New energy multi-station active and reactive power coordinated control method and system based on equivalent parameters

Abstract

The application discloses a new energy multi-station active and reactive power coordinated control method and system based on equivalent parameters, and on the basis of distributed independent response of each station, adopts an additional control mode of centralized decision to improve dynamic voltage frequency stability characteristics of a power system.The method comprises the following steps: adopting a system identification method to correct system equivalent parameters issued by a dispatching center in real time and to estimate equivalent active power imbalance at a grid-connected point, constructing a grid-connected point frequency and voltage control model on the basis, calculating a station coordinated control strategy by using the grid-connected point frequency and voltage control model, realizing coordinated control of active frequency, reactive voltage and both, and actively supporting system voltage frequency safety and stability in real time.The application realizes effective support for dynamic frequency and voltage of the power system through active and reactive power coordinated control of the new energy multi-station.

Description

Technical Field

[0001] This invention belongs to the field of power system safety and stability analysis and control technology, specifically relating to a method and system for coordinated active and reactive power control of multiple new energy power plants based on equivalent parameters. Background Technology

[0002] In a high-proportion renewable energy power system, the randomness and volatility of renewable energy output, as well as its uneven spatial distribution, severely impact the frequency and voltage security and stability of the power system. Currently, renewable energy power plant control is mostly passive and inconsistent in performance. Large-scale integration into weak grids alters the existing grid operation, leading to various problems such as voltage and frequency instability, posing new challenges to the safe and stable operation of the new power system. At present, the optimization control of renewable energy power plants mainly focuses on a single dimension of frequency or voltage, neglecting the strong coupling between the active and reactive power support capabilities of the power plants. In particular, since most renewable energy bases are located at the end of the grid, with fragile grid structures and low short-circuit capacity, existing active and reactive power decoupling control is insufficient to meet the system's security and stability requirements. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a method and system for coordinated active and reactive power control of multiple new energy power plants based on equivalent parameters. This method enables coordinated control of active frequency, reactive voltage, and both, providing real-time active support for the safe and stable operation of system frequency and voltage, and improving the accuracy and robustness of control.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0005] Firstly, a coordinated active and reactive power control method for multiple renewable energy power plants based on equivalent parameters includes the following steps:

[0006] Step 1: Based on the latest sampling or sample-and-hold period, obtain the historical and latest measured values ​​of the grid connection point frequency, and obtain the voltage phasor of each node, the complex power of each branch, and the node admittance matrix of each node in the online voltage monitoring area.

[0007] Step 2: Calculate the equivalent active power imbalance at the grid connection point based on the obtained historical frequency and latest measurement values ​​of the grid connection point, correct the Thevenin equivalent parameters issued by the dispatch center, obtain the estimated values ​​of the Thevenin equivalent parameters, and calculate the sensitivity coefficient of the grid connection point voltage to the active and reactive power output of each station based on the estimated values ​​of the Thevenin equivalent parameters, the voltage phasors of each node, the complex power of each branch, and the admittance matrix of each node.

[0008] Step 3: Determine whether the current grid connection point frequency or voltage exceeds the adjustment dead zone. If it does, proceed to Step 4; otherwise, wait to proceed to the next moment for another determination.

[0009] Step 4: Based on the sensitivity coefficients of the active and reactive power output of each power station and the node voltage phasor of the grid connection point voltage, calculate the reactive power control quantity of each power station. Based on the current grid connection point frequency and the equivalent active power imbalance power of the grid connection point, calculate the active power control quantity of each new energy power station. Issue the control quantity according to the active and reactive power coordination mechanism and perform power tracking.

[0010] Step 5: Proceed to the next moment, update the calculation model from Step 4 using the latest measurement data and calculation parameters, and solve again until the frequency and voltage are both restored to the adjustment dead zone.

[0011] Furthermore, based on the acquired historical frequency data and the latest measurement values ​​of the grid connection point, the equivalent active power imbalance at the grid connection point is calculated, including:

[0012] The measured grid connection point frequency data were smoothed using a weighted moving average. Based on the smoothed frequency values, a polynomial fitting method combined with numerical differentiation was used to calculate the rate of change of grid connection point frequency.

[0013] Based on the frequency variation rate at the grid connection point and relevant parameters issued by the dispatch center, the equivalent active power imbalance at the grid connection point is calculated using the following formula:

[0014]

[0015] In the formula, H is the power grid inertia time constant, and D... f The load regulation coefficient is given by both the load control factor and the load regulation factor, both of which are issued in real time by the dispatch center; s is the complex frequency, df / dt is the actual frequency difference at the grid connection point, and ΔP is the load regulation factor. unb This is the equivalent active unbalanced power.

[0016] Furthermore, the Thevenin equivalent parameters issued by the dispatch center are corrected to obtain estimated values ​​of the Thevenin equivalent parameters, including:

[0017] Based on the Thevenin equivalent parameters issued by the dispatch center, the system state variable X(k) of the Sage-Husa adaptive Kalman filter is constructed. The system observation matrix H(k) is established according to the equivalent node current phasors, and the system observation equation Y(k) = H(k)X(k) + r is constructed. k Y(k) is the system observation sequence, r k Measure the noise matrix for the system;

[0018] According to the system's dynamic equation X(k+1)=X(k)+q k Perform state update, where q k This is the process noise matrix;

[0019] Where X(k)=[E r (k),E i (k),R th(k),X th (k)] T E r (k),E i (k),R th (k),X th (k) represents the real part of Thevenin equivalent potential, the imaginary part of Thevenin equivalent potential, the real part of Thevenin equivalent impedance, and the imaginary part of Thevenin equivalent impedance, respectively.

