Reactive power optimization configuration method and system for extra-high-voltage direct-current sending-end power grid and readable storage medium

Abstract

The invention discloses a reactive power optimization configuration method and system for an extra-high-voltage direct-current sending-end power grid and a readable storage medium, and belongs to the technical field of power grid optimization configuration. The method comprises the following steps: acquiring topological structure data of an extra-high-voltage direct-current sending-end power grid to construct a power grid model; determining the number and working parameters of phase modifiers to be configured according to the topological structure data; analyzing the voltage and reactive sensitivity of the extra-high voltage direct current sending end power grid based on the power grid model to obtain an initial node set of the access position of the phase modifier; and initializing a population based on the initial node set, each individual in the population representing a phase modifier configuration scheme, and optimizing the phase modifier configuration scheme by using a quantum genetic algorithm to obtain a final phase modifier configuration scheme. According to the method, the position of the access point of the phase modifier is optimally configured, the transient voltage rise of an extra-high voltage direct current transmission sending end power grid can be inhibited, and the operation stability of the power grid is effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power grid optimization configuration, and specifically relates to a method, system and readable storage medium for optimizing reactive power configuration of a UHV DC power grid at the sending end, which are used to suppress transient voltage rise of a UHV DC power grid at the sending end and improve the operation stability of the power grid. Background Art

[0002] Compared with high-voltage AC transmission technology, high-voltage DC transmission technology has lower cable investment, smaller transmission loss, and can also achieve decoupled operation of two-end AC systems. Therefore, it has become the mainstream technology for ultra-long-distance cross-regional power transmission.

[0003] In the case of weak grid support near the energy base, the overvoltage caused by system failure becomes a key factor restricting the DC transmission capacity. For example, during the period of DC commutation failure, the voltage near the sending end shows the characteristic of "first decreasing and then increasing". The reactive power surplus caused by some wind turbines entering low voltage ride-through is superimposed on the reactive power surplus of the filter. In addition, the voltage effect of the wind farm reactive power compensation device aggravates the transient voltage increase, resulting in an increased risk of large-scale wind turbines disconnecting from the grid at high voltage. With the continuous increase in wind power installed capacity and grid-connected capacity, large-scale wind turbine chain disconnection will pose a serious threat to the safe and stable operation of the system.

[0004] In response to the above problems, many scholars have conducted research on reactive power source configuration and voltage support of UHV DC transmission-end power grids, focusing on new energy reactive power / voltage control strategies and reactive power / voltage regulation of DC systems, such as reactive power compensation devices such as filters and fixed capacitors in converter stations, fixed reactive power control strategies, static reactive compensator configuration strategies, and coordinated control of various reactive power compensation devices. The above strategies can improve the reactive power / voltage support capability of the system to a certain extent. In addition, some studies focus on the analysis of converter structure, combined with the reactive power support capability of the converter station near the converter station, and provide optimal reactive power compensation for converter stations in UHV DC transmission systems by means of grouping and dimension switching equipment. Other studies no longer regard the reactive power compensation capacity of capacitors as fixed, but combine the voltage level of specific nodes with the reactive power compensation amount of the node, analyze the QU characteristics of capacitors, set the objective function, and use adaptive genetic algorithms to solve the planning problem. However, the existing schemes are still unsatisfactory in achieving grid operation stability. Summary of the invention

[0005] The object of the present invention is to provide a method, system and readable storage medium for optimizing reactive power configuration of a UHV DC sending-end power grid, so as to improve the operation level and stability of the clean energy UHV DC sending-end.

[0006] A first aspect of an embodiment of the present invention provides a method for optimizing reactive power configuration of a UHV DC transmission-end power grid, the method comprising:

[0007] Obtain the topological structure data of the UHV DC sending-end power grid to build a power grid model;

[0008] Determine the number and working parameters of the phase regulators to be configured according to the topological structure data;

[0009] Based on the power grid model, the voltage and reactive power sensitivity of the UHV DC sending end grid are analyzed to obtain the initial node set of the phase shifter access location;

[0010] A population is initialized based on an initial node set, each individual in the population represents a phase modulator configuration scheme, and a quantum genetic algorithm is used to optimize the phase modulator configuration scheme to obtain a final phase modulator configuration scheme; wherein the phase modulator configuration scheme includes the access position of each phase modulator to be configured in the UHV DC sending-end power grid.

[0011] In other examples of the first aspect, in the process of optimizing the phase condenser configuration scheme by using a quantum genetic algorithm to obtain a final phase condenser configuration scheme, the optimization objective function is:

[0012]

[0013] Among them, V S0 is the initial voltage of the AC busbar of the converter station; V S is the AC bus voltage of the converter station; V Smax V is the maximum rated voltage of the AC busbar of the converter station; Ci0 is the transient voltage after the UHV DC lockout fault; V Cimax is the maximum transient voltage after the UHV DC lockout fault; ω1 and ω2 are weight coefficients; N B is the number of AC busbars in the converter station.

