CN105633984A - Frequency state parameter detection method - Google Patents

Abstract

The invention relates to a frequency state parameter detection method, which comprises the following steps: building a simplified RX model of an asynchronous fan of considering a frequency deviation; obtaining a simplified circuit shaped like a Chinese character 'chang' according to the simplified RX model, and constructing a measurement equation of considering the frequency deviation according to the simplified circuit shaped like the Chinese character 'chang'; constructing a jacobian matrix according to the measurement equation, building a state equation of the frequency state according to the jacobian matrix and an initial frequency state parameter of a power system, and carrying out iterative solving according to the state equation to obtain the state correction of the state equation; and correcting the initial frequency state parameter according to the state correction, and repeatedly building the state equation of the frequency state according to the jacobian matrix and the initial frequency state parameter until the state correction meets the preset convergence condition, and setting the corrected initial frequency state parameter to be the current frequency state of the power system.

Description

Frequency state parameter detection method

Technical field

The present invention relates to Operation of Electric Systems and control techniques field, particularly relate to a kind of frequency state parameter detection method.

Background technology

Because the service performance relative complex of the feature of wind energy random fluctuation and Wind turbines, energy management system (energymanagementsystem, EMS) is proposed new challenge by the access of wind-powered electricity generation. Power system state estimation (stateestimation, SE) is one of Core Feature of EMS, is also the basis of other advanced applied software. The result of state estimation directly affects intelligent analysis and the decision-making of dispatching of power netwoks, and it is the important ring between telemechanical installation and database. The running status of blower fan monitored is the basis ensureing wind power system safe and stable operation, but to be obtained their running statuses accurately, that is perfect with regard to necessarily requiring the function to state estimation to carry out, also claimed condition is estimated constantly to improve according to the development of electrical network simultaneously, thus realizes the level improving the senior application on site program of power system further.

Along with large-scale wind power accesses electrical network, the fluctuation of wind power output not only can change the original trend distribution of electrical network, also can electrical network frequency be made a significant impact, and traditional state estimation model is no longer applicable, the change being difficult to accurately reflect wind power system medium frequency, the accuracy of state estimation is lower.

Summary of the invention

Based on this, it is necessary to for the problem that prior art accuracy is lower, it is provided that a kind of frequency state parameter detection method.

A kind of frequency state parameter detection method, comprises the following steps:

Set up the simplification RX model of the asynchronous blower fan taking into account frequency variation, obtain �� shape according to described simplification RX model and simplify circuit, simplify, according to described �� shape, the measurement equation that circuit structure takes into account frequency variation;

Construct refined gram than matrix according to described measurement equation, set up the state equation of frequency state according to described Ya Ke than the original frequency state parameter of matrix and power system, described state equation is carried out iterative, obtain the status maintenance positive quantity of described state equation;

According to described status maintenance positive quantity, described original frequency state parameter is revised, compound radical of laying equal stress on sets up the step of the state equation of frequency state according to described Ya Ke than matrix and original frequency state parameter, until described status maintenance positive quantity meets default convergence condition, the original frequency state parameter after revising is set to the current frequency state of power system.

Said frequencies state parameter detects, by introducing frequency variation in the simplification RX model of asynchronous blower fan, and obtain �� shape and simplify circuit, the measurement equation that circuit structure takes into account frequency variation is simplified according to described �� shape, construct refined gram according to measurement equation and compare matrix, and obtain the status maintenance positive quantity of state equation, by described status maintenance positive quantity, original frequency state parameter is carried out iterated revision, until status maintenance positive quantity meets default convergence condition, frequency variation is incorporated in state estimation procedure as new quantity of state, can accurately reflect the change of wind power system medium frequency, improve the accuracy of state estimation.

Accompanying drawing explanation

Fig. 1 is the frequency state parameter detection method schema of the present invention;

Fig. 2 is the asynchronous blower fan T-shaped equivalent-circuit diagram taking into account frequency variation variable;

Fig. 3 is that the asynchronous blower fan �� shape taking into account frequency variation variable simplifies circuit.

