Wind power plant electromagnetic transient equivalence method and system for power grid stability control strategy verification

Abstract

The invention discloses a wind power plant electromagnetic transient equivalence method and system oriented to power grid stability control strategy verification. The method comprises the steps that the rotating speed and wind speed correlation characteristics of electromagnetic transient models of all wind turbine generators in a wind power plant, the networking form of the wind turbine generators in the wind power plant and the operation working condition of all the wind turbine generators before a fault are obtained; all wind turbine generators in a wind power plant are divided into three initial groups including a starting area, an MPPT area and a constant-rotating-speed constant-power area; the grouping of the starting area and the constant rotating speed and constant power area is kept unchanged, the wind turbine generator in the MPPT area is further subdivided into three subgroups, and a wind power plant equivalent model containing five subgroups is formed; calculating the equivalent wind speed and multiplication value of the grouped wind turbine generator, and calculating the equivalent parameter of the current collection line of the wind power plant; performing multi-scene and multi-working-condition test verification on the established wind power plant equivalent model; according to the method, the transient response precision is improved while the simulation efficiency is ensured, and the contradiction problem of insufficient equivalent precision of a traditional single machine and large calculation amount of a detailed model is effectively solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power simulation modeling, and particularly relates to a wind farm electromagnetic transient equivalence method and system for power grid stability control strategy verification. BACKGROUND

[0002] With the rapid development of new energy power systems, the penetration rate of large-scale wind farms in power grids is continuously increasing, and wind farms have become an important part of modern power systems. The interaction between wind farms and power grids is becoming increasingly complex, involving the coupling of multi-stability problems, and higher requirements are put forward for the safe and stable operation of power systems. As a key defense line to ensure the reliability of power grids, the effectiveness verification of the stability control strategy of the safety and stability control system is crucial. At present, the power industry generally adopts a digital simulation verification method of "power grid simulation + stability control device physical object", and the accuracy of the transient response of the wind farm directly affects the reliability of the stability control strategy verification, so high-precision wind farm modeling has become a research hotspot.

[0003] The traditional control mode of the stability control system is to control the entire wind farm as a control object for "whole station whole cutting", but as the scale of the wind farm station continues to increase, the "station level" control mode is not conducive to the safety and stability of the large power grid, nor is it conducive to the post-fault grid recovery of large-scale wind farms. With the increasing refinement of the control mode of the stability control system, large-scale wind farms currently adopt a "feeder level" control mode, and with the development of new energy panoramic monitoring systems, even "unit level" precise control can be achieved. The existing equivalence method is based on the equivalence of the wind farm operating state before the stability control action, and the stability control action will change the operating state of the wind farm, so it cannot represent the response characteristics of the wind farm after the stability control action. However, engineering verification personnel pay more attention to the response characteristics of the wind farm after the stability control action, because the response characteristics determine whether the system can remain stable and are the basis for judging the effectiveness of the stability control strategy. SUMMARY

[0004] The purpose of the present application is to provide a wind farm electromagnetic transient equivalence method for power grid stability control strategy verification that can improve simulation efficiency and transient response accuracy. On the other hand, a wind farm electromagnetic transient equivalence system for power grid stability control strategy verification is provided.

[0005] Technical solution: The wind farm electromagnetic transient equivalence method according to the present application comprises:

[0006] The rotational speed and wind speed correlation characteristics of the electromagnetic transient model of each wind turbine in the wind farm, the networking form of the wind turbines in the wind farm station, and the operating conditions of each wind turbine before the fault are obtained. By accurately obtaining the rotational speed-wind speed characteristics, networking form, and operating condition data of the wind turbine, comprehensive and accurate basic data support is provided for subsequent equivalence modeling, ensuring the reliability of the model parameters;

[0007] Based on the speed and wind speed correlation characteristics of the electromagnetic transient model and the operating conditions of each wind turbine before the fault, all wind turbines in the wind farm are divided into a starting zone, an MPPT zone and a constant speed constant power zone, effectively distinguishing the different operating states of the wind turbines, retaining the key dynamic characteristics and significantly reducing the model complexity, laying a foundation for subsequent fine grouping;

[0008] All wind turbines in the MPPT zone are further divided into three subgroups, and the three subgroups, the starting zone and the constant speed constant power zone are taken as each group, fully considering the dynamic response differences of the units in the maximum power tracking zone, and through multi-level division, the accurate characterization of the transient characteristics is realized.

[0009] According to the operating conditions of all wind turbines in each group before the fault, the wind speed and the multiplication value of the equivalent machine are calculated, and the equivalent parameters of the wind farm collection line are calculated based on the networking form of the wind turbines in the station, and the construction of the equivalent model of the wind farm is completed, fully considering the influence of the stability control action, so that the equivalent model can accurately reflect the transient response characteristics of the wind farm before and after the stability control action.

[0010] The established equivalent model of the wind farm is tested and verified under multiple scenarios and multiple operating conditions, and by comparing the response characteristics of the equivalent model and the detailed model, the applicability of the model under various operating conditions and fault types is ensured, providing a reliable guarantee for the verification of the stability control strategy.