[0014] In other examples of the first aspect, the constraints of the objective function include power balance constraints, steady-state constraints, and transient constraints.

[0015] In other examples of the first aspect, the power balance constraint is:

[0016]

[0017] Where i, j are the node numbers; P gi is the active power output of the power generation node, Q gi P is the reactive power output; di is the active load of the load node, Q di is the reactive load; U i ,θ i is the node voltage amplitude and phase angle; G ij , B ij are the conductance and susceptance elements in the node admittance matrix.

[0018] In other examples of the first aspect, the steady-state constraint is:

[0019]

[0020] Among them, Q ci is the reactive power compensation capacity of the node; U ik is the node voltage; P G is the active power of the power generation equipment, Q G is the reactive power of the generating equipment, n c 、n i is the number of nodes, n G is the number of power generation equipment.

[0021] In other examples of the first aspect, the transient constraint conditions include: after a fault occurs, the maximum power angle change value, the maximum transient voltage rise value of the AC bus of the converter station, and the maximum transient voltage rise value at the base end of the clean energy station are not greater than their respective set values.

[0022] In other examples of the first aspect, the voltage and reactive sensitivity of the UHV DC sending-end grid are analyzed based on the grid model to obtain an initial node set for the phase shifter access location, including: based on the grid model, executing power flow calculations in the power system simulation software to obtain the steady-state operating point of the grid, calculating the Jacobian matrix at the steady-state operating point, and obtaining the voltage sensitivity and reactive sensitivity matrices by solving the inverse of the Jacobian matrix, and then identifying the nodes that are most sensitive to voltage and reactive changes as the initial configuration nodes of the phase shifter based on the values ​​of the sensitivity matrices.

[0023] In other examples of the first aspect, in the analyzing the voltage and reactive sensitivity of the UHV DC sending-end grid based on the grid model, the voltage and reactive sensitivity of the UHV DC sending-end grid are analyzed and calculated using a decoupling algorithm, including:

[0024] Equivalent analysis is performed on the DC system and the AC system respectively; wherein the AC system is equivalent to a constant voltage applied to the corresponding converter, and the DC system is equivalent to a load equal to the active power and reactive power of the converter;

[0025] The sensitivity of the AC system node voltage to the transmission power and the sensitivity of the transmission power to each control variable of the DC system are calculated respectively, and the voltage stability sensitivity of the AC / DC system is obtained.

[0026] A second aspect of an embodiment of the present invention provides a reactive power optimization configuration system for a UHV DC sending-end power grid, the system comprising:

[0027] The acquisition module is configured to: obtain topological structure data of the UHV DC sending-end power grid to construct a power grid model;

[0028] The configuration module is configured to: determine the number and working parameters of the phase regulators to be configured according to the topological structure data;

[0029] The analysis module is configured to: analyze the voltage and reactive sensitivity of the UHV DC sending-end grid based on the grid model to obtain an initial node set of the phase shifter access location;

[0030] The optimization module is configured to: initialize a population based on an initial node set, each individual in the population represents a phase-shifting configuration scheme, and use a quantum genetic algorithm to optimize the phase-shifting configuration scheme to obtain a final phase-shifting configuration scheme; wherein the phase-shifting configuration scheme includes the access position of each phase-shifting to be configured in the ultra-high voltage direct current sending-end power grid.

[0031] In other examples of the second aspect, the quantum genetic algorithm is used to optimize the phase condenser configuration scheme to obtain the final phase condenser configuration scheme, and the optimization objective function is:

[0032]

[0033] Among them, V S0 is the initial voltage of the AC busbar of the converter station; V S is the AC bus voltage of the converter station; V Smax V is the maximum rated voltage of the AC busbar of the converter station; Ci0 is the transient voltage after the UHV DC lockout fault; V Cimax is the maximum transient voltage after the UHV DC lockout fault; ω1 and ω2 are weight coefficients; N B is the number of AC busbars in the converter station.

[0034] In other examples of the second aspect, the constraints of the objective function include power balance constraints, steady-state constraints, and transient constraints.

[0035] In other examples of the second aspect, the power balance constraint is:

[0036]

[0037] Where i, j are the node numbers; P gi is the active power output of the power generation node, Q gi P is the reactive power output; di is the active load of the load node, Q di is the reactive load; U i ,θ i is the node voltage amplitude and phase angle; G ij , B ij are the conductance and susceptance elements in the node admittance matrix.

[0038] In other examples of the second aspect, the steady-state constraint is:

[0039]

[0040] Among them, Q ci is the reactive power compensation capacity of the node; U ik is the node voltage; P G is the active power of the power generation equipment, Q G is the reactive power of the generating equipment, n c 、n i is the number of nodes, n G is the number of power generation equipment.

