Method and system for identifying parameters of extra-high voltage direct current electromagnetic transient model controller

Abstract

The invention discloses an ultrahigh-voltage direct-current electromagnetic transient model controller parameter identification method and system, and the method comprises the steps: dividing the parameters of a direct-current controller into upper and lower limit parameters, proportional gain parameters and time constant parameters according to the structure of a typical controller of an ultrahigh-voltage direct-current power transmission system and the response characteristics during a fault period; performing sensitivity analysis on the parameters of the direct-current controller based on a trajectory sensitivity method, and calculating the average trajectory sensitivity of the parameters of each controller; based on a calculation result of the average trajectory sensitivity, in combination with an identification sequence of first upper and lower limit type parameters and then proportional gain type parameters, performing identification in the same type of parameters according to a sequence from high to low of the average trajectory sensitivity; and updating an identification result to the electromagnetic transient model of the extra-high-voltage direct-current power transmission system, and identifying the time constant type parameters by using a particle swarm optimization algorithm. According to the method, the response characteristics of the actual direct-current power transmission project in the typical fault scene can be well reflected.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-high voltage direct current (UHV DC) transmission system modeling for electric power systems, and in particular to an ultra-high voltage direct current (UHV DC) electromagnetic transient model controller parameter identification method and system. Background Art

[0002] Ultra-high voltage direct current transmission has the advantages of long transmission distance, large transmission capacity, small transmission loss and low unit cost. It is widely used in large-scale new energy transmission, which greatly alleviates the electricity shortage in my country and has become one of the important research issues in the power system. With the rapid development and large-scale operation of ultra-high voltage direct current transmission projects, the dynamic characteristics of the power grid have changed, and new problems such as commutation failure, DC blocking and DC short circuit have been introduced, which seriously affect the power angle, frequency and voltage stability of the power grid and pose new challenges to the safe operation of the power grid. By establishing an ultra-high voltage direct current transmission simulation model, the actual power grid operation characteristics can be simulated to guide the commissioning and control of the actual project.

[0003] Regarding the establishment of UHV DC transmission system models, researchers have already come up with a variety of solutions, such as: 1. "Electromechanical Transient Equivalent Modeling and Parameter Measurement Method for UHV DC Control Systems" published by Wan Lei et al., 2017, Department of Electrical Engineering and Applied Electronics Technology, Tsinghua University. This paper proposed three UHV DC transmission system modeling methods based on electromechanical transient models, namely the aggregation equivalent method, the effective value equivalent method, and the substitution equivalent method. Combined with field measured data, the UHV DC transmission system model parameters were clarified through segmented and overall parameter verification, and the effectiveness of the proposed method was verified through simulation. 2. "Open Modeling of UHV DC Transmission Control and Protection System Based on ADPSS / ETSDAC" by Tan Yangchen et al., 2018, State Key Laboratory of High Electromagnetic Engineering and New Technologies (School of Electrical and Electronic Engineering, Huazhong University of Science and Technology). This paper establishes an open electromagnetic transient model of UHV DC transmission system based on the ADPSS electromagnetic transient simulation calculation platform. The DC controller parameters can be modified according to the control and protection characteristics of the actual DC project. Through simulation, the effectiveness of the commutation failure protection and bypass control links is verified. The effectiveness of the model is verified by comparing the simulation results of the model with those of the control and protection joint model during the fault period. 3. "Modeling and Simulation Analysis of UHV DC Transmission System Based on PSCAD" by Duo Yu et al., 2020, School of Energy and Electrical Engineering, Hohai University. This paper establishes a UHV DC transmission model based on PSCAD / EMTDC electromagnetic simulation software. Based on this model, the controller action during the DC commutation failure fault is analyzed, and the changes in the DC system during the commutation failure are clarified.

[0004] In summary, the current UHV DC transmission system modeling methods are mostly based on typical response characteristics. Although the work is carried out with reference to the actual model, the focus is still on the response characteristics during the fault response. There are still certain differences between the model output results and the actual DC transmission system. The controller parameters of the actual model need to be further clarified in order to better reflect the response characteristics of the actual DC transmission system during the fault. Summary of the invention

[0005] In view of the above existing problems, the present invention is proposed.

[0006] Therefore, the present invention provides a method and system for identifying parameters of a UHV DC electromagnetic transient model controller to solve the problem that there is still a certain difference between the simulation results of the electromagnetic transient model of the current UHV DC transmission system and the actual DC transmission system.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] In a first aspect, the present invention provides a method for identifying parameters of a UHV DC electromagnetic transient model controller, comprising: dividing the DC controller parameters into upper and lower limit parameters, proportional gain parameters and time constant parameters according to the response characteristics of the rectifier side and inverter side controllers under different fault scenarios and the influence of the DC controller parameters on the DC voltage, DC current and AC voltage on the rectifier side; performing sensitivity analysis on the DC controller parameters based on a trajectory sensitivity method, and calculating the average trajectory sensitivity of each controller parameter; based on the calculation result of the average trajectory sensitivity, combined with the identification order of first the upper and lower limit parameters and then the proportional gain parameters, carrying out identification in the same category parameters in the order of the average trajectory sensitivity from high to low; updating the identification result to the electromagnetic transient model of the UHV DC transmission system, and identifying the time constant parameters using a particle swarm optimization algorithm.

