;

K _iThe feedback gain of the i platform motor that expression is asked.

Can not effectively be transferred to state feedback controller at the limited situation lower part quantity of state of generation communication, this moment, the state-space model of system was as follows:

$\left\{\begin{array}{c}x(k+1)={\hat{A}}_{i}x\left(k\right)+{\hat{B}}_{i}u\left(k\right)\\ u\left(k\right)=k_i\stackrel{\‾}{x}\left(k\right)\end{array}\right.----\left(2\right)$

Wherein,

System state variables under the limited situation of expression communication, M _σ(k) the expression system is at the communication matrix in k sampling period.

2) adopt Lyapunov stability theory and the LMI method whole wide area electric system The Sufficient Conditions of Stability under the limited problem of communication that can be guaranteed:

${\mathrm{\τ}}_a>{\mathrm{\τ}}_a^{*}=\frac{\ln \mathrm{\μ}}{2\ln {\mathrm{\λ}}^{-1}}---\left(3\right)$

P _a≤μP _b (4)

$\left[\begin{array}{cc}-{\mathrm{\&lambda;}}^2{P}_j& *\\ Y^T{\hat{A}}_i+{\mathrm{ZM}}_j& -Y-Y^T+P_j\end{array}\right]<0---\left(5\right)$

Can solve matrix Z and Y by the LMI tool box among the Matlab, then the controller gain of being asked is

The gain that will obtain is designed in the state feedback controller adding system again, makes system keep stable.

Technical conceive of the present invention is: the Stability Control with wide area measurement electric system under the limited WAMS modeling of communication and the limited problem of communicating by letter.

The mathematical model of synchronous generator has a variety of, and as classical model 3～8 rank models etc., in Electrical Power System Dynamic was analyzed, excitation system was dynamic when taking into account, and when avoiding dimension calamity that high-order model brings again, third-order model is a good selection.Therefore, the present invention chooses third-order model WAMS is studied.For the electric system that many generators are arranged, the model of i platform motor can be expressed as:

$\left\{\begin{array}{c}{\stackrel{.}{\mathrm{\&delta;}}}_i={\mathrm{\&omega;}}_{i0}({\mathrm{\&omega;}}_i-1)\\ {\stackrel{.}{\mathrm{\&omega;}}}_i=\frac{1}{M_i}[P_{\mathrm{mi}}-P_{\mathrm{ei}}-D_i({\mathrm{\&omega;}}_i-1)]\\ {\stackrel{.}{E}}_{\mathrm{qi}}^{\&prime;}=\frac{1}{T_{d0i}^{\&prime;}}(E_{\mathrm{fdi}0}-E_{\mathrm{qi}}+u_{\mathrm{fi}})\end{array}\right.---\left(6\right)$

Wherein, δ _iBe the rotor angle of i platform motor, unit is rad; ω _iPerunit value for the angular velocity of motor; M _iInertia time constant for motor; P _MiPerunit value for electromechanics power; P _EiIt is the perunit value of motor excitation power; D _iBe the motor damping coefficient; E ' _QiBe synchronous motor q axle transient potential perunit value; T ' _D0iBe field copper transient state time constant; E _Fdi0Be field voltage stable state perunit value; E _QiBe q axle electromotive force perunit value; u _FiPerunit value for the field voltage increment;

$P_{\mathrm{ei}}=\frac{E_{\mathrm{qi}}^{\&prime;}{V}_{\mathrm{ti}}\sin {\mathrm{\&delta;}}_i}{x_{\mathrm{di}}^{\&prime;}}+(\frac{1}{x_{\mathrm{qi}}}-\frac{1}{x_{\mathrm{di}}^{\&prime;}})\frac{V_{\mathrm{ti}}^2\sin 2{\mathrm{\&delta;}}_i}{2};$

E _qi=E′ _qi+(x _di-x′ _di)i _di；

$i_{\mathrm{di}}=\frac{E_{\mathrm{qi}}^{\&prime;}-V_{\mathrm{ti}}\cos {\mathrm{\&delta;}}_i}{x_{\mathrm{di}}^{\&prime;}}.$

