A fault switching method, a reactive power compensation device, a control device and a storage medium

Abstract

The application discloses a kind of fault switching method and reactive power compensation equipment, control device, storage medium, the reactive power compensation equipment includes three bridge arm components, each the bridge arm component includes the multiple power sub-modules connected in turn, the first end of the bridge arm component is connected with power grid system, the tail end of three bridge arm components is interconnected, fault switching method includes: obtaining the voltage instantaneous effective value of power grid system;When voltage instantaneous effective value is in voltage threshold range, then control reactive power compensation equipment to operate with grid type mode;When voltage instantaneous effective value exceeds voltage threshold range, then control reactive power compensation equipment to operate with tracking type mode;The design can automatically switch corresponding control mode when fault voltage changes, can provide support to the voltage and frequency of power grid system, inhibit power grid frequency change, while also can quickly provide reactive current support for power grid.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of computer control of power grid equipment, and in particular to a fault switching method, a reactive power compensation device, a control device and a storage medium. BACKGROUND

[0002] A conventional reactive power compensation device (SVG) includes three bridge arm assemblies corresponding to three-phase lines of an interconnected power grid system, each of the bridge arm assemblies includes a plurality of power sub-modules connected in sequence, and a control module controls the power sub-modules to compensate for reactive power of the power grid system.

[0003] The conventional control of the reactive power compensation device cannot provide active support for voltage and frequency of the power grid system. Although some control methods can increase the damping of the power grid system to a certain extent and inhibit the rapid change of the frequency of the power grid system, which is helpful to the stability of the power grid system, when a short-circuit fault occurs in the power grid and the voltage decreases, the main requirement of the power grid is not to inhibit the change of the frequency of the power grid, but to quickly provide reactive current support for the power grid. Thus, different control methods for the reactive power compensation device have their respective advantages and disadvantages, but cannot be compatible. SUMMARY

[0004] The present application aims to at least solve one of the technical problems in the prior art. To this end, the present application provides a fault switching method, a reactive power compensation device, a control device and a storage medium, which can automatically switch the corresponding control mode when the fault voltage changes, can provide support for the voltage and frequency of the power grid system, inhibit the change of the frequency of the power grid system, and also can quickly provide reactive current support for the power grid.

[0005] The fault switching method according to the first aspect of the present application is applied to a reactive power compensation device, the reactive power compensation device includes three bridge arm assemblies, each of the bridge arm assemblies includes a plurality of power sub-modules connected in sequence, the head end of the bridge arm assembly is connected with a power grid system, and the tail ends of the three bridge arm assemblies are connected with each other, and the fault switching method comprises: acquiring an instantaneous effective value of voltage of the power grid system; when the instantaneous effective value of voltage is within a voltage threshold range, controlling the reactive power compensation device to operate in a grid-forming mode; and when the instantaneous effective value of voltage exceeds the voltage threshold range, controlling the reactive power compensation device to operate in a tracking mode.

[0006] In the grid-forming mode, the required active power increment of the power grid system is acquired

[0007] According to the total DC voltage rated value of the reactive power compensation device , the total DC voltage actual value of the reactive power compensation device and the active power increment , the active given value is calculated ; according to the active given value , virtual moment of inertia and virtual damping coefficient obtain the angular velocity given value ; according to the angular velocity given value and the synchronous angular velocity value of the power grid system calculate the virtual internal electromotive force phase angle of the reactive power compensation device ; use the virtual internal electromotive force phase angle construct the dq vector coordinate system; obtain the AC voltage module value of the power grid side , according to the actual output of the reactive power compensation device reactive power given value calculate the voltage amplitude increment, according to the AC voltage module value and the voltage amplitude increment, obtain the virtual internal electromotive force amplitude of the power grid system ; the virtual internal electromotive force amplitude as the voltage given of d-axis in dq vector coordinate system, set the voltage given of q-axis as 0, obtain the new d-axis voltage component and q-axis voltage component of virtual internal electromotive force ; according to the d-axis voltage component and q-axis voltage component , obtain the switching control instruction to control the power sub-module to run;