[0009] As a preferred solution of the method for identifying parameters of a UHV DC electromagnetic transient model controller according to the present invention, the identification of the upper and lower limit parameters includes:

[0010] By setting the three-phase short circuit fault on the rectifier side, the three-phase short circuit fault on the inverter side and the DC short circuit fault, the collected signals are focused on to identify the upper and lower limit parameters, which include the input and output limits of each controller and the upper and lower limits of voltage and current in the low voltage current limiting link.

[0011] As a preferred solution of the method for identifying parameters of the UHV DC electromagnetic transient model controller of the present invention, the identification of the proportional gain parameters includes:

[0012] When the system is in steady-state operation, a step signal is applied to the reference DC current command of the constant current controller on the rectifier side and a step signal is applied to the reference turn-off angle command of the constant turn-off angle controller to identify the proportional gain parameters of each controller;

[0013] Set the three-phase short circuit fault on the rectifier side, the three-phase short circuit fault on the inverter side and the DC short circuit fault to switch the control dominance of the inverter side, apply a step signal to the corresponding controller reference command when the constant current controller and the constant voltage controller on the inverter side play a leading role, and identify the proportional gain parameters of the corresponding controller;

[0014] The proportional gain parameters include proportional link coefficients of a constant current controller, a constant voltage controller and a constant turn-off angle controller.

[0015] As a preferred solution of the method for identifying parameters of a UHV DC electromagnetic transient model controller according to the present invention, the electromagnetic transient model of the UHV DC power transmission system includes:

[0016] The electromagnetic transient model of the ultra-high voltage direct current transmission system is established by covering a variety of ultra-high voltage direct current transmission system controller structures. The electromagnetic transient model of the ultra-high voltage direct current transmission system realizes the control of the ultra-high voltage direct current transmission system through the methods of rectifier side constant current control, inverter side constant current control, inverter side constant shutdown angle control, inverter side constant voltage control, low voltage current limiting control, and current deviation control;

[0017] The rectifier side trigger angle signal is output by the constant current controller, and the inverter side trigger angle signal takes the minimum value of the three controller output signals of the inverter side constant current control, the inverter side constant turn-off angle control, and the inverter side constant voltage control.

[0018] As a preferred solution of the method for identifying parameters of the UHV DC electromagnetic transient model controller of the present invention, the method of obtaining data of the UHV DC transmission system electromagnetic transient model and the black box UHV DC transmission system model under various working conditions before identification includes:

[0019] The data under the various working conditions include the fault ride-through full process test data of the UHV DC transmission system electromagnetic transient model and the black box UHV DC transmission system model and the dominant parameters affecting the fault ride-through full process;

[0020] The dominant parameters include the proportional integral coefficient and output limit parameter of the constant current controller on the rectifier side, the proportional integral coefficient and output limit parameter of the constant current controller on the inverter side, the proportional integral coefficient and output limit parameter of the constant voltage controller on the inverter side, the proportional integral coefficient and output limit parameter of the constant shutdown angle controller on the inverter side, the upper limit threshold parameter of the low voltage current limiting controller on the inverter side and the proportional coefficient of the current deviation controller on the inverter side.

[0021] As a preferred solution of the method for identifying parameters of an ultra-high voltage direct current electromagnetic transient model controller of the present invention, the identification is carried out in the order of the average trajectory sensitivity from high to low in the parameters of the same category, so that the error between the steady-state response result and the transient response result of the electromagnetic transient model of the ultra-high voltage direct current transmission system and the black box ultra-high voltage direct current transmission system model meets the preset requirements, and the identification of the parameters of the electromagnetic transient model controller of the ultra-high voltage direct current transmission system is completed.

[0022] As a preferred solution of the method for identifying parameters of a UHV DC electromagnetic transient model controller according to the present invention, the method for identifying the time constant parameters by using a particle swarm optimization algorithm includes:

[0023] The unidentified time constant type parameters are updated to the electromagnetic transient model of the UHV DC power transmission system by default as empirical values;

[0024] The three-phase short-circuit fault of the AC busbar on the rectifier side and the inverter side and the DC line fault are set respectively, and the size of the time constant parameters is adjusted to obtain the value range of each time constant parameter;

[0025] The time constant type parameters to be identified are set as position parameters, and the initial values ​​of the position parameters are obtained based on the value ranges of the time constant type parameters;

[0026] taking the error between the simulation results of the electromagnetic transient model of the UHV DC transmission system and the black box UHV DC transmission system model as the objective function;

[0027] Calculate whether the objective function is less than a preset threshold value. If it is not less than the threshold value, update the speed and position of the particle, and then update the controller parameter value. If it is less than the threshold value, output the parameter group at this time.

