Parallel converter low voltage ride through control method and device, electronic equipment and medium

Abstract

The application relates to a parallel converter low-voltage ride-through control method and device, electronic equipment and a medium. The method comprises the following steps: based on the topological parameters of a power system and the current output power of a synchronous generator, the power angle and the angular frequency of the synchronous generator during power system failure are calculated; based on the power angle and the angular frequency during power system failure, the rotor acceleration area of the synchronous generator during power system failure is calculated; the target rotor deceleration area of the synchronous generator is determined based on the rotor acceleration area, and the active power absorbed by the converter is controlled based on the target rotor deceleration area until the power angle of the synchronous generator after power system failure is in a preset stable state. Therefore, by controlling the active power absorbed by the converter after the failure is removed according to the acceleration area information of the generator rotor at the moment of failure removal, the problem that the power angle stability of the generator is poor caused by the low-voltage ride-through mode of the existing parallel converter is solved, thereby improving the stability and reliability of the power system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric power, and particularly relates to a parallel converter low-voltage ride-through control method and device, electronic equipment and medium. BACKGROUND

[0002] In the power system, the low-voltage ride-through technology of the grid-connected converter refers to the ability of the converter to maintain normal operation, not to be disconnected from the grid and not to interrupt the power transmission to the grid when the grid voltage is temporarily reduced. It is a key technology to ensure that the power system can still operate stably under voltage sag.

[0003] In the related art, after the power system fault is removed, the converter near the generator is still in the low-voltage ride-through mode, and the parallel converter will gradually restore the rated active power output.

[0004] However, this method affects the electromagnetic power output of the generator, causing poor power angle stability of the generator, which needs to be solved urgently. SUMMARY

[0005] The present application provides a parallel converter low-voltage ride-through control method, device, electronic equipment and medium to solve the problem of poor power angle stability of the generator caused by the low-voltage ride-through mode of the existing parallel converter, realize accurate control of the power angle stability of the synchronous generator, and further improve the stability and reliability of the power system.

[0006] To achieve the above-mentioned purpose, the first aspect of the present application provides a parallel converter low-voltage ride-through control method, comprising the following steps:

[0007] Obtain the topological parameters of the power system and the current output power of the synchronous generator, and based on the topological parameters and the current output power, calculate the power angle and the angular frequency of the synchronous generator during the power system fault;

[0008] Based on the power angle and the angular frequency of the synchronous generator during the power system fault, calculate the rotor acceleration area of the synchronous generator during the power system fault;

[0009] Determine the target rotor deceleration area of the synchronous generator based on the rotor acceleration area, and control the converter to absorb active power based on the target rotor deceleration area until the power angle of the synchronous generator after the power system fault is removed is in a preset stable state.

[0010] According to one embodiment of the present application, the determination of the target rotor deceleration area of the synchronous generator based on the rotor acceleration area comprises:

[0011] Determine whether the fault of the power system is removed;

[0012] In the case of fault clearing of the power system, an initial rotor deceleration area of the synchronous generator is acquired;

[0013] It is judged whether the rotor acceleration area is greater than or equal to the initial rotor deceleration area;

[0014] In the case that the rotor acceleration area is greater than or equal to the initial rotor deceleration area, a target rotor deceleration area of the synchronous generator is determined based on the rotor acceleration area.

[0015] According to one embodiment of the present application, the control of the converter to absorb active power based on the target rotor deceleration area comprises:

[0016] Based on the target rotor deceleration area and the initial rotor deceleration area, a rotor deceleration area increase is determined;

[0017] The current state of the converter is adjusted to a preset active regulation mode, and the converter is controlled to absorb active power by using a variable-coefficient droop control strategy based on the rotor deceleration area increase.

[0018] According to one embodiment of the present application, the active power is:

[0019]

[0020] Wherein, P ref is a reference value of the active power of the converter, S4 is the target rotor deceleration area, S2 is the initial rotor deceleration area, δ u is a power angle corresponding to an unstable equilibrium point of the synchronous generator, δ S is a power angle corresponding to a stable equilibrium point of the synchronous generator, f is the frequency of the synchronous generator, f0 is the power frequency, and a and b are to-be-determined coefficients.