[0020] Furthermore, based on the estimated values ​​of Thevenin equivalent parameters and the voltage phasors of each node, the complex power of each branch, and the admittance matrix of each node, the sensitivity coefficients of the grid connection point voltage to the active and reactive power outputs of each power station are calculated, including:

[0021] The nodes within the region are divided into a set of PQ nodes, and the system-side nodes are divided into a set of relaxed nodes. The connection impedance is taken as the Thevenin equivalent impedance, and the voltage value is taken as the Thevenin equivalent potential. The node admittance matrix is ​​determined based on the Thevenin equivalent impedance and the Thevenin equivalent potential. The power flow equation is constructed based on the voltage phasor of each node and the complex power injected into each station. The partial derivatives of the power flow equation with respect to active and reactive power are calculated respectively. The sensitivity coefficients of active and reactive power output of each station are obtained by using the power flow Jacobian matrix method.

[0022] Furthermore, based on the sensitivity coefficients of the grid connection point voltage to the active and reactive power outputs of each power station and the node voltage phasors, the reactive power control quantity of each power station is calculated, and the calculation formula is as follows:

[0023]

[0024] In the formula, Let r be the time t. * Active power control quantities of a multi-site coordinated control system for new energy sources. For the preset rth * The active power control coefficient, f, of the coordinated control system for multiple new energy power plants. min Here, f(t) represents the system frequency protection threshold, f(t) represents the grid connection frequency at time t, and ΔP represents the frequency at the grid connection point. unb (t) represents the system's equivalent active power imbalance estimated at the grid connection point at time t.

[0025] Furthermore, based on the current grid connection frequency and the equivalent active power imbalance at the grid connection point, the active power control quantities for each renewable energy power station are calculated, including:

[0026] The reactive power control quantities of each new energy power station are obtained by solving the following optimization problem:

[0027] Objective function:

[0028]

[0029] In the formula, Qg This is the column vector of reactive power control quantities for each power station; This is the sensitivity coefficient matrix of the grid connection point voltage to the reactive power output of each power station; To control the voltage column vectors of each station node, ||·||2 represents the 2-norm of the matrix, and μ represents the phasor of the rated voltage distribution of the node;

[0030] Constraints:

[0031]

[0032] Where: vector Q g and These represent the lower limits of reactive power at each power station. Q g and reactive power limit The column vector formed.

[0033] Furthermore, control quantities are issued based on the active and reactive power coordination mechanism, including:

[0034] If the grid connection point voltage exceeds the regulation dead zone, reactive power voltage coordination control is initiated to solve for the reactive power control quantity of each power station; if the grid connection point frequency exceeds the regulation dead zone, active power coordination control is initiated to calculate the active power control quantity of each power station. Then, based on the sensitivity coefficient of the active power output of each power station to the grid connection point voltage, the grid connection point voltage after the active power control command is evaluated, and it is evaluated whether the grid connection point voltage exceeds the regulation dead zone. If it exceeds the regulation dead zone, the reactive power control quantity is solved based on the evaluated grid connection point voltage value, and the active power and reactive power commands are issued and executed simultaneously.

[0035] If the grid connection point voltage and frequency both exceed the regulation dead zone, the active power control quantity of each substation is first calculated. Then, based on the sensitivity coefficient of the active power output of each substation to the grid connection point voltage, the grid connection point voltage after the active power control command is evaluated, and it is evaluated whether the grid connection point voltage exceeds the regulation dead zone. If it exceeds the regulation dead zone, the reactive power control quantity is solved based on the evaluated grid connection point voltage value, and the active power and reactive power commands are issued and executed simultaneously.

[0036] Secondly, a coordinated active and reactive power control system for multiple new energy power plants based on equivalent parameters is provided, including:

[0037] The data measurement module is used to obtain the historical and latest measurement values ​​of the grid connection point frequency based on the latest sampling or sample-and-hold period, and to obtain the voltage phasor of each node, the complex power of each branch, and the admittance matrix of each node in the online voltage monitoring area.

[0038] The parameter calculation module is used to calculate the equivalent active power imbalance at the grid connection point based on the historical frequency and latest measurement values ​​of the grid connection point, correct the Thevenin equivalent parameters issued by the dispatch center, obtain the estimated value of the Thevenin equivalent parameters, and calculate the sensitivity coefficient of the grid connection point voltage to the active and reactive power output of each station based on the estimated value of the Thevenin equivalent parameters, the voltage phasor of each node, the complex power of each branch, and the admittance matrix of each node.

[0039] The judgment module is used to determine whether the current grid connection point frequency or voltage exceeds the adjustment dead zone. If it exceeds the adjustment dead zone, the control quantity calculation and issuance module is called; otherwise, it waits to enter the next moment to judge again.

[0040] The control quantity calculation and distribution module is used to calculate the reactive power control quantity of each power station based on the sensitivity coefficient of the active and reactive power output of each power station and the node voltage phasor of the grid connection point voltage. It also calculates the active power control quantity of each new energy power station based on the current grid connection point frequency and the equivalent active power imbalance power of the grid connection point. Finally, it distributes the control quantity according to the active and reactive power coordination mechanism and performs power tracking.

[0041] The cyclic control module is used to update the calculation model of the control quantity calculation and distribution module with the latest measurement data and calculation parameters when entering the next time step, and solve it again until the frequency and voltage are restored to the dead zone.