[0028] The initial value of the time constant parameter is changed, and the particle swarm optimization algorithm is performed again to obtain the time constant parameter value, and the average value of ten time constant parameter identification results is taken as the final identification result.

[0029] In a second aspect, the present invention provides a UHV DC electromagnetic transient model controller parameter identification system, comprising:

[0030] A parameter grouping module, used to divide the DC controller parameters into upper and lower limit parameters, proportional gain parameters and time constant parameters according to the response characteristics of the rectifier and inverter side controllers under different fault scenarios and the influence of the DC controller parameters on the DC voltage, DC current and the rectifier side AC voltage;

[0031] A sensitivity analysis module, used to perform sensitivity analysis on the DC controller parameters based on a trajectory sensitivity method, and calculate the average trajectory sensitivity of each controller parameter;

[0032] A first identification module is used to identify the parameters of the same category in the order of the average trajectory sensitivity from high to low based on the calculation result of the average trajectory sensitivity and in combination with the identification order of first the upper and lower limit parameters and then the proportional gain parameters;

[0033] The second identification module is used to update the identification result to the electromagnetic transient model of the ultra-high voltage direct current transmission system, and use the particle swarm optimization algorithm to identify the time constant type parameters.

[0034] In a third aspect, the present invention provides a computing device, comprising:

[0035] Memory and processor;

[0036] The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the parameter identification method of the ultra-high voltage direct current electromagnetic transient model controller are implemented.

[0037] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the method for identifying parameters of the ultra-high voltage direct current electromagnetic transient model controller.

[0038] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a method and system for identifying the parameters of the electromagnetic transient model controller of an ultra-high voltage direct current transmission system based on a black box ultra-high voltage direct current transmission system model, which can establish an electromagnetic transient model and perform parameter identification on the black box ultra-high voltage direct current transmission system model of an actual ultra-high voltage direct current transmission system. The purpose of parameter identification is to make the external characteristics of the electromagnetic transient model of the ultra-high voltage direct current transmission system under different working conditions consistent with the actual device within a certain error range, and the result of parameter identification is the controller parameters of the ultra-high voltage direct current transmission system. The method provided by the present invention is not a blind parameter optimization algorithm. By classifying the parameters and identifying them step by step, the controller parameters can be accurately obtained to a certain extent. Based on the partially accurate controller parameters, the remaining parameters are identified within a certain range. By improving the particle swarm optimization algorithm, the identification results are optimized, ensuring that the model characteristics are consistent with the actual project, and making the simulation results more suitable for actual engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0040] Figure 1 A schematic diagram of the overall process logic of a method for identifying parameters of a UHV DC electromagnetic transient model controller according to an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of the hardware circuit structure of a UHV DC power transmission system of a method for identifying parameters of a UHV DC electromagnetic transient model controller according to an embodiment of the present invention;

[0042] Figure 3 A schematic diagram of the control circuit structure of an ultra-high voltage direct current transmission system of an ultra-high voltage direct current electromagnetic transient model controller parameter identification method according to an embodiment of the present invention;

[0043] Figure 4 A flow chart of parameter identification of an electromagnetic transient model controller of an ultra-high voltage direct current transmission system according to an ultra-high voltage direct current electromagnetic transient model controller parameter identification method according to an embodiment of the present invention;

[0044] Figure 5 A comparison diagram of simulation results of AC voltage on the rectifier side of a black box UHV DC transmission system model under a three-phase short circuit fault on the inverter side of an UHV DC electromagnetic transient model controller parameter identification method according to an embodiment of the present invention;

[0045] Figure 6 A comparison diagram of DC voltage simulation results of an UHV DC system electromagnetic transient model of a UHV DC electromagnetic transient model controller parameter identification method according to an embodiment of the present invention and a black box UHV DC system model under a three-phase short circuit fault on the inverter side;

[0046] Figure 7 A comparison diagram of DC current simulation results of an UHV DC system electromagnetic transient model of a UHV DC electromagnetic transient model controller parameter identification method according to an embodiment of the present invention and a black box UHV DC system model under a three-phase short circuit fault on the inverter side;

[0047] Figure 8 A schematic diagram of error calculation between an electromagnetic transient model of an ultra-high voltage direct current transmission system of a method for identifying parameters of an ultra-high voltage direct current electromagnetic transient model controller according to an embodiment of the present invention and a simulation result of a black box ultra-high voltage direct current transmission system model under a three-phase short circuit fault on the inverter side. DETAILED DESCRIPTION

[0048] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0049] Example 1

[0050] Reference Figure 1-Figure 8 As an embodiment of the present invention, a method for identifying parameters of a UHV DC electromagnetic transient model controller is provided. Figure 1 The specific steps shown include:

[0051] S100: According to the response characteristics of the rectifier-side and inverter-side controllers under different fault scenarios and the influence of the DC controller parameters on the DC voltage, DC current, and AC voltage on the rectifier side, the DC controller parameters are divided into upper and lower limit parameters, proportional gain parameters, and time constant parameters;

[0052] S200: Perform sensitivity analysis on the DC controller parameters based on the trajectory sensitivity method and calculate the average trajectory sensitivity of each controller parameter;

[0053] S300: Based on the calculation result of the average trajectory sensitivity, combined with the identification order of first the upper and lower limit parameters and then the proportional gain parameters, the parameters of the same category are identified in the order of the average trajectory sensitivity from high to low;

[0054] S400: updating the identification result to the electromagnetic transient model of the UHV DC transmission system, and identifying time constant parameters using a particle swarm optimization algorithm;

[0055] It should be noted that the present invention provides a method and system for identifying the parameters of the electromagnetic transient model controller of an ultra-high voltage direct current transmission system based on a black box ultra-high voltage direct current transmission system model, which can establish an electromagnetic transient model and identify parameters of the black box ultra-high voltage direct current transmission system model of the actual ultra-high voltage direct current transmission system. The purpose of parameter identification is to make the external characteristics of the electromagnetic transient model of the ultra-high voltage direct current transmission system under different working conditions consistent with the actual device within a certain error range, and the result of parameter identification is the controller parameters of the ultra-high voltage direct current transmission system. The method provided by the present invention is not a blind parameter optimization algorithm. By classifying the parameters and identifying them step by step, the controller parameters can be accurately obtained to a certain extent. Based on the partially accurate controller parameters, the remaining parameters are identified within a certain range. By improving the particle swarm optimization algorithm, the identification results are optimized, ensuring that the model characteristics are consistent with the actual project, and making the simulation results more suitable for actual engineering applications.

[0056] In the embodiment of the present application, the above step S100 is based on the current mainstream PSCAD / EMTDC simulation software, and by covering the UHV DC transmission system controller structure of various structures, an electromagnetic transient model of the UHV DC transmission system is constructed. The hardware circuit structure of the model is as follows: Figure 2 As shown, it contains AC system, DC transmission line, AC and DC filter group, smoothing reactor, bypass circuit breaker, rectifier station and inverter station, etc. Each converter station is bipolar transmission, each pole is composed of two groups of 12-pulse converters in series, with a rated DC voltage of ±800kV and a transmission power of 8000MW. The UHV DC transmission system mainly contains constant current control, constant voltage control, fixed shutdown angle control, low voltage current limiting control and current deviation control. The controller structure is as follows Figure 3 The electromagnetic transient model of the UHV DC transmission system realizes the control of the UHV DC transmission system through the methods of constant current control on the rectifier side, constant current control on the inverter side, constant turn-off angle control on the inverter side, constant voltage control on the inverter side, low voltage current limiting control, and current deviation control; the trigger angle signal on the rectifier side is output by the constant current controller, and the trigger angle signal on the inverter side takes the minimum value of the output signals of the three controllers: constant current control on the inverter side, constant turn-off angle control on the inverter side, and constant voltage control on the inverter side.

[0057] Specifically, before identification is performed, data of the electromagnetic transient model of the UHV DC transmission system and the black box UHV DC transmission system model under various working conditions are obtained, wherein the data under various working conditions include the full-process test data of the electromagnetic transient model of the UHV DC transmission system and the black box UHV DC transmission system model for fault ride-through and dominant parameters affecting the full-process of fault ride-through;

[0058] Specifically, the dominant parameters that affect the response characteristics of the UHV DC transmission system during a fault include: the proportional coefficient K of the constant current controller on the rectifier sideIpr , integral coefficient T Iir , output upper limit α max , output lower limit α min ; Inverter side constant current controller proportional coefficient K Ipi , integral coefficient T Iii , output upper limit β Imax , output lower limit β Imin ; Inverter side fixed cut-off angle controller proportional coefficient K Gpi , integral coefficient T Gii , output upper limit β Gmax , output lower limit β Gmin ; Inverter side constant voltage controller proportional coefficient K Vpi , integral coefficient T Vii , output upper limit β Vmax , output lower limit β Vmin ; Inverter side low voltage current limiting controller voltage upper limit U high , voltage lower limit U dlow 、Current upper limit I olim , Current lower limit I omin ; Proportional coefficient K of inverter side current deviation controller CEC And the filter time constant T of each controller input rI , T iI , T iG , T iV .