[0008] In tracking mode: obtain the three-phase voltage of the power grid system through the phase-locked loop to obtain the voltage vector phase angle in phase with the voltage of the power grid system ; construct the dq vector coordinate system with the voltage vector phase angle ; sample the current instantaneous value of the three-phase output of the reactive power compensation device , , , and sample the voltage instantaneous value of the three-phase of the power grid system , , , the current instantaneous value , , and the voltage instantaneous value , , respectively through the Park transformation to obtain the current effective value , and the voltage effective value , ; according to the total DC voltage rated value of the reactive power compensation device , the total DC voltage actual value of the reactive power compensation device obtain the output current d-axis given value , obtaining an output current q-axis given value according to a preset voltage ride-through rule of the reactive power compensation device ; taking the voltage effective value as the voltage given value of the d-axis in the dq coordinate system, and taking the voltage effective value as the voltage given value of the q-axis in the dq coordinate system, obtaining a new d-axis voltage component and a q-axis voltage component of the virtual internal electromotive force according to the output current d-axis given value and the output current q-axis given value ; obtaining a switch control instruction according to the d-axis voltage component and the q-axis voltage component to control the power sub-module to operate.

[0009] According to the fault switching method provided in the embodiments of the present application, at least the following beneficial effects are achieved:

[0010] In the fault switching method, the voltage instantaneous effective value of the power grid system is obtained, when the voltage instantaneous effective value is within the voltage threshold range, the reactive power compensation device is controlled to operate in the grid-forming mode, the reactive power compensation device can provide active support for the voltage and frequency of the power grid when operating in the grid-forming mode, can increase the damping of the power grid to a certain extent, and can inhibit the rapid change of the frequency of the power grid, which is helpful to the stability of the power grid, and when the voltage instantaneous effective value exceeds the voltage threshold range, a fault occurs, the reactive power compensation device is controlled to operate in the tracking mode, and the reactive power compensation device can quickly provide reactive current support for the power grid in the tracking mode, and after the fault is eliminated, the reactive power compensation device can be switched to operate in the grid-forming mode again, the design can automatically switch the corresponding control mode when the fault voltage changes, can provide support for the voltage and frequency of the power grid system, and can inhibit the change of the frequency of the power grid, and can also quickly provide reactive current support for the power grid.

[0011] According to some embodiments of the present application, in the step of obtaining the angular velocity given value according to the active given value , the virtual moment of inertia and the virtual damping coefficient , the following is performed:

[0012] .

[0013] According to some embodiments of the present application, in the step of taking the virtual internal electromotive force amplitude as the voltage given value of the d-axis in the dq vector coordinate system, and taking the voltage given value of the q-axis as 0, obtaining a new d-axis voltage component and a q-axis voltage component of the virtual internal electromotive force, the following is performed:

[0014] ;

[0015] ;

[0016] wherein, is a virtual resistance, is a virtual inductance.

[0017] According to some embodiments of the present application, in the step of obtaining the output current q-axis given value according to the preset voltage ride-through rule of the reactive power compensation device as the voltage of d-axis in dq coordinate system, the voltage effective value as the voltage of q-axis in dq coordinate system, a new d-axis voltage component of the virtual internal potential and a q-axis voltage component are obtained.

[0018] ;

[0019] ;

[0020] wherein, is a virtual resistance, is a virtual inductance.

[0021] According to some embodiments of the present application, in the step of obtaining the output current q-axis given value according to the preset voltage ride-through rule of the reactive power compensation device , the following step is included: in the process of the fault, when the voltage instantaneous effective value of the grid-connected point drops below the voltage standard value, and recovers to a first voltage recovery value within a first time threshold of the occurrence of the drop, the ratio of the first voltage recovery value to the voltage standard value is , wherein, is less than 1; the output current q-axis given value is:

[0022] ;

[0023] wherein, is a low-voltage reactive current proportionality coefficient, is a real-time per-unit value of the voltage of the grid-connected point, is a rated voltage per-unit value of the reactive power compensation device, is a high-voltage reactive current proportionality coefficient.