[0041] In other examples of the second aspect, the transient constraint conditions include: after a fault occurs, the maximum power angle change value, the maximum transient voltage rise value of the AC bus of the converter station, and the maximum transient voltage rise value at the base end of the clean energy station are not greater than their respective set values.

[0042] In other examples of the second aspect, the voltage and reactive sensitivity of the UHV DC sending-end grid are analyzed based on the grid model to obtain an initial node set for the phase shifter access location, including: based on the grid model, performing power flow calculations in the power system simulation software to obtain the steady-state operating point of the grid, calculating the Jacobian matrix at the steady-state operating point, and obtaining the voltage sensitivity and reactive sensitivity matrices by solving the inverse of the Jacobian matrix, and then identifying the nodes that are most sensitive to voltage and reactive changes as the initial configuration nodes of the phase shifter based on the values ​​of the sensitivity matrices.

[0043] In other examples of the second aspect, in the analysis of the voltage and reactive sensitivity of the UHV DC sending-end grid based on the grid model, the voltage and reactive sensitivity of the UHV DC sending-end grid are analyzed and calculated using a decoupling algorithm, including:

[0044] Equivalent analysis is performed on the DC system and the AC system respectively; wherein the AC system is equivalent to a constant voltage applied to the corresponding converter, and the DC system is equivalent to a load equal to the active power and reactive power of the converter;

[0045] The sensitivity of the AC system node voltage to the transmission power and the sensitivity of the transmission power to each control variable of the DC system are calculated respectively, and the voltage stability sensitivity of the AC / DC system is obtained.

[0046] According to a third aspect of an embodiment of the present invention, a readable storage medium is provided, on which a computer program is stored; when the computer program is executed, the method for optimizing reactive power configuration of the UHV DC sending-end power grid described in the first aspect is implemented.

[0047] Aiming at the reactive power configuration problem of the clean energy UHV sending-end network, the present invention proposes a multi-type reactive power supply configuration method based on DC operation mode and stability constraints, which can effectively improve the operation level and stability of the clean energy UHV DC sending-end.

[0048] In addition, when optimizing the configuration of the UHV DC sending-end power grid, the present invention takes into account the transient constraints when a DC fault occurs, and establishes an optimization model based on the AC bus voltage deviation of key nodes, so that the transient voltage rise can be reduced as much as possible when a fault occurs, thereby reducing the AC bus voltage fluctuation caused by the power grid fault, greatly reducing the risk of endangering the safe and stable operation of the entire power grid system.

[0049] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0051] Figure 1 A schematic flow chart of a method for optimizing reactive power configuration of a UHV DC sending-end power grid according to an embodiment of the present invention;

[0052] Figure 2 This is a schematic diagram of the calculation process for sensitivity decoupling of AC and DC systems;

[0053] Figure 3 This is a schematic diagram of the quantum genetic algorithm process;

[0054] Figure 4 Schematic diagram of a reactive power optimization configuration system for a UHV DC sending-end power grid according to an embodiment of the present invention. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0056] With the significant improvements in the capacity, instantaneous reactive output characteristics and maintenance of phase regulators, although the dynamic reactive reserve capacity of the system can be improved by installing phase regulators at the DC sending end, due to the certain electrical distance between the new energy grid connection point and the converter station (rectifier station), the solution of configuring centralized phase regulators on the AC bus of the converter station is not effective in suppressing transient overvoltages on the new energy side. Distributed configuration of distributed phase regulators near new energy stations is more helpful in suppressing the overall overvoltage of the system and avoiding new energy high-voltage grid disconnection. Therefore, the present invention also adopts a distributed phase regulator solution to provide voltage support capability.

[0057] The present invention analyzes the mechanism of transient voltage fluctuations at the converter station and the new energy station side when a DC fault occurs in the system, considers the system voltage stability and economy according to the mechanism of transient voltage fluctuations and the factors affecting transient voltage, and proposes a reasonable configuration scheme through the site selection and capacity setting of the phase shifter. At the same time, in order to meet the reactive power demand of the new energy collection area, the present invention considers optimizing the phase shifter excitation control system to give full play to the dynamic reactive power compensation capability of the distributed phase shifter.

[0058] Figure 1 This is a flow chart of a method for optimizing reactive power configuration of a UHV DC power grid at the sending end according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps:

[0059] Step 101, obtaining topological structure data of a UHV DC sending-end power grid to construct a power grid model;

[0060] Collect the topological structure data of the UHV DC transmission grid, including grid nodes, lines, voltage levels, power generation equipment, and load data. For example, the grid has 100 nodes, of which 20 are photovoltaic power generation nodes, wind power generation nodes, and other new energy power generation nodes.

[0061] As an example, power system simulation software, such as PowerFactory, PSS / E, etc., can be used to establish a power grid simulation model that reflects the operating status of the actual power grid based on the topology data.