[0059] In the embodiment of the present application, the above step S200 includes the following sub-steps B1-B2;

[0060] In B1: sensitivity analysis of DC controller parameters is performed based on trajectory sensitivity method;

[0061] In B2: Calculate the average trajectory sensitivity of each controller parameter;

[0062] In an optional implementation, the controllers on the rectifier side and the inverter side of the DC control system are coupled to each other. There are many controller parameters and the degree of influence on the DC results is different. It is necessary to quantify the sensitivity of the controller parameters and select the parameters with higher sensitivity for priority identification. The calculation method of the trajectory sensitivity is expressed as:

[0063]

[0064] Among them, θ i is the controller parameter, θ i0 is the initial value of the i-th controller parameter, Δθ i is the change of the i-th controller parameter, j is the different working conditions, t is the number of all parameters, is the trajectory sensitivity of the controller parameters, yj0 The parameter is θ under working condition j i0 The simulation results are as follows: is the parameter θ i Increase Δθ i The simulation results under working condition j are: is the parameter θ i Reduce Δθ i Simulation results under working condition j.

[0065] In an optional implementation, in the process of calculating the sensitivity of the controller parameter, the average trajectory sensitivity is calculated. The larger the calculation result, the stronger the sensitivity of the parameter. The average trajectory sensitivity is expressed as:

[0066]

[0067] in, is the average trajectory sensitivity calculation result of parameter i under working condition j, and N is the number of all sampling points involved in the sensitivity calculation.

[0068] It should be noted that the above step S200 performs sensitivity analysis on the DC controller parameters based on the trajectory sensitivity method, calculates the average trajectory sensitivity of each controller parameter, and thus can quantify the influence of different parameters on the dynamic behavior of the system. This method can not only identify the parameters that have the greatest impact on the system performance, but also provide a basis for subsequent parameter identification, ensuring that those parameters that are critical to the system stability and performance are adjusted first, thereby improving the control accuracy and response speed of the UHV DC transmission system.

[0069] In the embodiment of the present application, the above step S300 includes the following sub-steps C1-C2;

[0070] In C1: the upper and lower limit parameters are identified in the order of average trajectory sensitivity from high to low;

[0071] In C2: the proportional gain parameters are identified in the order of average trajectory sensitivity from high to low;

[0072] In an optional embodiment, identifying the upper and lower limit parameters includes: identifying the upper and lower limit parameters by paying attention to the collected signals through setting the three-phase short circuit fault on the rectifier side, the three-phase short circuit fault on the inverter side and the DC short circuit fault, and the upper and lower limits are reached when the slope of the curve is 0, wherein the upper and lower limit parameters include the input and output limits of each controller and the upper and lower limits of voltage and current in the low voltage current limiting link.

[0073] In an optional implementation, identifying the proportional gain parameters includes:

[0074] When the system is in steady-state operation, a step signal is applied to the reference DC current command of the constant current controller on the rectifier side and a step signal is applied to the reference turn-off angle command of the constant turn-off angle controller to identify the proportional gain parameters of each controller;

[0075] Set the three-phase short circuit fault on the rectifier side, the three-phase short circuit fault on the inverter side and the DC short circuit fault to switch the control dominance of the inverter side, apply a step signal to the corresponding controller reference command when the constant current controller and the constant voltage controller on the inverter side play a leading role, and identify the proportional gain parameters of the corresponding controller;

[0076] Among them, the proportional gain parameters include the proportional link coefficients of the constant current controller, the constant voltage controller and the constant turn-off angle controller.

[0077] Specifically, the proportional gain parameters identified by setting the step signal can be expressed as:

[0078]

[0079] Among them, K u K is a proportional gain parameter when an upward step signal is applied. d K is a proportional gain parameter when a step signal is applied. p is a proportional gain parameter of a controller, ΔP ou is the applied upward step signal command, ΔP od is the applied lower step signal command, α u is the output of the controller when an upward step signal is applied, α d is the output of the controller when the next step signal is applied, α 0 is the output of the controller in steady state, N u and N d are the number of up-step tests and down-step tests respectively.

[0080] It should be noted that the above step S300 is based on the calculation result of the average trajectory sensitivity, and according to the pre-set parameter identification order (upper and lower limit parameters first, then proportional gain parameters), parameter identification is performed in the same category in the order of high to low average trajectory sensitivity. This can ensure that the parameters that have the greatest impact on system performance are adjusted first, thereby efficiently optimizing the behavior of the control system, and helping the system to reach the ideal operating state more quickly, thereby improving the stability and reliability of the UHV DC transmission system.