The non-linear electric power system models in 3 rank (6) in the linearization of equilibrium point place, are obtained following POWER SYSTEM STATE spatial model:

$\left\{\begin{array}{c}\stackrel{.}{x}=A_{i}x+B_{i}u\\ u=K_{i}x\end{array}\right.---\left(7\right)$

Wherein, x=[Δ δ _iΔ ω _iΔ E ' _Qi] ^ΤBe state variable, u=Δ u _FiBe control variable, A _i, B _iBe respectively constant matrices, K _iBe controller gain.

$A_i=\left[\begin{array}{ccc}0& {\mathrm{\&omega;}}_{0i}& 0\\ \frac{P_1}{M_i}& -\frac{D_i}{M_i}& \frac{P_2}{M_i}\\ \frac{P_3}{T_{d0i}^{\&prime;}}& 0& \frac{P_4}{T_{d0i}^{\&prime;}}\end{array}\right]$

$B_i={\left[\begin{array}{ccc}0& 0& \frac{1}{T_{d0i}^{\&prime;}}\end{array}\right]}^T$

Wherein,

${\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HDA00003048464200031.png,HDA00003048464200041.png"\; state="\{\{state\}\}">P</figure-callout>}}_1=-\frac{E_{\mathrm{qi}}^{\&prime;}{V}_{\mathrm{ti}}\cos {\mathrm{\&delta;}}_i}{x_{\mathrm{di}}^{\&prime;}}-(\frac{1}{x_{\mathrm{qi}}}-\frac{1}{x_{\mathrm{di}}^{\text{\&prime;}}})V_{\mathrm{ti}}^2\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA00003048464200031.png,HDA00003048464200041.png"\; state="\{\{state\}\}">cos</figure-callout>}2{\mathrm{\&delta;}}_i$

${\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA00003048464200031.png,HDA00003048464200041.png"\; state="\{\{state\}\}">P</figure-callout>}}_2=-\frac{V_{\mathrm{ti}}\sin {\mathrm{\&delta;}}_i}{x_{\mathrm{di}}^{\&prime;}}$

$P_3=\frac{x_{\mathrm{di}}^{\&prime;}-x_{\mathrm{di}}}{x_{\mathrm{di}}^{\&prime;}}{V}_{\mathrm{ti}}\sin {\mathrm{\&delta;}}_i$

${\mathrm{<figure-callout\; id="4"\; label="P"\; filenames="HDA00003048464200031.png,HDA00003048464200041.png"\; state="\{\{state\}\}">P</figure-callout>}}_4=-\frac{x_{\mathrm{di}}}{x_{\mathrm{di}}^{\&prime;}}$

M _i=2H _i

ω _0i, E ' _Qi, V _Ti, δ _iBe equilibrium point place value.

In the middle of the wide area measurement electric system, the collection of information is finished by PMU, and PMU measured electric system state quantity with the fixing sampling period, then was that the electric system discretization model in sampling period is (1) formula with T, wherein, ${\hat{A}}_i=e^{A_{i}T},{\hat{B}}_i=\left({\&Integral;}_0^T{e}^{A_i\mathrm{\&sigma;}}\mathrm{d\&sigma;}\right)B_i.$

The metrical information that PMU obtains is transferred to monitoring central station by communication network.Yet, because the limited bandwidth of communication network, the transmission route that the PMU of different genset need obtain data by the competition network transmission route, thereby can cause in the same sampling period, having only limited PMU to send data by network, promptly for a WAMS with n PMU, under the limited situation of medium access, (l＜n) information of individual PMU collection can be finished transmission by network to have only l in each transmission cycle.

