New energy station reactive voltage response control method and system for suppressing transient voltage rise

Abstract

The invention discloses a new energy station reactive voltage response control method and system for suppressing transient voltage rise, and belongs to the technical field of new energy grid connection. The method comprises the following steps: establishing a new energy field station group low-voltage fault ride-through response control model, an SVG low-voltage fault ride-through reactive voltage response control model and a new energy unit transient voltage rise threshold; based on the time domain simulation result of the fault disturbance, a fitting curve of the new energy machine end transient voltage rise changing along with the low-pass reactive current coefficient is obtained; establishing a linear optimization model for suppressing transient voltage rise under the iteration, and solving and determining an optimal solution of the SVG low-pass reactive current coefficient; and performing time domain simulation based on the new SVG low-pass reactive current coefficient to determine and check whether the transient voltage rise of the new energy station meets a preset requirement, and performing loop iteration to establish and solve a linear optimization model until a new energy station SVG reactive voltage response control parameter optimal solution coordinated with the new energy unit is obtained. The method can promote new energy acceptance.

Description

Technical Field

[0001] The present invention relates to the field of new energy grid-connected technology, and more specifically, to a new energy station reactive voltage response control method and system for suppressing transient voltage rise. Background Art

[0002] The construction of a new power system with new energy as the main body is an effective way to achieve the dual carbon goals. The scale of new energy development and construction will further increase in the future. With the gradual increase of access capacity, the short-circuit ratio of new energy will further decrease. After the fault disturbance, the transient voltage fluctuation of new energy will be more intense, and the risk of new energy fault crossing and disconnection will increase. The disconnection will affect the safety of the power grid. Especially after the large-scale access of new energy, the disconnection will have a "domino" effect, and the impact on the power grid will become more serious. Therefore, the problem of new energy disconnection due to transient voltage fluctuations under fault disturbance has become a major restriction on the access and transmission of new energy. The transient voltage fluctuation problem is divided into transient low voltage and high voltage problems. Under the condition of low short-circuit ratio, the interaction of external AC and DC fault disturbances and power electronics time delays makes the transient high voltage problem more prominent than the low voltage problem. In order to release the transmission capacity of new energy and promote its acceptance, it is urgent to carry out optimization control research on the transient voltage rise problem existing in fault disturbances under low short-circuit ratio and weak power grid, so as to reduce the transient voltage rise of new energy, and then increase the access and transmission capacity of new energy, which has important theoretical and practical significance for the development and construction of new energy.

[0003] A great deal of research has been carried out on suppressing the transient voltage rise during the access of new energy. The transient voltage rise, also known as transient overvoltage, can be classified according to the time scale into: switching overvoltage, resonance overvoltage, electromechanical transient overvoltage, etc. This invention mainly focuses on the voltage rise problem at the electromechanical scale. The relevant research results around the electromechanical transient voltage rise are classified as follows: First, in terms of the mechanism and law of transient voltage rise: When large-scale new energy is transmitted through UHV DC, when faults such as commutation failure and blocking occur in the UHV DC, the DC active power is cut off or fluctuates greatly, and the reactive power of the supporting filter is excessive, leading to the problem of transient voltage rise. With the increase in the access of new energy and the increase in the DC transmission capacity, the amplitude of the transient voltage rise after the fault disturbance will be greater; When large-scale new energy is transmitted through high-voltage AC transmission channels, when a fault occurs in the AC transmission channel, during the fault, power electronic devices such as new energy power stations emit capacitive reactive power, but the relay protection acts to cut off the fault. Due to effects such as time delay, the power electronic devices still maintain the state of emitting capacitive reactive power. The degree of voltage rise after the original fault is cut off will be greater under the action of the excessive reactive power. When the access scale of new energy becomes larger, the short-circuit ratio becomes smaller, and the "voltage-fixing" ability decreases, and the amplitude of voltage climbing will be more intense, triggering the new energy fault ride-through protection to cut off the new energy and resulting in the problem of disconnection; Second, in terms of suppressing the transient voltage rise: Strengthen the grid connection framework of new energy access, and improve the short-circuit ratio of new energy access by configuring synchronous condensers and other equipment at new energy power stations, thereby fundamentally alleviating the voltage change amplitude under fault disturbances; Certain research has been carried out on the coordinated control of active and reactive power optimization for the fault ride-through of new energy power stations, and the fault ride-through control strategies for wind farms, photovoltaic power stations, and supporting SVG during the fault ride-through period have been optimized and proposed, reducing the voltage fluctuation amplitude; Third, currently, more are grid-following wind power. The grid-forming wind power is different from the grid-following type in terms of the phase-locking principle, overload and overvoltage bearing capacity, response speed, etc. Relevant research on the control strategy for suppressing the transient voltage rise of grid-forming wind power has also been carried out. In summary, for the currently mainstream grid-following new energy grid connection, certain research has been carried out on the control strategies such as active and reactive power for fault ride-through to suppress the transient voltage fluctuation, but new energy power stations generally configure dynamic reactive power compensation devices such as SVG (Static Var Generator). There are few relevant results on how SVG coordinates and cooperates with new energy to jointly suppress the transient voltage fluctuation under fault control. Summary of the Invention

[0004] In view of the above problems, the present invention proposes a reactive power voltage response control method for a new energy power station to suppress transient voltage rise, including:

[0005] For a new energy power station connected to the main grid, establish a steady-state / transient model, and generate a data file for simulation calculation based on the steady-state / transient model. Based on the data file, establish a low-voltage fault ride-through response control model for a new energy power station group, a low-voltage fault ride-through reactive power voltage response control model for SVG, and a transient voltage rise threshold for new energy units.

[0006] Based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG and the transient voltage rise threshold of the new energy unit, a time domain simulation under fault disturbance is performed to obtain a transient voltage rise fitting curve at the new energy unit end, and to determine whether the transient voltage rise of the new energy unit is lower than the voltage rise threshold. If it is lower than the voltage rise threshold, the process ends and the final SVG low-voltage ride-through reactive current coefficient optimization solution is obtained. If it is greater than or equal to the threshold, the current SVG low-voltage ride-through reactive current coefficient and the corresponding new energy transient voltage rise are used as the initial values ​​of a new iteration;

[0007] For one cycle iteration, multiple physical quantities are calculated according to the transient voltage rise fitting curve at the new energy machine end and the initial value of a new iteration, and a linear optimization model for suppressing transient voltage rise is established based on the multiple physical quantities;

[0008] Solve the linear optimization model for suppressing transient voltage rise to determine the optimization solution of the SVG low-through reactive current coefficient under this iteration, and perform time domain simulation with the optimization solution to determine whether the transient voltage rise of the new energy station meets the preset requirements. If not, continue to iterate and establish and solve the linear optimization model until the transient voltage rise of the new energy station meets the threshold requirements;

[0009] An optimized solution for reactive voltage response control parameters of the SVG of the new energy station that matches and coordinates with the new energy generating unit is determined, and the new energy station is controlled by the optimized solution for reactive voltage response control parameters of the SVG of the new energy station to suppress transient voltage rise of the new energy station.

[0010] Optional new energy stations include: wind power new energy stations and photovoltaic new energy stations.

[0011] Optionally, the steady-state / transient model is an equivalent aggregation model of a wind power new energy station and a photovoltaic new energy station.

[0012] Optionally, the equivalent aggregation models of the wind power new energy station and the photovoltaic new energy station include: a fault ride-through state judgment model WEV, an active power control model WLP under the fault ride-through state, and a reactive power control model WLQ under the fault ride-through state.

[0013] Optionally, a low-voltage fault ride-through reactive voltage response control model of the SVG is used to provide a target output current of the SVG, and open-loop control is performed through the target output current of the SVG.

[0014] Optionally, the transient voltage rise threshold of the new energy unit is used to compare with the transient voltage rise value obtained from the new energy unit terminal voltage curve under a typical fault disturbance output by simulation. If the transient voltage rise value is greater than the transient voltage rise threshold, it is determined that a transient voltage rise exceeds the limit at the new energy station.

[0015] Optionally, based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of the SVG and the transient voltage rise threshold of the new energy unit, a time domain simulation under fault disturbance is performed, including:

[0016] Based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG and the transient voltage rise threshold of the new energy unit, the PSD simulation software is used to output the voltage simulation curve of the new energy machine end under the fault disturbance, and the transient voltage rise value of the new energy machine end is obtained. Based on the transient voltage rise value of the new energy machine end, the transient voltage rise fitting curve of the new energy station and SVG under different low-voltage ride-through reactive current coefficients is obtained;

[0017] According to the magnitude of the transient voltage rise value at the new energy machine end, the SVG low-through reactive current coefficient setting value corresponding to the over-limit new energy transient voltage rise is determined, and the SVG low-through reactive current coefficient setting value is used as the initial value of a new iteration.

[0018] Optionally, multiple physical quantities include: the sensitivity of the voltage rise at the new energy machine end to the SVG low-through reactive current coefficient obtained based on the transient voltage rise fitting curve at the new energy machine end, the adjustment amount of the SVG low-through reactive current coefficient and the maximum adjustment amount for each iteration, and the transient voltage rise value at the new energy machine end after the SVG low-through reactive current coefficient is adjusted.

[0019] Optionally, a linear programming method is used to solve a linear optimization model for suppressing transient voltage rise;

[0020] The objective function of the linear optimization model for suppressing transient voltage rise in each iteration is as follows:

[0021] minΔK s,v

[0022] The constraints are as follows:

[0023] S vk ΔK s,v ≤0.3-ΔV 0

[0024]

[0025]

[0026] Among them, K s,v is the SVG low wear reactive current coefficient, This is the initial value of the SVG low-through reactive current coefficient for this iteration, ΔK s,v is the adjustment value of SVG low-through reactive current coefficient, and the objective function minΔKs,v To minimize the reactive current coefficient adjustment of SVG low wear, ΔV 0 is the initial value of transient voltage rise at the new energy machine end, S vk is the sensitivity of the transient voltage rise at the new energy generator end to the SVG low-through reactive current coefficient, S vk ΔK s,v It is the transient voltage rise change value after the SVG low-through reactive current coefficient is adjusted. is the upper limit of SVG low-through reactive current coefficient, ΔK ad The maximum adjustment of the SVG low-penetration reactive coefficient for this iteration.