[0024] According to some embodiments of the present application, in the step of obtaining the output current q-axis given value according to the preset voltage ride-through rule of the reactive power compensation device , the following step is included: in the process of the fault, when the voltage instantaneous effective value of the grid-connected point rises above the voltage standard value, and recovers to a second voltage recovery value within a second time threshold of the occurrence of the rise, the ratio of the second voltage recovery value to the voltage standard value is , wherein, Less than 1; the output current q-axis given value is:

[0025] ;

[0026] wherein, is a low-voltage reactive current proportional coefficient, is a real-time voltage per unit of the grid connection point, is a rated voltage per unit of the reactive power compensation device, is a high-voltage reactive current proportional coefficient.

[0027] According to some embodiments of the present application, in the calculation of the voltage amplitude increment according to the actual output of the reactive power compensation device and the given value of the reactive power , the difference between the actual output of the reactive power and the given value of the reactive power is multiplied by to obtain the voltage amplitude increment, wherein, is a preset increment proportional coefficient.

[0028] According to the second aspect of the present application, the reactive power compensation device comprises three bridge arm assemblies and a control module, each of the bridge arm assemblies comprises a plurality of power sub-modules connected in sequence, the head end of the bridge arm assembly is connected with the grid system, the tail end of the three bridge arm assemblies is connected with each other, the control module is connected with the controlled end of each power sub-module, and the control module executes the fault switching method disclosed in any of the above embodiments to control the operation of the power sub-module.

[0029] According to the reactive power compensation device of the present application, at least the following beneficial effects are achieved:

[0030] The reactive power compensation device executes the fault switching method disclosed in any of the above embodiments to control the operation of the power sub-module, can automatically switch the corresponding control mode when the fault voltage changes, can provide support for the voltage and frequency of the grid system, inhibit the change of the grid frequency, and also can quickly provide reactive current support for the grid.

[0031] According to the control device of the third aspect of the present application, the control device comprises a memory and a processor, the memory stores a computer program, and the processor executes the computer program to realize the fault switching method disclosed in any of the above embodiments.

[0032] According to the computer readable storage medium of the fourth aspect of the present application, the computer readable storage medium stores a computer program, and the computer program is executed by a processor to realize the fault switching method disclosed in any of the above embodiments.

[0033] Additional aspects and advantages of the present application will be apparent from the following description of the application and as defined in the appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0034] The above and / or additional aspects and advantages of the present application will become apparent and be more readily understood through consideration of the following description of the embodiments, taken in conjunction with the accompanying drawings.

[0035] Figure 1 A schematic block diagram of a principle structure of one embodiment of the reactive power compensation device of the present application;

[0036] Figure 2 A first flow chart of one embodiment of the fault switching method of the present application;

[0037] Figure 3 A second flow chart of one embodiment of the fault switching method of the present application;

[0038] Figure 4 A third flow chart of one embodiment of the fault switching method of the present application;

[0039] Figure 5 A schematic block diagram of a principle structure of one embodiment of the control device of the present application.

[0040] REFERENCE NUMERALS

[0041] Bridge arm assembly 410; power sub-module 420; power grid system 500; processor 610; memory 620; input / output interface 630; communication interface 640; bus 650. DETAILED DESCRIPTION

[0042] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0043] It should be noted that although the functional modules are divided in the device schematic diagram, and the logical order is shown in the flow chart, in some cases, the steps shown or described can be executed in a manner different from the module division in the device or the order in the flow chart. The terms "first", "second", etc. in the specification and claims and the above drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.

[0044] In the description of the present application, the meaning of "one or more" is one or more, the meaning of "more" is two or more, and greater than, less than, more than, etc. are understood as not including the number, and above, below, within, etc. are understood as including the number.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0046] like Figures 1-4 As shown, a fault switching method according to a first aspect embodiment of the present invention is applied to a reactive power compensation device, the reactive power compensation device including three bridge arm assemblies 410, each bridge arm assembly 410 including a plurality of power sub-modules 420 connected in sequence, the first end of the bridge arm assembly 410 being connected to the power grid system 500, and the tail ends of the three bridge arm assemblies 410 being interconnected, the fault switching method including:

[0047] S110. Obtain the instantaneous effective value of the voltage of the power grid system;

[0048] S120. When the instantaneous effective value of the voltage is within the voltage threshold range, the reactive power compensation equipment is controlled to operate in grid-type mode.