Introduce two value functions

Represent j (j=1,2 ... n) individual PMU unit is in the information transmission situation of k transmission cycle, wherein, σ _j(k)=1 j PMU unit of expression can communicate σ in k transmission cycle _j(k)=0 j PMU unit of expression can not communicate in k transmission cycle, and in a communication cycle

So, the signal intelligence that has the WAMS of n PMU unit in k transmission cycle can be expressed as communication sequence σ (k)=[σ ₁(k), σ ₂(k) ..., σ _n(k)].Note σ (k) institute might value set be Θ, then gather among the Θ and have

Individual value, wherein

Be illustrated in the number of combinations of getting l in n the element.Introduce following communication sequence matrix form:

M _σ(k)=diag{σ ₁(k),σ ₂(k),...,σ _n(k)} (8)

Wherein, M _σ(k) be by σ _j(k) diagonal matrix of element composition.

Therefore, considering under the limited situation of communication, the closed loop NETWORK STRUCTURE PRESERVING POWER SYSTEM as shown in Figure 1, wherein, x (k) is the state variable of system after the discretize, M _σ(k) be the communication sequence of k transmission cycle, u (k) is the output of controller.This moment, the power system state equation was:

$\left\{\begin{array}{c}x(k+1)={\hat{A}}_{i}x\left(k\right)+{\hat{B}}_{i}u\left(k\right)\\ u\left(k\right)=K_i\stackrel{\&OverBar;}{x}\left(k\right)\end{array}\right.$

For a system with a plurality of communication cycles, the communication sequence matrix of m communication cycle is M _{σ m}, corresponding following electric system closed loop model:

$x(k+1)=({\hat{A}}_i+{\hat{B}}_i{K}_i{M}_{\mathrm{\&sigma;m}})x\left(k\right)---\left(9\right)$

For system (9), because σ (k) is a vector, in order to represent that conveniently, definition is mapping one by one

Because σ (k) has

So value among the set Θ of individual element is definition

Wherein element is corresponding one by one with element among the Θ.Based on this mapping, closed-loop system (9) but equivalent representation be:

S _ρ(k):x(k+1)=Φ _ρ(k)x(k) (10)

Wherein, ρ (k) is a switching signal.

J ∈ H, M _jCommunication sequence matrix during expression ρ (k)=j.

For above-mentioned switched system with a plurality of subsystems, by the Lyapunov stability theory as can be known, if, have matrix P to j ∈ H arbitrarily _j0, make with lower inequality

${\mathrm{\&Phi;}}_j^T{P}_j{\mathrm{\&Phi;}}_j-{\mathrm{\&lambda;}}^2{P}_j<0---\left(11\right)$

Set up, then the subsystem S of system (10) _jStable.Wherein, scalar lambda＜1.

For matrix A and P arbitrarily〉0, formula A ^TPA-P＜0 sets up, and and if only if exists matrix G, makes following MATRIX INEQUALITIES set up:

$\left[\begin{array}{cc}-(G+G^T)+P& G^{T}A\\ A^{T}G& -P\end{array}\right]<0---\left(12\right)$

Then, formula (11) can be converted into:

$\left[\begin{array}{cc}-{\mathrm{\&lambda;}}^2{P}_j& *\\ Y^T{\hat{A}}_i+{\mathrm{ZM}}_j& -Y-Y^T+P_j\end{array}\right]<0$

For above-mentioned switched system, stable in order to make total system, also need average residence time τ _aSatisfy (3) formula, and P _a≤ μ P _b, a wherein, b ∈ H, μ are not less than 1 scalar.Can be as the lower inequality group:

$\left\{\begin{array}{c}\left[\begin{array}{cc}-{\mathrm{\&lambda;}}^2{P}_j& *\\ Y^T({\hat{A}}_i+{\hat{B}}_i{K}_i{M}_j)& -Y-Y^T+P_j\end{array}\right]<0\\ P_a\&le;{\mathrm{\&mu;P}}_b\end{array}\right.---\left(13\right)$

Wherein, Y is any matrix of corresponding dimension.The defining variable matrix

Formula (13) can change into system stability constraint inequality (4), (5), and satisfied (3) formula of average residence time, can solve the controller gain K that is asked _i

From technique scheme as can be seen, beneficial effect of the present invention mainly shows: can guarantee the stability of wide area electric system under the communication confined condition, the efficient utilization of communication channel has effectively avoided communication network congested, reduce the consumption in the communication network development, had economy.