[0027] On the other hand, the present invention also proposes a reactive voltage response control system for a new energy station for suppressing transient voltage rise, comprising:

[0028] The initial unit is used to establish a steady-state / transient model for the new energy station connected to the main grid, and generate a data file for simulation calculation based on the steady-state / transient model, and establish a low-voltage fault ride-through response control model for the new energy station group, a low-voltage fault ride-through reactive voltage response control model for SVG, and a transient voltage rise threshold of the new energy unit based on the data file;

[0029] A calculation unit is used to perform time domain simulation under fault disturbance based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG and the transient voltage rise threshold of the new energy unit, so as to obtain the transient voltage rise fitting curve of the new energy unit end, and judge whether the transient voltage rise of the new energy unit is lower than the voltage rise threshold. If it is lower than the voltage rise threshold, the process is terminated to obtain the final SVG low-voltage ride-through reactive current coefficient optimization solution. If it is greater than or equal to the threshold, the current SVG low-voltage ride-through reactive current coefficient and the corresponding new energy transient voltage rise are used as the initial values ​​of a new iteration. For one cycle iteration, multiple physical quantities are calculated according to the transient voltage rise fitting curve of the new energy unit end and the initial value of the new iteration, and a linear optimization model for suppressing transient voltage rise is established based on the multiple physical quantities;

[0030] A control unit is used to solve the linear optimization model for suppressing transient voltage rise, so as to determine the optimized solution of the SVG low-through reactive current coefficient under this iteration, and to perform time domain simulation with the optimized solution to determine whether the transient voltage rise of the new energy station meets the preset requirements. If not, the linear optimization model is established and solved in a cyclic iteration until the transient voltage rise of the new energy station meets the threshold requirements; determine the optimized solution of the reactive voltage response control parameters of the SVG of the new energy station that matches and coordinates with the new energy unit, and control the new energy station through the optimized solution of the reactive voltage response control parameters of the SVG of the new energy station to suppress the transient voltage rise of the new energy station.

[0031] Optional new energy stations include: wind power new energy stations and photovoltaic new energy stations.

[0032] Optionally, the steady-state / transient model is an equivalent aggregation model of a wind power new energy station and a photovoltaic new energy station.

[0033] Optionally, the equivalent aggregation models of the wind power new energy station and the photovoltaic new energy station include: a fault ride-through state judgment model WEV, an active power control model WLP under the fault ride-through state, and a reactive power control model WLQ under the fault ride-through state.

[0034] Optionally, a low-voltage fault ride-through reactive voltage response control model of the SVG is used to provide a target output current of the SVG, and open-loop control is performed through the target output current of the SVG.

[0035] Optionally, the transient voltage rise threshold of the new energy unit is used to compare with the transient voltage rise value obtained from the new energy unit terminal voltage curve under a typical fault disturbance output by simulation. If the transient voltage rise value is greater than the transient voltage rise threshold, it is determined that a transient voltage rise exceeds the limit at the new energy station.

[0036] Optionally, based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of the SVG and the transient voltage rise threshold of the new energy unit, a time domain simulation under fault disturbance is performed, including:

[0037] Based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG and the transient voltage rise threshold of the new energy unit, the PSD simulation software is used to output the voltage simulation curve of the new energy machine end under the fault disturbance, and the transient voltage rise value of the new energy machine end is obtained. Based on the transient voltage rise value of the new energy machine end, the transient voltage rise fitting curve of the new energy station and SVG under different low-voltage ride-through reactive current coefficients is obtained;

[0038] According to the magnitude of the transient voltage rise value at the new energy machine end, the SVG low-through reactive current coefficient setting value corresponding to the over-limit new energy transient voltage rise is determined, and the SVG low-through reactive current coefficient setting value is used as the initial value of a new iteration.

[0039] Optionally, multiple physical quantities include: the sensitivity of the voltage rise at the new energy machine end to the SVG low-through reactive current coefficient obtained based on the transient voltage rise fitting curve at the new energy machine end, the adjustment amount of the SVG low-through reactive current coefficient and the maximum adjustment amount for each iteration, and the transient voltage rise value at the new energy machine end after the SVG low-through reactive current coefficient is adjusted.

[0040] Optionally, a linear programming method is used to solve a linear optimization model for suppressing transient voltage rise;

[0041] The objective function of the linear optimization model for suppressing transient voltage rise in each iteration is as follows:

[0042] minΔK s,v

[0043] The constraints are as follows:

[0044] S vk ΔK s,v ≤0.3-ΔV 0

[0045]

[0046]

[0047] Among them, K s,v is the SVG low wear reactive current coefficient, This is the initial value of the SVG low-through reactive current coefficient for this iteration, ΔK s,v is the adjustment value of SVG low-through reactive current coefficient, and the objective function minΔK s,v To minimize the reactive current coefficient adjustment of SVG low wear, ΔV 0 is the initial value of transient voltage rise at the new energy machine end, S vk is the sensitivity of the transient voltage rise at the new energy generator end to the SVG low-through reactive current coefficient, S vk ΔK s,v It is the transient voltage rise change value after the SVG low-through reactive current coefficient is adjusted. is the upper limit of SVG low-through reactive current coefficient, ΔK ad The maximum adjustment of the SVG low-penetration reactive coefficient for this iteration.

[0048] In yet another aspect, the present invention further provides a computing device, comprising: one or more processors;

[0049] a processor for executing one or more programs;

[0050] When the one or more programs are executed by the one or more processors, the above-described method is implemented.

[0051] In yet another aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed, the method described above is implemented.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The present invention provides a reactive voltage response control method for a new energy station for suppressing transient voltage rise, comprising: establishing a steady-state / transient model for a new energy station connected to a main grid, and generating a data file for simulation calculation based on the steady-state / transient model; establishing a low-voltage fault ride-through response control model of a new energy station group, a low-voltage fault ride-through reactive voltage response control model of SVG, and a transient voltage rise threshold of a new energy unit based on the data file; performing a time domain simulation under a fault disturbance based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG, and the transient voltage rise threshold of the new energy unit, so as to obtain a transient voltage rise fitting curve at the new energy machine end, and judging whether the transient voltage rise of the new energy unit is lower than the voltage rise threshold; if it is lower than the voltage rise threshold, then ending the simulation to obtain a final SVG low-through reactive current coefficient optimization solution; if it is greater than or equal to the threshold, then setting the current SVG low-through reactive current coefficient to the optimal solution. The current coefficient and the corresponding transient voltage rise of new energy are used as the initial value of a new iteration; for a cyclic iteration, multiple physical quantities are calculated according to the transient voltage rise fitting curve of the new energy machine end and the initial value of the new iteration, and a linear optimization model for suppressing transient voltage rise is established based on the multiple physical quantities; the linear optimization model for suppressing transient voltage rise is solved to determine the optimization solution of the SVG low-through reactive current coefficient under this iteration, and the time domain simulation is performed with the optimization solution to determine whether the transient voltage rise of the new energy station meets the preset requirements. If not, the linear optimization model is established and solved by cyclic iteration until the transient voltage rise of new energy meets the threshold requirements; the optimization solution of the reactive voltage response control parameter of the SVG of the new energy station that matches and coordinates with the new energy unit is determined, and the new energy station is controlled through the optimization solution of the reactive voltage response control parameter of the SVG of the new energy station to suppress the transient voltage rise of the new energy station. The present invention can improve the safety of new energy grid connection and promote the acceptance of new energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a flow chart of the method of the present invention;

[0055] Figure 2 Flow chart of an embodiment of the method of the present invention

[0056] Figure 3 A structural diagram of a wind turbine model according to an embodiment of the method of the present invention;

[0057] Figure 4 A photovoltaic model structure diagram of an embodiment of the method of the present invention;

[0058] Figure 5 A schematic diagram of a three-stage simulation method for controlling external characteristics of reactive power response during a new energy fault ride-through period according to an embodiment of the method of the present invention;

[0059] Figure 6It is a schematic diagram of a three-stage simulation method for controlling external characteristics of reactive power response during SVG fault ride-through according to a method embodiment of the present invention;

[0060] Figure 7 A schematic diagram of the power grid access and typical power flow distribution of a new energy station group in an embodiment of the method of the present invention;

[0061] Figure 8 It is a simulation curve diagram of the voltage at the hgg photovoltaic machine end under the 220kV line arq-tjb three-period N-1 fault of the method embodiment of the present invention;

[0062] Fig. 9 It is an enlarged view of the hgg photovoltaic terminal voltage simulation curve in the above figure of the method embodiment of the present invention;

[0063] Fig.10a and 10b They are respectively a hgg photovoltaic voltage simulation curve under fault disturbance and a local "magnified" voltage simulation curve diagram of an embodiment of the method of the present invention;

[0064] Fig.11a and 11b It is a hgg photovoltaic low-through reactive current simulation curve and a partially "enlarged" reactive current simulation curve diagram under a fault disturbance of an embodiment of the method of the present invention;

[0065] Fig.12a and 12b It is a low-penetration reactive current simulation curve of SVG under fault disturbance and a partially "enlarged" reactive current simulation curve diagram of an embodiment of the method of the present invention;

[0066] Fig.13 This is a transient voltage rise variation trend diagram when the hgg low-through reactive current coefficient is 2.5 in the embodiment of the method of the present invention as the SVG low-through reactive current coefficient increases;

[0067] Fig.14 This is a transient voltage rise variation trend diagram when the SVG low-through reactive current coefficient is 0.8 according to the method embodiment of the present invention, as the hgg photovoltaic low-through reactive current coefficient increases;

[0068] Fig.15a and 15b It is a hgg photovoltaic voltage simulation curve under different reactive current response coefficients of VG low penetration and a locally "enlarged" hgg voltage simulation curve diagram of an embodiment of the method of the present invention;

[0069] Fig.16a and 16b It is a reactive current simulation curve of SVG under different reactive current response coefficients of SVG low penetration and a partially "magnified" reactive current simulation curve of SVG in an embodiment of the method of the present invention;

[0070] Fig.17 It is a simulation result diagram of the output reactive current under different reactive current response coefficients of SVG low penetration of the method embodiment of the present invention, and the hgg low penetration reactive current coefficient is 2.5;

[0071] Fig.18 It is a structural diagram of the system of the present invention. DETAILED DESCRIPTION

[0072] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0073] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0074] Embodiment 1:

[0075] The present invention proposes a reactive voltage response control method for a new energy station to suppress transient voltage rise, such as Figure 1 As shown, including:

[0076] Step 1: For the new energy stations connected to the main grid, a steady-state / transient model is established, and a data file for simulation calculation is generated based on the steady-state / transient model. Based on the data file, a low-voltage fault ride-through response control model of the new energy station group, a low-voltage fault ride-through reactive voltage response control model of the SVG, and a transient voltage rise threshold of the new energy unit are established;

[0077] Step 2: Based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG and the transient voltage rise threshold of the new energy unit, a time domain simulation under fault disturbance is performed to obtain a transient voltage rise fitting curve at the new energy unit end, and to determine whether the transient voltage rise of the new energy unit is lower than the voltage rise threshold. If it is lower than the voltage rise threshold, the process ends and the final SVG low-voltage ride-through reactive current coefficient optimization solution is obtained. If it is greater than or equal to the threshold, the current SVG low-voltage ride-through reactive current coefficient and the corresponding new energy transient voltage rise are used as the initial values ​​of a new iteration.