[0062] Step 102, determining the number and working parameters of the phase regulators to be configured according to the topological structure data;

[0063] Based on the topological data, the number of phase regulators and their operating parameters can be preliminarily determined by using expert systems, intelligent models or power system simulation software, such as PowerFactory, PSS / E, etc. In addition, the number of phase regulators and their operating parameters can also be determined by consulting experts in the field. As an example, assume that 5 phase regulators are required, each with a rated capacity of 300Mvar and a reactive power regulation range of ±300Mvar.

[0064] Step 103, analyzing the voltage and reactive sensitivity of the UHV DC sending-end grid based on the grid model to obtain an initial node set of the phase regulator access location;

[0065] The phase shifter access position is essentially a nonlinear programming problem. If each access position (new energy generation node in the power grid) is directly calculated and compared, the calculation scale is quite huge. Therefore, in order to facilitate the calculation, the present invention first compares each access position, divides the more suitable access position, and then selects the access position according to the sensitivity, so that the reactive power optimization configuration has a better optimization effect.

[0066] In the present invention, the output sensitivity index and the state sensitivity index include: (1) an index reflecting the change of load node voltage with load power; (2) an index reflecting the change of generator reactive power with load power; (3) the sensitivity of load node voltage to independent parameters; wherein the independent parameters include line parameter admittance.

[0067] According to the meaning of each variable, the variables for analyzing sensitivity are divided into 4 categories:

[0068] (1) State vector X, including the generator voltage phase angle δ g 、Load voltage phase angle θ L and amplitude U L ;

[0069] (2) Independent parameter vector α, including line parameter admittance (conductance G, susceptance B), etc.

[0070] (3) Output vector Y, including generator reactive power Q g wait;

[0071] (4) Control vector T, including generator voltage U g and active power P g wait.

[0072] Based on the above divided variables, the sensitivity analysis equation is:

[0073] F(X, T, α) = 0 (1)

[0074] Y=G(X,T,α) (2)

[0075] Wherein, formula (1) includes the active power balance equations of the PQ node and the PV node, etc. Formula (2) includes the power flow equations and the balance node equations of the PV node, etc.

[0076] The output sensitivity index dY / dT and the state sensitivity index dX / dT include: (1) the index dV that reflects the change of load node voltage with load power L / dQ L and dV L / dP L ; (2) The indicator dQ that reflects the change of generator reactive power with load power g / dP L and dQ g / dQ L ; (3) The sensitivity of load node voltage to independent parameters, etc.

[0077] According to the relationship between the control variables, the total differential solution of equation (1) and equation (2) is obtained to obtain the output and state variables respectively for the control variable Tk Sensitivity:

[0078]

[0079] In the UHV DC power grid, the DC system (DC system) and the AC system (AC system) are connected via a converter station (rectifier station), so the bus voltage of the AC system is affected by the control method and parameters of the DC system. Therefore, the present invention separates the AC and DC systems and uses a decoupling algorithm to analyze and calculate the voltage and reactive sensitivity of the UHV new energy power grid. Decoupling is to replace an equation with multiple variables with a set of equations represented by a single variable, so that each variable cannot directly affect the solution of an equation at the same time, simplifying the solution process. Figure 2 As shown, the specific steps of the decoupling algorithm are as follows:

[0080] (1) Perform equivalent analysis on the DC system and the AC system respectively; wherein the AC system is equivalent to a constant voltage applied to the corresponding converter, and the DC system is equivalent to a load equal to the active power and reactive power of the converter;

[0081] (2) The sensitivity of the AC system node voltage to the transmission power and the sensitivity of the transmission power to each control variable of the DC system are calculated respectively to obtain the voltage stability sensitivity of the AC / DC system.

[0082] Decoupling can simplify the solution process of multivariable equations, improve computational efficiency and accuracy, and thus better optimize system operation.

[0083] As an example, based on the constructed power grid model, the steady-state operating point of the power grid can be obtained by performing power flow calculations in the power system simulation software. The Jacobian matrix is ​​calculated at the steady-state operating point, and the voltage sensitivity and reactive power sensitivity matrices can be obtained by solving the inverse of the Jacobian matrix. Then, based on the values ​​of the sensitivity matrices, the nodes that are most sensitive to voltage and reactive power changes can be identified as the initial configuration positions of the phase regulators.

[0084] Since the reactive power optimization configuration problem of dynamic reactive power compensation devices such as phase regulators is a multi-objective nonlinear programming problem, if each reactive device access point is calculated and compared one by one by traversal, a large amount of memory will be occupied, resulting in a decrease in the convergence speed of the subsequent genetic optimization algorithm. In order to effectively reduce the amount of calculation of reactive power optimization configuration, before performing reactive power optimization configuration, the present invention preferentially screens a part of reactive power configuration access points based on the set sensitivity index, in the hope of achieving a better reactive power configuration optimization effect.