[0049] S130. When the instantaneous effective value of the voltage exceeds the voltage threshold range, the reactive power compensation equipment is controlled to operate in tracking mode.

[0050] In the network-type mode:

[0051] S210. Obtain the required active power increment of the power grid system.

[0052] S220, Based on the rated total DC voltage of the reactive power compensation equipment Actual value of total DC voltage of reactive power compensation equipment and active power increment Calculate the active power setpoint Among them, the total rated DC voltage of the reactive power compensation equipment is calculated. Actual value of total DC voltage of reactive power compensation equipment The difference is determined by a PI1 proportional-integral converter in the system, which is used to measure the total rated DC voltage. Compared with the actual value of total DC voltage The difference is adjusted by the PI1 proportional-integral converter, and then the output value is reduced by the active power increment. The active power setpoint can then be calculated. ;

[0053] S230, based on the active power setpoint Virtual moment of inertia and virtual damping coefficient Obtain angular velocity setpoint ;

[0054] S240, obtaining the angular velocity given value according to the angular velocity and the synchronous angular velocity value of the power grid system calculating the virtual internal electromotive phase angle of the reactive power compensation device ;

[0055] S250, constructing the dq vector coordinate system by using the virtual internal electromotive phase angle ;

[0056] S260, obtaining the AC voltage module value of the power grid side , calculating the voltage amplitude increment according to the actual output reactive power of the reactive power compensation device and the reactive power given value , obtaining the virtual internal electromotive amplitude of the power grid system according to the AC voltage module value and the voltage amplitude increment ;

[0057] S270, taking the virtual internal electromotive amplitude as the voltage given value of the d-axis in the dq vector coordinate system, taking the voltage given value of the q-axis as 0, obtaining the d-axis voltage component and the q-axis voltage component of the new virtual internal electromotive;

[0058] S280, obtaining the switching control instruction to control the power sub-module to operate according to the d-axis voltage component and the q-axis voltage component ; , performing inverse Park transformation on the d-axis voltage component and the q-axis voltage component

[0059] calculated by the virtual impedance, obtaining the modulation signal of the PWM, and then generating the control instruction by the PWM modulator to control each power sub-module of the reactive power compensation device;

[0060] In the tracking type mode: ;

[0061] S320, constructing the dq vector coordinate system by using the voltage vector phase angle ;

[0062] S330, sampling the current instantaneous value of the three-phase output of the reactive power compensation device , , , and sampling the voltage instantaneous value of the three-phase of the power grid system , , The current instantaneous value , , and the voltage instantaneous value , , respectively through the Park transformation to obtain the current effective value , and the voltage effective value , ;

[0063] S340, according to the total DC voltage rating of the reactive power compensation device , the total DC voltage actual value of the reactive power compensation device obtain the output current d-axis given value , according to the preset voltage ride-through rule of the reactive power compensation device to obtain the output current q-axis given value ; wherein, the system is provided with a PI2 proportional integrator, the total DC voltage rating of the reactive power compensation device , the total DC voltage actual value of the reactive power compensation device through the PI2 proportional integrator to obtain the current d-axis given value ;

[0064] S350, the voltage effective value as the voltage given of the d-axis in the dq coordinate system, the voltage effective value as the voltage given of the q-axis in the dq coordinate system, according to the output current d-axis given value and the output current q-axis given value obtain the d-axis voltage component and the q-axis voltage component of the new virtual internal potential;

[0065] S360, according to the d-axis voltage component and the q-axis voltage component obtain the switch control instruction to control the power sub-module to operate, specifically, the d-axis voltage component and the q-axis voltage component are inversely Park transformed to obtain the modulation signal of PWM, and then the control instruction is generated by the PWM modulator to control each power sub-module of the reactive power compensation device.