[0078] Step 3: for one cycle iteration, multiple physical quantities are calculated according to the transient voltage rise fitting curve at the new energy machine end and the initial value of a new iteration, and a linear optimization model for suppressing transient voltage rise is established based on the multiple physical quantities;

[0079] Step 4: Solve the linear optimization model for suppressing transient voltage rise to determine the optimization solution of the SVG low-through reactive current coefficient under this iteration, and perform time domain simulation with the optimization solution to determine whether the transient voltage rise of the new energy station meets the preset requirements. If not, continue to iterate and establish and solve the linear optimization model until the transient voltage rise of the new energy meets the threshold requirements.

[0080] Step 5: Determine an optimized solution for reactive voltage response control parameters of the SVG of the new energy station that matches and coordinates with the new energy unit, and control the new energy station through the optimized solution for reactive voltage response control parameters of the SVG of the new energy station to suppress transient voltage rise of the new energy station.

[0081] Among them, new energy stations include: wind power new energy stations and photovoltaic new energy stations.

[0082] Among them, the steady-state / transient model is an equivalent aggregation model of wind power new energy stations and photovoltaic new energy stations.

[0083] Among them, the equivalent aggregation models of wind power new energy stations and photovoltaic new energy stations include: fault ride-through state judgment model WEV, active power control model WLP under fault ride-through state and reactive power control model WLQ under fault ride-through state.

[0084] The low-voltage fault ride-through reactive voltage response control model of the SVG is used to provide a target output current of the SVG, and open-loop control is performed through the target output current of the SVG.

[0085] Among them, the transient voltage rise threshold of the new energy unit is used to compare with the transient voltage rise value obtained from the new energy machine-end voltage curve under the typical fault disturbance output by simulation. If the transient voltage rise value is greater than the transient voltage rise threshold, it is determined that the transient voltage rise exceeds the limit at the new energy station.

[0086] Among them, based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG and the transient voltage rise threshold of the new energy unit, a time domain simulation under fault disturbance is performed, including:

[0087] Based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG and the transient voltage rise threshold of the new energy unit, the PSD simulation software is used to output the voltage simulation curve of the new energy machine end under the fault disturbance, and the transient voltage rise value of the new energy machine end is obtained. Based on the transient voltage rise value of the new energy machine end, the transient voltage rise fitting curve of the new energy station and SVG under different low-voltage ride-through reactive current coefficients is obtained;

[0088] According to the magnitude of the transient voltage rise value at the new energy machine end, the SVG low-through reactive current coefficient setting value corresponding to the over-limit new energy transient voltage rise is determined, and the SVG low-through reactive current coefficient setting value is used as the initial value of a new iteration.

[0089] Among them, multiple physical quantities include: the sensitivity of the voltage rise at the new energy machine end to the SVG low-through reactive current coefficient obtained based on the transient voltage rise fitting curve at the new energy machine end, the adjustment amount of the SVG low-through reactive current coefficient and the maximum adjustment amount of each iteration, and the transient voltage rise value at the new energy machine end after the SVG low-through reactive current coefficient is adjusted.

[0090] Among them, the linear programming method is used to solve the linear optimization model for suppressing transient voltage rise;

[0091] The objective function of the linear optimization model for suppressing transient voltage rise in each iteration is as follows:

[0092] minΔK s,v

[0093] The constraints are as follows:

[0094] S vk ΔK s,v ≤0.3-ΔV 0

[0095]

[0096]

[0097] Among them, K s,v is the SVG low wear reactive current coefficient, This is the initial value of the SVG low-through reactive current coefficient for this iteration, ΔK s,v is the adjustment value of SVG low-through reactive current coefficient, and the objective function minΔK s,v To minimize the reactive current coefficient adjustment of SVG low wear, ΔV 0 is the initial value of transient voltage rise at the new energy machine end, S vk is the sensitivity of the transient voltage rise at the new energy generator end to the SVG low-through reactive current coefficient, D vk ΔK s,vIt is the transient voltage rise change value after the SVG low-through reactive current coefficient is adjusted. is the upper limit of SVG low-through reactive current coefficient, ΔK ad The maximum adjustment of the SVG low-penetration reactive coefficient for this iteration.

[0098] The present invention will be further described below in conjunction with embodiments:

[0099] Process such as Figure 2 As shown, specifically including:

[0100] (1) Based on the PSD power system simulation analysis software, steady-state and transient models of wind power, photovoltaic and other new energy stations connected to the main grid are established, and data files for simulation calculations are generated respectively.

[0101] (2) Establish a low-voltage fault ride-through response control model for new energy stations such as wind and solar power, with a focus on establishing a reactive voltage response control model.

[0102] (3) Establish a low-voltage fault-crossing reactive voltage response control model for new energy stations SVG.

[0103] (4) Determine the transient voltage rise threshold for evaluating wind and solar renewable energy units under fault disturbance.

[0104] (5) Under the typical settings of SVG and new energy low wear exit recovery form and recovery time constant, select the new energy low wear reactive current coefficient K within the setting range of the new energy low wear reactive current coefficient. n,v Typical values ​​are 1.5, 2.0, and 2.5. Consider the setting range of SVG low-through reactive current coefficient and set the SVG low-through reactive current coefficient K. s,v The typical values ​​are 0.1, 0.8, 1.5, etc. Under different combinations of new energy and SVG low-through reactive current coefficients, the PSD simulation software is used to output the voltage simulation curve of the new energy machine under fault disturbance, and the transient voltage rise value of the new energy machine end is obtained, and then the transient voltage rise fitting curve ΔV(K) corresponding to the new energy and SVG low-through reactive current coefficients is obtained. n,v ,K s,v ). When the new energy low-through strategy is known, the transient voltage rise fitting curve of the new energy generator end is only related to the SVG low-through reactive current coefficient K s,v Related, that is:

[0105] (6) When the new energy and SVG low penetration strategy and other parameters are known, the corresponding SVG low penetration reactive current coefficient K s,v , the PSD software can be used to simulate the voltage rise of the new energy generator under fault disturbance. If the voltage rise of the generator is greater than 0.3, the current SVG low-through reactive current coefficient setting value K s,vAs the initial value of a new iteration And jump to step (7), otherwise end.

[0106] (7) Based on the transient voltage rise fitting curve of the new energy machine end The initial value is calculated as Sensitivity of voltage rise at the new energy generator end to SVG low-through reactive current coefficient S vk .

[0107] (8) Based on the initial value of SVG low-through reactive current coefficient Define the adjustment value ΔK of SVG low-power reactive current coefficient s,v .

[0108] (9) Based on the initial value of SVG low-through reactive current coefficient Calculate the SVG low-breakdown reactive current coefficient adjustment ΔK s,v After the transient voltage rise of the new energy machine end ΔV=ΔV 0 +S vk ΔK s,v , the goal is to control the voltage rise at the new energy machine end within the upper limit of 0.3pu;

[0109] (10) Based on the effective interval of linear sensitivity of the current initial operating condition, during the iteration process, the control variable ΔK s,v The control range is limited by the maximum adjustment amount ΔK per iteration. ad The limitation of can ensure that the solution remains within the valid domain of the linearized model.

[0110] (11) Based on the calculation of the physical quantities in steps (7) to (10), a linear optimization model for setting the SVG low-through reactive current coefficient that suppresses transient voltage rise in coordination with new energy sources is established.

[0111] (12) The linear programming method is used to solve the linear optimization model of step (11) to obtain the optimal adjustment solution ΔK of the SVG low-through reactive current coefficient. sv , and get the initial value based on SVG low wear reactive current coefficient

[0112] (13) Go to step (6) and use PSD software to perform time domain simulation to verify whether the transient voltage rise of the new energy station meets the requirement of less than 0.3pu.

[0113] Preferably, the step (1) comprises:

[0114] Wind farms and photovoltaic power stations use equivalent aggregation models. Taking photovoltaic power stations as an example, multiple photovoltaic modules in the station are aggregated according to the lighting conditions of the photovoltaic power station, the connection form of multiple photovoltaic modules in the power station, and different control strategies of grid-connected power electronics. Taking a typical 200MW photovoltaic power station with a single photovoltaic module of 1.5MW and a total of about 134 modules as an example, it is generally aggregated into 2-4 equivalent photovoltaic arrays. The equivalent photovoltaic array capacity is a multiple of a single photovoltaic module. The aggregated photovoltaic transient model adopts the typical control model, structure and parameters of the grid-connected power electronic converter; in addition to the photovoltaic module and converter models, the photovoltaic power station access modeling also includes the modeling of photovoltaic unit transformers, internal cables, grid-connected boost transformers, supporting SVGs, and grid-connected lines; the equivalent aggregation and grid access model of wind farms is the same as photovoltaics, so it will not be repeated. According to the scope of influence of the aggregation, access, and transmission of new energy station groups, the main grid is modeled in detail or simplified. Generally, the regional power grid where new energy is connected needs detailed modeling, and the main grid outside the regional power grid can be modeled in an equivalent and simplified manner according to the situation;

[0115] Preferably, the step (2) comprises:

[0116] Based on the PSD simulation software, a wind power and photovoltaic low-voltage fault ride-through control model is established. First, based on the PSD simulation software, a transient model of a wind farm and a photovoltaic power station containing multiple control function modules is established. The doubly fed / direct-drive wind turbine model is unified into multiple modules as shown in the figure below. The control systems of the two are consistent, but the generator processing part is different, that is, the doubly fed wind turbine is processed as an equivalent voltage source, and the direct-drive wind turbine is processed as an equivalent current source. Among them, the wind turbine fault ride-through control model is: WEV, WLP, WLQ, and the model structure is as follows: Figure 3 As shown;

[0117] WDF, WFC models——doubly fed, direct drive generator models;

[0118] WES model - converter current control and limiting model;

[0119] WEV model——fault-travel state judgment model;

[0120] WLP model——active power control model under fault ride-through state;

[0121] WLQ model - reactive power control model under fault ride-through state;

[0122] WME model – axis system model;

[0123] WTG model – wind power model;

[0124] WGF model——pitch angle control model;

[0125] WEP model——active power control model under normal operating conditions;

[0126] WEQ model - reactive power control model under normal operating conditions.