[0081] In the embodiment of the present application, the above step S400 is as follows Figure 4 The method includes the following sub-steps D1-D2;

[0082] In D1: After carrying out identification in the order of average trajectory sensitivity from high to low in the same category of parameters, the steady-state response results and transient response results of the electromagnetic transient model of the UHV DC transmission system and the errors of the black box UHV DC transmission system model meet the preset requirements, and the parameter identification of the electromagnetic transient model controller of the UHV DC transmission system is completed;

[0083] In D2: the particle swarm optimization algorithm is used to identify time constant parameters;

[0084] In a feasible implementation, using a particle swarm optimization algorithm to identify time constant parameters includes:

[0085] The unidentified time constant parameters are updated to the electromagnetic transient model of the UHV DC transmission system by defaulting to the empirical values;

[0086] The three-phase short-circuit fault of the AC busbar on the rectifier side and the inverter side and the DC line fault are set respectively, and the size of the time constant parameters is adjusted to obtain the value range of each time constant parameter;

[0087] The time constant type parameters to be identified are set as position parameters, and the initial values ​​of the position parameters are obtained based on the value ranges of the time constant type parameters;

[0088] The error between the simulation results of the electromagnetic transient model of the UHV DC transmission system and the black box UHV DC transmission system model is used as the objective function;

[0089] Calculate whether the objective function is less than the preset threshold value of 0.125. If it is not less than the threshold value, update the particle speed and position, and then update the controller parameter value. If it is less than the threshold value, output the parameter group at this time.

[0090] The initial value of the time constant parameter is changed, and the particle swarm optimization algorithm is used again to obtain the time constant parameter value. The average value of the ten time constant parameter identification results is taken as the final identification result.

[0091] Specifically, the time constant parameters to be identified are grouped according to the controllers they belong to. The time constant parameters to be identified in the rectifier side constant current controller, inverter side constant current controller, constant voltage controller, fixed turn-off angle controller and current deviation control link are each divided into a group of particles. Each parameter is a particle in the corresponding particle group. The controller parameter value is specified as the particle position. The objective function f can be expressed as:

[0092]

[0093] Among them, x is the current particle swarm position set, y(x) is the simulation result of the electromagnetic transient model of the UHV DC transmission system obtained by the current parameter group, y is the simulation result of the black box model, and i is different operating scenarios;

[0094] The velocity and position of a particle can be expressed as:

[0095]

[0096] ν jd (t) = w*v jd (t-1)+c1*r1*(p id (t)-x jd (t-1))+c2*r2*(p gd (t)-x jd (t-1))

[0097] x jd (t) = x jd (t-1)+ν jd (t)

[0098] Among them, w is the inertia weight, v is the particle velocity, j is the particle sequence, d is the decision variable sequence, t is the number of iterations, c1 and c2 are learning factors, r1 and r2 are random functions in [0,1], and p i is the individual optimum, p g is the optimal value for the group, and x is the particle position;

[0099] Based on the particle swarm optimization algorithm, ten groups of different initial values ​​are used for particle swarm optimization. The average value of ten identification results is taken as the final identification result. The initial position of the particle swarm can be defined as:

[0100]

[0101] Among them, (h+1) is the number of optimizations, a x and b x are the lower and upper limits of the value range of particle x respectively.

[0102] It should be noted that the above step S400 can effectively handle complex optimization problems and find the global optimal solution through swarm intelligence, thereby improving the setting of time constant parameters, enhancing the system's adaptability and stability to different working conditions, and ensuring that the UHV DC transmission system can maintain good dynamic performance under various operating conditions.

[0103] The following is an application example of a method for identifying parameters of a UHV DC electromagnetic transient model controller provided by this embodiment, specifically:

[0104] In the embodiment of the present application, the verification method of the identification result is: refer to the "GB / T 40580-2021 Technical Guidelines for Electromechanical Transient Simulation Modeling of High Voltage Direct Current Transmission Technology" to perform error analysis on the identification result, divide the fault interval into three intervals: A (transient before fault), B (transient during fault), C (steady state after fault), and assign weights to each interval. For the divided intervals, the steady-state interval average error F1, transient interval average error F2, steady-state interval maximum error F3 and weighted average total error F of all intervals are calculated according to the following formula for each electrical quantity: PG :

[0105]

[0106] F PG =K A F AP +K B1 F B1P +K B2 F B2P +K Cl F ClP +K C2 F C2P

[0107] Among them, X M is the per unit value of the electrical quantity simulation result of the black box model, X S To identify the per unit value of the model electrical quantity simulation results, K M_Start , K S_Start , K M_End , K S_End They are the first and last data of the corresponding interval respectively;

[0108] In the embodiment of the present application, a three-phase short circuit fault is applied to the inverter-side AC busbar, and the simulation results of the electromagnetic transient model and the black box model of the ultra-high voltage DC transmission system are observed. The simulation results of the rectifier-side AC voltage, the inverter-side DC voltage, and the rectifier-side DC current are as follows: Figure 5 , Figure 6 , Figure 7 As shown in the figure, the error calculation results of the electromagnetic transient model of the UHV DC transmission system and the black box model are as follows: AC voltage on the rectifier side, DC voltage on the rectifier side, DC voltage on the inverter side, DC current on the rectifier side, DC current on the inverter side, trigger angle on the rectifier side, and trigger angle on the inverter side. Figure 8 shown.