[0085] Step 104, initializing a population based on an initial node set, wherein each individual represents a phase-shifting configuration scheme, and optimizing the phase-shifting configuration scheme using a quantum genetic algorithm to obtain a final phase-shifting configuration scheme.

[0086] The steps of quantum genetic algorithm are as follows:

[0087] (1) First, we need to randomly generate n chromosomes encoded with quantum bits. Initialize the population Q(t0) and encode the 2nm quantum bits of the n chromosomes in the population All are initialized to It means that all possible states contained in a chromosome are equally likely, that is:

[0088]

[0089] Where: |S k > is the kth state of the chromosome, represented by a binary number of length m (x1, x2, ..., x m ), where x i Is 0 or 1.

[0090] Measure all individuals in Q(t) and obtain a set of solutions p(t). is the jth (j=1, 2, ..., n) solution in the tth generation population. The whole measurement process is as follows: randomly generate a number [0, 1], and set the probability of the quantum bit or Compare with the generated number, if that number is greater than or The result is 1 if yes, 0 otherwise.

[0091] (2) According to the set objective function, evaluate the fitness of each determined solution p(t) and record the optimal individual and its fitness value.

[0092] (3) The rotation angle adjustment strategy of the quantum rotating gate (which is a universal strategy) is used to calculate the quantum rotation angle and update the quantum rotating gate.

[0093] (4) Determine whether the calculation can be terminated. If the termination condition is met, the calculation ends; otherwise, the iteration continues, the population is updated using the quantum rotating gate, and the algorithm returns to step (2).

[0094] Figure 3 This is a schematic diagram of the quantum genetic algorithm process. Figure 3 As shown, the process includes the following:

[0095] S1, initialize the population, each individual represents a phase regulator configuration scheme, that is, the configuration scheme of each phase regulator to be configured at the access position of the UHV DC sending-end power grid;

[0096] Assume that through voltage and reactive power sensitivity analysis, nodes 15, 27, 34, 56, 78, and 90 are determined as the initial position set. Using quantum genetic algorithm, 50 individuals are initialized, and each individual represents a combination of 5 nodes selected from the initial set.

[0097] Here, the configuration of each individual can be modified through Power Factory to ensure the feasibility of the solution.

[0098] S2, simulate at this position, calculate and record the objective function value of each individual; perform transient simulation on each individual in the Power Factory, ignore the steady-state indicators, calculate and record the objective function value of each individual.

[0099] S3, execute the above calculation process on all individuals in the initial population, obtain the evaluation index of each individual, evaluate the fitness of each individual, and record the fitness of the best individual;

[0100] The fitness of each individual is evaluated according to the objective function value. The lower the objective function value, the higher the fitness. The fitness of the best individual is recorded, that is, the individual with the highest fitness in the current generation of the population and its fitness value are recorded.

[0101] S4, use the quantum rotating gate to update the population, generate a new generation of population, use the updated population as the new initial population, execute the above steps, and perform the next round of calculations.

[0102] The present invention sets the minimum voltage deviation of the converter station AC bus and UHV DC after the fault as the optimization target, and establishes a reactive configuration optimization model in combination with the transient constraints of the power grid after the DC fault occurs, focusing on suppressing the transient voltage rise after the fault. The reactive optimization objective function is as follows, that is, to minimize the voltage deviation of the main converter station and key node bus:

[0103]

[0104] Among them, V S0 is the initial voltage of the AC busbar of the converter station; V S is the AC bus voltage of the converter station; V Smax V is the maximum rated voltage of the AC busbar of the converter station; Ci0 is the transient voltage after the UHV DC lockout fault; V Cimax is the maximum transient voltage after the UHV DC lockout fault; ω1 and ω2 are weight coefficients; N B is the number of AC busbars in the converter station.

[0105] The constraints include power balance constraints, steady-state constraints and transient constraints.

[0106] As an example, the power balance constraint is:

[0107]

[0108] Where i, j are the node numbers; P gi is the active power output of the power generation node, Q gi P is the reactive power output; di is the active load of the load node, Q di is the reactive load; U i ,Q ij is the node voltage amplitude and phase angle; G ij , B ij are the conductance and susceptance elements in the node admittance matrix.

[0109] As an example, the steady-state constraint

[0110]

[0111] Among them, Q ci is the reactive power compensation capacity of the node; U ik is the node voltage; P G is the active power of the power generation equipment, Q G is the reactive power of the power generation equipment.

[0112] As an example, for transient constraints, after a fault occurs, the power grid should still meet the power angle stability constraint, that is, the maximum power angle change value is not greater than the set value:

[0113] max(Δδ′)≤ξ (8)

[0114] At the same time, it should also meet the voltage stability constraints, that is, the maximum transient voltage rise of the AC bus of the converter station is not greater than the set value, such as 1.3pu; the maximum transient voltage rise of the base end of the clean energy station is not greater than the set value, such as 1.3pu.