Description of drawings

Fig. 1 is the limited POWER SYSTEM STATE feedback control structure figure of communication that has of the present invention.

Fig. 2 is four machines, two district system synoptic diagram of the present invention.

Fig. 3 is the mechanical output and the exciting power difference P of four motors when not adding controller of the present invention _aFigure.

Fig. 4 is the rotor velocity ω figure of four motors behind the adding controller of the present invention.

Fig. 5 is the mechanical output and the exciting power difference P of four motors behind the adding controller of the present invention _aFigure.

Fig. 6 is the set end voltage V of four motors behind the adding controller of the present invention _tFigure.

Embodiment

Below in conjunction with accompanying drawing the present invention is further described.

Embodiment

The present invention is an example with four machines, the two regional electric system of Kundur, verifies the control algolithm that is proposed in Simulink, and four machines, two district system structural drawing as shown in Figure 2.

Native system comprises two similar zones, and each zone comprises the unit of two couplings, and the rated power of each unit is 900MVA, and rated voltage is 20KV, and the ratio of damping D of motor is 0, and each motor major parameter perunit value is as follows:

X _d=1.8 X _q=1.7 X _l=0.2 X′ _d=0.3

X′ _q=0.55 X′′ _d=0.25 X′′ _q=0.25 R _a=0.0025

T′ _d0=8.0s T′ _q0=0.4s T′′ _d0=0.03s T′′ _q0=0.05s

H _G1=6.5 H _G2=6.5 H _G3=6.175 H _G4=6.175

Transformer rated power is 900MVA, and the transformation grade is 20KV/230KV, and the impedance perunit value is 0+j0.15.The rated voltage of power transmission line is 230KV, each transmission line length as shown in Figure 2, the transmission line parameter perunit value is as follows under 100MVA and 230KV reference value:

r=0.0001pu/km x _L=0.001pu/km b _C=0.00175pu/km

When system moved, zone one carried the power of 400MV to zone two, and the power that each motor sends is as follows:

G ₁:P=700MW Q=185MVAr E _t=1.03∠20.2°

G ₂:P=700MW Q=235MVAr E _t=1.01∠10.5°

G ₃:P=719MW Q=176MVAr E _t=1.03∠-6.8°

G ₄:P=700MW Q=202MVAr E _t=1.01∠-17.0°

The power of system load is as follows:

Load 1:P _L=967MW Q _L=100MVAr Q _C=200MVAr

Load 2:P _L=1767MW Q _L=100MVAr Q _C=350MVAr

Communicate by letter when limited when four machines, two district system generation multiple electric motors, system can not stable operation as shown in Figure 3.Consider the coupling of two motors in the single zone, choose communication sequence by the zone.Adopt the state variable in three rank motor models, two zones to be respectively:

x ₁=[Δδ ₁ Δω ₁ ΔE′ _q1 Δδ ₂ Δω ₂ ΔE′ _q2] ^Τ

x ₂=[Δδ ₃ Δω ₃ ΔE′ _q3 Δδ ₄ Δω ₄ ΔE′ _q4] ^Τ

Specifically realize Stability Control as follows:

Step S1: operation four machines two district system models in Simulink, when the limited problem of communication took place, system operated in the equilibrium point place, and this moment, system balancing point place value was:

Model in the linearization of equilibrium point place, is obtained the state-space model of system, as (7) formula.