[0011] Preferably, the electromagnetic transient model speed and wind speed correlation characteristics of each wind turbine in the wind farm are obtained by: testing the corresponding speed value of the wind turbine based on the electromagnetic transient model according to a preset wind speed interval, from the cut-in wind speed v in to the cut-out wind speed v out in the wind speed range, and establishing a wind speed-speed corresponding relationship table;

[0012] The networking form of the wind turbines in the station includes the wind farm topology structure data, the length parameters of each collection line and the line unit impedance parameters;

[0013] The operating conditions of each wind turbine before the fault include the actual wind speed data of each wind turbine before the fault.

[0014] By establishing the wind speed-speed corresponding relationship table at a high precision interval of 0.1 m / s, and combining the comprehensive collection of the wind farm topology structure, the collection line parameters and the real-time wind speed data of the units, the fine characterization of the operating characteristics of the wind turbines is realized, providing an accurate and reliable data basis for subsequent equivalent modeling, effectively avoiding the model distortion problem caused by rough parameters in the traditional method, and significantly improving the accuracy and reliability of the equivalent model.

[0015] Preferably, the initial grouping of all wind turbines in the wind farm into three clusters—start-up zone, MPPT zone, and constant speed and constant power zone—includes:

[0016] The operating conditions of each wind turbine before the fault include the actual wind speed data of each wind turbine before the fault. The rotational speed value of each wind turbine is obtained based on the correlation characteristics between rotational speed and wind speed in the electromagnetic transient model. When the rotational speed value of the wind turbine is in the range of cut-in speed to first set threshold, the wind turbine is classified into the start-up zone; when the rotational speed value of the wind turbine is in the range of first set threshold to rated speed, the wind turbine is classified into the MPPT zone; when the rotational speed value of the wind turbine reaches the rated speed, the wind turbine is classified into the constant speed and constant power zone.

[0017] By using a three-zone division method based on the rotational speed-wind speed characteristics, the accurate classification of wind turbines in different operating states within a wind farm is achieved. The start-up zone characterizes the dynamic characteristics of low-wind-speed turbines, the MPPT zone reflects the operating characteristics under maximum power point tracking (MPPT) conditions, and the constant rotational speed and constant power zone accurately depicts the operating characteristics under rated operating conditions. This division method not only preserves the differences in dynamic characteristics between each operating zone but also significantly reduces the model complexity, laying a scientific foundation for the subsequent fine-grained grouping of the MPPT zone and effectively improving the accuracy of the equivalent model in representing the overall dynamic response of the wind farm.

[0018] Preferably, the further subdivision of all wind turbines within the MPPT zone into three subgroups includes:

[0019] The steady-state active power of all wind turbines in the MPPT zone shall not exceed P. div The units in the MPPT area are designated as group Q1, and the wind turbine units in group Q1 are designated as group Q2.

[0020] Calculate the function value g(P) corresponding to each active power partition point. div ):

[0021]

[0022] in, This represents the steady-state average power before the fault in group Q1. P represents the steady-state average power before the fault in group Q2. MPPT This represents the total active power generated before the MPPT area fault, and n represents the number of units in the MPPT area;

[0023] Select g(P) div The active power partition point that achieves the maximum value is taken as the first partition point of the MPPT region.

[0024] The average power of the Q2 group is used as the second partition point of the MPPT region.

[0025] according to and The MPPT region is finally divided into three subgroups.

[0026] Through the innovative MPPT region three-subgroup dynamic division algorithm, the optimal active split point search strategy and the clustering method based on power response similarity are adopted to realize the fine classification of wind turbines in the MPPT operating region. By constructing the objective function g(P div ) to quantify the grouping effect and automatically determine the optimal split point, the consistency of the transient response of the same group is retained, and the dynamic characteristic differences of the units at different output levels are accurately reflected, effectively solving the problem of insufficient modeling accuracy of the traditional equivalent method in the MPPT region, and significantly improving the transient response accuracy of the wind farm equivalent model under complex conditions.

[0027] Preferably, the calculation of the wind speed and multiplication value of the equivalent machine in each subgroup comprises:

[0028] The wind speed of the equivalent machine is calculated by the equivalent wind speed corresponding to the average power of all wind turbines in the group, and the calculation formula is:

[0029]

[0030] Where N is the number of units in the same subgroup; v eq represents the wind speed of the equivalent machine; f(·) represents the unit output power-wind speed characteristic function; v i represents the wind speed of the i th wind turbine;

[0031] The calculation formula of the multiplication value of the equivalent machine is:

[0032]

[0033] Where n is the multiplication value of the equivalent machine; n' represents the multiplication value of the equivalent machine; t k represents the stable control action time; S represents the set of retained units in the same subgroup after stable control action.