Embodiment

Below in conjunction with accompanying drawing, the embodiment of the frequency state parameter detection method of the present invention is described.

Fig. 1 is the frequency state parameter detection method schema of the present invention. As shown in Figure 1, described frequency state parameter detection method can comprise the steps:

S1, sets up the simplification RX model of the asynchronous blower fan taking into account frequency variation, obtains �� shape according to described simplification RX model and simplifies circuit, simplifies, according to described �� shape, the measurement equation that circuit structure takes into account frequency variation;

Wherein, the simplification RX model of the asynchronous blower fan taking into account frequency variation is set up by such as under type:

Obtain the network parameter of power system; Described network parameter can comprise bus numbering, title, compensation electric capacity, the branch road number of transmitting line, headend node and end node serial number, series resistance, series reactance, conductance in parallel, shunt susceptance, transformer voltage ratio and impedance, the density of air of wind energy turbine set, wind speed, blower fan type parameter and system original frequency.

According to described network parameter, the state parameter of power system is carried out initialize operation;

The simplification RX model of the asynchronous blower fan taking into account frequency variation is set up according to the state parameter of described network parameter and initialize.

The present invention analyzes the frequency response characteristic of blower fan for the quasi steady state model of asynchronous blower fan. When considering power system frequency deviation variables, the Type Equivalent Circuit Model of aerogenerator is as shown in Figure 2. R in figure₁��R₂And R_mIt is respectively stator resistance, rotor resistance and excitation resistance; X₁��X₂And X_mRepresent stator reactance, rotor reactance and excitation reactance respectively; I₁��I₂And I_mIt is respectively the electric current flowing through stator winding, rotor windings and field copper; S is sliding poor; �� f is frequency variation amount; P_g��Q_gThe wattful power sent for asynchronous generator and wattless power.

In order to simplify calculating, adopt RX model herein. The asynchronous machine of capacity relatively big (being greater than 40kW), due to its X₁<<X_m, and R₁And R_mIt is negligible, can Approximate Equivalent be the �� shape circuit shown in Fig. 3.

In Fig. 3, make X₁₂=X₁+X₂, then the rotor electric current I of RX model is simplified₂, active-power P_gAnd reactive power Q_gIt is respectively:

$I_2=\frac{U}{|R_2/s+{\mathrm{jX}}_{12}(1+\mathrm{\&Delta;}f)|}=\frac{U}{\sqrt{{(R_2/s)}^2+{\&lsqb;X_{12}(1+\mathrm{\&Delta;}f)\&rsqb;}^2}}$

$P_g=-\frac{I_2^2{R}_2}{s}=-\frac{U^2{R}_{2}s}{R_2^2+s^2{X}_{12}^2{(1+\mathrm{\&Delta;}f)}^2}$

$Q_g=-\&lsqb;\frac{U^2}{X_m(1+\mathrm{\&Delta;}f)}+I_2^2{X}_{12}(1+\mathrm{\&Delta;}f)\&rsqb;=-\frac{U^2}{X_m(1+\mathrm{\&Delta;}f)}-\frac{s^2{U}^2{X}_{12}(1+\mathrm{\&Delta;}f)}{s^2{X}_{12}^2{(1+\mathrm{\&Delta;}f)}^2+R_2^2}$

By formula above it will be seen that when sliding difference s or frequency offset �� f changes, P_g��Q_gCapital changes thereupon.

In order to consider that grid side frequency variation is on the impact of synchronous generator, synchronous generator adopts quasi steady state model below:

$P_G=P_{G\_set}-\frac{P_R}{R_R}\mathrm{\&Delta;}f$

$Q_G=Q_{G\_set}+a_Q(-\frac{P_R}{R_R}\mathrm{\&Delta;}f)+b_Q{(-\frac{P_R}{R_R}\mathrm{\&Delta;}f)}^2$

In formula: P_GAnd Q_GRepresent the wattful power value that synchronous generator exports and reactive power value respectively, P_{G_set}And Q_{G_set}It is the initial wattful power value of synchronous generator and reactive power value respectively, P_RIt is specified wattful power value, R_RIt is the speed change rate of corresponding synchronous generator, a_QAnd b_QIt is the idle corresponding adjustment factor of exerting oneself of synchronous generator, the deviation of frequency and rated value when �� f represents systematic steady state.