[0115] After completing a round of calculation, determine whether the termination condition is met, such as the number of iterations reaches the upper limit (e.g., 100 generations) or the change in the fitness of the best individual is less than the set threshold, such as 0.01%. If the termination condition is met, the iterative calculation ends and the final phase-shifting configuration plan is output. The final phase-shifting configuration plan output includes the specific access location and related parameters of each phase-shifting. For example, the optimal solution finally determined is to install 5 phase-shifting units at nodes 15, 27, 34, 56, and 78, and the parameters of each phase-shifting unit are 300Mvar.

[0116] According to another embodiment of the present invention, Figure 4 As shown, a reactive power optimization configuration system for a UHV DC sending-end power grid is also provided, the system comprising:

[0117] The acquisition module 401 is configured to: acquire topological structure data of the UHV DC sending-end power grid to construct a power grid model;

[0118] The configuration module 402 is configured to: determine the number and working parameters of the phase regulators to be configured according to the topological structure data;

[0119] The analysis module 403 is configured to: analyze the voltage and reactive sensitivity of the UHV DC sending-end grid based on the grid model to obtain an initial node set of the phase-shifting phase access location;

[0120] The optimization module 404 is configured to: initialize the population based on the initial node set, each individual in the population represents a phase-shifting configuration scheme, and use a quantum genetic algorithm to optimize the phase-shifting configuration scheme to obtain a final phase-shifting configuration scheme, which includes the access position and working parameters of each phase-shifting.

[0121] In other examples of the system, the quantum genetic algorithm is used to optimize the phase condenser configuration scheme to obtain the final phase condenser configuration scheme, and the optimization objective function is:

[0122]

[0123] Among them, V S0 is the initial voltage of the AC busbar of the converter station; V S is the AC bus voltage of the converter station; V Smax V is the maximum rated voltage of the AC busbar of the converter station; Ci0 is the transient voltage after the UHV DC lockout fault; V Cimax is the maximum transient voltage after the UHV DC lockout fault; ω1 and ω2 are weight coefficients; N B is the number of AC busbars in the converter station.

[0124] In other examples of the system, the constraints of the objective function include power balance constraints, steady-state constraints, and transient constraints.

[0125] In other examples of this system, the power balance constraint is:

[0126]

[0127] Where i, j are the node numbers; P gi is the active power output of the power generation node, Q gi P is the reactive power output; di is the active load of the load node, Q di is the reactive load; U i ,θ i is the node voltage amplitude and phase angle; G ij , Bij are the conductance and susceptance elements in the node admittance matrix.

[0128] In other examples of this system, the steady-state constraints are:

[0129]

[0130] Among them, Q ci is the reactive power compensation capacity of the node; U ik is the node voltage; P G is the active power of the power generation equipment, Q G is the reactive power of the generating equipment, n c 、n i is the number of nodes, n G is the number of power generation equipment.

[0131] In other examples of the system, transient constraints include: after a fault occurs, the maximum power angle change value, the maximum transient voltage rise value of the converter station AC bus, and the maximum transient voltage rise value at the base end of the clean energy station are not greater than their respective set values.

[0132] In other examples of the system, the voltage and reactive sensitivity of the UHV DC sending-end grid are analyzed based on the grid model to obtain an initial node set for the phase shifter access location, including: based on the grid model, performing power flow calculations in the power system simulation software to obtain the steady-state operating point of the grid, calculating the Jacobian matrix at the steady-state operating point, and obtaining the voltage sensitivity and reactive sensitivity matrices by solving the inverse of the Jacobian matrix, and then identifying the nodes that are most sensitive to voltage and reactive changes as the initial configuration nodes of the phase shifter based on the values ​​of the sensitivity matrices.

[0133] In other examples of the system, in the analysis of the voltage and reactive sensitivity of the UHV DC sending-end grid based on the grid model, the decoupling algorithm is used to analyze and calculate the voltage and reactive sensitivity of the UHV DC sending-end grid, including:

[0134] Equivalent analysis is performed on the DC system and the AC system respectively; wherein the AC system is equivalent to a constant voltage applied to the corresponding converter, and the DC system is equivalent to a load equal to the active power and reactive power of the converter;

[0135] The sensitivity of the AC system node voltage to the transmission power and the sensitivity of the transmission power to each control variable of the DC system are calculated respectively, and the voltage stability sensitivity of the AC / DC system is obtained.

[0136] According to another embodiment of the present invention, a readable storage medium is provided, on which a computer program is stored; when the computer program is executed, the method for optimizing reactive power configuration of the UHV DC sending-end power grid is implemented.