[0021] According to one embodiment of the present application, after the power angle of the synchronous generator is in the preset stable state after the fault clearing of the power system, the method further comprises:

[0022] The converter is controlled to be switched from the preset active regulation mode to a preset steady-state regulation mode.

[0023] According to the low-voltage ride-through control method of the parallel converter provided in the embodiments of the present application, by analyzing the power system topology and the generator output power, the power angle and the angular frequency of the generator during the fault can be calculated; the generator rotor acceleration area at the time of the fault is determined by using the data, and the target rotor deceleration area is set accordingly; by controlling the active power absorbed by the converter, it is ensured that the generator can recover to the preset stable state after the fault is removed. Thus, by controlling the active power absorbed by the converter after the fault is removed according to the acceleration area information of the generator rotor at the moment of the fault removal, the problem of poor power angle stability of the generator caused by the low-voltage ride-through mode of the existing parallel converter is solved, the precise control of the power angle stability of the synchronous generator is realized, and the stability and reliability of the power system are further improved.

[0024] To achieve the above object, the second aspect of the present application provides a low-voltage ride-through control device of a parallel converter, comprising:

[0025] A first calculation module is configured to obtain the topology parameters of a power system and the current output power of a synchronous generator, and calculate the power angle and the angular frequency of the synchronous generator during a power system fault based on the topology parameters and the current output power;

[0026] A second calculation module is configured to calculate the rotor acceleration area of the synchronous generator during the power system fault based on the power angle and the angular frequency of the synchronous generator during the power system fault;

[0027] A control module is configured to determine the target rotor deceleration area of the synchronous generator based on the rotor acceleration area, and control the active power absorbed by the converter based on the target rotor deceleration area, until the power angle of the synchronous generator after the power system fault is removed is in a preset stable state.

[0028] According to one embodiment of the present application, the control module is specifically configured to:

[0029] determine whether the fault of the power system is removed;

[0030] in the case that the fault of the power system is removed, obtain the initial rotor deceleration area of the synchronous generator;

[0031] determine whether the rotor acceleration area is greater than or equal to the initial rotor deceleration area;

[0032] in the case that the rotor acceleration area is greater than or equal to the initial rotor deceleration area, determine the target rotor deceleration area of the synchronous generator based on the rotor acceleration area.

[0033] According to one embodiment of the present application, the control module is specifically configured to:

[0034] determine a rotor deceleration area increase amount based on the target rotor deceleration area and the initial rotor deceleration area;

[0035] adjust a current state of the converter to a preset active power regulation mode, and control the converter to absorb active power by using a variable-coefficient droop control strategy based on the rotor deceleration area increase amount.

[0036] According to an embodiment of the present application, the active power is:

[0037]

[0038] wherein P ref is a reference value of active power of the converter, S4 is the target rotor deceleration area, S2 is the initial rotor deceleration area, δ u is a power angle corresponding to an unstable equilibrium point of the synchronous generator, δ S is a power angle corresponding to a stable equilibrium point of the synchronous generator, f is a frequency of the synchronous generator, f0 is a power frequency, and a and b are to-be-determined coefficients.

[0039] According to an embodiment of the present application, after the power angle of the synchronous generator is in the preset stable state after the power system fault is removed, the control module is further configured to:

[0040] control the converter to switch from the preset active power regulation mode to a preset steady-state regulation mode.

[0041] According to the parallel converter low-voltage ride-through control device provided by the embodiments of the present application, the power angle and the angular frequency of the generator during the fault can be calculated by analyzing the power system topology and the generator output power; the rotor acceleration area of the generator during the fault is determined by using the data, and the target rotor deceleration area is set accordingly; the active power absorbed by the converter is controlled to ensure that the generator can recover to the preset stable state after the fault is removed. Thus, by controlling the converter to absorb active power according to the acceleration area information of the generator rotor at the moment of fault removal, the problem of poor power angle stability of the generator caused by the low-voltage ride-through mode of the existing parallel converter is solved, the precise control of the power angle stability of the synchronous generator is realized, and the stability and reliability of the power system are further improved.