The quasi steady model of load adopts the static model considering change of frequency, and its multinomial model can be expressed as follows:

$P_L=P_{L\_set}(1+K_p\mathrm{\&Delta;}f)(p_p+p_c(\frac{U_L}{U_{LB}})+p_z{\left(\frac{U_L}{U_{LB}}\right)}^2)$

$Q_L=Q_{L\_set}(1+K_q\mathrm{\&Delta;}f)(q_p+q_c(\frac{U_L}{U_{LB}})+q_z{\left(\frac{U_L}{U_{LB}}\right)}^2)$

In formula: P_LAnd Q_LRepresent the meritorious of this load respectively and without work value, P_{L_set}And Q_{L_set}Represent the meritorious and idle initial value of this load respectively, K_pAnd K_qRepresent the meritorious mediating effect+6 coefficient with idle correspondence of load respectively. p_p��p_c��p_zAnd q_p��q_c��q_zRepresent load model static voltage characteristic coefficient, U_LAnd U_LBIt is voltage operation value and the load voltage value of this load respectively.

Measurement equation can comprise:

Generator injecting power measurement equation is:

$P_{Gi}=P_{G\_set}-\frac{P_R}{R_R}\mathrm{\&Delta;}f+U_i\underset{j=1}{\overset{n}{\&Sigma;}}{U}_j(G_{ij}{\mathrm{cos\&theta;}}_{ij}+B_{ij}{\mathrm{sin\&theta;}}_{ij})$

$Q_{Gi}=Q_{G\_set}+a_Q(-\frac{P_R}{R_R}\mathrm{\&Delta;}f)+b_Q{(-\frac{P_R}{R_R}\mathrm{\&Delta;}f)}^2+U_i\underset{j=1}{\overset{n}{\&Sigma;}}{U}_j(G_{ij}{\mathrm{sin\&theta;}}_{ij}-B_{ij}{\mathrm{cos\&theta;}}_{ij})$

Wherein, P_{G_set}And Q_{G_set}It is the initial wattful power value of synchronous generator and reactive power value respectively, P_RIt is specified wattful power value, R_RIt is the speed change rate of corresponding synchronous generator, a_QAnd b_QIt is the idle corresponding adjustment factor of exerting oneself of synchronous generator, the deviation of frequency and rated value when �� f represents systematic steady state, U_iAnd U_jRepresent the voltage magnitude of node i and j respectively, ��_ijIt is the phase difference of voltage that node i arrives node j, G_ijAnd B_ijThen representing in node admittance battle array the conductance between corresponding node i and j and susceptance, n is system node total number;

Load injecting power measurement equation is:

$P_{Li}=P_{L\_set}(1+K_p\mathrm{\&Delta;}f)(p_p+p_c(\frac{U_L}{U_{LB}})+p_z{\left(\frac{U_L}{U_{LB}}\right)}^2)+U_i\underset{j=1}{\overset{n}{\mathrm{\&Sigma;}}}{U}_j(G_{ij}{\mathrm{cos\&theta;}}_{ij}+B_{ij}{\mathrm{sin\&theta;}}_{ij})$

$Q_{Li}=Q_{L\_set}(1+K_q\mathrm{\&Delta;}f)(q_p+q_c(\frac{U_L}{U_{LB}})+q_z{\left(\frac{U_L}{U_{LB}}\right)}^2)+U_i\underset{j=1}{\overset{n}{\mathrm{\&Sigma;}}}{U}_j(G_{ij}{\mathrm{sin\&theta;}}_{ij}-B_{ij}{\mathrm{cos\&theta;}}_{ij})$