[0127] The specific structure of the photovoltaic power generation system model is shown in the figure below, which includes transient models of multiple modules. Among them, the photovoltaic fault ride-through control related models are: WEV, WLP, WLQ. The model structure is as follows Figure 4 As shown;

[0128] PSL model – Photovoltaic power generation model;

[0129] WES card - converter current control and limiting model;

[0130] WEV card – fault-crossing state judgment model;

[0131] WLP card - active power control model in fault ride-through state;

[0132] WLQ card - reactive power control model in fault ride-through state;

[0133] WAF card – frequency control model;

[0134] WAI card - inertia control model;

[0135] WEU card - active power control model under normal operating conditions;

[0136] WEQ card - reactive power control model under normal operating conditions

[0137] The models that are strongly related to the transient voltage rise problem are the WEV and WLQ models. That is, the WEV fault ride-through state judgment model is used to determine whether to trigger the low-voltage ride-through response control. Generally, the low-voltage ride-through response control is triggered when the voltage of the new energy unit is lower than the threshold of 0.9pu. The WLQ is a reactive power response control model under the low-voltage ride-through state. The three-stage simulation method is used to simulate the external characteristics of the low-voltage ride-through reactive power response control, as follows:

[0138] (1) The first paragraph is "Control of reactive power during low-voltage wear-through", corresponding to Figure 5 In the first section, i.e., the low-voltage penetration period t1-t2, the reactive current that the unit should provide is set. Generally, the following formula for calculating reactive current based on voltage drop is used to obtain the reactive current that should be provided during the low-voltage penetration period: IQ n,ref =K n,v ×(V n,set -V t )×I n,N +K n,i ×IQ n,0 +IQ n,set , the current, voltage and other physical quantities in the formula are all per unit values ​​relative to the rated parameters of the unit itself.n,N is the rated current of new energy, with a unit value of 1; K n,v V is the dynamic reactive current proportional coefficient of the new energy station, and its value range should generally be no less than 1.5 and preferably no more than 3; t is the voltage amplitude of the new energy terminal under fault, V n,set The low penetration action threshold is 0.9pu; IQ n,0 is the initial reactive current, K n,i The proportional coefficient is the corresponding one. Generally, the new energy unit adopts the reactive power control mode with a constant power factor of 1 during steady-state operation, that is, the reactive power is 0, corresponding to IQ n,0 Also 0; IQ n,set A constant coefficient is set to fit the external characteristics of reactive current. It is assigned a value according to the fitting needs and can generally be assigned to 0.

[0139] (2) The second section is "the initial value of reactive power recovery after the low-voltage penetration ends", which corresponds to section ② in the figure above. Generally, the method of specifying reactive current is adopted. The following formula can be used to calculate the initial value of reactive current recovery after the low-voltage penetration ends: IQ n,ref =K n,i *IQ n,lv +IQ n,set The current physical quantity in the formula is the per unit value relative to the rated parameters of the unit itself, where IQ n,lv is the reactive current during low-voltage wear-through, coefficient K n,i , IQ n,set The two proportional coefficients set to fit the external characteristic curve are typical parameters adopted in the present invention, K n,i =1, IQ n,set is 0, that is, the reactive current during the low-voltage break-through period is used as the initial value for recovery.

[0140] (3) The third section is the "reactive power recovery process after the low-voltage penetration ends", which corresponds to section ③ in the above figure. It can generally be set to recover in an exponential form, corresponding to the recovery period t2-t3 after the low-voltage penetration ends in the above figure. At the same time, the time constant of the exponential recovery needs to be set, and finally the reactive power operation initial value during steady-state operation is recovered. Generally, the unit adopts a constant power factor of 1 for steady-state operation, that is, the reactive power output is 0 Mvar. Therefore, after the low-voltage penetration ends, the reactive power recovers to the initial value of 0.

[0141] The active response control model WLP under low-through state will affect the transient voltage rise characteristics to a certain extent, and this invention takes it as the boundary condition for research. Similar to reactive response control, a three-stage simulation method can also be used to simulate the external characteristics of low-through active response control: For stage ①, the control method during the through period, select the control method of the specified active current, and the active current formula is: IP ref =K v ×V t +KI ×IP 0 +IP set The current and voltage in the formula are relative to the unit's rated parameters, where IP 0 is the initial active current, V t is the voltage amplitude at the machine end, and the coefficient K v , K I and IP set It is set to fit the external characteristics of active current. For section ②, the active current during the crossing period is used as the recovery starting point; for section ③, the recovery process control mode is selected as immediate recovery.

[0142] Preferably, the step (3) comprises:

[0143] The SVG low-breakthrough reactive voltage response control strategy of the present invention is that during the low-breakthrough process, the outer loop voltage control is no longer subject to proportional (Proportional) and integral (Integral) control (PI control for short), but directly gives the target output current of the SVG, that is, open-loop control, thereby improving the response speed and can be used to suppress transient voltage rise at the ms level.

[0144] The threshold for SVG to enter low-through response control is when the voltage at the SVG access point is lower than 0.9pu, and the threshold for exiting low-through is when the voltage at the SVG access point is higher than 0.9pu. After triggering low-through, SVG quickly provides the target output current through low-through open-loop response control. When the voltage recovers, SVG exits low-through and recovers to the initial current after a short delay (the reactive current during the delay period is still maintained during the cross-over period). Based on PSD simulation software, a three-stage simulation method is used to simulate the reactive current response control characteristics of SVG during low-through.

[0145] like Figure 6 As shown in the figure, the reactive voltage response output current formula during the first section of SVG low wear period is: IQ s,ref =K s,v ×(V s,set -V t )×I s,N +IQ s,0 , where the current and voltage in the formula are the per unit values ​​relative to the rated parameters of the device itself, I s,N is the rated current of SVG, with a unit value of 1; K s,v V is the SVG dynamic reactive current proportionality coefficient; t is the voltage amplitude of the SVG access point under fault, V s,set It is the SVG low penetration action threshold, which is generally set to the low penetration threshold of new energy 0.9pu; IQ s,0is the initial reactive current. The initial value of reactive power recovery after the low-break of the second section SVG is generally the reactive current during the fault ride-through period. The reactive power recovery process after the low-break of the third section SVG is generally restored to the steady-state initial reactive current after a short delay. The delay can be set to a typical parameter of 1 cycle (SVG still maintains the reactive current of the fault ride-through during the delay of 1 cycle).

[0146] Preferably, the step (4) comprises:

[0147] Based on the PSD simulation software, the voltage curve of the new energy machine terminal under typical fault disturbance is simulated and output, and compared with the threshold required for transient voltage rise. If it is greater than the corresponding threshold, a transient voltage rise over-limit problem occurs.

[0148] "GB / T 19963.1-2021 Technical Regulations for Wind Farm Access to Power System Part 1: Onshore Wind Power" stipulates the high-voltage ride-through protection of wind turbines: If the voltage rises to more than 1.3pu during the fault disturbance, the wind turbine is allowed to be disconnected from the grid. Therefore, 1.3pu can be used as the critical value of transient voltage rise. Since the steady-state operating voltage range of wind turbines is 0.9-1.1pu, the initial voltage can be any value in this range. When studying the problem of transient voltage rise, from the perspective of operating habits and conservatism, the present invention sets the initial value of the steady-state operating voltage to 1p.u. After the fault disturbance, the transient voltage of the new energy rises to 1.3pu, which is considered to reach the transient voltage rise limit. Therefore, the transient voltage rise difference of 0.3pu at this time is taken as the judgment threshold for the transient voltage rise of wind power to reach the critical value. Photovoltaics is similar, and 0.3pu is also taken as the judgment threshold for the transient voltage rise to reach the critical value.

[0149] Based on the PSD simulation software, the voltage curve of the new energy machine end after the fault disturbance is simulated and output, the maximum transient voltage in the voltage curve is taken, and the difference is made with the initial operating voltage to obtain the magnitude of the transient voltage rise. If the difference is greater than 0.3pu, it is considered that the new energy has a transient voltage rise problem.

[0150] Preferably, the step (5) comprises:

[0151] Considering various low penetration response control strategies and parameter conditions of new energy stations:

[0152] (1) After the new energy exits the low penetration, it recovers exponentially and the recovery time constant is a typical 0.5 cycle (10ms);

[0153] (2) Consider multiple groups of typical low-throughput reactive current response coefficients of new energy.

[0154] Considering various low penetration response control strategies and parameter conditions of SVG in new energy stations:

[0155] (1) The delay of SVG exiting the low-pass is set according to the typical parameters of 1 cycle (20ms);

[0156] (2) Taking into account multiple groups of typical low-throughput reactive current response coefficients of SVG.