[0034] Through the equivalent wind speed calculation method and the multiplication value algorithm considering the timing characteristics of stable control action, the dynamic characteristics of the wind farm are accurately characterized: the equivalent wind speed calculation adopts the backstepping method based on the average power, which accurately reflects the comprehensive operating state of the units in the group; the multiplication value calculation introduces the stable control execution time and the unit outage set, dynamically quantifies the influence of protection action on the equivalent model, so that the equivalent result can not only maintain the steady-state accuracy, but also accurately reflect the dynamic response characteristics before and after the stable control action, significantly improving the applicability of the wind farm equivalent model in the stable control strategy verification.

[0035] Preferably, the calculation of the equivalent parameters of the wind farm collection line comprises:

[0036] The calculation formula of the equivalent length of the collection line is:

[0037]

[0038] wherein, l eq represents the equivalent length of the collector line before the action of the stability control; l' eq represents the equivalent length of the collector line before the action of the stability control; l i represents the length of the collector line connected to the i-th unit; P(l i ) represents the steady-state active power flowing through the collector line l i ; p i represents the steady-state active power sent out by the i-th unit.

[0039] The equivalent impedance calculation formula of the collector line is:

[0040]

[0041] wherein, Z l represents the equivalent impedance of the collector line before the action of the stability control; Z' l represents the equivalent impedance of the collector line after the action of the stability control; z0 represents the unit impedance of the collector line.

[0042] Based on the principle that the equivalent steady-state active power losses before and after the action of the stability control are equal, the collector line parameters are calculated, the influence of the action of the stability control on the active power loss is considered, the accurate equivalence of the collector network of the wind farm is realized, and the accuracy of the equivalent model of the wind farm in the transient process analysis is effectively improved.

[0043] Preferably, the multi-scenario and multi-condition test verification on the established equivalent model of the wind farm comprises:

[0044] Based on the topology structure data of the wind farm, a detailed model of the wind farm is built, the active and reactive power response curves of the detailed model and the equivalent model under the same fault type and different operating conditions, and the active and reactive power response curves under the same operating condition and different fault types are obtained, the similarity of the active and reactive power response curves of the detailed model and the equivalent model is compared based on the observation method, and the rationality of the equivalent scheme is judged based on the comparison result.

[0045] By establishing a multi-dimensional verification system and using the comparison test method of the detailed model and the equivalent model, the accuracy of the equivalent model of the wind farm is comprehensively evaluated: through the test of fixing the fault type and changing the operating condition, the adaptability of the model under different wind speed conditions is verified; through the test of fixing the operating condition and changing the fault type, the response accuracy of the model to various voltage drop scenarios is ensured, this cross verification mechanism not only verifies the static accuracy of the equivalent model, but also verifies its dynamic response characteristics, provides a reliable model basis for the stability control strategy verification, and significantly improves the credibility of the equivalent result.

[0046] The wind farm electromagnetic transient equivalent system comprises:

[0047] A data acquisition module is configured to acquire electromagnetic transient model speed and wind speed correlation characteristics of each wind turbine in the wind farm, network form of the wind turbines in the station, and operating conditions of each wind turbine before the fault;

[0048] An initial grouping module is configured to divide all wind turbines in the wind farm into a starting area, an MPPT area, and a constant speed constant power area based on the electromagnetic transient model speed and wind speed correlation characteristics and the operating conditions of each wind turbine before the fault;

[0049] A fine grouping module is configured to further divide all wind turbines in the MPPT area into three subgroups, and take the three subgroups, the starting area, and the constant speed constant power area as each group;

[0050] A parameter calculation module is configured to calculate wind speed and multiplication values of the equivalent machine according to the operating conditions of all wind turbines in each group before the fault, and calculate equivalent parameters of a power collection line of the wind farm based on the network form of the wind turbines in the station, so as to complete construction of the equivalent model of the wind farm;

[0051] A verification test module is configured to test and verify the established equivalent model of the wind farm in multiple scenes and multiple conditions.

[0052] Preferably, the data acquisition module is specifically configured to establish a wind speed-speed corresponding relationship table according to corresponding speed values of wind turbines in the electromagnetic transient model test within a wind speed range from a cut-in wind speed v in to a cut-out wind speed v out at preset wind speed intervals; the network form of the wind turbines in the station comprises wind farm topology structure data, length parameters of each power collection line, and line unit impedance parameters; and the operating conditions of each wind turbine before the fault comprise actual wind speed data of each wind turbine before the fault.

[0053] Preferably, the operating conditions of each wind turbine before the fault comprise actual wind speed data of each wind turbine before the fault, and the initial grouping module is specifically configured to obtain speed values of each wind turbine according to the electromagnetic transient model speed and wind speed correlation characteristics, divide the wind turbines into the starting area when the speed values of the wind turbines are in a range from a cut-in speed to a first set threshold, divide the wind turbines into the MPPT area when the speed values of the wind turbines are in a range from the first set threshold to a rated speed, and divide the wind turbines into the constant speed constant power area when the speed values of the wind turbines reach the rated speed.

[0054] Preferably, the fine grouping module is specifically configured to record wind turbines with steady-state active power less than P div as a Q1 group, and record wind turbines in the MPPT area except the wind turbines in the Q1 group as a Q2 group.