Wherein, P_{L_set}And Q_{L_set}Represent the meritorious and idle initial value of this load respectively, K_pAnd K_qRepresent the meritorious mediating effect+6 coefficient with idle correspondence of load respectively, p_p��p_c��p_zAnd q_p��q_c��q_zRepresent load model static voltage characteristic coefficient, U_LAnd U_LBIt is voltage operation value and the load voltage value of this load respectively;

Asynchronous blower fan injecting power measurement equation is:

$P_{gi}=-\frac{U^2{R}_{2}s}{R_2^2+s^2{X}_{12}^2{(1+\mathrm{\&Delta;}f)}^2}$

$Q_{gi}=-\frac{U^2}{X_m(1+\mathrm{\&Delta;}f)}-\frac{s^2{U}^2{X}_{12}(1+\mathrm{\&Delta;}f)}{s^2{X}_{12}^2{(1+\mathrm{\&Delta;}f)}^2+R_2^2}$

Wherein, P_giAnd Q_giIt is respectively wattful power and wattless power that asynchronous blower fan injects, the deviation of frequency and rated value when �� f represents systematic steady state, R₂For rotor resistance; S is sliding poor, and U is the voltage that blower fan exports, X₁₂=X₁+X₂, X₁And X₂Represent stator reactance and rotor reactance, X respectively_mFor excitation reactance.

S2, construct refined gram according to described measurement equation and compare matrix, set up the state equation of frequency state according to described Ya Ke than the original frequency state parameter of matrix and power system, described state equation is carried out iterative, obtains the status maintenance positive quantity of described state equation;

The real time execution of power system and control need the true operation condition of understanding system, and due to aspects such as measurement and transmission, the raw data obtained exist error unavoidably, and state estimation can improve the precision of data to a certain extent. The basic weighted least-squares of the most basic algorithm (weightedleastsquares of Power system state estimation is proposed from people such as the Xu Huaipi (F.C.Schweppe) of the masschusetts, u.s.a Institute of Technology in 1969, WLS), since state estimation algorithm, weighted least-squares method becomes applies maximum algorithms in Power system state estimation. Its basic thought is the minimum method of estimation as objective criteria of sum of squares taking measurement and the difference measuring estimated value. Basic weighted least-squares method is the most basic skills of Power system state estimation, and the method model is simple, good convergence, estimated quality height, is one of method of being most widely used at present. The deficiency of the method is exactly calculate refined gram than needing manual derivation differential formulas during matrix and to write differential code, works loaded down with trivial details and easily makes mistakes, inefficiency. After frequency variation is as newly-increased quantity of state, refined gram can be more complicated than element, and the shortcoming of the method is also more obvious.

In order to overcome above-mentioned defect, the present invention, when refined gram of structure is than matrix, can adopt automatic differential (AutomaticDifferentiation, AD) technology. Refined gram can be constructed according to described measurement equation to comprise than the step of matrix:

By the position of the refined gram of constant element than in matrix and value storage in a chain table;

According to described measurement equation, and adopt refined gram of AD technique computes than the variable element in matrix;

Position according to described constant element and numerical value, and variable element constructs refined gram and compares matrix.

Application refined gram of AD technique computes, than the variable element in matrix, reads the constant element of corresponding matrix in chain table simultaneously, and refined gram needed for acquisition is compared matrix; Wherein expand refined gram can be than matrix containing quantity of state voltage phase angle ��, voltage magnitude U, the sliding piecemeal differing from s and frequency variation amount �� f:

$H=\left[\begin{array}{cccc}\frac{\&part;P}{\&part;\mathrm{\&theta;}}& \frac{\&part;P}{\&part;U}& \frac{\&part;P}{\&part;s}& \frac{\&part;P}{\&part;\mathrm{\&Delta;}f}\\ \frac{\&part;Q}{\&part;\mathrm{\&theta;}}& \frac{\&part;Q}{\&part;U}& \frac{\&part;Q}{\&part;s}& \frac{\&part;Q}{\&part;\mathrm{\&Delta;}f}\\ \frac{\&part;P_i}{\&part;\mathrm{\&theta;}}& \frac{\&part;P_i}{\&part;U}& \frac{\&part;P_i}{\&part;s}& \frac{\&part;P_i}{\&part;\mathrm{\&Delta;}f}\\ \frac{\&part;Q_i}{\&part;\mathrm{\&theta;}}& \frac{\&part;Q_i}{\&part;U}& \frac{\&part;Q_i}{\&part;s}& \frac{\&part;Q_i}{\&part;\mathrm{\&Delta;}f}\end{array}\right]$

Wherein, P and Q represents that meritorious the exerting oneself that common generator is corresponding is exerted oneself with idle respectively, P_iAnd Q_iIt is respectively corresponding meritorious of the access node i of asynchronous blower fan to exert oneself and idle exert oneself,WithDimension identical with the number of system apoplexy electric field node.

Above-mentioned refined gram than in matrix, P_iComprise the active-power P of the asynchronous blower fan in measurement equation_gi, Q_iComprise the reactive power Q of the asynchronous blower fan in measurement equation_gi. P comprises the active-power P that generator injects_GiWith the active-power P that load injects_Li, Q comprises the reactive power Q that generator injects_GiWith the reactive power Q that load injects_Li��

S3, according to described status maintenance positive quantity, described original frequency state parameter is revised, compound radical of laying equal stress on sets up the step of the state equation of frequency state according to described Ya Ke than matrix and original frequency state parameter, until described status maintenance positive quantity meets default convergence condition, the original frequency state parameter after revising is set to the current frequency state of power system.

Solve following equation and obtain status maintenance positive quantity �� x^(k), chooseAnd revise quantity of state and obtain x^(k+1):

��x^(k)=[H^T(x^(k))WH(x^(k))]^-1H^T(x^(k))W[z-h(x^(k))]

x^(k+1)=x^(k)+��x^(k)

Wherein, k is iteration number of times, �� x^(k)For status maintenance positive quantity during kth time iteration, x is quantity of state, and z is measurement, and h is non-linear measurement function, refined gram that H (x) is h (x) than matrix, T represents the transposition of matrix, and W is diagonal angle weight matrix, W_ii=1/ ��_i ², ��_iFor standard deviation, x^(k)For the quantity of state before kth time iteration, x^(k+1)For the quantity of state after kth time iteration; Measurement z can comprise: the first end wattful power of voltage magnitude, generator active power, generator reactive power, blower fan wattful power, blower fan wattless power, load wattful power, reactive load power, circuit, the first end wattless power of circuit, line end wattful power and line end wattless power.

WhenWhen being less than the convergence precision �� of setting, then calculating and terminate, export state estimation result, otherwise revise quantity of state and carry out kth+1 state estimation, i is the numbering of quantity of state.

The present invention has the following advantages:

(1) frequency variation is incorporated in state estimation procedure as new quantity of state, it is possible to the accurately change of reflection wind power system medium frequency, it is to increase the accuracy of state estimation.

(2) automatically calculated by AD technology and obtain refined gram than matrix, effectively prevent truncation error, it is to increase the counting yield of algorithm and the development efficiency of program.

Each technology feature of the above embodiment can combine arbitrarily, for making description succinct, each all possible combination of technology feature in above-described embodiment is not all described, but, as long as the combination of these technology features does not exist contradiction, all it is considered to be the scope that this specification sheets is recorded.

The above embodiment only have expressed several enforcement modes of the present invention, and it describes comparatively concrete and detailed, but can not therefore be construed as limiting the scope of the patent. , it is also possible to make some distortion and improvement, it should be appreciated that for the person of ordinary skill of the art, without departing from the inventive concept of the premise these all belong to protection scope of the present invention. Therefore, the protection domain of patent of the present invention should be as the criterion with claims.