[0066] The fault switching method of the application obtains the voltage instantaneous effective value of the power grid system, when the voltage instantaneous effective value is within the voltage threshold range, the reactive power compensation device is controlled to operate in the grid type mode, the reactive power compensation device can provide active support for the voltage and frequency of the power grid, can increase the power grid damping to a certain extent, inhibit the rapid change of the power grid frequency, help the power grid stability, and when the voltage instantaneous effective value exceeds the voltage threshold range, a fault occurs, the reactive power compensation device is controlled to operate in the tracking type mode, in the tracking type mode, the reactive power compensation device rapidly provides reactive current support for the power grid, and when the fault is eliminated, the reactive power compensation device can be switched to the grid type mode again, the design can automatically switch the corresponding control mode when the fault voltage changes, can provide support for the voltage and frequency of the power grid system, inhibit the change of the power grid frequency, and can also rapidly provide reactive current support for the power grid.

[0067] In some embodiments of the application, in the obtaining of the angular velocity given value , the virtual rotational inertia and the virtual damping coefficient :

[0068] .

[0069] Specifically, the angular velocity given value is integrated to obtain the virtual internal electric potential phase angle , that is:

[0070] .

[0071] In some embodiments of the application, in the obtaining of the d-axis voltage component and the q-axis voltage component of the new virtual internal electric potential by taking the virtual internal electric potential amplitude as the voltage given value of the d-axis in the dq vector coordinate system and setting the voltage given value of the q-axis as 0:

[0072] ;

[0073] ;

[0074] wherein, R is a virtual resistance, L is a virtual inductance, specifically, the current instantaneous values , , of the three-phase output of the reactive power compensation device are sampled, the current instantaneous values , , are subjected to Park transformation to obtain current effective values​ 、 .

[0075] In some embodiments of the present application, the voltage effective value is given as the voltage of the d-axis in the dq coordinate system, the voltage effective value is given as the voltage of the q-axis in the dq coordinate system, the d-axis voltage component and the q-axis voltage component of the new virtual internal potential are obtained.

[0076] ;

[0077] ;

[0078] wherein, is a virtual resistance, is a virtual inductance, and specifically, the virtual voltage signal generated by superimposing the virtual impedance on the basis of the given d-axis and q-axis voltages is obtained, and the d-axis voltage component and the q-axis voltage component of the new virtual internal potential are obtained.

[0079] In some embodiments of the present application, the output current q-axis given value is obtained according to the preset voltage ride-through rule of the reactive power compensation device.

[0080] In the fault process, when the voltage instantaneous effective value of the grid-connected point drops below the voltage standard value, and is restored to a first voltage recovery value within a first time threshold after the drop, the ratio of the first voltage recovery value to the voltage standard value is , wherein, is less than 1; the output current q-axis given value is:

[0081] ;

[0082] wherein, is a low-voltage reactive current proportionality coefficient, is the real-time per-unit value of the voltage of the grid-connected point, is the rated voltage per-unit value of the reactive power compensation device, is a high-voltage reactive current proportionality coefficient.

[0083] For example, when the voltage instantaneous effective value of the grid-connected point drops to 20% of the voltage standard value, the wind turbine set in the wind farm should ensure continuous operation without disconnection for 625 ms (which can also be other time values, set according to actual conditions), and when the voltage instantaneous effective value of the grid-connected point can recover to 90% of the voltage low value (i.e. ) within 2 s (i.e. the first time threshold, which can also be other time values, set according to actual conditions) after the drop, the wind turbine set in the wind farm should ensure continuous operation without disconnection, the reactive power compensation device enters the low voltage ride-through state during the fault, and the output current q-axis given value .

[0084] In some embodiments of the present application, the output current q-axis given value is obtained according to the preset voltage ride-through rule of the reactive power compensation device .

[0085] During the fault process, when the voltage instantaneous effective value of the grid-connected point rises above the voltage standard value and recovers to a second voltage recovery value within a second time threshold after the rise, the ratio of the second voltage recovery value to the voltage standard value is , wherein is less than 1; the output current q-axis given value is:

[0086] .