Zone one matrix of coefficients:

${\stackrel{\&OverBar;}{A}}_1=\left[\begin{array}{cc}{A}_1& 0\\ 0& A_2\end{array}\right]=\left[\begin{array}{cccccc}0& 1& 0& 0& 0& 0\\ -0.1712& 0& -0.1916& 0& 0& 0\\ -0.467& 0& -0.75& 0& 0& 0\\ 0& 0& 0& 0& 1& 0\\ 0& 0& 0& -0.1691& 0& -0.1881\\ 0& 0& 0& -0.458& 0& -0.75\end{array}\right]$

${\stackrel{\&OverBar;}{B}}_1={\left[\begin{array}{cc}{B}_1^T& B_2^T\end{array}\right]}^T={\left[\begin{array}{cccccc}0& 0& 0.125& 0& 0& 0.125\end{array}\right]}^T$

Zone two matrix of coefficients:

${\stackrel{\&OverBar;}{A}}_2=\left[\begin{array}{cccccc}0& 1& 0& 0& 0& 0\\ -0.1840& 0& -0.2054& 0& 0& 0\\ -0.476& 0& -0.75& 0& 0& 0\\ 0& 0& 0& 0& 1& 0\\ 0& 0& 0& -0.1811& 0& -0.2031\\ 0& 0& 0& -0.470& 0& -0.75\end{array}\right]$

${\stackrel{\&OverBar;}{B}}_2={\left[\begin{array}{cccccc}0& 0& 0.125& 0& 0& 0.125\end{array}\right]}^T$

With the electric system closed loop state-space model discretize that obtains, choosing T=0.015s is the sampling period, by formula ${\hat{A}}_i=e^{{\stackrel{\&OverBar;}{A}}_{i}T},{\hat{B}}_i=\left({\&Integral;}_0^T{e}^{{\stackrel{\&OverBar;}{A}}_i\mathrm{\&sigma;}}\mathrm{d\&sigma;}\right){\stackrel{\&OverBar;}{B}}_i$ Can get:

${\hat{A}}_1=\left[\begin{array}{cccccc}1.00& 0.015& 0& 0& 0& 0\\ -0.0026& 1.00& -0.0029& 0& 0& 0\\ -0.007& -0.0001& 0.9888& 0& 0& 0\\ 0& 0& 0& 1.00& 0.015& 0\\ 0& 0& 0& -0.0024& 1.00& -0.0028\\ 0& 0& 0& -0.0068& -0.0001& 0.9888\end{array}\right]$

${\hat{B}}_1={\left[\begin{array}{cccccc}0& 0& 0.186& 0& 0& 0.186\end{array}\right]}^T$

${\hat{A}}_2=\left[\begin{array}{cccccc}1.00& 0.015& 0& 0& 0& 0\\ -0.0027& 1.00& -0.0031& 0& 0& 0\\ -0.0071& -0.0001& 0.9888& 0& 0& 0\\ 0& 0& 0& 1.00& 0.015& 0\\ 0& 0& 0& -0.0027& 1.00& -0.003\\ 0& 0& 0& -0.0070& -0.0001& 0.9888\end{array}\right]$

${\hat{B}}_2={\left[\begin{array}{cccccc}0& 0& 0.186& 0& 0& 0.186\end{array}\right]}^T$

Can obtain electric system discretization model shown in (1) formula this moment.

Choose suitable communication sequence, make the average residence time of system satisfy (3) formula.

For zone one, 6 state variables are arranged, when generation communication is limited, suppose can only transmit in each transmission cycle the value of 5 quantity of states, then information transmits following 6 kinds of situations:

S ₁→{1 2 3 4 5}S ₂→{1 2 3 4 6}S ₃→{1 2 3 5 6}

S ₄→{1 2 4 5 6}S ₅→{1 3 4 5 6}S ₆→{2 3 4 5 6}

Expression respectively: the 6th variable can not transmit; The 5th variable can not transmit; The 4th variable can not transmit; The 3rd variable can not transmit; The 2nd variable can not transmit; The 1st variable can not transmit.

Each transmission cycle is got T=0.015s, μ=1.58, and λ=0.9 is chosen 1200 cycles system is carried out emulation, by the following communication subsystem of choosing:

As seen system has been switched 7 times in 1200 transmission cycles, average residence time τ _a=1200/7=171.43s, obviously

Satisfy inequality (3).