[0042] Furthermore, based on the acquired historical frequency data and the latest measurement values ​​of the grid connection point, the equivalent active power imbalance at the grid connection point is calculated, including:

[0043] The measured grid connection point frequency data were smoothed using a weighted moving average. Based on the smoothed frequency values, a polynomial fitting method combined with numerical differentiation was used to calculate the rate of change of grid connection point frequency.

[0044] Based on the frequency variation rate at the grid connection point and relevant parameters issued by the dispatch center, the equivalent active power imbalance at the grid connection point is calculated using the following formula:

[0045]

[0046] In the formula, H is the power grid inertia time constant, and D... f The load regulation coefficient is given by both the load control factor and the load regulation factor, both of which are issued in real time by the dispatch center; s is the complex frequency, df / dt is the actual frequency difference at the grid connection point, and ΔP is the load regulation factor. unb This is the equivalent active unbalanced power.

[0047] Furthermore, the Thevenin equivalent parameters issued by the dispatch center are corrected to obtain estimated values ​​of the Thevenin equivalent parameters, including:

[0048] Based on the Thevenin equivalent parameters issued by the dispatch center, the system state variable X(k) of the Sage-Husa adaptive Kalman filter is constructed. The system observation matrix H(k) is established according to the equivalent node current phasors, and the system observation equation Y(k) = H(k)X(k) + r is constructed. k Y(k) is the system observation sequence, r k Measure the noise matrix for the system;

[0049] According to the system's dynamic equation X(k+1)=X(k)+q k Perform state update, where q k This is the process noise matrix;

[0050] Where X(k)=[E r (k),E i (k),R th (k),X th (k)] T E r (k),E i (k),R th (k),X th (k) represents the real part of Thevenin equivalent potential, the imaginary part of Thevenin equivalent potential, the real part of Thevenin equivalent impedance, and the imaginary part of Thevenin equivalent impedance, respectively.

[0051] Furthermore, based on the estimated values ​​of Thevenin equivalent parameters and the voltage phasors of each node, the complex power of each branch, and the admittance matrix of each node, the sensitivity coefficients of the grid connection point voltage to the active and reactive power outputs of each power station are calculated, including:

[0052] The nodes within the region are divided into a set of PQ nodes, and the system-side nodes are divided into a set of relaxed nodes. The connection impedance is taken as the Thevenin equivalent impedance, and the voltage value is taken as the Thevenin equivalent potential. The node admittance matrix is ​​determined based on the Thevenin equivalent impedance and the Thevenin equivalent potential. The power flow equation is constructed based on the voltage phasor of each node and the complex power injected into each station. The partial derivatives of the power flow equation with respect to active and reactive power are calculated respectively. The sensitivity coefficients of active and reactive power output of each station are obtained by using the power flow Jacobian matrix method.

[0053] Furthermore, based on the sensitivity coefficients of the grid connection point voltage to the active and reactive power outputs of each power station and the node voltage phasors, the reactive power control quantity of each power station is calculated, and the calculation formula is as follows:

[0054]

[0055] In the formula, Let r be the time t. * Active power control quantities of a multi-site coordinated control system for new energy sources. For the preset rth *The active power control coefficient, f, of the coordinated control system for multiple new energy power plants. min Here, f(t) represents the system frequency protection threshold, f(t) represents the grid connection frequency at time t, and ΔP represents the frequency at the grid connection point. unb (t) represents the system's equivalent active power imbalance estimated at the grid connection point at time t.

[0056] Furthermore, based on the current grid connection frequency and the equivalent active power imbalance at the grid connection point, the active power control quantities for each renewable energy power station are calculated, including:

[0057] The reactive power control quantities of each new energy power station are obtained by solving the following optimization problem:

[0058] Objective function:

[0059]

[0060] In the formula, Q g This is the column vector of reactive power control quantities for each power station; This is the sensitivity coefficient matrix of the grid connection point voltage to the reactive power output of each power station; To control the voltage column vectors of each station node, ||·||2 represents the 2-norm of the matrix, and μ represents the phasor of the rated voltage distribution of the node;

[0061] Constraints:

[0062]

[0063] Where: vector Q g and These represent the lower limits of reactive power at each power station. Q g and reactive power limit The column vector formed.

[0064] Furthermore, control quantities are issued based on the active and reactive power coordination mechanism, including:

[0065] If the grid connection point voltage exceeds the regulation dead zone, reactive power voltage coordination control is initiated to solve for the reactive power control quantity of each power station; if the grid connection point frequency exceeds the regulation dead zone, active power coordination control is initiated to calculate the active power control quantity of each power station. Then, based on the sensitivity coefficient of the active power output of each power station to the grid connection point voltage, the grid connection point voltage after the active power control command is evaluated, and it is evaluated whether the grid connection point voltage exceeds the regulation dead zone. If it exceeds the regulation dead zone, the reactive power control quantity is solved based on the evaluated grid connection point voltage value, and the active power and reactive power commands are issued and executed simultaneously.

[0066] If the grid connection point voltage and frequency both exceed the regulation dead zone, the active power control quantity of each substation is first calculated. Then, based on the sensitivity coefficient of the active power output of each substation to the grid connection point voltage, the grid connection point voltage after the active power control command is evaluated, and it is evaluated whether the grid connection point voltage exceeds the regulation dead zone. If it exceeds the regulation dead zone, the reactive power control quantity is solved based on the evaluated grid connection point voltage value, and the active power and reactive power commands are issued and executed simultaneously.

[0067] Thirdly, an electronic device is provided, comprising: one or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, wherein when the programs are executed by the processors, they implement the active and reactive power coordinated control method for new energy multi-stations based on equivalent parameters as described in the first aspect.