[0157] Under the above-mentioned new energy units and SVG low-through conditions, the transient voltage rise characteristics and laws generated by the interaction between new energy, SVG and the main grid under fault disturbance are simulated and evaluated. Among them, 1.5, 2.0, and 2.5 are typical settings for the low-through reactive current coefficient of new energy; 0.1, 0.8, and 1.5 are typical settings for the low-through reactive current coefficient of SVG. Under different combinations of new energy and SVG low-through reactive current coefficient settings, the PSD simulation software is used to output the voltage simulation curve of the new energy machine under fault disturbance, and the transient voltage rise value of the new energy machine is obtained, and then the transient voltage rise fitting curve ΔV(K) corresponding to the different low-through reactive current coefficients of new energy and SVG is obtained. n,v ,K s,v ). When the new energy low-through strategy is known, the transient voltage rise fitting curve of the new energy generator end is only related to the SVG low-through reactive current coefficient K s,v Related, that is:

[0158] Preferably, the step (11) comprises:

[0159] In each iteration, the following linear optimization model of wind farm dynamic reactive capacity demand is established:

[0160] Objective function:

[0161] minΔK s,v (1)

[0162] The following constraints are met:

[0163] S vk ΔK s,v ≤0.3-ΔV 0 (2)

[0164]

[0165]

[0166] In the formula, the adjustment amount of the low-through reactive current coefficient of the SVG of the new energy station in this iteration is ΔK s,v ; Objective function minΔK s,v In order to control the transient voltage rise of renewable energy within the range of 0.3pu, the SVG low-through reactive current coefficient is adjusted to a minimum; in the constraint, S vk is the initial value calculated based on the transient voltage rise fitting curve of the new energy machine end The sensitivity of transient voltage rise of new energy generator to SVG low-through reactive current coefficient under the condition of ΔV 0 is the initial value of the voltage rise at the new energy machine end in this iteration, S vk ΔK s,v Change ΔK for SVG low wear reactive current coefficient s,v The voltage rise change value of the new energy generator after the iteration. Constraint (2) indicates that after the SVG low-through reactive current coefficient adjustment, the transient voltage rise of the new energy is reduced to less than 0.3pu; Constraint (3) indicates that the SVG of the new energy station is adjusted under the low-through reactive current coefficient. Adjustment should be made based on the K s,v Upper limit The present invention adopts the method of equivalently treating the nonlinear optimization model as a sequential linear programming model. Since a linear sensitivity model is established in each iteration, the effective interval of the linear sensitivity should be considered. In each iteration, the control range is limited to the control variable to ensure that the solution is maintained within the effective domain of the linearized model. For the adjustment of the low-throughput reactive current coefficient of the SVG of the new energy station, constraint (4) must be satisfied, where ΔK ad The maximum adjustment amount of the SVG low-pass reactive coefficient is set. The present invention takes 0.01. After adopting this strategy, the adjustment amount of each iteration can be minimized to be not too large, and far exceeds its linear effective range.

[0167] The main effects of the present invention are as follows:

[0168] 1) The transient voltage rise characteristics and laws of new energy caused by the incoordination between new energy and SVG low-throughput strategy and parameter setting are given: The transient voltage rise characteristics and laws of new energy and SVG interacting with the main grid under various conditions such as low-throughput reactive current coefficient and exit low-throughput recovery strategy are evaluated, and the fitting curve of the transient voltage rise at the new energy machine end with the change of new energy units, SVG low-throughput strategy and parameters is given, and the direction of optimizing the control parameters of SVG low-throughput reactive voltage response coordinated with new energy is determined.

[0169] 2) A low-through reactive voltage response control strategy and parameter optimization setting model for SVG coordinated with renewable energy are proposed and solved. The effectiveness of the optimization strategy and parameters is verified by simulation: In order to solve the transient voltage rise problem caused by the incoordination of the low-through reactive voltage response control strategy and parameter setting between renewable energy and SVG, an optimization model for suppressing transient voltage rise and coordinating the control parameters of the low-through reactive voltage response of SVG coordinated with renewable energy is established. The model solution method is given, and the optimization setting scheme of the low-through reactive current coefficient of SVG supporting renewable energy stations is obtained. The simulation verifies the effect of alleviating transient voltage rise, which can improve the safety of renewable energy grid connection and promote the acceptance of renewable energy.

[0170] The following takes the access of a certain new energy station group to the power grid as an example to further explain the specific implementation mode of the present invention in detail.

[0171] The schematic diagram of the grid structure of the new energy station cluster connected to the power grid is as follows: Figure 7 As shown, ld is a 500kV power station with a 220kV power grid underneath. This 220kV power grid has no conventional power supply access, and is connected to 4 wind farms and 1 photovoltaic power station to form a new energy station group. Among them, the installed capacity of the hgg photovoltaic power station is 200MW, and the installed capacities of the mqf, hnf, glf, and zlf wind farms are 300MW, 100MW, 150MW, and 150MW respectively. The total installed capacity of this new energy station group is 900MW; the capacity of a single wind turbine is 6.25MW, so there are 32 wind turbines in a 200MW wind farm and 48 wind turbines in a 300MW wind farm; each hgg photovoltaic power generation unit is 1.5MW, and the 200MW photovoltaic power station has a total of about 134 power generation units. The 500kV substation ld is connected to the 500kV substation arq. There is a wind farm group with an installed capacity of about 2200MW under the arq station. Considering the output simultaneity rate and grid safety constraints, the wind farm group arranges its output at a simultaneity rate of 75% of the installed capacity, and sends about 1625MW of active power through the arq station.

[0172] The present invention focuses on the research of the access of about 900MW new energy station group under the 500kV substation ld station. The single small-capacity photovoltaic unit and wind turbine group of the new energy station are boosted to 35kV through the unit transformer. The 35kV medium-voltage cable is connected to the 35 / 220kV booster station hg, mq, hn, gl, zl of each new energy station, boosted to 220kV and connected to the power grid. SVG is configured on the low-voltage side of each new energy booster station to meet the requirements of reactive balance and voltage control. Among them, the hgg photovoltaic power station 35 is configured with 2 SVGs with a single capacity of 30Mvar. After a part of the power of the new energy field group under the 500kV substation ld is consumed by the local load, most of the remaining power is sent through the ld transformer.

[0173] Based on the typical access mode of new energy station cluster, the research is carried out. The relevant active and reactive power flows and node voltages of the power grid are shown in the figure below: (1) The active power flow is as follows: The wind power and photovoltaic new energy station cluster with an installed capacity of 900MW outputs active power. After a part of the local 220kV load is consumed, the remaining new energy power of about 777MW is sent through the 500kV substation mld. (2) The reactive voltage situation is as follows: the grid-connected bus voltage and main grid voltage of the 220kV new energy station should meet the operating requirements. The voltage operating requirement is 97% to 107% of the nominal voltage of 220kV, that is, 213.4 to 235.4kV. By adjusting the SVG reactive output of the five new energy stations, the voltage of the new energy grid-connected bus and the main grid bus can meet the operating requirements. The wind turbines and photovoltaic power generation units of the new energy stations operate at a fixed power factor of 1, and the reactive output is 0Mvar. Among them, the SVG reactive output of the hgg photovoltaic power station is -3Mvar, the hgg photovoltaic terminal voltage is 0.962pu, and the 220kV grid-connected point bus voltage is 222.2kV.

[0174] The specific implementation includes the following steps:

[0175] (1) Based on the grid structure and typical methods of the above-mentioned new energy station clusters connected to the power grid, steady-state and transient modeling of the new energy station cluster access is carried out to form the data files required for calculation and analysis.

[0176] (2) Based on this example, a reactive voltage response control model for low-voltage fault crossing in renewable energy stations such as wind and solar power is established.

[0177] Based on PSD simulation software, WEV, WLP, and WLQ models are used to simulate the fault ride-through state judgment of starting low voltage ride-through control, active power control under low voltage ride-through state, and reactive power control under low voltage ride-through state, taking the access to the terminal hgg photovoltaic station as an example:

[0178]

[0179] In the WEV model, the voltage type for starting low-voltage and high-voltage ride-through control is positive-sequence voltage; the voltage thresholds for entering fault ride-through and starting low-voltage and high-voltage ride-through control are 0.9pu and 1.1pu respectively, and the voltage thresholds for exiting fault ride-through and low-voltage and high-voltage ride-through control are 0.91pu and 1.09pu respectively.

[0180] The "L" symbol in WLQ represents the reactive power control strategy during low-voltage ride-through. In this example, the reactive power ride-through control adopts a three-stage simulation method. The control method during low-voltage ride-through in the first stage selects the specified reactive current control method and sets it according to the reactive current formula: IQ n,ref =K n,v ×(Vn,set -V t )×I n,N +K n,i ×IQ n,0 +IQ n,set , where V t is the voltage amplitude at the machine end, V n,set The low penetration start threshold is 0.9pu, and the coefficient K n,v Set to three typical values ​​of 1.5, 2.0, and 2.5; according to the unit's steady-state operation at a constant power factor of 1, set IQ n,0 Set to 0, coefficient K n,i Set to 1; IQ set The reactive current constant coefficient is set to 0. ② After the low-breakthrough is completed, the reactive current recovery starting point control method can use the following formula to specify the initial value of reactive current recovery: IQ n,ref =K n,i *IQ n,lv +IQ n,set , where IQ n,lv It is the reactive current during the low-power wear period, that is, the low-power wear current setting value IQ of the above section ① n,ref , coefficient K n,i , IQ n,set Two proportional coefficients are set to fit the external characteristic curve. The typical parameters used in this invention are K n,i =1, IQ n,set =0, that is, the reactive current during the low-voltage penetration period is used as the initial value of the reactive current recovery after the low-voltage penetration of stage ② ends. After the low-voltage penetration of stage ③ ends, the reactive power recovery process can generally be set to recover in an exponential form, and the exponential recovery time constant is set to 0.01s (0.5 cycle).

[0181] The "L" symbol in WLP represents the active power control strategy during the low-power ride-through period. In this example, a three-stage simulation method for active power ride-through control is adopted. The control method during the low-power ride-through period is selected to specify the active current control method. The active current formula is: IP ref =K v ×V t +K I ×IP 0 +IP set , where IP 0 is the initial active current of steady-state operation, which can be obtained from the initial active power and voltage of renewable energy in steady state; in the calculation example, the coefficient K v Set to a typical value of 0, K I 0.29, IP set After the ② and ③ stages are selected to exit the low-breakthrough, the active power will immediately return to the steady-state initial value, so the relevant parameters can be set to 0.

[0182] (3) Based on this example, a typical fault set for the connection of new energy stations to the nearby main grid is established, and an evaluation is performed in combination with the transient voltage rise threshold.

[0183] Combined with this specific example, the fault set is mainly the typical faults of three-way N-1 and N-2 of the line near the grid-connected area of ​​the new energy station group, such as the three-way N-1 of 220kV lines arq-ml, arq-tjb, arq-ay, ay-ld, ld-tjb, ld-mgq, and the three-way N-1 of 500kV lines ld-xl and ld-ft; such as the three-way N-2 of 220kV double-circuit lines arq-ml and ld-tjb, and the three-way N-2 of 500kV double-circuit lines ld-ft and ld-xl. Among them, the fault breaking time of 220kV line is 6 cycles; the fault breaking time of 500kV line is 5 cycles. Take the transient voltage rise difference of 0.3pu as the judgment threshold for the transient voltage rise of new energy to reach the critical value. Based on the PSD simulation software, the voltage curve at the end of the new energy machine after the fault disturbance is simulated, the maximum value of the transient voltage of the voltage curve is taken, and the difference is obtained from the initial operating voltage to obtain the transient voltage rise difference. If the difference is greater than 0.3pu, it is considered that the new energy has a transient voltage rise problem.