[0055] Calculate the function value g(P) corresponding to each active power partition point. div ):

[0056]

[0057] in, This represents the steady-state average power before the fault in group Q1. P represents the steady-state average power before the fault in group Q2. MPPT This represents the total active power generated before the MPPT area fault, and n represents the number of units in the MPPT area;

[0058] Select g(P) div The active power partition point that achieves the maximum value is taken as the first partition point of the MPPT region.

[0059] The average power of the Q2 group is used as the second partition point of the MPPT region.

[0060] Based on the dividing point and The steady-state power of each wind turbine in the MPPT zone before the fault will eventually divide the wind turbines in the MPPT zone into three subgroups.

[0061] Preferably, the parameter calculation module is specifically used to calculate the wind speed and multiplication factor of the isostat within each subgroup, including:

[0062] The wind speed of the equivalent turbine is calculated using the equivalent wind speed corresponding to the average power of all wind turbines in the group. The calculation formula is as follows:

[0063]

[0064] Where N is the number of units in the same subgroup; v eq The wind speed is represented by the equivalent wind speed; f(·) represents the unit output power-wind speed characteristic function; v i Indicates the wind speed of the i-th fan;

[0065] The formula for calculating the multiplier value of the isostat is:

[0066]

[0067] Where n is the equivalent multiplier value; n' represents the equivalent multiplier value; t k Indicates the time of the stabilization action; S represents the set of units retained in the same subgroup after the stabilization action.

[0068] Preferably, the parameter calculation module is specifically used to calculate the equivalent length of the collector line, and the formula is:

[0069]

[0070] wherein, l eq represents the equivalent length of the collector line before the action of the stability control; l' eq represents the equivalent length of the collector line before the action of the stability control; l i represents the length of the collector line connected to the i-th unit; P(l i ) represents the steady-state active power flowing through the collector line l i represents the steady-state active power; p i represents the steady-state active power sent out by the i-th unit.

[0071] The equivalent impedance calculation formula of the collector line is:

[0072]

[0073] wherein, Z l represents the equivalent impedance of the collector line before the action of the stability control; Z' l represents the equivalent impedance of the collector line after the action of the stability control; z0 represents the unit impedance of the collector line.

[0074] Preferably, the verification test module is specifically used for building a detailed model of the wind farm based on the topology data of the wind farm, obtaining the active and reactive power response curves of the detailed model and the equivalent model of the wind farm under the same fault type and different operating conditions, and the active and reactive power response curves under the same operating condition and different fault types, comparing the similarity of the active and reactive power response curves of the detailed model and the equivalent model based on the observation method, and judging the rationality of the equivalent scheme based on the comparison result.

[0075] A computer readable storage medium having a computer program stored thereon, wherein the computer program is executed by a processor to implement the wind farm electromagnetic transient equivalence method for grid stability control strategy verification.

[0076] An electronic device comprising a memory, a processor, and a program stored on the memory and executable on the processor, wherein the processor implements the wind farm electromagnetic transient equivalence method for grid stability control strategy verification when executing the program.

[0077] Beneficial effects: compared with the prior art, the present application has the following remarkable advantages: 1, by analyzing the speed-wind speed characteristics and operating conditions of the wind turbine, the wind farm units are divided into starting area, MPPT area and constant speed constant power area, and the MPPT area is further subdivided, a more accurate equivalent model of the wind farm is established, multiple scene verification is carried out, the accuracy and efficiency of the grid stability control strategy verification are improved, and it is suitable for electromagnetic transient simulation of complex wind farms; 2, by establishing the wind speed-speed corresponding relationship table and clearly defining the sampling wind speed interval from cut-in to cut-out, the refinement degree of model parameters is enhanced; at the same time, the network form data such as wind farm topology and line impedance and the operating conditions before fault (such as speed, wind speed range) are integrated, which provides a reliable data basis for subsequent grouping and equivalent modeling, and ensures the consistency of the model and the actual system; 3, based on the threshold interval of speed and wind speed (such as cut-in speed, rated speed, etc.), the wind turbine is divided into starting area, MPPT area and constant speed constant power area, realizing reasonable classification of unit operating state, this partition method is in line with the actual control characteristics of the wind turbine, simplifying the complexity of equivalent modeling, while retaining the key dynamic response characteristics, which is beneficial to subsequent refinement equivalent; 4, by defining Q1, Q2 group and calculating the active power segmentation point function, the MPPT area is subdivided into three subgroups, the difference representation of unit power distribution is optimized, the segmentation point is determined by using the average power and maximum function value, so that the equivalent model can better reflect the dynamic behavior difference of different subgroups under fault, improving the transient simulation accuracy, especially suitable for stability control strategy verification of large-capacity wind farms. BRIEF DESCRIPTION OF DRAWINGS

[0078] Figure 1 The flowchart of the present application is shown in the figure;

[0079] Figure 2 The wind farm five-machine grouping method of the present application is shown in the figure;

[0080] Figure 3 The wind farm five-machine equivalent model of the present application is shown in the figure. DETAILED DESCRIPTION

[0081] The technical solutions of the present application will be further described below in combination with the drawings.