[0068] Fourthly, a computer-readable storage medium is provided, on which a computer program is stored, wherein when the computer program is executed by a processor, it implements the active and reactive power coordinated control method for multiple new energy power plants based on equivalent parameters as described in the first aspect.

[0069] Compared with the prior art, the present invention has the following beneficial effects:

[0070] (1) Based on the distributed autonomous response of each station, an additional control method based on centralized decision-making is adopted to improve the dynamic voltage and frequency safety and stability of the system. Compared with completely centralized control and distributed autonomous control, on the one hand, each station supports the system voltage and frequency safety and stability control faster based on pre-set control parameters and its own measured voltage and frequency information; on the other hand, centralized decision-making can effectively coordinate the adjustable resources and control capabilities of each station, and the additional control method can further improve the dynamic voltage and frequency safety and stability of the system.

[0071] (2) The grid connection point frequency and voltage control model is used to calculate the station coordination control strategy to realize the coordinated control of active frequency, reactive voltage and the two, and ensure the accuracy and robustness of real-time active support system frequency and voltage safety and stability control. Attached Figure Description

[0072] Figure 1 This is a flowchart of the active and reactive power coordinated control method for multiple new energy power plants based on equivalent parameters in an embodiment of the present invention. Detailed Implementation

[0073] The technical solutions in the embodiments of the present invention will now be clearly and completely described in conjunction with the accompanying drawings.

[0074] The first embodiment of this invention proposes a coordinated active and reactive power control method for multiple renewable energy power plants based on equivalent parameters. Building upon the distributed autonomous response of each power plant, it employs an additional control method based on centralized decision-making to improve the dynamic voltage and frequency security and stability of the system. (Refer to...) Figure 1 The method includes the following steps:

[0075] Step 1: Based on the latest sampling or sample-and-hold period, obtain the historical and latest measured values ​​of the grid connection point frequency. Simultaneously, obtain the voltage phasors of each node, the complex power of each branch, and the node admittance matrix for the online voltage monitoring area.

[0076] According to an embodiment of the present invention, obtaining historical and latest measured values ​​of the grid connection point frequency is to combine data smoothing and polynomial fitting to improve the numerical differentiation method for calculating the rate of change of the grid connection point frequency, thereby obtaining the equivalent active power imbalance. The method for calculating the imbalance power is described below. Here, the actual frequency difference at the grid connection point is obtained by differentiating the historical frequency values. Before data fitting, a weighted moving average is used to smooth the measured grid connection point frequency data to reduce the influence of noise.

[0077] The obtained node voltage phasors, branch complex power, and node admittance matrices are used to calculate the sensitivity coefficients of the grid connection point voltage to the active and reactive power outputs of each power station. The specific calculation method is described below. Step 2: Estimate the Thevenin equivalent parameters of the system, calculate the sensitivity coefficients of the grid connection point voltage to the active and reactive power outputs of each power station, and the equivalent active unbalanced power at the grid connection point.

[0078] According to an embodiment of the present invention, based on the Thevenin equivalent parameters of the system at the most recent moment issued by the scheduling center, the estimated values ​​of the system's Thevenin equivalent parameters are obtained by correcting them using the Sage-Husa adaptive Kalman filter method with the measurement data at the current moment. The Thevenin equivalent parameters include the Thevenin equivalent potential and the Thevenin equivalent impedance, both of which are complex numbers (phasors) with real and imaginary parts.

[0079] Specifically, in the Sage-Husa adaptive Kalman filter method:

[0080] X(k)=[E r (k),E i (k),R th (k),X th (k)] T

[0081] In the formula, X(k) is the system state variable, and E r (k),E i (k),R th (k),X th(k) represents the real part of the Thevenin equivalent potential, the imaginary part of the Thevenin equivalent potential, the real part of the Thevenin equivalent impedance, and the imaginary part of the Thevenin equivalent impedance, respectively. E(k) = E r (k)+jE i (k) represents the Thevenin equivalent potential of the system at time k, Z th (k)=R th (k)+jX th (k) represents the Thevenin equivalent impedance of the system at time k.

[0082]

[0083] In the formula, H(k) is the system observation matrix, and I(k) = g(k) + jh(k) is the equivalent node current phasor at time k. Here, g(k) is the real part of the current phasor, and h(k) is the imaginary part of the current phasor.

[0084] The system observation equation is:

[0085] Y(k)=H(k)X(k)+r k

[0086] In the formula, Y(k)=[U r (k)U i (k)] T U r (k) and U i (k) represents the real and imaginary parts of the equivalent node voltage phasor, respectively, and U(k) = U r (k)+jU i (k) represents the equivalent node voltage phasor at time k, Y(k) represents the system observation sequence, and r k Measure the noise matrix for the system.

[0087] The dynamic equation of the system is:

[0088] X(k+1)=X(k)+q k

[0089] In the formula, q k This is the process noise matrix.

[0090] The initial values ​​for the Sage-Husa adaptive Kalman filter iteration are taken as the Thevenin equivalent parameters of the system at the most recent moment, issued by the scheduling center. The estimated values ​​of the Thevenin equivalent parameters of the system are obtained by correcting them using the above formula.

[0091] Traditional methods for solving sensitivity coefficients include power flow calculations and adjoint network methods. This invention designs a phasor calculation method based on local electrical quantities, dividing the nodes within the region into PQ node sets and relaxed node sets, and combining power flow calculations and the Jacobian matrix method to solve for the sensitivity coefficients. The PQ nodes represent the nodes of each station within the region, with known injected active power P and reactive power Q, and the voltage amplitude V and phase angle θ to be determined. The relaxed nodes are system-side nodes with fixed voltage amplitudes and phase angles, described by Thevenin equivalent parameters (potential and impedance).