[0184] After evaluating the transient voltage rise of new energy under the condition of multiple component failures, it was found that the most serious transient voltage rise problem of new energy occurred in the Sanyong N-1 fault on the ARQ side of the 220kV ARQ-TJB single-circuit line. The new energy with the most serious transient voltage rise was the HGG photovoltaic power station. The transient voltage rise at the photovoltaic machine end was greater than 0.3pu, and the risk of grid disconnection was relatively high. It was necessary to coordinate the optimization and setting of the SVG and photovoltaic low-through reactive voltage response control strategy of the HGG photovoltaic power station to reduce the risk of transient voltage rise.

[0185] The voltage simulation curve of the hgg photovoltaic machine terminal under the 220kV line arq-tjb Sanyong N-1 fault is as follows Figure 8 and 9 As shown:

[0186] The 220kV line arq-tjb three-period N-1 fault occurred at 0.1s and was cleared at 0.22s. From the simulation curve, it can be seen that the maximum transient voltage of hgg photovoltaic occurs at 0.24s, and the maximum transient voltage is 1.344pu, that is, it occurs at 0.02s (1 cycle) after the fault is cleared. The initial steady-state voltage of hgg photovoltaic is 0.962pu, and the maximum transient voltage rise of hgg photovoltaic is 1.344-0.962=0.382pu, which is greater than the transient voltage rise threshold of 0.3pu.

[0187] (4) Based on this example, a low-voltage fault ride-through reactive voltage response control model for the SVG of a new energy station is established.

[0188] Based on PSD simulation software, the VGQ model is used to simulate the SVG low-through reactive voltage response control strategy of the hgg photovoltaic power station connected to the 35kV side of the step-up transformer:

[0189] VGQhgg_s 35.LVRT10.9 1.5 00.00.11.00.0.9 0.91 0.0.

[0190] The target output current formula of SVG low-break response control is: IQ s,ref =K s,v ×(V s,set -V t )×I s,N +IQ s,0 , where I s,N is the rated current of SVG, with a unit value of 1; K s,v is the SVG dynamic reactive current proportionality factor, the typical parameter setting range is less than or equal to 1.5, V t is the voltage amplitude of the SVG access point under fault, V s,set is the SVG low-breakthrough action voltage threshold, which is set to the new energy low-breakthrough threshold of 0.9pu; IQ s,0 is the initial reactive current. After a short delay of 1 cycle (during the delay of 1 cycle, the reactive current is still maintained at low level), SVG exits the low level and the current returns to the initial value of the steady-state reactive current.

[0191] (5) Combined with this example, the risk and cause of transient voltage rise caused by the inconsistency between new energy and SVG low penetration strategy and parameter setting are simulated and analyzed.

[0192] Considering various low-breakdown response control strategies and parameter conditions of HGG photovoltaics:

[0193] 1) After HGG PV exits the low penetration, it recovers exponentially and the recovery time constant takes a typical value of 0.5 cycle (10ms);

[0194] 2) The typical low-penetration reactive current response coefficients of multiple groups of hgg photovoltaic are: 1.5, 2.0, and 2.5 respectively.

[0195] Considering the various low penetration response control strategies and parameter conditions of SVG of HGG photovoltaic power station:

[0196] 1) The delay of SVG exiting low penetration is set according to the typical parameters of 1 cycle (20ms);

[0197] 2) SVG has multiple groups of typical low-penetration reactive current response coefficients, which are 0.1, 0.8, and 1.5 respectively.

[0198] Under the conditions of multiple low-break strategies and parameter settings of HGG photovoltaic and SVG, the transient voltage rise problems and risks caused by the interaction between HGG photovoltaic, SVG and the main grid under fault disturbance are simulated and evaluated. The transient voltage rise risk assessment list 1 is as follows:

[0199] Table 1

[0200]

[0201] It can be seen from the above risk assessment list that: after the hgg photovoltaic low-breakthrough ends, it recovers in an exponential form with a time constant of 0.5 cycle, and when the hgg photovoltaic power station supporting SVG exits the low-breakthrough recovery delay of 1 cycle, under the multiple parameter combination schemes of hgg photovoltaic and SVG low-breakthrough reactive current coefficient, there will be a risk of transient voltage rise greater than 0.3pu.

[0202] Taking the HGG photovoltaic low-through coefficient of 2.5 and the SVG low-through coefficient of 1.5 as examples, the transient voltage rise after the fault reaches 0.382pu, and the transient voltage rise exceeds the limit. Combined with the simulation analysis results, the cause of the transient voltage rise problem is analyzed.

[0203] The 220kV line arq-tjb Sanyong N-1 fault simulation curves are shown in 10a, 10b, 11a, 11b, 12a and 12b;

[0204] A three-phase N-1 fault occurred on the arq-tjb line at 0.1s, which was cleared at 0.22s. The fault lasted for 0.12s (6 cycles). During the fault duration, the voltage at the fault point was close to 0p.u., and the voltage of the hgg photovoltaic and photovoltaic supporting SVG in the fault area was also relatively low, lower than the threshold of 0.9pu, triggering the photovoltaic and SVG low-through reactive voltage response control action, and issuing capacitive reactive power to improve the voltage reactive support during the fault. After the fault was cleared at 0.22s, the main grid voltage increased. At this time, the hgg photovoltaic and SVG low-through reactive currents did not immediately recover to 0 due to the delay. The hgg photovoltaic capacitive reactive current gradually decreased exponentially until it reached 0, and reached a maximum value of 0.763pu at 0.24s during the recovery process. The SVG reactive current still maintained a low-through reactive current of about 0.916pu and lasted for 1 cycle (0.02s). After 0.24s, the capacitive reactive current immediately dropped to 0 until the inductive reactive current was issued. Furthermore, in the recovery process of fault removal and exiting low-breakdown, the capacitive reactive current superimposed by HGG PV and SVG reached the maximum at 0.24s, which promoted the transient increase of HGG PV voltage after fault removal. The maximum value of HGG PV transient voltage reached 1.344pu, the initial steady-state voltage of HGG was 0.962pu, the transient voltage rise after the fault was 0.382pu, and the transient voltage difference exceeded the threshold of 0.3pu.

[0205] After the hgg photovoltaic low-breakthrough ends, it recovers exponentially with a time constant of 0.5 cycles. At the same time, the supporting SVG exits the low-breakthrough recovery delay of 1 cycle. When the hgg low-breakthrough reactive current coefficient is a certain set value, as the SVG low-breakthrough reactive current coefficient increases, the transient voltage rise risk increases successively. Under the condition of hgg low-breakthrough reactive current coefficient of 2.5, as the SVG low-breakthrough reactive current coefficient increases, the change trend of the transient voltage rise is as follows Fig.13 As shown:

[0206] After the HGG photovoltaic low-breakthrough ends, it recovers exponentially with a time constant of 0.5 cycles. At the same time, the supporting SVG exits the low-breakthrough recovery delay of 1 cycle. When the SVG low-breakthrough reactive current coefficient is a certain set value, as the HGG photovoltaic low-breakthrough reactive current coefficient increases, the transient voltage rise risk also increases. When the SVG low-breakthrough reactive current coefficient is 0.8, as the HGG photovoltaic low-breakthrough reactive current coefficient increases, the change trend of the transient voltage rise is as follows Fig.14 As shown:

[0207] Based on the transient voltage rise risk analysis mentioned above in this example, after the hgg photovoltaic low-breakthrough ends, it recovers exponentially with a time constant of 0.5 cycle. At the same time, the supporting SVG exits the low-breakthrough and recovers with a delay of 1 cycle. The reasons for the transient voltage rise risk under the various parameter combination schemes of hgg photovoltaic and SVG low-breakthrough reactive current coefficients are as follows: After the fault is removed, the main grid voltage naturally rises, and the hgg photovoltaic power station and supporting power electronic equipment such as SVG will exit the low-breakthrough due to the increase in voltage, and generally recover with the low-breakthrough current as the starting value. There is a certain delay in the process of power electronic equipment exiting the low-breakthrough, and the reactive current cannot be restored to 0 or the initial value immediately, and the reactive current is still maintained at a large value and continues for a short delay time. Therefore, in the recovery process of exiting the low-breakthrough, the superposition of new energy and SVG capacitive reactive current is the reason for the further increase in transient voltage after the fault is removed.

[0208] (6) Based on this example, a sequential linear optimization model for adjusting the SVG low-through reactive current coefficient to suppress transient voltage rise is built and solved, and multiple groups of optimization schemes for SVG low-through reactive voltage response control strategies and parameters that coordinate with new energy sources are given.

[0209] Combined with the calculation example, based on the fitting curve of the transient voltage rise of new energy with the change of hgg photovoltaic power station and SVG low-through reactive current coefficient, sensitivity analysis is used to obtain the influence of the combination of photovoltaic power station and SVG low-through reactive current parameters on the transient voltage rise: 1) When the hgg photovoltaic low-through reactive current coefficient is a typical fixed value, as the SVG low-through reactive current coefficient increases, the risk of transient voltage rise increases successively; 2) When the SVG photovoltaic low-through reactive current coefficient is a typical fixed value, as the hgg photovoltaic low-through reactive current coefficient increases, the risk of transient voltage rise also increases successively. In conjunction with the low-through strategy of new energy, the SVG low-through reactive voltage response strategy and parameters are coordinated to achieve the purpose of collaboratively mitigating transient voltage rise.

[0210] The following strategy is used to optimize the SVG low-throughput parameters that are coordinated with new energy sources: under the condition that the low-throughput reactive current response coefficient of the new energy station is a typical fixed parameter, a linear optimization model for the setting of the SVG low-throughput reactive current response coefficient that suppresses transient voltage rise is established, and the linear optimization model is solved by the linear programming method to obtain the optimized setting value of the SVG low-throughput reactive current coefficient for this iteration. The transient voltage rise under the SVG low-throughput reactive current coefficient is simulated and analyzed, and it is iterated repeatedly until the transient voltage rise approaches the threshold value of 0.3pu. The SVG low-throughput reactive current coefficient corresponding to the transient voltage rise threshold of 0.3pu is set as the threshold for the optimization setting of the SVG low-throughput reactive current coefficient. The SVG low-throughput reactive current coefficient should be less than this SVG reactive current coefficient threshold to ensure that the transient voltage rise is lower than 0.3pu.