[0082] As shown in the figure, Figure 1 the electromagnetic transient equivalent method of the wind farm of the present application comprises the following steps:

[0083] S1, obtaining the speed-wind speed correlation characteristics of the electromagnetic transient model of the wind turbine, and the network form and operating conditions of each wind turbine before fault in the station, specifically including: testing the speed-wind speed correlation characteristics of the electromagnetic transient model of the wind turbine at intervals of 0.1 m / s from the cut-in wind speed v in to the cut-out wind speed v outThe wind turbine electromagnetic transient model corresponds to the rotating speed, the station networking form in the station includes the station topological structure, the length of the power collection line and the unit impedance of the line, and the operating condition of each wind turbine before the fault refers to the actual wind speed of each wind turbine before the fault.

[0084] S2, all wind turbines in the wind farm are divided into three groups of start-up area, MPPT area and constant rotating speed and constant power area according to the operating condition before the fault, which specifically includes that the operating condition of each wind turbine before the fault includes the actual wind speed data of each wind turbine before the fault, the rotating speed value of each wind turbine is obtained according to the rotating speed and wind speed correlation characteristics of the electromagnetic transient model, when the rotating speed value of the wind turbine is in the interval from the cut-in rotating speed to the first set threshold, the wind turbine is divided into the start-up area; when the rotating speed value of the wind turbine is in the interval from the first set threshold to the rated rotating speed, the wind turbine is divided into the MPPT area; when the rotating speed value of the wind turbine reaches the rated rotating speed, the wind turbine is divided into the constant rotating speed and constant power area.

[0085] S3, the group results of the wind turbines in the start-up area and the constant rotating speed and constant power area are kept, the wind turbines in the MPPT area are further divided into three groups, and finally the wind farm is divided into five groups, which specifically includes:

[0086] S3.1, test the steady-state active power of each wind turbine in the MPPT area based on the electromagnetic transient model of the wind turbine

[0087] S3.2, take the steady-state active power segmentation point P div = p1.

[0088] S3.3, record the wind turbines in the MPPT area whose steady-state active power does not exceed P div as Q1 group, and record the rest of the wind turbines in the MPPT area as Q2 group, and record the function value corresponding to the active power segmentation point:

[0089]

[0090] In the formula, represents the steady-state average power of Q1 group before the fault, represents the steady-state average power of Q2 group before the fault, P MPPT represents the total active power sent by the MPPT area before the fault, and n represents the number of wind turbines in the MPPT area.

[0091] S3.4, take the steady-state active power segmentation point P div = p2, repeat S3.2-S3.3, and so on, until P div = p n-1 stops the cycle.

[0092] S3.5, compare the function value g(P div ) of n-1 groups. div) the maximum value corresponding to the steady-state active power split point P div Take the first active power split point of the MPPT region as MPPT

[0093] S3.6, take the average power of Q2 machine group as the second steady-state active split point of MPPT region

[0094] S3.7, as shown in Figure 2 MPPT region is divided into 3 groups through two steady-state active split points and , and finally the wind farm is divided into 5 groups with the starting region and the constant speed constant power region.

[0095] S4, the equivalent wind speed and multiplication value of the equivalent unit after grouping are calculated, and the equivalent parameters of the wind farm collection line are calculated, which specifically includes:

[0096] S4.1, test the steady-state active power corresponding to the electromagnetic transient model of the wind turbine under different wind speeds, the wind speed range is from the cut-in wind speed to the cut-out wind speed, the wind speed interval is taken as 0.1 m / s, and the wind speed-power function relationship of the wind turbine is obtained by the piecewise polynomial curve fitting method as follows:

[0097]

[0098] In the formula: a n (n∈Z) represents the polynomial coefficient; p N represents the rated power of the wind turbine; v represents the wind speed; n represents the highest power of the fitting polynomial, generally taken as 2; v N represents the rated wind speed.

[0099] S4.2, the equivalent wind speed of the equivalent unit is calculated by the equivalent wind speed corresponding to the average power of each unit in the group, and the calculation method is as follows:

[0100]

[0101] In the formula: N is the number of the same grouped units; v eq represents the equivalent wind speed of the equivalent machine; f(·) represents the unit output power-wind speed characteristic function; v i represents the wind speed of the i th wind turbine.

[0102] S4.3, if the wind farm stability control execution station does not receive the control instruction issued by the upper-level stability control device, the single machine multiplication value is the number of the group; if the wind farm stability control execution station receives the control instruction issued by the upper-level stability control device, the execution station performs machine cutting according to the minimum overcut principle according to the priority set in advance, at this time the multiplication value needs to be corrected. Therefore, the equivalent unit multiplication value calculation formula is as follows:

[0103]

[0104] In the formula: n is the equivalent machine multiplication value; n' represents the equivalent machine multiplication value; t k represents the stable control action time; S represents the same group of reserved units after the stable control action.