[0092] According to an embodiment of the present invention, the sensitivity coefficient of the grid connection point voltage to the active and reactive power output of each power station is calculated as follows: Each node in the region is divided into a PQ node set, and the system-side nodes are divided into a relaxed node set. A node admittance matrix is ​​constructed, the connection impedance is taken as the Thevenin equivalent impedance, and the voltage value is taken as the Thevenin equivalent potential. Based on the power flow equations, partial derivatives are calculated with respect to active and reactive power, respectively. The sensitivity coefficients of the active and reactive power output of each power station can be obtained using the power flow Jacobian matrix method. Specifically, the parameters involved in the above method include the voltage phasors of each node in the coordinated control system region, the injected complex power of each power station, and the node admittance matrix. The first two are obtained from the power station and are used to construct the power flow equations and update the Jacobian matrix. The admittance matrix is ​​constructed based on the network topology and the Thevenin equivalent impedance, reflecting the system connection relationship.

[0093] According to an embodiment of the present invention, the equivalent active power imbalance at the grid connection point is determined by solving the following formula:

[0094]

[0095] In the formula, H is the power grid inertia time constant, and D... f Both are load regulation coefficients, and are issued in real time by the dispatch center. s is the complex frequency. df / dt is the actual frequency difference at the grid connection point, i.e., the rate of change of frequency at the grid connection point. ΔP unb This is the equivalent active unbalanced power.

[0096] Step 3: Determine if the frequency or voltage at the grid connection point exceeds the regulation dead zone. If it does, proceed to Step 4; otherwise, wait for the next time step to determine the dead zone again. In a power system, the regulation dead zone refers to a specific range within which the system's regulating devices will not operate. The regulation dead zone will also be referred to as the dead zone in the following text.

[0097] Step 4: Solve for the active and reactive power control quantities of each new energy power station, issue the control quantities and perform power tracking.

[0098] According to an embodiment of the present invention, the total active power control quantity of each new energy power station is obtained by solving the following formula:

[0099]

[0100] In the formula, Let r be the time t. * Active power control quantities of a multi-site coordinated control system for new energy sources. For the preset rth * The active power control coefficient, f, of the coordinated control system for multiple new energy power plants. min The system frequency protection threshold, also known as the frequency threshold value, is given by f(t), where f(t) is the grid connection frequency at time t, and ΔP is the frequency value. unb (t) represents the system's equivalent active power imbalance at time t, estimated at the grid connection point. This formula uses the equivalent active power imbalance to solve for the total active power control quantity at the final grid connection point frequency, and is also referred to as the grid connection point frequency control model in this paper.

[0101] When allocating the total active power control quantity to each new energy power station, the active power control quantity is allocated proportionally according to the size of the available reserve capacity, based on the active power reserve capacity transmitted by each power station.

[0102] According to an embodiment of the present invention, the reactive power control quantities of each new energy power station are obtained by solving the following optimization problem:

[0103] Objective function:

[0104]

[0105] In the formula, Q g This is the column vector of reactive power control quantities for each power station; This is the sensitivity coefficient matrix of the grid connection point voltage to the reactive power output of each power station; To control the voltage column vectors of each station node, ||·||2 represents the 2-norm of the matrix, and μ represents the phasor of the node's rated voltage distribution. f(Q g ) is the objective function of the column vector of reactive power control quantities of the power station. The reactive power control quantities of the power station are obtained by solving the optimal solution of the objective function.

[0106] Constraints:

[0107]

[0108] Where: vector Q g and These represent the lower limits of reactive power at each power station. Q g and reactive power limit The column vector formed.

[0109] Control quantities are issued according to the active and reactive power coordination mechanism, including: when the grid connection point voltage exceeds the regulation dead zone, reactive power and voltage coordination control is initiated, and the voltage optimization control model is solved, that is, the above-mentioned bounded constraint quadratic programming voltage optimization objective function is solved to obtain the reactive power control quantity of each power station. When the grid connection point frequency exceeds the regulation dead zone, active power coordination control is initiated, and the active power control quantity of each power station is calculated. Then, based on the sensitivity coefficient of the active power output of each power station to the grid connection point voltage, the grid connection point voltage after the active power control command is executed (i.e., after active power increase) is evaluated. If the requirements are not met, that is, the grid connection point voltage exceeds its regulation dead zone, the voltage optimization control model is solved to obtain the reactive power control quantity of each power station, and the active power and reactive power commands are issued and executed simultaneously. If the grid connection point voltage and frequency do not meet the requirements, i.e. both exceed the regulation dead zone, the active power control quantity is calculated first. Based on the calculated active power control quantity, the grid connection point voltage after the active power control command is evaluated based on the sensitivity coefficient of the active power output of each power station, and it is evaluated whether the grid connection point voltage exceeds the regulation dead zone. If it exceeds the dead zone, the reactive power control quantity needs to be solved based on the evaluated grid connection point voltage value, and the active power and reactive power commands are issued and executed simultaneously.

[0110] Step 5: Proceed to the next moment, update the model using the latest measurement data and calculation parameters, and solve again until the frequency and voltage are both restored to the dead zone.

[0111] This invention employs a grid connection point frequency and voltage control model to calculate the station's coordinated control strategy, achieving coordinated control of active frequency, reactive voltage, and both, thus ensuring the accuracy and robustness of real-time active support system frequency and voltage safety and stability control.