[0211] Combined with the calculation example, simulation analysis is performed to obtain the SVG low-power reactive response strategy and parameter optimization setting values ​​that are coordinated with the HGG photovoltaic power station low-power strategy and parameters, as shown in Table 2 below:

[0212] Table 2

[0213]

[0214] Taking the new energy low-through reactive current coefficient of 2.5 as an example, the simulation results of optimizing the setting of SVG low-through reactive current coefficient are shown in 15a, 15b, 16a, 16b, and 17:

[0215] The superposition of reactive current during the recovery process of SVG and HGG photovoltaic exiting low-voltage breakover is the main reason for the increase of HGG voltage after fault removal. Fig.14It can be seen that the transient voltage rise of hgg photovoltaic reaches the highest value at 0.24s; from the simulation result Figure 16, it can be seen that under different reactive current response coefficients of SVG low wear, since the reactive current coefficient of hgg low wear is 2.5, the output reactive current of hgg at the maximum moment of transient voltage rise of 0.24s is approximately the same, that is, under the conditions of hgg photovoltaic low wear strategy and fixed parameters, the transient voltage rise is more affected by the SVG low wear strategy; from the comparison of simulation result Figures 15 and 14, it can be seen that under different reactive currents of SVG low wear, the degree of transient voltage rise gradually increases. With the gradual increase of SVG low wear coefficients of 0.43, 0.63, 0.83, 0.93, 1.13, 1.33, and 1.5, the transient voltage rise of hgg photovoltaic gradually increases. When the SVG low wear coefficient is 0.83, the maximum value of hgg photovoltaic transient voltage is about 1.262pu, which is different from the steady-state initial voltage value of 0.962, and the transient voltage rise value is 0.3pu. Therefore, the following conclusions are drawn: when the new energy low-penetration recovers in an exponential form with a recovery time constant of 0.5 cycles and the SVG exits the low-penetration with a delay of 1 cycle, when the new energy low-penetration reactive current coefficient is 2.5, in order to avoid the occurrence of transient voltage rise problems, in conjunction with the new energy low-penetration strategy, the optimized SVG low-penetration reactive current response coefficient should be less than 0.83.

[0216] The method of the present invention can coordinate and give the optimized setting value or range of the SVG low-breakthrough recovery strategy and reactive current response coefficient of the new energy station under the conditions of new energy recovery strategy, low-breakthrough reactive current coefficient, etc., with the goal of maintaining the transient voltage rise of new energy below 0.3pu. It can be seen from the above calculation table 2 that by selecting three groups of typical parameters of new energy, the SVG reactive voltage response control strategy and parameters coordinated with new energy are obtained as follows to alleviate the transient voltage rise:

[0217] 1) After the low-throughput of the hgg photovoltaic power station ends, it recovers in an exponential form with a recovery time constant of 0.5 cycles. At the same time, when the low-throughput reactive current coefficient of the hgg photovoltaic is 1.5, the low-throughput reactive voltage coordinated response strategy of SVG is: when SVG exits the low-throughput delay of 1 cycle and recovers, the optimization setting range of the low-throughput reactive current coefficient of SVG is less than 1.26.

[0218] 2) After the low-throughput of the hgg photovoltaic power station ends, it recovers in an exponential form with a recovery time constant of 0.5 cycles. At the same time, when the hgg photovoltaic low-throughput reactive current coefficient is 2.0, the low-throughput reactive voltage coordinated response strategy of SVG is: when SVG exits the low-throughput delay of 1 cycle and recovers, the optimization setting range of the SVG low-throughput reactive current coefficient is less than 0.98.

[0219] 3) After the low-breakthrough of the hgg photovoltaic power station ends, it recovers in an exponential form with a recovery time constant of 0.5 cycles. At the same time, when the low-breakthrough reactive current coefficient of the hgg photovoltaic is 2.5, the low-breakthrough reactive voltage coordinated response strategy of the supporting SVG is: when the SVG exits the low-breakthrough delay of 1 cycle and recovers, the optimization setting range of the SVG low-breakthrough reactive current coefficient is less than 0.83.

[0220] Embodiment 2:

[0221] The present invention also proposes a reactive voltage response control system 200 for suppressing transient voltage rise in a new energy station, such as Fig.18 As shown, including:

[0222] The initial unit 201 is used to establish a steady-state / transient model for the new energy station connected to the main grid, and generate a data file for simulation calculation based on the steady-state / transient model, and establish a low-voltage fault ride-through response control model of the new energy station group, a low-voltage fault ride-through reactive voltage response control model of the SVG, and a transient voltage rise threshold of the new energy unit based on the data file;

[0223] The calculation unit 202 is used to perform time domain simulation under fault disturbance based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of the SVG and the transient voltage rise threshold of the new energy unit, so as to obtain the transient voltage rise fitting curve of the new energy unit end, and judge whether the transient voltage rise of the new energy unit is lower than the voltage rise threshold. If it is lower than the voltage rise threshold, the process ends and the final SVG low-voltage ride-through reactive current coefficient optimization solution is obtained. If it is greater than or equal to the threshold, the current SVG low-voltage ride-through reactive current coefficient and the corresponding new energy transient voltage rise are used as the initial values ​​of a new iteration. For one cycle iteration, multiple physical quantities are calculated according to the transient voltage rise fitting curve of the new energy unit end and the initial value of the new iteration, and a linear optimization model for suppressing transient voltage rise is established based on the multiple physical quantities;

[0224] The control unit 203 is used to solve the linear optimization model for suppressing transient voltage rise, so as to determine the optimized solution of the SVG low-through reactive current coefficient under this iteration, and perform time domain simulation with the optimized solution to determine whether the transient voltage rise of the new energy station meets the preset requirements. If not, the linear optimization model is established and solved in a cyclic iteration until the transient voltage rise of the new energy meets the threshold requirements; determine the optimized solution of the reactive voltage response control parameters of the new energy station SVG that matches and coordinates with the new energy unit, and control the new energy station through the optimized solution of the reactive voltage response control parameters of the new energy station SVG to suppress the transient voltage rise of the new energy station.

[0225] Among them, new energy stations include: wind power new energy stations and photovoltaic new energy stations.

[0226] Among them, the steady-state / transient model is an equivalent aggregation model of wind power new energy stations and photovoltaic new energy stations.

[0227] Among them, the equivalent aggregation models of wind power new energy stations and photovoltaic new energy stations include: fault ride-through state judgment model WEV, active power control model WLP under fault ride-through state and reactive power control model WLQ under fault ride-through state.

[0228] The low-voltage fault ride-through reactive voltage response control model of the SVG is used to provide a target output current of the SVG, and open-loop control is performed through the target output current of the SVG.

[0229] Among them, the transient voltage rise threshold of the new energy unit is used to compare with the transient voltage rise value obtained from the new energy machine-end voltage curve under the typical fault disturbance output by simulation. If the transient voltage rise value is greater than the transient voltage rise threshold, it is determined that the transient voltage rise exceeds the limit at the new energy station.

[0230] Among them, based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG and the transient voltage rise threshold of the new energy unit, a time domain simulation under fault disturbance is performed, including:

[0231] Based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG and the transient voltage rise threshold of the new energy unit, the PSD simulation software is used to output the voltage simulation curve of the new energy machine end under the fault disturbance, and the transient voltage rise value of the new energy machine end is obtained. Based on the transient voltage rise value of the new energy machine end, the transient voltage rise fitting curve of the new energy station and SVG under different low-voltage ride-through reactive current coefficients is obtained;

[0232] According to the magnitude of the transient voltage rise value at the new energy machine end, the SVG low-through reactive current coefficient setting value corresponding to the over-limit new energy transient voltage rise is determined, and the SVG low-through reactive current coefficient setting value is used as the initial value of a new iteration.

[0233] Among them, multiple physical quantities include: the sensitivity of the voltage rise at the new energy machine end to the SVG low-through reactive current coefficient obtained based on the transient voltage rise fitting curve at the new energy machine end, the adjustment amount of the SVG low-through reactive current coefficient and the maximum adjustment amount of each iteration, and the transient voltage rise value at the new energy machine end after the SVG low-through reactive current coefficient is adjusted.

[0234] Among them, the linear programming method is used to solve the linear optimization model for suppressing transient voltage rise;

[0235] The objective function of the linear optimization model for suppressing transient voltage rise in each iteration is as follows:

[0236] minΔK s,v

[0237] The constraints are as follows:

[0238] S vk ΔK s,v ≤0.3-ΔV 0

[0239]

[0240]

[0241] Among them, K s,v is the SVG low wear reactive current coefficient, This is the initial value of the SVG low-through reactive current coefficient for this iteration, ΔK s,v is the adjustment value of SVG low-through reactive current coefficient, and the objective function minΔK s,v To minimize the reactive current coefficient adjustment of SVG low wear, ΔV 0 is the initial value of transient voltage rise at the new energy machine end, S vk is the sensitivity of the transient voltage rise at the new energy generator end to the SVG low-through reactive current coefficient, S vk ΔK s,v It is the transient voltage rise change value after the SVG low-through reactive current coefficient is adjusted. is the upper limit of SVG low-through reactive current coefficient, ΔK ad The maximum adjustment of the SVG low-penetration reactive coefficient for this iteration.

[0242] The present invention can improve the safety of renewable energy grid connection and promote the acceptance of renewable energy.

[0243] Embodiment 3:

[0244] Based on the same inventive concept, the present invention also provides a computer device, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding functions, so as to implement the steps of the method in the above embodiment.

[0245] Embodiment 4:

[0246] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both a built-in storage medium in a computer device and an extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the method in the above embodiment.

[0247] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take 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.) containing computer-usable program codes. The schemes in the embodiments of the present invention may be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0248] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks 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 produce 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.

[0249] 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.

[0250] 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 1 The steps for the functions specified in one or more boxes.

[0251] Although the preferred embodiments of the present invention 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 that fall within the scope of the present invention.