[0137] The present invention constructs a transient mathematical model of a phase regulator, a reactive compensation device, after a DC lockout fault occurs in an ultra-high voltage DC transmission end network, takes minimizing the voltage deviation between the AC bus of a converter station and the AC bus of a power grid collection substation as an optimization target, constructs a nonlinear programming function with dual targets, proposes a reactive configuration method combining sensitivity screening with an improved quantum genetic algorithm, and verifies with algorithm solving software and power grid transient analysis software that the present invention is used to optimize the configuration of the phase regulator access point position, which can suppress the transient voltage rise of the ultra-high voltage DC transmission transmission sending end power grid, and effectively improves the stability of power grid operation.

[0138] In addition, under the conditions of large-scale clean energy access, the present invention proposes a reactive power configuration method that combines sensitivity screening and quantum genetic algorithm to optimize the configuration of reactive power compensation equipment, which is more conducive to suppressing the transient voltage rise at the base end of clean energy and better implementing the principle of stratified and zoned reactive power compensation and local consumption, so as to achieve the purpose of better responding to various reactive power compensation needs that arise during the operation of complex power grids.

[0139] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A method for optimizing reactive power configuration of a UHV DC sending-end power grid, characterized in that: The method includes: Obtain the topological structure data of the UHV DC sending-end power grid to build a power grid model; Determine the number and working parameters of the phase regulators to be configured according to the topological structure data; Based on the power grid model, the voltage and reactive power sensitivity of the UHV DC sending end grid are analyzed to obtain the initial node set of the phase shifter access location; A population is initialized based on an initial node set, each individual in the population represents a phase modulator configuration scheme, and a quantum genetic algorithm is used to optimize the phase modulator configuration scheme to obtain a final phase modulator configuration scheme; wherein the phase modulator configuration scheme includes the access position of each phase modulator to be configured in the UHV DC sending-end power grid.

2. The method for optimizing reactive power configuration of a UHV DC sending-end power grid according to claim 1, characterized in that: The quantum genetic algorithm is used to optimize the phase-shifting configuration scheme to obtain the final phase-shifting configuration scheme. The optimization objective function is: Among them, V S0 is the initial voltage of the AC busbar of the converter station; V S is the AC bus voltage of the converter station; V Smax is the maximum rated voltage of the AC busbar of the converter station; V Ci0 is the transient voltage after the UHV DC lockout fault; V Cimax is the maximum transient voltage after the UHV DC lockout fault; ω1 and ω2 are weight coefficients; N B is the number of AC busbars in the converter station.

3. The method for optimizing reactive power configuration of a UHV DC sending-end power grid according to claim 2, characterized in that: The constraints of the objective function include power balance constraints, steady-state constraints and transient constraints.

4. The method for optimizing reactive power configuration of a UHV DC sending-end power grid according to claim 3, characterized in that: The power balance constraints are: Where i, j are the node numbers; P gi is the active power output of the power generation node, Q gi P is the reactive power output; di is the active load of the load node, Q di is the reactive load; U i ,θ i is the node voltage amplitude and phase angle; G ij , B ij are the conductance and susceptance elements in the node admittance matrix.

5. The method for optimizing reactive power configuration of a UHV DC sending-end power grid according to claim 3, characterized in that: The steady-state constraints are: Among them, Q ci is the reactive power compensation capacity of the node; U ik is the node voltage; P G is the active power of the power generation equipment, Q G is the reactive power of the generating equipment, n c 、n i is the number of nodes, n G is the number of power generation equipment.

6. The method for optimizing reactive power configuration of a UHV DC sending-end power grid according to claim 3, characterized in that: The transient constraint conditions include: after a fault occurs, the maximum power angle change value, the maximum transient voltage rise value of the converter station AC bus, and the maximum transient voltage rise value at the base end of the clean energy station are not greater than their respective set values.

7. The method for optimizing reactive power configuration of a UHV DC sending-end power grid according to claim 1, characterized in that: The method analyzes the voltage and reactive power sensitivity of the UHV DC sending-end power grid based on the power grid model to obtain an initial node set for the phase shifter access position, including: based on the power grid model, executing power flow calculation in power system simulation software to obtain the steady-state operating point of the power grid, calculating the Jacobian matrix at the steady-state operating point, and obtaining the voltage sensitivity and reactive power sensitivity matrices by solving the inverse of the Jacobian matrix, and then identifying the nodes most sensitive to voltage and reactive power changes as the initial configuration nodes of the phase shifter according to the values ​​of the sensitivity matrix.