Step S2: bring parameter into inequality (13), the controller gain in zone one can be obtained in the LMI tool box among the utilization Matlab:

K ₁=[0.5607 0.1201 -79.55 0.5499 0.1178 -77.59]

In like manner can get regional two controller gain:

K ₂=[0.5715 0.1285 -78.37 0.5643 0.1270 -79.59]

Resulting gain is designed to state feedback controller, is added in four machines, the two region S imulink models, observe simulation waveform and whether satisfy the stability of power system requirement.System can keep stable after adding controller as can be seen from Fig. 4, Fig. 5, Fig. 6.

Fig. 4 is the rotor velocity ω of four motors behind the adding controller of the present invention.Incipient stage is because the switching of subsystem makes the value fluctuation of ω bigger, but all in all the running status of four motors is all drawn close to equilibrium point.The angular velocity omega of motor has carried out the transition to equilibrium point 0.9987 (pu) from initial value 0.999 (pu) among the figure, and amplitude of variation is very little, can not cause the vibration of motor.

Fig. 5 is the mechanical output and the exciting power difference P of four motors behind the adding controller of the present invention _aAs can be seen from the figure P _aThrough the concussion of short time, finally get back to 0 point.

Fig. 6 is the set end voltage V of four motors behind the adding controller of the present invention _tBecause identical communication sequence one and two has been chosen in the zone, as can be seen from the figure two different levels of height, but all reached equilibrium point separately, satisfy the requirement of power system stability operation.

What more than set forth is the example that the present invention provides, and simulation result has embodied technical scheme proposed by the invention and had good control effect for four electro-mechanical force systems.It is pointed out that the present invention is not only limited to the foregoing description, have the limited multi-machine power system of communication, adopt technical scheme of the present invention, all can effectively avoid communication channel congestion, guarantee stability of power system for other.

Claims (1)

1. one kind has the limited wide area measurement electric power system control method of communication, and it is characterized in that: described control method may further comprise the steps:

1) in the middle of WAMS, the collection of information is finished by PMU, PMU measured electric system state quantity with the fixing sampling period, under the situation of the limited problem of not communicating by letter, was that the closed loop electric system discretize state-space model in sampling period is with T:

$\left\{\begin{array}{c}x(k+1)={\hat{A}}_{i}x\left(k\right)+{\hat{B}}_{i}u\left(k\right)\\ u\left(k\right)=K_{i}x\left(k\right)\end{array}\right.$

Wherein,

K represents k transmission cycle kT;

The constant matrices of representing i platform motor;

The electric system of x (k+1) expression wide area is in the state variable in k+1 cycle;

The feedback variable of u (k) expression system;

K _iThe feedback gain of the i platform motor that expression is asked.

Can not effectively be transferred to state feedback controller at the limited situation lower part quantity of state of generation communication, this moment, the state-space model of system was as follows:

$\left\{\begin{array}{c}x(k+1)={\hat{A}}_{i}x\left(k\right)+{\hat{B}}_{i}u\left(k\right)\\ u\left(k\right)=K_i\stackrel{\&OverBar;}{x}\left(k\right)\end{array}\right.$

Wherein, System state variables under the limited situation of expression communication, M _σ(k) the expression system is at the communication matrix in k sampling period.

2) adopt Lyapunov stability theory and the LMI method whole wide area electric system The Sufficient Conditions of Stability under the limited problem of communication that can be guaranteed:

${\mathrm{\&tau;}}_a>{\mathrm{\&tau;}}_a^{*}=\frac{\ln \mathrm{\&mu;}}{2\ln {\mathrm{\&lambda;}}^{-1}}$

P _a≤μP _b

$\left[\begin{array}{cc}{-\mathrm{\&lambda;}}^2{P}_j& *\\ Y^T\widehat{A_i}+{\mathrm{ZM}}_j& -Y-Y^T+P_j\end{array}\right]<0$

Can solve matrix Z and Y by the LMI tool box among the Matlab, then the controller gain of being asked is

The gain that will obtain is designed in the state feedback controller adding system again, makes system keep stable.

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