Claims (10)

1. a frequency state parameter detection method, it is characterised in that, comprise the following steps:

Set up the simplification RX model of the asynchronous blower fan taking into account frequency variation, obtain �� shape according to described simplification RX model and simplify circuit, simplify, according to described �� shape, the measurement equation that circuit structure takes into account frequency variation;

Construct refined gram than matrix according to described measurement equation, set up the state equation of frequency state according to described Ya Ke than the original frequency state parameter of matrix and power system, described state equation is carried out iterative, obtain the status maintenance positive quantity of described state equation;

According to described status maintenance positive quantity, described original frequency state parameter is revised, compound radical of laying equal stress on sets up the step of the state equation of frequency state according to described Ya Ke than matrix and original frequency state parameter, until described status maintenance positive quantity meets default convergence condition, the original frequency state parameter after revising is set to the current frequency state of power system.

2. frequency state parameter detection method according to claim 1, it is characterised in that, construct refined gram according to described measurement equation and comprise than the step of matrix:

By the position of the refined gram of constant element than in matrix and value storage in a chain table;

According to described measurement equation, and adopt refined gram of AD technique computes than the variable element in matrix;

Position according to described constant element and numerical value, and variable element constructs refined gram and compares matrix.

3. frequency state parameter detection method according to claim 1, it is characterised in that, the step of the simplification RX model setting up the asynchronous blower fan taking into account frequency variation comprises:

Obtain the network parameter of power system;

According to described network parameter, the state parameter of power system is carried out initialize operation;

The simplification RX model of the asynchronous blower fan taking into account frequency variation is set up according to the state parameter of described network parameter and initialize.

4. frequency state parameter detection method according to claim 3, it is characterized in that, described network parameter comprises bus numbering, title, compensation electric capacity, the branch road number of transmitting line, headend node and end node serial number, series resistance, series reactance, conductance in parallel, shunt susceptance, transformer voltage ratio and impedance, the density of air of wind energy turbine set, wind speed, blower fan type parameter and system original frequency.

5. frequency state parameter detection method according to claim 1, it is characterised in that, it is to construct the step of the measurement equation taking into account frequency variation comprises:

Set up generator injecting power measurement equation, load injecting power measurement equation and asynchronous blower fan injecting power measurement equation;

The measurement equation of frequency variation is taken into account according to described generator injecting power measurement equation, load injecting power measurement equation and asynchronous blower fan injecting power measurement equation structure.

6. frequency state parameter detection method according to claim 5, it is characterised in that, described generator injecting power measurement equation is:

$P_{Gi}=P_{G\_set}-\frac{P_R}{R_R}\mathrm{\&Delta;}f+U_i\underset{j=1}{\overset{n}{\&Sigma;}}{U}_j(G_{ij}{\mathrm{cos\&theta;}}_{ij}+B_{ij}{\mathrm{sin\&theta;}}_{ij})$

$Q_{Gi}=Q_{G\_set}+a_Q(-\frac{P_R}{R_R}\mathrm{\&Delta;}f)+b_Q{(-\frac{P_R}{R_R}\mathrm{\&Delta;}f)}^2+U_i\underset{j=1}{\overset{n}{\&Sigma;}}{U}_j(G_{ij}{\mathrm{cos\&theta;}}_{ij}-B_{ij}{\mathrm{sin\&theta;}}_{ij})$

Wherein, P_GiAnd Q_GiIt is respectively wattful power and wattless power that generator injects, P_{G_set}And Q_{G_set}It is the initial wattful power value of synchronous generator and reactive power value respectively, P_RIt is specified wattful power value, R_RIt is the speed change rate of corresponding synchronous generator, a_QAnd b_QIt is the idle corresponding adjustment factor of exerting oneself of synchronous generator, the deviation of frequency and rated value when �� f represents systematic steady state, U_iAnd U_jRepresent the voltage magnitude of node i and j respectively, ��_ijIt is the phase difference of voltage that node i arrives node j, G_ijAnd B_ijRepresenting in node admittance battle array the conductance between corresponding node i and j and susceptance, n is system node total number.