[0087] , wherein is a low voltage reactive current proportion coefficient, is a real-time per-unit value of the voltage of the grid-connected point, is a rated voltage per-unit value of the reactive power compensation device, is a high voltage reactive current proportion coefficient.

[0088] For example, when the voltage instantaneous effective value of the grid-connected point rises to 125%-130% of the voltage standard value, the wind turbine set in the wind farm should ensure continuous operation without disconnection for 500 ms (which can also be other time values, set according to actual conditions); when the voltage instantaneous effective value of the grid-connected point rises to 120%-125% of the voltage standard value, the wind turbine set in the wind farm should ensure continuous operation without disconnection for 1 s voltage standard value; and when the grid-connected point voltage rises to 110%-120% of the nominal voltage (i.e. ), the wind turbine set in the wind farm should ensure continuous operation without disconnection for 10 s (i.e. the second time threshold, which can also be other time values, set according to actual conditions).

[0089] In some embodiments of the present application, the voltage amplitude increment is calculated according to the actual output reactive power of the reactive power compensation device and the reactive power given value .

[0090] the difference between the actual output reactive power and the given value of reactive power is multiplied by to obtain the voltage amplitude increment, wherein, is a preset increment ratio coefficient, which is set by a user according to an actual power grid condition.

[0091] According to the reactive power compensation device of the second aspect of the present application, as shown in Figure 1 , the reactive power compensation device comprises three bridge arm assemblies 410 and a control module, each of the bridge arm assemblies 410 comprises a plurality of power sub-modules 420 connected in sequence, the head end of the bridge arm assembly 410 is connected with a power grid system 500, the tail end of the three bridge arm assemblies 410 is connected with each other, the control module is connected with the controlled end of each power sub-module 420, and the control module executes the fault switching method disclosed in any of the above embodiments to control the operation of the power sub-module 420.

[0092] The reactive power compensation device executes the fault switching method disclosed in any of the above embodiments to control the operation of the power sub-module, can automatically switch the corresponding control mode when the fault voltage changes, can provide support for the voltage and frequency of the power grid system, inhibit the change of the power grid frequency, and also can quickly provide reactive current support for the power grid.

[0093] According to the control device of the third aspect of the present application, the control device comprises a memory and a processor, the memory stores a computer program, and the processor realizes the fault switching method disclosed in any of the above embodiments when executing the computer program.

[0094] The control device can be any intelligent terminal such as a central computer, a remote device terminal computer, etc.

[0095] As shown in Figure 5 , Figure 5 the hardware structure of the control device of another embodiment is also shown, and the control device comprises:

[0096] The processor 610 can be implemented in a general central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits, etc., and is used to execute related programs to realize the technical solutions provided in the embodiments of the present application.

[0097] The memory 620 can be implemented in the form of a read only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM), etc. The memory 620 can store an operating system and other application programs. When the technical solutions provided by the embodiments of the present specification are implemented by software or firmware, the related program codes are stored in the memory 620 and are called and executed by the processor 610 to implement the fault switching method of the embodiments of the present application;

[0098] The input / output interface 630 is configured to realize information input and output.

[0099] The communication interface 640 is configured to realize the communication interaction between the device and other devices. The communication can be realized by a wired manner (for example, a USB, a network cable, etc.) or a wireless manner (for example, a mobile network, WIFI, Bluetooth, etc.).

[0100] The bus 650 is configured to transmit information between various components (for example, the processor 610, the memory 620, the input / output interface 630, and the communication interface 640) of the device. The bus 650 can also be used to access the smart Internet of Things.

[0101] The processor 610, the memory 620, the input / output interface 630, and the communication interface 640 are connected to each other through the bus 650 to realize the communication connection between the devices.

[0102] The computer readable storage medium according to the fourth aspect of the embodiments of the present application stores a computer program. When the computer program is executed by the processor, the fault switching method disclosed in any of the above embodiments is realized.