[0105] S4.4, the equivalent length calculation method of the collection line based on the active loss equivalence principle is as follows:

[0106]

[0107] In the formula: l eq represents the equivalent length of the collection line before the stable control action; l′ eq represents the equivalent length of the collection line before the stable control action; l i represents the length of the collection line connected to the i th unit; P(l i ) represents the steady-state active power flowing through the collection line l i ; p i represents the steady-state active power of the i th unit.

[0108] S4.5, the equivalent impedance of the collection line is calculated, and the specific process is as follows:

[0109]

[0110] In the formula: Z l represents the equivalent impedance of the collection line before the stable control action; Z′ l represents the equivalent impedance of the collection line after the stable control action; z0 represents the unit impedance of the collection line.

[0111] S4.6, as Figure 3 shown, the five-machine equivalent model of the wind farm is established.

[0112] S5, the new energy station equivalent model is tested and verified under multiple scenes and multiple operating conditions, and the specific process is as follows: based on the topology structure of the wind farm, a detailed model of the wind farm is built, and under the same fault type, the active and reactive response curves of the equivalent model and the detailed model of the wind farm under different operating conditions are compared; under the same operating condition, the active and reactive response curves of the equivalent model and the detailed model under different voltage drops are compared.

[0113] The wind farm electromagnetic transient equivalent system corresponding to the wind farm electromagnetic transient equivalent method comprises the following modules:

[0114] A data acquisition module is used to obtain the electromagnetic transient model speed and wind speed correlation characteristics of each wind turbine in the wind farm, the networking form of the wind turbines in the station, and the operating condition of each wind turbine before the fault;

[0115] The initial clustering module is used to divide all wind turbines in the wind farm into the start-up zone, MPPT zone and constant speed and constant power zone based on the correlation characteristics between rotational speed and wind speed in the electromagnetic transient model and the operating conditions of each wind turbine before the fault.

[0116] The fine clustering module is used to further subdivide all wind turbines in the MPPT area into three subgroups, with the three subgroups, the startup area, and the constant speed and constant power area as each subgroup.

[0117] The parameter calculation module is used to calculate the equivalent wind speed and multiplier value based on the operating conditions of all wind turbines in each subgroup before the fault, and to calculate the equivalent parameters of the wind farm collection line based on the network configuration of the wind turbines in the site, thus completing the construction of the wind farm equivalent model.

[0118] The verification and testing module is used to perform multi-scenario and multi-condition testing and verification on the established wind farm equivalent model.

[0119] Furthermore, the data acquisition module is specifically used to test the cut-in wind speed v based on the electromagnetic transient model of the wind turbine at preset wind speed intervals. in to cut off wind speed v out The corresponding rotational speed values ​​within the wind speed range are used to establish a wind speed-rotational speed correspondence table; the network configuration of wind turbines within the site includes wind farm topology data, length parameters of each collection line, and unit impedance parameters of the lines; the operating conditions of each wind turbine before the fault include the actual wind speed data of each wind turbine before the fault.

[0120] Furthermore, the operating conditions of each wind turbine before the fault include the actual wind speed data of each wind turbine before the fault. The initial grouping module is specifically used to obtain the speed value of each wind turbine based on the correlation characteristics between the speed and wind speed of the electromagnetic transient model. When the speed value of the wind turbine is in the range of cut-in speed to first set threshold, the wind turbine is classified into the start-up zone; when the speed value of the wind turbine is in the range of first set threshold to rated speed, the wind turbine is classified into the MPPT zone; when the speed value of the wind turbine reaches the rated speed, the wind turbine is classified into the constant speed and constant power zone.

[0121] Furthermore, the fine-grained clustering module is specifically used to ensure that the steady-state active power of all wind turbines in the MPPT region does not exceed P. div The units in the MPPT area are designated as group Q1, and the wind turbine units in group Q1 are designated as group Q2.

[0122] Calculate the function value g(P) corresponding to each active power partition point. div ):

[0123]

[0124] in, This represents the steady-state average power before the fault in group Q1. P represents the average steady-state power of Q2 group before fault MPPT P represents the total active power sent out by MPPT zone before fault, n represents the number of units in MPPT zone;

[0125] Select the active power point that makes g(P div ) maximum as the first division point of MPPT zone

[0126] Take the average power of Q2 group as the second division point of MPPT zone

[0127] According to the division points and and the steady-state power of each wind turbine in MPPT zone before fault, the wind turbines in MPPT zone are finally divided into three subgroups.

[0128] Further, the parameter calculation module is specifically used for calculating the wind speed and multiplication value of the equivalent machine in each subgroup, including:

[0129] The wind speed of the equivalent machine is calculated by the equivalent wind speed corresponding to the average power of all wind turbines in the group, and the calculation formula is:

[0130]

[0131] Wherein, N is the number of units in the same subgroup; v eq represents the wind speed of the equivalent machine; f(·) represents the unit output power-wind speed characteristic function; v i represents the wind speed of the i-th wind turbine;

[0132] The calculation formula of the multiplication value of the equivalent machine is:

[0133]

[0134] Wherein, n is the multiplication value of the equivalent machine; n' represents the multiplication value of the equivalent machine; t k represents the stability control action time; S represents the reserved unit set of the same subgroup after stability control action.