[0252] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A reactive voltage response control method for a new energy station to suppress transient voltage rise, characterized in that: include: For the new energy stations connected to the main grid, a steady-state / transient model is established, and a data file for simulation calculation is generated based on the steady-state / transient model. Based on the data file, a low-voltage fault ride-through response control model of the new energy station group, a low-voltage fault ride-through reactive voltage response control model of SVG, and a transient voltage rise threshold of the new energy unit are established; Based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG and the transient voltage rise threshold of the new energy unit, a time domain simulation under fault disturbance is performed to obtain a transient voltage rise fitting curve at the new energy unit end, and to determine whether the transient voltage rise of the new energy unit is lower than the voltage rise threshold. If it is lower than the voltage rise threshold, the process ends and the final SVG low-voltage ride-through reactive current coefficient optimization solution is obtained. If it is greater than or equal to the threshold, the current SVG low-voltage ride-through reactive current coefficient and the corresponding new energy transient voltage rise are used as the initial values ​​of a new iteration; For one cycle iteration, multiple physical quantities are calculated according to the transient voltage rise fitting curve at the new energy machine end and the initial value of a new iteration, and a linear optimization model for suppressing transient voltage rise is established based on the multiple physical quantities; Solve the linear optimization model for suppressing transient voltage rise to determine the optimization solution of the SVG low-through reactive current coefficient under this iteration, and perform time domain simulation with the optimization solution to determine whether the transient voltage rise of the new energy station meets the preset requirements. If not, continue to iterate and establish and solve the linear optimization model until the transient voltage rise of the new energy station meets the threshold requirements; An optimized solution for reactive voltage response control parameters of the SVG of the new energy station that matches and coordinates with the new energy generating unit is determined, and the new energy station is controlled by the optimized solution for reactive voltage response control parameters of the SVG of the new energy station to suppress transient voltage rise of the new energy station.

2. The reactive voltage response control method according to claim 1, characterized in that: The new energy stations include: wind power new energy stations and photovoltaic new energy stations.

3. The reactive voltage response control method according to claim 1, characterized in that: The steady-state / transient model is an equivalent aggregation model of a wind power new energy station and a photovoltaic new energy station.

4. The reactive voltage response control method according to claim 3, characterized in that: The equivalent aggregation models of the wind power new energy station and the photovoltaic new energy station include: a fault ride-through state judgment model WEV, an active power control model WLP under the fault ride-through state, and a reactive power control model WLQ under the fault ride-through state.

5. The reactive voltage response control method according to claim 1, characterized in that: The low-voltage fault ride-through reactive voltage response control model of the SVG is used to provide a target output current of the SVG, and to perform open-loop control through the target output current of the SVG.

6. The reactive voltage response control method according to claim 1, characterized in that: The transient voltage rise threshold of the new energy unit is used to compare with the transient voltage rise value obtained from the new energy unit terminal voltage curve under the typical fault disturbance output by simulation. If the transient voltage rise value is greater than the transient voltage rise threshold, it is determined that the new energy station has a transient voltage rise exceeding the limit.

7. The reactive voltage response control method according to claim 1, characterized in that: The time domain simulation under fault disturbance is performed based on the low voltage fault ride-through response control model of the new energy station group, the low voltage fault ride-through reactive voltage response control model of the SVG and the transient voltage rise threshold of the new energy unit, including: Based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG and the transient voltage rise threshold of the new energy unit, the PSD simulation software is used to output the voltage simulation curve of the new energy machine end under the fault disturbance, and the transient voltage rise value of the new energy machine end is obtained. Based on the transient voltage rise value of the new energy machine end, the transient voltage rise fitting curve of the new energy station and SVG under different low-voltage ride-through reactive current coefficients is obtained; According to the magnitude of the transient voltage rise value at the new energy machine end, the SVG low-through reactive current coefficient setting value corresponding to the over-limit new energy transient voltage rise is determined, and the SVG low-through reactive current coefficient setting value is used as the initial value of a new iteration.

8. The reactive voltage response control method according to claim 1, characterized in that: The multiple physical quantities include: the sensitivity of the voltage rise at the new energy machine end to the SVG low-through reactive current coefficient obtained based on the transient voltage rise fitting curve at the new energy machine end, the adjustment amount of the SVG low-through reactive current coefficient and the maximum adjustment amount of each iteration, and the transient voltage rise value at the new energy machine end after the SVG low-through reactive current coefficient is adjusted.

9. The reactive voltage response control method according to claim 1, characterized in that: The linear programming method is used to solve the linear optimization model for suppressing transient voltage rise; The objective function of the linear optimization model for suppressing transient voltage rise in each iteration is as follows: minΔK s,v The constraints are as follows: S vk ·ΔK s,v ≤0.3-ΔV0 Among them, K s,v is the SVG low wear reactive current coefficient, This is the initial value of the SVG low-through reactive current coefficient for this iteration, ΔK s,v is the adjustment value of SVG low-through reactive current coefficient, and the objective function minΔK s,v is the adjustment minimization of the SVG low-through reactive current coefficient, ΔV0 is the initial value of the transient voltage rise at the new energy generator end, S vk is the sensitivity of the transient voltage rise at the new energy generator end to the SVG low-through reactive current coefficient, D vk ΔK s,v It is the transient voltage rise change value after the SVG low-through reactive current coefficient is adjusted. ΔK is the upper limit of SVG low-through reactive current coefficient. ad The maximum adjustment of the SVG low-penetration reactive coefficient for this iteration.

10. A reactive voltage response control system for a new energy station that suppresses transient voltage rise, characterized in that: include: The initial unit is used to establish a steady-state / transient model for the new energy station connected to the main grid, and generate a data file for simulation calculation based on the steady-state / transient model, and establish a low-voltage fault ride-through response control model for the new energy station group, a low-voltage fault ride-through reactive voltage response control model for SVG, and a transient voltage rise threshold of the new energy unit based on the data file; A calculation unit is used to perform time domain simulation under fault disturbance based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG and the transient voltage rise threshold of the new energy unit, so as to obtain the transient voltage rise fitting curve of the new energy unit end, and judge whether the transient voltage rise of the new energy unit is lower than the voltage rise threshold. If it is lower than the voltage rise threshold, the process is terminated to obtain the final SVG low-voltage ride-through reactive current coefficient optimization solution. If it is greater than or equal to the threshold, the current SVG low-voltage ride-through reactive current coefficient and the corresponding new energy transient voltage rise are used as the initial values ​​of a new iteration. For one cycle iteration, multiple physical quantities are calculated according to the transient voltage rise fitting curve of the new energy unit end and the initial value of the new iteration, and a linear optimization model for suppressing transient voltage rise is established based on the multiple physical quantities; A control unit is used to solve the linear optimization model for suppressing transient voltage rise, so as to determine the optimized solution of the SVG low-through reactive current coefficient under this iteration, and to perform time domain simulation with the optimized solution to determine whether the transient voltage rise of the new energy station meets the preset requirements. If not, the linear optimization model is established and solved in a cyclic iteration until the transient voltage rise of the new energy station meets the threshold requirements; determine the optimized solution of the reactive voltage response control parameters of the SVG of the new energy station that matches and coordinates with the new energy unit, and control the new energy station through the optimized solution of the reactive voltage response control parameters of the SVG of the new energy station to suppress the transient voltage rise of the new energy station.

11. The reactive voltage response control system according to claim 10, characterized in that: The new energy stations include: wind power new energy stations and photovoltaic new energy stations.

12. The reactive voltage response control system according to claim 10, characterized in that: The steady-state / transient model is an equivalent aggregation model of a wind power new energy station and a photovoltaic new energy station.

13. The reactive voltage response control system according to claim 12, characterized in that: The equivalent aggregation models of the wind power new energy station and the photovoltaic new energy station include: a fault ride-through state judgment model WEV, an active power control model WLP under the fault ride-through state, and a reactive power control model WLQ under the fault ride-through state.

14. The reactive voltage response control system according to claim 10, characterized in that: The low-voltage fault ride-through reactive voltage response control model of the SVG is used to provide a target output current of the SVG, and to perform open-loop control through the target output current of the SVG.

15. The reactive voltage response control system according to claim 10, characterized in that: The transient voltage rise threshold of the new energy unit is used to compare with the transient voltage rise value obtained from the new energy unit terminal voltage curve under the typical fault disturbance output by simulation. If the transient voltage rise value is greater than the transient voltage rise threshold, it is determined that the new energy station has a transient voltage rise exceeding the limit.

16. The reactive voltage response control system according to claim 10, characterized in that: The time domain simulation under fault disturbance is performed based on the low voltage fault ride-through response control model of the new energy station group, the low voltage fault ride-through reactive voltage response control model of the SVG and the transient voltage rise threshold of the new energy unit, including: Based on the low-voltage fault ride-through response control model of the new energy station group, the low-voltage fault ride-through reactive voltage response control model of SVG and the transient voltage rise threshold of the new energy unit, the PSD simulation software is used to output the voltage simulation curve of the new energy machine end under the fault disturbance, and the transient voltage rise value of the new energy machine end is obtained. Based on the transient voltage rise value of the new energy machine end, the transient voltage rise fitting curve of the new energy station and SVG under different low-voltage ride-through reactive current coefficients is obtained; According to the magnitude of the transient voltage rise value at the new energy machine end, the SVG low-through reactive current coefficient setting value corresponding to the over-limit new energy transient voltage rise is determined, and the SVG low-through reactive current coefficient setting value is used as the initial value of a new iteration.

17. The reactive voltage response control system according to claim 10, characterized in that: The multiple physical quantities include: the sensitivity of the voltage rise at the new energy machine end to the SVG low-through reactive current coefficient obtained based on the transient voltage rise fitting curve at the new energy machine end, the adjustment amount of the SVG low-through reactive current coefficient and the maximum adjustment amount of each iteration, and the transient voltage rise value at the new energy machine end after the SVG low-through reactive current coefficient is adjusted.

18. The reactive voltage response control system according to claim 10, characterized in that: The linear programming method is used to solve the linear optimization model for suppressing transient voltage rise; The objective function of the linear optimization model for suppressing transient voltage rise in each iteration is as follows: minΔK s,v The constraints are as follows: S vk ·ΔK s,v ≤0.3-ΔV0 Among them, K s,v is the SVG low wear reactive current coefficient, This is the initial value of the SVG low-through reactive current coefficient for this iteration, ΔK s,v is the adjustment value of SVG low-through reactive current coefficient, and the objective function minΔK s,v is the adjustment minimization of the SVG low-through reactive current coefficient, ΔV0 is the initial value of the transient voltage rise at the new energy generator end, S vk is the sensitivity of the transient voltage rise at the new energy generator end to the SVG low-through reactive current coefficient, S vk ΔK s,v It is the transient voltage rise change value after the SVG low-through reactive current coefficient is adjusted. ΔK is the upper limit of SVG low-through reactive current coefficient. ad The maximum adjustment of the SVG low-penetration reactive coefficient for this iteration.

19. A computer device, characterized in that: include: one or more processors; a processor for executing one or more programs; When the one or more programs are executed by the one or more processors, the method according to any one of claims 1 to 9 is implemented.

20. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the method according to any one of claims 1 to 9 is implemented.

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