[0103] The memory is a non-transitory computer readable storage medium, which can be used to store a non-transitory software program and a non-transitory computer executable program. In addition, the memory can include a high-speed random access memory and can also include a non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state memory device. In some embodiments, the memory can optionally include a memory remotely arranged relative to the processor, and these remote memories can be connected to the processor through a network. Examples of the above network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.

[0104] The embodiments described in the embodiments of the present application are used to more clearly illustrate the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art can know that, with the evolution of technology and the appearance of new application scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0105] Those skilled in the art can understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and can include more or fewer steps than the figures, or combine certain steps, or different steps.

[0106] The device embodiments described above are merely illustrative, and units described as separate components can or can not be physically separated, i.e., can be located in one place, or can be distributed to multiple network units. Part or all of the modules can be selected to achieve the purpose of the embodiments according to actual needs.

[0107] Those skilled in the art can understand that all or some of the steps in the above disclosed method, the function modules / units in the system and the device can be implemented as software, firmware, hardware and their appropriate combinations.

[0108] The terms "first", "second", "third", "fourth" and the like (if any) in the specification of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a particular order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0109] The preferred embodiments of the embodiments of the present application are described above with reference to the accompanying drawings, and are not limited to the scope of the embodiments of the present application. Any modifications, equivalent replacements and improvements made by those skilled in the art without departing from the scope and spirit of the embodiments of the present application shall be within the scope of the embodiments of the present application.

[0110] Each technical feature of the above-described embodiments can be combined arbitrarily, and in order to make the description brief, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not exist contradictory, it should be considered as the scope of the present disclosure.

[0111] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

[0112] Each technical feature of the above-described embodiments can be combined with any other technical feature, and for the sake of brevity, not all possible combinations are described, but it is understood that the scope of the specification includes all possible combinations.

[0113] While the embodiments of the present application have been illustrated and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and alterations can be made therein without departing from the spirit and scope of the application, which are defined by the following claims and their equivalents.

Claims

1. A fault switching method applied to a reactive power compensation device, the reactive power compensation device comprising three bridge arm assemblies, each bridge arm assembly comprising a plurality of power sub-modules connected in sequence, the first end of each bridge arm assembly being connected to a power grid system, and the last ends of the three bridge arm assemblies being interconnected, characterized in that, Fault switching methods include: Obtain the instantaneous effective value of the voltage in the power grid system; When the instantaneous effective value of the voltage is within the voltage threshold range, the reactive power compensation equipment is controlled to operate in grid-type mode; When the instantaneous effective value of the voltage exceeds the voltage threshold range, the reactive power compensation equipment is controlled to operate in tracking mode. In the network-type mode: Obtain the required active power increment of the power grid system Based on the rated total DC voltage of the reactive power compensation equipment Actual value of total DC voltage of reactive power compensation equipment and active power increment Calculate the active power setpoint ; Based on the active power setpoint Virtual moment of inertia and virtual damping coefficient Obtain angular velocity setpoint ; Based on the given angular velocity value Synchronous angular velocity value of the power grid system Calculate the virtual internal potential phase angle of the reactive power compensation device. ; Using virtual internal potential phase angle Construct a dq vector coordinate system; Obtain the AC voltage magnitude on the grid side Based on the actual reactive power output of the reactive power compensation equipment and reactive power setpoint Calculate the voltage amplitude increment based on the AC voltage magnitude. The virtual internal potential amplitude of the power grid system is obtained by combining the voltage amplitude increment. ; virtual internal potential amplitude Using the voltage reference along the d-axis in the dq vector coordinate system, the voltage reference along the q-axis is set to 0, resulting in the new d-axis voltage component of the virtual internal potential. and q-axis voltage component ; Based on the d-axis voltage component and q-axis voltage component A switch control command is generated to control the operation of the power submodule; In tracking mode: Obtain the three-phase voltage of the power grid system The voltage vector phase angle obtained after passing through the phase-locked loop is in phase with the grid system voltage. ; With voltage vector phase angle Construct a dq vector coordinate system; The instantaneous current value of the three-phase output of the sampling reactive power compensation device , , And the instantaneous voltage values ​​of the three phases of the sampled power grid system. , , The instantaneous value of the current , , and instantaneous voltage value , , The effective value of the current was obtained by performing Parker transformation. , and the effective value of voltage , ; Based on the rated total DC voltage of the reactive power compensation equipment Actual value of total DC voltage of reactive power compensation equipment Obtain the d-axis setpoint of the output current. The output current q-axis setpoint is obtained according to the preset voltage ride-through rule of the reactive power compensation device. ; The effective value of the voltage As the voltage reference along the d-axis in the dq coordinate system, the effective voltage value As the voltage reference along the q-axis in the dq coordinate system, the output current is referenced based on the d-axis reference value. and output current q-axis setpoint The d-axis voltage component of the new virtual internal potential is obtained. and q-axis voltage component ; Based on the d-axis voltage component and q-axis voltage component The switching control command is generated to control the operation of the power submodule.