[0135] Further, the parameter calculation module is specifically used for calculating the equivalent length of the collection line, and the formula is:

[0136]

[0137] Wherein, l eq represents the equivalent length of the collection line before stability control action; l′ eq represents the equivalent length of the collection line before stability control action; l i represents the length of the collection line connected with the i-th unit; P(l i ) represents the current flowing through the collection line li Steady-state active power; p i represents the steady-state active power of the ith unit.

[0138] The equivalent impedance calculation formula of the collector line is:

[0139]

[0140] wherein, Z l represents the equivalent impedance of the collector line before the action of the stability control; Z' l represents the equivalent impedance of the collector line after the action of the stability control; z0 represents the unit impedance of the collector line.

[0141] Further, the verification test module is specifically configured to build a wind farm detailed model based on wind farm topology structure data, obtain active power and reactive power response curves of the wind farm detailed model and the wind farm equivalent model under the same fault type and different operating conditions, and active power and reactive power response curves under the same operating condition and different fault types, compare the similarity of the active power and reactive power response curves of the detailed model and the equivalent model based on the observation method, and judge the rationality of the equivalent scheme based on the comparison result.

[0142] The application further discloses a computer device.

[0143] Specifically, the computer device can be a desktop computer, a notebook computer, a palm computer, a cloud server, and the like. The computer device can include, but is not limited to, a processor and a memory. The processor and the memory can be connected through a bus or other manners. The processor can be a central processing unit (CPU). The processor can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, graphics processing units (GPU), embedded neural network processing units (NPU) or other dedicated deep learning coprocessors, discrete gate or transistor logic devices, discrete hardware components, and the like chips, or combinations of the above chips.

[0144] The memory, as a non-transitory computer readable storage medium, can be used to store non-transitory software programs, non-transitory computer executable programs and modules. The processor performs various functional applications and data processing of the processor by running the non-transitory software programs, instructions and modules stored in the memory. The memory can include a program storage area and a data storage area, wherein the program storage area can store application programs required by the control unit and at least one function; the data storage area can store data created by the processor and the like. In addition, the memory can include a high-speed random access memory, and can also include a non-transitory memory. In some embodiments, the memory can optionally include a memory remotely arranged relative to the processor, and these remote memories can be connected to the processor through a network. Examples of the above-mentioned network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network and a combination thereof.

[0145] The application further discloses a computer readable storage medium.

[0146] Specifically, the computer readable storage medium is used to store a computer program, and the computer program is executed by the processor to realize the method in the above-mentioned method embodiments. Those skilled in the art can understand that all or part of the processes in the above-mentioned method embodiments of the application can be completed by a computer program instructing related hardware, and the program can be stored in a computer readable storage medium. When the program is executed, it can include the processes of the above-mentioned method embodiments. The storage medium can be a magnetic disc, an optical disc, a read-only memory (ROM), a random access memory (RAM), a flash memory, a hard disk drive (HDD) or a solid-state drive (SSD), etc. The storage medium can also include a combination of the above-mentioned types of memories.

Claims

1. A wind farm electromagnetic transient equivalent method for grid stability control strategy verification, characterized in that, The method comprises the following steps: obtaining the electromagnetic transient model speed and wind speed correlation characteristics of each wind turbine in the wind farm, the network form of the wind turbines in the station, and the operating conditions of each wind turbine before the fault; based on the electromagnetic transient model speed and wind speed correlation characteristics and the operating conditions of each wind turbine before the fault, all wind turbines in the wind farm are divided into a starting area, an MPPT area and a constant speed and constant power area; all wind turbines in the MPPT area are further divided into three subgroups, and the three subgroups, the starting area and the constant speed and constant power area are each subgroup; based on the operating conditions of all wind turbines in each subgroup before the fault, the wind speed and the multiplication value of the equivalent machine are calculated, and the equivalent parameters of the wind farm collection line are calculated based on the network form of the wind turbines in the station to complete the construction of the equivalent model of the wind farm; the established equivalent model of the wind farm is tested and verified under multiple scenarios and multiple operating conditions.

2. The electromagnetic transient equivalence method for a wind farm of claim 1, wherein, The obtaining the electromagnetic transient model speed- wind speed correlation characteristics of each wind turbine in the wind farm comprises: according to a preset wind speed interval, based on the electromagnetic transient model test of the wind turbine from the cut-in wind speed v in to the cut-out wind speed v out , the corresponding speed value in the wind speed range is established to establish a wind speed-speed corresponding relationship table; The network form of the wind turbines in the station includes wind farm topology structure data, length parameters and line unit impedance parameters of each collection line; The operating conditions of each wind turbine before the fault include actual wind speed data of each wind turbine before the fault.