[0109] It can be concluded from the above experimental results that the present invention can establish an electromagnetic transient model and identify parameters for the black box UHV DC transmission system model of the actual UHV DC transmission system. The purpose of parameter identification is to make the external characteristics of the electromagnetic transient model of the UHV DC transmission system under different working conditions consistent with the actual device within a certain error range. The result of parameter identification is the controller parameters of the UHV DC transmission system. The method provided by the present invention is not a blind parameter optimization algorithm. By classifying the parameters and identifying them step by step, the controller parameters can be accurately obtained to a certain extent. Based on the partially accurate controller parameters, the remaining parameters are identified within a certain range. By improving the particle swarm optimization algorithm, the identification results are optimized, ensuring that the model characteristics are consistent with the actual project, and making the simulation results more suitable for actual engineering applications.

[0110] Example 2

[0111] This embodiment provides a UHV DC electromagnetic transient model controller parameter identification system, including a parameter grouping module, a sensitivity analysis module, a first identification module and a second identification module;

[0112] Specifically, the parameter grouping module is used to divide the DC controller parameters into upper and lower limit parameters, proportional gain parameters and time constant parameters according to the response characteristics of the rectifier and inverter side controllers under different fault scenarios and the influence of the DC controller parameters on the DC voltage, DC current and the rectifier side AC voltage;

[0113] Specifically, the sensitivity analysis module is used to perform sensitivity analysis on the DC controller parameters based on the trajectory sensitivity method and calculate the average trajectory sensitivity of each controller parameter;

[0114] Specifically, the first identification module is used to carry out identification in the same category of parameters in the order of average trajectory sensitivity from high to low based on the calculation result of the average trajectory sensitivity, combined with the identification order of upper and lower limit parameters first and then proportional gain parameters;

[0115] Specifically, the second identification module is used to update the identification results to the electromagnetic transient model of the ultra-high voltage direct current transmission system, and use the particle swarm optimization algorithm to identify time constant parameters.

[0116] It should be noted that the technical solution of the system for identifying parameters of the ultra-high voltage direct current electromagnetic transient model controller and the technical solution of the above-mentioned method for identifying parameters of the ultra-high voltage direct current electromagnetic transient model controller belong to the same concept. For the details not described in detail in the technical solution of the system for identifying parameters of the ultra-high voltage direct current electromagnetic transient model controller in this embodiment, please refer to the description of the technical solution of the above-mentioned method for identifying parameters of the ultra-high voltage direct current electromagnetic transient model controller.

[0117] The above-mentioned unit modules may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above-mentioned modules.

[0118] This embodiment also provides a computing device, which includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, an operator network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for identifying parameters of a UHV DC electromagnetic transient model controller is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a button, trackball or touchpad set on the housing of the computer device, or an external keyboard, touchpad or mouse.

[0119] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method proposed in the above embodiment is implemented.

[0120] The storage medium proposed in this embodiment and the method proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0121] Through the above description of the implementation methods, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ReadOnly, Memory, ROM), random access memory (RandomAccess Memory, RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform the methods of various embodiments of the present invention.

[0122] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0123] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0124] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0125] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0126] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1The steps for the functions specified in one or more boxes.

[0127] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0128] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for identifying parameters of a UHV DC electromagnetic transient model controller, characterized in that: include: According to the response characteristics of the rectifier and inverter side controllers under different fault scenarios and the influence of the DC controller parameters on the DC voltage, DC current and the AC voltage on the rectifier side, the DC controller parameters are divided into upper and lower limit parameters, proportional gain parameters and time constant parameters; Performing sensitivity analysis on the DC controller parameters based on the trajectory sensitivity method, and calculating the average trajectory sensitivity of each controller parameter; Based on the calculation result of the average trajectory sensitivity, combined with the identification order of upper and lower limit parameters first and then proportional gain parameters, the identification is carried out in the same category of parameters in the order of the average trajectory sensitivity from high to low; The identification results are updated to the electromagnetic transient model of the ultra-high voltage direct current transmission system, and the time constant parameters are identified using a particle swarm optimization algorithm.

2. The method for identifying parameters of a UHV DC electromagnetic transient model controller according to claim 1, characterized in that: Identifying the upper and lower limit parameters includes: By setting the three-phase short circuit fault on the rectifier side, the three-phase short circuit fault on the inverter side and the DC short circuit fault, the collected signals are focused on to identify the upper and lower limit parameters, which include the input and output limits of each controller and the upper and lower limits of voltage and current in the low voltage current limiting link.

3. The method for identifying parameters of a UHV DC electromagnetic transient model controller according to claim 2, characterized in that: Identifying the proportional gain parameters includes: When the system is in steady-state operation, a step signal is applied to the reference DC current command of the constant current controller on the rectifier side and a step signal is applied to the reference turn-off angle command of the constant turn-off angle controller to identify the proportional gain parameters of each controller; Set the three-phase short circuit fault on the rectifier side, the three-phase short circuit fault on the inverter side and the DC short circuit fault to switch the control dominance of the inverter side, apply a step signal to the corresponding controller reference command when the constant current controller and the constant voltage controller on the inverter side play a leading role, and identify the proportional gain parameters of the corresponding controller; The proportional gain parameters include proportional link coefficients of a constant current controller, a constant voltage controller and a constant turn-off angle controller.