2. The fault switching method according to claim 1, characterized in that: According to the active power setpoint Virtual moment of inertia and virtual damping coefficient Obtain angular velocity setpoint middle: 。 3. The fault switching method according to claim 1, characterized in that: The virtual internal potential amplitude Using the voltage reference along the d-axis in the dq vector coordinate system, the voltage reference along the q-axis is set to 0, resulting in the new d-axis voltage component of the virtual internal potential. and q-axis voltage component middle: ； ； in, For virtual resistance, This is a virtual inductance.

4. The fault switching method according to claim 1, characterized in that: The effective value of the voltage As the voltage reference along the d-axis in the dq coordinate system, the effective voltage value Using the voltage along the q-axis in the dq coordinate system as a given value, the d-axis voltage component of the new virtual internal potential is obtained. and q-axis voltage component middle: ； ； in, For virtual resistance, This is a virtual inductance.

5. The fault switching method according to claim 1, characterized in that: The output current q-axis setpoint is obtained according to the preset voltage ride-through rule of the reactive power compensation device. Includes: During a fault, when the instantaneous effective value of the voltage at the grid connection point drops below the standard voltage value, and recovers to the first voltage recovery value within the first time threshold after the drop, the ratio of the first voltage recovery value to the standard voltage value is: ,in, If the value is less than 1, then the output current q-axis setpoint is... for: ； in, This is the low-voltage reactive current proportionality coefficient. This is the real-time per-unit value of the voltage at the grid connection point. This refers to the per-unit value of the rated voltage of the reactive power compensation equipment. This is the high-voltage reactive current proportionality coefficient.

6. The fault switching method according to claim 1, characterized in that: The output current q-axis setpoint is obtained according to the preset voltage ride-through rule of the reactive power compensation device. Includes: During a fault, when the instantaneous effective value of the voltage at the grid connection point rises above the standard voltage value, and recovers to the second voltage recovery value within a second time threshold after the rise, the ratio of the second voltage recovery value to the standard voltage value is: ,in, If the value is less than 1, then the output current q-axis setpoint is... for: ； in, This is the low-voltage reactive current proportionality coefficient. This is the real-time per-unit value of the voltage at the grid connection point. This refers to the per-unit value of the rated voltage of the reactive power compensation equipment. This is the high-voltage reactive current proportionality coefficient.

7. The fault switching method according to claim 1, characterized in that: The reactive power output based on the actual reactive power of the reactive power compensation equipment. and reactive power setpoint The calculation of voltage magnitude increment includes: The actual output reactive power and reactive power setpoint The difference is then multiplied by The voltage amplitude increment is obtained, where, This is the preset growth rate coefficient.

8. A reactive power compensation device, characterized in that, The system includes three bridge arm assemblies and a control module. Each bridge arm assembly includes multiple power sub-modules connected in sequence. The head end of each bridge arm assembly is connected to the power grid system, and the tail ends of the three bridge arm assemblies are connected to each other. The control module is connected to the controlled end of each power sub-module. The control module executes a fault switching method as described in any one of claims 1-7 to control the operation of the power sub-modules.

9. A control device, characterized in that, The control device includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement a fault switching method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements a fault switching method according to any one of claims 1 to 7.

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