7. frequency state parameter detection method according to claim 5, it is characterised in that, described load injecting power measurement equation is:

$P_{Li}=P_{L\_set}(1+K_p\mathrm{\&Delta;}f)(p_p+p_c(\frac{U_L}{U_{LB}})+p_z{\left(\frac{U_L}{U_{LB}}\right)}^2)+U_i\underset{j=1}{\overset{n}{\&Sigma;}}{U}_j(G_{ij}{\mathrm{cos\&theta;}}_{ij}+B_{ij}{\mathrm{sin\&theta;}}_{ij})$

$Q_{Li}=Q_{L\_set}(1+K_q\mathrm{\&Delta;}f)(q_p+q_c(\frac{U_L}{U_{LB}})+q_z{\left(\frac{U_L}{U_{LB}}\right)}^2)+U_i\underset{j=1}{\overset{n}{\&Sigma;}}{U}_j(G_{ij}{\mathrm{sin\&theta;}}_{ij}-B_{ij}{\mathrm{cos\&theta;}}_{ij})$

Wherein, P_LiAnd Q_LiIt is respectively wattful power and wattless power that load injects, P_{L_set}And Q_{L_set}Represent the meritorious and idle initial value of this load respectively, the deviation of frequency and rated value when �� f represents systematic steady state, U_iAnd U_jRepresent the voltage magnitude of node i and j respectively, ��_ijIt is the phase difference of voltage that node i arrives node j, G_ijAnd B_ijRepresent in node admittance battle array the conductance between corresponding node i and j and susceptance, K_pAnd K_qRepresent the meritorious mediating effect+6 coefficient with idle correspondence of load respectively, p_p��p_c��p_zAnd q_p��q_c��q_zRepresent load model static voltage characteristic coefficient, U_LAnd U_LBIt is voltage operation value and the load voltage value of this load respectively.

8. frequency state parameter detection method according to claim 5, it is characterised in that, described asynchronous blower fan injecting power measurement equation is:

$P_{gi}=-\frac{U^2{R}_{2}s}{R_2^2+s^2{X}_{12}^2{(1+\mathrm{\&Delta;}f)}^2}$

$Q_{gi}=-\frac{U^2}{X_m(1+\mathrm{\&Delta;}f)}-\frac{s^2{U}^2{X}_{12}(1+\mathrm{\&Delta;}f)}{s^2{X}_{12}^2{(1+\mathrm{\&Delta;}f)}^2+R_2^2}$

Wherein, P_giAnd Q_giIt is respectively wattful power and wattless power that asynchronous blower fan injects, the deviation of frequency and rated value when �� f represents systematic steady state, R₂For rotor resistance; S is sliding poor, and U is the voltage that blower fan exports, X₁₂=X₁+X₂, X₁And X₂Represent stator reactance and rotor reactance, X respectively_mFor excitation reactance.

9. frequency state parameter detection method according to claim 2, it is characterised in that, described state equation is:

��x^(k)=[H^T(x^(k))WH(x^(k))]^-1H^T(x^(k))W[z-h(x^(k))]

x^(k+1)=x^(k)+��x^(k)

Wherein, k is iteration number of times, �� x^(k)For status maintenance positive quantity during kth time iteration, x is quantity of state, and z is measurement, and h is non-linear measurement function, refined gram that H (x) is h (x) than matrix, T represents the transposition of matrix, and W is diagonal angle weight matrix, W_ii=1/ ��_i ², ��_iFor standard deviation, x^(k)For the quantity of state before kth time iteration, x^(k+1)For the quantity of state after kth time iteration.

10. frequency state parameter detection method according to claim 9, it is characterised in that, described convergence condition is:

$|{\mathrm{\&Delta;x}}_i^{\left(k\right)}{|}_{max}<\mathrm{\&lambda;}$

Wherein, �� is the convergence precision of setting, and i is the numbering of quantity of state.