8. The method for optimizing reactive power configuration of a UHV DC sending-end power grid according to claim 1, characterized in that: In the analysis of the voltage and reactive power sensitivity of the UHV DC sending-end grid based on the grid model, the voltage and reactive power sensitivity of the UHV DC sending-end grid are analyzed and calculated using a decoupling algorithm, including: Equivalent analysis is performed on the DC system and the AC system respectively; wherein the AC system is equivalent to a constant voltage applied to the corresponding converter, and the DC system is equivalent to a load equal to the active power and reactive power of the converter; The sensitivity of the AC system node voltage to the transmission power and the sensitivity of the transmission power to each control variable of the DC system are calculated respectively, and the voltage stability sensitivity of the AC / DC system is obtained.

9. A reactive power optimization configuration system for a UHV DC sending-end power grid, characterized in that: The system includes: The acquisition module is configured to: obtain topological structure data of the UHV DC sending-end power grid to construct a power grid model; The configuration module is configured to: determine the number and working parameters of the phase regulators to be configured according to the topological structure data; The analysis module is configured to: analyze the voltage and reactive sensitivity of the UHV DC sending-end grid based on the grid model to obtain an initial node set of the phase shifter access location; The optimization module is configured to: initialize a population based on an initial node set, each individual in the population represents a phase-shifting configuration scheme, and use a quantum genetic algorithm to optimize the phase-shifting configuration scheme to obtain a final phase-shifting configuration scheme; wherein the phase-shifting configuration scheme includes the access position of each phase-shifting to be configured in the ultra-high voltage direct current sending-end power grid.

10. The reactive power optimization configuration system for the UHV DC sending-end power grid according to claim 9, characterized in that: The quantum genetic algorithm is used to optimize the phase-shifting configuration scheme to obtain the final phase-shifting configuration scheme. The optimization objective function is: Among them, V S0 is the initial voltage of the AC busbar of the converter station; V S is the AC bus voltage of the converter station; V Smax is the maximum rated voltage of the AC busbar of the converter station; V Ci0 is the transient voltage after the UHV DC lockout fault; V Cimax is the maximum transient voltage after the UHV DC lockout fault; ω1 and ω2 are weight coefficients; N B is the number of AC busbars in the converter station.

11. The reactive power optimization configuration system for the UHV DC sending-end power grid according to claim 10, characterized in that: The constraints of the objective function include power balance constraints, steady-state constraints and transient constraints.

12. The reactive power optimization configuration system for the UHV DC sending-end power grid according to claim 11, characterized in that: The power balance constraints are: Where i, j are the node numbers; P gi is the active power output of the power generation node, Q gi P is the reactive power output; di is the active load of the load node, Q di is the reactive load; U i ,θ i is the node voltage amplitude and phase angle; G ij , B ij are the conductance and susceptance elements in the node admittance matrix.

13. The reactive power optimization configuration system for the UHV DC sending-end power grid according to claim 11, characterized in that: The steady-state constraints are: Among them, Q ci is the reactive power compensation capacity of the node; U ik is the node voltage; P G is the active power of the power generation equipment, Q G is the reactive power of the generating equipment, n c 、n i is the number of nodes, n G is the number of power generation equipment.

14. The reactive power optimization configuration system for the UHV DC sending-end power grid according to claim 11, characterized in that: The transient constraint conditions include: after a fault occurs, the maximum power angle change value, the maximum transient voltage rise value of the converter station AC bus, and the maximum transient voltage rise value at the base end of the clean energy station are not greater than their respective set values.

15. The reactive power optimization configuration system for the UHV DC sending-end power grid according to claim 9, characterized in that: The method analyzes the voltage and reactive power sensitivity of the UHV DC sending-end power grid based on the power grid model to obtain an initial node set for the phase shifter access position, including: based on the power grid model, executing power flow calculation in power system simulation software to obtain the steady-state operating point of the power grid, calculating the Jacobian matrix at the steady-state operating point, and obtaining the voltage sensitivity and reactive power sensitivity matrices by solving the inverse of the Jacobian matrix, and then identifying the nodes most sensitive to voltage and reactive power changes as the initial configuration nodes of the phase shifter according to the values ​​of the sensitivity matrix.

16. The reactive power optimization configuration system for the UHV DC sending-end power grid according to claim 9, characterized in that: In the analysis of the voltage and reactive power sensitivity of the UHV DC sending-end grid based on the grid model, the voltage and reactive power sensitivity of the UHV DC sending-end grid are analyzed and calculated using a decoupling algorithm, including: Equivalent analysis is performed on the DC system and the AC system respectively; wherein the AC system is equivalent to a constant voltage applied to the corresponding converter, and the DC system is equivalent to a load equal to the active power and reactive power of the converter; The sensitivity of the AC system node voltage to the transmission power and the sensitivity of the transmission power to each control variable of the DC system are calculated respectively, and the voltage stability sensitivity of the AC / DC system is obtained.

17. A readable storage medium, characterized in that: The readable storage medium stores a computer program; when the computer program is executed, the method for optimizing reactive power configuration of the UHV DC sending-end power grid as described in any one of claims 1 to 8 is implemented.

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