[0112] Based on the same technical concept as the above method, the second embodiment of the present invention provides a coordinated active and reactive power control system for multiple new energy power plants based on equivalent parameters, including:

[0113] The data measurement module is used to obtain the historical and latest measurement values ​​of the grid connection point frequency based on the latest sampling or sample-and-hold period, and to obtain the voltage phasor of each node, the complex power of each branch, and the admittance matrix of each node in the online voltage monitoring area.

[0114] The parameter calculation module is used to calculate the equivalent active power imbalance at the grid connection point based on the historical frequency and latest measurement values ​​of the grid connection point, correct the Thevenin equivalent parameters issued by the dispatch center, obtain the estimated value of the Thevenin equivalent parameters, and calculate the sensitivity coefficient of the grid connection point voltage to the active and reactive power output of each station based on the estimated value of the Thevenin equivalent parameters, the voltage phasor of each node, the complex power of each branch, and the admittance matrix of each node.

[0115] The judgment module is used to determine whether the current grid connection point frequency or voltage exceeds the adjustment dead zone. If it exceeds the adjustment dead zone, the control quantity calculation and issuance module is called; otherwise, it waits to enter the next moment to judge again.

[0116] The control quantity calculation and distribution module is used to calculate the reactive power control quantity of each power station based on the sensitivity coefficient of the active and reactive power output of each power station and the node voltage phasor of the grid connection point voltage. It also calculates the active power control quantity of each new energy power station based on the current grid connection point frequency and the equivalent active power imbalance power of the grid connection point. Finally, it distributes the control quantity according to the active and reactive power coordination mechanism and performs power tracking.

[0117] The cyclic control module is used to update the calculation model of the control quantity calculation and distribution module with the latest measurement data and calculation parameters when entering the next time step, and solve it again until the frequency and voltage are restored to the dead zone.

[0118] A third embodiment of the present invention provides an electronic device, including: one or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the programs, when executed by the processors, implement the active and reactive power coordinated control method for multiple new energy power plants based on equivalent parameters as described above.

[0119] The fourth embodiment of the present invention provides a computer-readable storage medium storing a computer program thereon. When the computer program is executed by a processor, it implements the active and reactive power coordinated control method for multiple new energy power plants based on equivalent parameters as described above.

[0120] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus (systems), electronic devices, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0121] This invention is described with reference to a flowchart of a method according to embodiments of the invention. It should be understood that each step in the flowchart and combinations thereof can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing device, generate instructions for implementing the process. Figure 1 A device for a function specified in one or more processes.

[0122] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 The function specified in one or more processes.

[0123] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 Steps of a specified function in one or more processes.

Claims

1. A method for coordinated active and reactive power control of multiple new energy power plants based on equivalent parameters, characterized in that, Includes the following steps: Step 1: Based on the latest sampling or sample-and-hold period, obtain the historical and latest measured values ​​of the grid connection point frequency, and obtain the voltage phasor of each node, the complex power of each branch, and the node admittance matrix of each node in the online voltage monitoring area. Step 2: Calculate the equivalent active power imbalance at the grid connection point based on the obtained historical frequency and latest measurement values ​​of the grid connection point, correct the Thevenin equivalent parameters issued by the dispatch center, obtain the estimated values ​​of the Thevenin equivalent parameters, and calculate the sensitivity coefficient of the grid connection point voltage to the active and reactive power output of each station based on the estimated values ​​of the Thevenin equivalent parameters, the voltage phasors of each node, the complex power of each branch, and the admittance matrix of each node. Step 3: Determine whether the current grid connection point frequency or voltage exceeds the adjustment dead zone. If it does, proceed to Step 4; otherwise, wait to proceed to the next moment for another determination. Step 4: Based on the sensitivity coefficients of the active and reactive power output of each power station and the node voltage phasor of the grid connection point voltage, calculate the reactive power control quantity of each power station. Based on the current grid connection point frequency and the equivalent active power imbalance power of the grid connection point, calculate the active power control quantity of each new energy power station. Issue the control quantity according to the active and reactive power coordination mechanism and perform power tracking. Step 5: Proceed to the next moment, update the calculation model from Step 4 using the latest measurement data and calculation parameters, and solve again until the frequency and voltage are both restored to the adjustment dead zone.

2. The method according to claim 1, characterized in that, The equivalent active power imbalance at the grid connection point is calculated based on the obtained historical frequency data and the latest measurement values, including: The measured grid connection point frequency data were smoothed using a weighted moving average. Based on the smoothed frequency values, a polynomial fitting method combined with numerical differentiation was used to calculate the rate of change of grid connection point frequency. Based on the frequency variation rate at the grid connection point and relevant parameters issued by the dispatch center, the equivalent active power imbalance at the grid connection point is calculated using the following formula: In the formula, H is the power grid inertia time constant, and D... f The load regulation coefficient is given by both the load control factor and the load regulation factor, both of which are issued in real time by the dispatch center; s is the complex frequency, df / dt is the actual frequency difference at the grid connection point, and ΔP is the load regulation factor. unb This is the equivalent active unbalanced power.

3. The method according to claim 1, characterized in that, The estimated values ​​of the Thevenin equivalent parameters issued by the dispatch center are corrected to obtain the estimated values ​​of the Thevenin equivalent parameters, including: Based on the Thevenin equivalent parameters issued by the dispatch center, the system state variable X(k) of the Sage-Husa adaptive Kalman filter is constructed. The system observation matrix H(k) is established according to the equivalent node current phasors, and the system observation equation Y(k) = H(k)X(k) + r is constructed. k Y(k) is the system observation sequence, r k Measure the noise matrix of the system; According to the system's dynamic equation X(k+1)=X(k)+q k Perform state update, where q k This is the process noise matrix; Where X(k)=[E r (k),E i (k),R th (k),X th (k)] T E r (k),E i (k),R th (k),X th (k) represents the real part of Thevenin equivalent potential, the imaginary part of Thevenin equivalent potential, the real part of Thevenin equivalent impedance, and the imaginary part of Thevenin equivalent impedance, respectively.