3. The electromagnetic transient equivalence method for a wind farm of claim 1, wherein, The three initial subgroups of all wind turbines in the wind farm include: The operating conditions of each wind turbine before the fault include actual wind speed data of each wind turbine before the fault, and the speed value of each wind turbine is obtained according to the electromagnetic transient model speed and wind speed correlation characteristics, when the speed value of the wind turbine is in the interval from the cut-in speed to the first set threshold, the wind turbine is divided into the starting area; when the speed value of the wind turbine is in the interval from the first set threshold to the rated speed, the wind turbine is divided into the MPPT area; when the speed value of the wind turbine reaches the rated speed, the wind turbine is divided into the constant speed and constant power area.

4. The electromagnetic transient equivalence method for a wind farm of claim 1, wherein, The further subdivision of all wind turbines in the MPPT area into three subgroups includes: All wind turbines in the MPPT area whose steady-state active power is less than P div are recorded as Q1 group, and the wind turbines in the MPPT area except those in the Q1 group are recorded as Q2 group. calculating the function value g(P div ) corresponding to each active division point wherein, represents the steady-state average power of Q1 group before fault, represents the steady-state average power of Q2 group before fault, P MPPT represents the total active power sent out by MPPT area before fault, n represents the number of units in MPPT area; The active power point is selected as the first division point of the MPPT region div ) to obtain the maximum value Taking the average power of the Q2 group as the second division point of the MPPT region According to the division point and The steady state power of each wind turbine in the MPPT region before the fault will be in the wind turbine in the MPPT region.

5. The electromagnetic transient equivalence method for wind farms of claim 1, wherein, The calculation of the wind speed and the multiplication value of the equivalent machine in each subgroup includes: The wind speed of the equivalent machine is calculated by the equivalent wind speed corresponding to the average power of all wind turbines in the group, and the calculation formula is: where N is the number of the same cluster units; v eq represents the equivalent wind speed; f(·) represents the unit output power-wind speed characteristic function; v i represents the i-th wind turbine wind speed; The calculation formula of the multiplication value of the equivalent machine is: Wherein, n is the equivalent machine multiplication value; n' represents the equivalent machine multiplication value; t k S represents the same group of reserved units after the stable control action.

6. The electromagnetic transient equalization method for a wind farm of claim 1, wherein, The calculation of the equivalent parameters of the wind farm collection line includes: The equivalent length calculation formula of the collection line is: Wherein, l eq represents the equivalent length of the collector line before the action of the stability control; l' eq represents the equivalent length of the collector line before the action of the stability control; l i represents the length of the collector line connected to the i-th unit; P(l i ) represents the steady-state active power flowing through the collector line l i ; p i represents the steady-state active power sent out by the i-th unit. The equivalent impedance calculation formula of the collection line is: wherein Z l represents the equivalent impedance of the collector line before the stabilizing control action; Z' l represents the equivalent impedance of the collector line after the stabilizing control action; and z0 represents the unit impedance of the collector line.

7. The electromagnetic transient equalization method for a wind farm of claim 1, wherein, The multiple scenario and multiple operating condition test and verification of the established equivalent model of the wind farm includes: Based on the wind farm topology structure data, a detailed model of the wind farm is built, active and reactive response curves of the detailed model and the equivalent model under the same fault type and different operating conditions, and active and reactive response curves under the same operating condition and different fault types are obtained, the similarity of the active and reactive response curves of the detailed model and the equivalent model is compared based on the observation method, and the rationality of the equivalent scheme is judged based on the comparison result. 8.A wind farm electromagnetic transient equivalent system for grid stability control strategy verification, characterized in that, The method comprises the following steps: a data acquisition module for obtaining the electromagnetic transient model speed and wind speed correlation characteristics of each wind turbine in the wind farm, the network form of the wind turbines in the station, and the operating conditions of each wind turbine before the fault; The initial grouping module is configured to divide all wind turbines in the wind farm into a start-up area, an MPPT area and a constant-speed constant-power area based on the speed and wind speed correlation characteristics of the electromagnetic transient model and the operating conditions of each wind turbine before the fault; The fine grouping module is configured to further divide all wind turbines in the MPPT area into three subgroups, and to take the three subgroups, the start-up area and the constant-speed constant-power area as each group; The parameter calculation module is configured to calculate the wind speed and the multiplication value of the equivalent machine according to the operating conditions of all wind turbines in each group before the fault, and to calculate the equivalent parameters of the power collection line of the wind farm based on the networking form of the wind turbines in the station, so as to complete the construction of the equivalent model of the wind farm; The verification test module is configured to test and verify the established equivalent model of the wind farm in multiple scenarios and multiple operating conditions.

9. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the wind farm electromagnetic transient equivalent method for grid stability control strategy verification according to any one of claims 1 to 7.

10. An electronic device comprising a memory, a processor, and a program stored on the memory and executable on the processor, characterized in that, The processor executes the program to implement the wind farm electromagnetic transient equivalent method for grid stability control strategy verification according to any one of claims 1 to 7.

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