4. The method for identifying parameters of a UHV DC electromagnetic transient model controller according to claim 1, characterized in that: The electromagnetic transient model of the UHV DC transmission system includes: The electromagnetic transient model of the ultra-high voltage direct current transmission system is established by covering a variety of ultra-high voltage direct current transmission system controller structures. The electromagnetic transient model of the ultra-high voltage direct current transmission system realizes the control of the ultra-high voltage direct current transmission system through the methods of rectifier side constant current control, inverter side constant current control, inverter side constant shutdown angle control, inverter side constant voltage control, low voltage current limiting control, and current deviation control; The rectifier side trigger angle signal is output by the constant current controller, and the inverter side trigger angle signal takes the minimum value of the three controller output signals of the inverter side constant current control, the inverter side constant turn-off angle control, and the inverter side constant voltage control.

5. The method for identifying parameters of a UHV DC electromagnetic transient model controller according to claim 4, characterized in that: Before identification, the data of the electromagnetic transient model of the UHV DC transmission system and the black box UHV DC transmission system model under various working conditions are obtained, including: The data under the various working conditions include the fault ride-through full process test data of the UHV DC transmission system electromagnetic transient model and the black box UHV DC transmission system model and the dominant parameters affecting the fault ride-through full process; The dominant parameters include the proportional integral coefficient and output limit parameter of the constant current controller on the rectifier side, the proportional integral coefficient and output limit parameter of the constant current controller on the inverter side, the proportional integral coefficient and output limit parameter of the constant voltage controller on the inverter side, the proportional integral coefficient and output limit parameter of the constant shutdown angle controller on the inverter side, the upper limit threshold parameter of the low voltage current limiting controller on the inverter side and the proportional coefficient of the current deviation controller on the inverter side.

6. The method for identifying parameters of a UHV DC electromagnetic transient model controller according to claim 1, characterized in that: After carrying out identification in the order of the average trajectory sensitivity from high to low in the parameters of the same category, the steady-state response result and the transient response result of the electromagnetic transient model of the ultra-high voltage direct current transmission system and the error of the black box ultra-high voltage direct current transmission system model meet the preset requirements, and the parameter identification of the electromagnetic transient model controller of the ultra-high voltage direct current transmission system is completed.

7. The method for identifying parameters of a UHV DC electromagnetic transient model controller according to claim 6, characterized in that: The method of using a particle swarm optimization algorithm to identify the time constant parameters includes: The unidentified time constant type parameters are updated to the electromagnetic transient model of the UHV DC power transmission system by default as empirical values; The three-phase short-circuit fault of the AC busbar on the rectifier side and the inverter side and the DC line fault are set respectively, and the size of the time constant parameters is adjusted to obtain the value range of each time constant parameter; The time constant type parameters to be identified are set as position parameters, and the initial values ​​of the position parameters are obtained based on the value ranges of the time constant type parameters; taking the error between the simulation results of the electromagnetic transient model of the UHV DC transmission system and the black box UHV DC transmission system model as the objective function; Calculate whether the objective function is less than a preset threshold value. If it is not less than the threshold value, update the speed and position of the particle, and then update the controller parameter value. If it is less than the threshold value, output the parameter group at this time. The initial value of the time constant parameter is changed, and the particle swarm optimization algorithm is performed again to obtain the time constant parameter value, and the average value of ten time constant parameter identification results is taken as the final identification result.

8. A system using the method for identifying parameters of a UHV DC electromagnetic transient model controller according to any one of claims 1 to 7, characterized in that: include: A parameter grouping module, used to divide the DC controller parameters into upper and lower limit parameters, proportional gain parameters and time constant parameters according to the response characteristics of the rectifier and inverter side controllers under different fault scenarios and the influence of the DC controller parameters on the DC voltage, DC current and the rectifier side AC voltage; A sensitivity analysis module, used to perform sensitivity analysis on the DC controller parameters based on a trajectory sensitivity method, and calculate the average trajectory sensitivity of each controller parameter; A first identification module is used to identify the parameters of the same category in the order of the average trajectory sensitivity from high to low based on the calculation result of the average trajectory sensitivity and in combination with the identification order of first the upper and lower limit parameters and then the proportional gain parameters; The second identification module is used to update the identification result to the electromagnetic transient model of the ultra-high voltage direct current transmission system, and use the particle swarm optimization algorithm to identify the time constant type parameters.

9. An electronic device, comprising: Memory and processor; The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the UHV DC electromagnetic transient model controller parameter identification method described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the method for identifying parameters of an ultra-high voltage direct current electromagnetic transient model controller according to any one of claims 1 to 7.

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