4. The method according to claim 1, characterized in that, Based on the estimated values ​​of Thevenin equivalent parameters, and the voltage phasors of each node, the complex power of each branch, and the admittance matrix of each node, the sensitivity coefficients of the grid connection point voltage to the active and reactive power outputs of each power station are calculated, including: The nodes within the region are divided into a set of PQ nodes, and the system-side nodes are divided into a set of relaxed nodes. The connection impedance is taken as the Thevenin equivalent impedance, and the voltage value is taken as the Thevenin equivalent potential. The node admittance matrix is ​​determined based on the Thevenin equivalent impedance and the Thevenin equivalent potential. The power flow equation is constructed based on the voltage phasor of each node and the complex power injected into each station. The partial derivatives of the power flow equation with respect to active and reactive power are calculated respectively. The sensitivity coefficients of active and reactive power output of each station are obtained by using the power flow Jacobian matrix method.

5. The method according to claim 1, characterized in that, Based on the sensitivity coefficients of the grid connection point voltage to the active and reactive power output of each power station and the nodal voltage phasors, the reactive power control quantity of each power station is calculated, and the calculation formula is as follows: In the formula, Let time t be the rth time * Active power control quantities of a multi-site coordinated control system for new energy sources. For the preset rth * The active power control coefficient, f, of the coordinated control system for multiple new energy power plants. min Here, f(t) represents the system frequency protection threshold, f(t) represents the grid connection frequency at time t, and ΔP is the voltage level. unb (t) represents the system's equivalent active power imbalance estimated at the grid connection point at time t.

6. The method according to claim 1, characterized in that, The active power control quantities for each renewable energy power station are calculated based on the current grid connection frequency and the equivalent active power imbalance at the grid connection point, including: The reactive power control quantities of each new energy power station are obtained by solving the following optimization problem: Objective function: In the formula, Q g This is the column vector of reactive power control quantities for each power station; This is the sensitivity coefficient matrix of the grid connection point voltage to the reactive power output of each power station; To control the voltage column vectors of each station node, ||·||2 represents the 2-norm of the matrix, and μ represents the phasor of the rated voltage distribution of the node; Constraints: In the formula: vector Q g and These represent the lower limit of reactive power Q of each power station. g and reactive power limit The column vector formed.

7. The method according to claim 1, characterized in that, Control quantities are issued according to the active and reactive power coordination mechanism, including: If the grid connection point voltage exceeds the regulation dead zone, reactive power voltage coordination control is initiated to solve for the reactive power control quantity of each power station; if the grid connection point frequency exceeds the regulation dead zone, active power coordination control is initiated to calculate the active power control quantity of each power station. Then, based on the sensitivity coefficient of the active power output of each power station to the grid connection point voltage, the grid connection point voltage after the active power control command is evaluated, and it is evaluated whether the grid connection point voltage exceeds the regulation dead zone. If it exceeds the regulation dead zone, the reactive power control quantity is solved based on the evaluated grid connection point voltage value, and the active power and reactive power commands are issued and executed simultaneously. If the grid connection point voltage and frequency both exceed the regulation dead zone, the active power control quantity of each substation is first calculated. Then, based on the sensitivity coefficient of the active power output of each substation to the grid connection point voltage, the grid connection point voltage after the active power control command is evaluated, and it is evaluated whether the grid connection point voltage exceeds the regulation dead zone. If it exceeds the regulation dead zone, the reactive power control quantity is solved based on the evaluated grid connection point voltage value, and the active power and reactive power commands are issued and executed simultaneously.

8. A coordinated active and reactive power control system for multiple new energy power plants based on equivalent parameters, characterized in that, include: The data measurement module is used to obtain the historical and latest measurement values ​​of the grid connection point frequency based on the latest sampling or sample-and-hold period, and to obtain the voltage phasor of each node, the complex power of each branch, and the admittance matrix of each node in the online voltage monitoring area. The parameter calculation module is used to calculate the equivalent active power imbalance at the grid connection point based on the historical frequency and latest measurement values ​​of the grid connection point, correct the Thevenin equivalent parameters issued by the dispatch center, obtain the estimated value of the Thevenin equivalent parameters, and calculate the sensitivity coefficient of the grid connection point voltage to the active and reactive power output of each station based on the estimated value of the Thevenin equivalent parameters, the voltage phasor of each node, the complex power of each branch, and the admittance matrix of each node. The judgment module is used to determine whether the current grid connection point frequency or voltage exceeds the adjustment dead zone. If it exceeds the adjustment dead zone, the control quantity calculation and issuance module is called; otherwise, it waits to enter the next moment to judge again. The control quantity calculation and distribution module is used to calculate the reactive power control quantity of each power station based on the sensitivity coefficient of the active and reactive power output of each power station and the node voltage phasor of the grid connection point voltage. It also calculates the active power control quantity of each new energy power station based on the current grid connection point frequency and the equivalent active power imbalance power of the grid connection point. Finally, it distributes the control quantity according to the active and reactive power coordination mechanism and performs power tracking. The cyclic control module is used to update the calculation model of the control quantity calculation and distribution module with the latest measurement data and calculation parameters when entering the next time step, and solve it again until the frequency and voltage are restored to the dead zone.

9. The system according to claim 8, characterized in that, The equivalent active power imbalance at the grid connection point is calculated based on the obtained historical frequency data and the latest measurement values, including: The measured grid connection point frequency data were smoothed using a weighted moving average. Based on the smoothed frequency values, a polynomial fitting method combined with numerical differentiation was used to calculate the rate of change of grid connection point frequency. Based on the frequency variation rate at the grid connection point and relevant parameters issued by the dispatch center, the equivalent active power imbalance at the grid connection point is calculated using the following formula: In the formula, H is the power grid inertia time constant, and D... f The load regulation coefficient is given by both the load control factor and the load regulation factor, both of which are issued in real time by the dispatch center; s is the complex frequency, df / dt is the actual frequency difference at the grid connection point, and ΔP is the load regulation factor. unb This is the equivalent active unbalanced power.

10. The system according to claim 8, characterized in that, The estimated values ​​of the Thevenin equivalent parameters issued by the dispatch center are corrected to obtain the estimated values ​​of the Thevenin equivalent parameters, including: Based on the Thevenin equivalent parameters issued by the dispatch center, the system state variable X(k) of the Sage-Husa adaptive Kalman filter is constructed. The system observation matrix H(k) is established according to the equivalent node current phasors, and the system observation equation Y(k) = H(k)X(k) + r is constructed. k Y(k) is the system observation sequence, r k Measure the noise matrix of the system; According to the system's dynamic equation X(k+1)=X(k)+q k Perform state update, where q k This is the process noise matrix; Where X(k)=[E r (k),E i (k),R th (k),X th (k)] T E r (k),E i (k),R th (k),X th (k) represents the real part of Thevenin equivalent potential, the imaginary part of Thevenin equivalent potential, the real part of Thevenin equivalent impedance, and the imaginary part of Thevenin equivalent impedance, respectively.

11. The system according to claim 8, characterized in that, Based on the estimated values ​​of Thevenin equivalent parameters, and the voltage phasors of each node, the complex power of each branch, and the admittance matrix of each node, the sensitivity coefficients of the grid connection point voltage to the active and reactive power outputs of each power station are calculated, including: The nodes within the region are divided into a set of PQ nodes, and the system-side nodes are divided into a set of relaxed nodes. The connection impedance is taken as the Thevenin equivalent impedance, and the voltage value is taken as the Thevenin equivalent potential. The node admittance matrix is ​​determined based on the Thevenin equivalent impedance and the Thevenin equivalent potential. The power flow equation is constructed based on the voltage phasor of each node and the complex power injected into each station. The partial derivatives of the power flow equation with respect to active and reactive power are calculated respectively. The sensitivity coefficients of active and reactive power output of each station are obtained by using the power flow Jacobian matrix method.

12. The system according to claim 8, characterized in that, Based on the sensitivity coefficients of the grid connection point voltage to the active and reactive power output of each power station and the nodal voltage phasors, the reactive power control quantity of each power station is calculated, and the calculation formula is as follows: In the formula, Let time t be the rth time * Active power control quantities of a multi-site coordinated control system for new energy sources. For the preset rth * The active power control coefficient, f, of the coordinated control system for multiple new energy power plants. min Here, f(t) represents the system frequency protection threshold, f(t) represents the grid connection frequency at time t, and ΔP is the voltage level. unb (t) represents the system's equivalent active power imbalance estimated at the grid connection point at time t.

13. The system according to claim 8, characterized in that, The active power control quantities for each renewable energy power station are calculated based on the current grid connection frequency and the equivalent active power imbalance at the grid connection point, including: The reactive power control quantities of each new energy power station are obtained by solving the following optimization problem: Objective function: In the formula, Q g This is the column vector of reactive power control quantities for each power station; This is the sensitivity coefficient matrix of the grid connection point voltage to the reactive power output of each power station; To control the voltage column vectors of each station node, ||·||2 represents the 2-norm of the matrix, and μ represents the phasor of the rated voltage distribution of the node; Constraints: In the formula: vector Q g and These represent the lower limit of reactive power Q of each power station. g and reactive power limit The column vector formed.

14. The system according to claim 8, characterized in that, Control quantities are issued according to the active and reactive power coordination mechanism, including: If the grid connection point voltage exceeds the regulation dead zone, reactive power voltage coordination control is initiated to solve for the reactive power control quantity of each power station; if the grid connection point frequency exceeds the regulation dead zone, active power coordination control is initiated to calculate the active power control quantity of each power station. Then, based on the sensitivity coefficient of the active power output of each power station to the grid connection point voltage, the grid connection point voltage after the active power control command is evaluated, and it is evaluated whether the grid connection point voltage exceeds the regulation dead zone. If it exceeds the regulation dead zone, the reactive power control quantity is solved based on the evaluated grid connection point voltage value, and the active power and reactive power commands are issued and executed simultaneously. If the grid connection point voltage and frequency both exceed the regulation dead zone, the active power control quantity of each substation is first calculated. Then, based on the sensitivity coefficient of the active power output of each substation to the grid connection point voltage, the grid connection point voltage after the active power control command is evaluated, and it is evaluated whether the grid connection point voltage exceeds the regulation dead zone. If it exceeds the regulation dead zone, the reactive power control quantity is solved based on the evaluated grid connection point voltage value, and the active power and reactive power commands are issued and executed simultaneously.

15. Electronic devices, including: One or more processors; Memory; And one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, wherein when the programs are executed by the processors, they implement the active and reactive power coordinated control method for new energy multi-stations based on equivalent parameters as described in any one of claims 1-7.

16. A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the active and reactive power coordinated control method for multiple new energy power plants based on equivalent parameters as described in any one of claims 1-7.

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