[0042] To achieve the above object, a third aspect of the present application provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the parallel converter low-voltage ride-through control method as described in the above embodiments.

[0043] To achieve the above object, the fourth aspect of the present application provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to implement the low voltage ride through control method of parallel converter.

[0044] To achieve the above object, the fifth aspect of the present application provides a computer program product, which comprises a computer program, and the computer program is executed by a processor to implement the low voltage ride through control method of parallel converter.

[0045] Additional aspects and advantages of the present application will be made apparent by the following description and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0046] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the accompanying drawings.

[0047] Figure 1 A flow chart of a low voltage ride through control method of parallel converter according to an embodiment of the present application;

[0048] Figure 2 A schematic diagram of a low voltage ride through curve of an energy storage converter in the related art;

[0049] Figure 3 A topological schematic diagram of a power system according to an embodiment of the present application;

[0050] Figure 4 A power angle characteristic curve schematic diagram of a synchronous generator according to an embodiment of the present application;

[0051] Figure 5 A block schematic diagram of a low voltage ride through control device of parallel converter according to an embodiment of the present application;

[0052] Figure 6 A structural schematic diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0053] The embodiments of the present application are described in detail below with reference to the accompanying drawings. The embodiments described below are examples for explaining the present application and should not be understood as limiting the present application.

[0054] The low voltage ride through control method, device, electronic device and medium of parallel converter according to the embodiments of the present application are described below with reference to the accompanying drawings.

[0055] Figure 1 This is a flowchart of a low-voltage ride-through control method for a parallel converter according to an embodiment of this application.

[0056] Before introducing the low-voltage ride-through control method for parallel converters proposed in the embodiments of this application, we will first introduce the low-voltage ride-through method for grid-connected converters in related technologies.

[0057] like Figure 2 As shown, in a power system, a converter can generate reactive current as needed under low voltage conditions. Reactive current refers to current that is not converted into energy. After meeting the reactive power demand, the converter will use its remaining capacity to provide active current, which is the actual work done. However, when a power system fault occurs, the electromagnetic power generated by the generator will decrease significantly, causing the generator rotor to accelerate. After the fault is cleared, although the generator's electromagnetic power recovers somewhat, the rotor deceleration area is insufficient to allow the rotor to return to normal speed. If the generator's power angle (i.e., the phase difference between the synchronous generator terminal voltage phase angle and the grid phase angle) exceeds the critical value of the unstable equilibrium point, the generator will lose synchronization, or out of sync. After the fault is cleared, if the converters near the generator are still in low voltage ride-through mode, i.e., the converters gradually recover to their rated active power output, this will further affect the generator's electromagnetic power output, thus hindering the generator's rotor deceleration and increasing the difficulty of restoring the generator to stable operation.

[0058] Based on the above problems, this application proposes a new low-voltage ride-through control method for parallel converters. According to the acceleration area information of the generator rotor at the moment of fault clearing, the converter is controlled to absorb active power after the fault is cleared, thereby increasing the deceleration area of ​​the generator rotor. This solves the problem of poor power angle stability of the generator caused by the existing low-voltage ride-through method of parallel converters, realizes precise control of the power angle stability of synchronous generators, and further improves the stability and reliability of the power system.

[0059] For example, such as Figure 1 As shown, the low-voltage ride-through control method for the parallel converter includes the following steps:

[0060] In step S101, the topology parameters of the power system and the current output power of the synchronous generator are obtained, and the power angle and angular frequency of the synchronous generator during the power system fault are calculated based on the topology parameters and the current output power.

[0061] Among these, topology parameters refer to data describing the connection relationships and electrical characteristics of various devices in a power system. Power angle refers to the phase difference between the phase angle of the synchronous generator terminal voltage and the phase angle of the power grid during synchronous generator operation. Angular frequency reflects the rotational speed of the synchronous generator rotor.

[0062] Specifically, the power system topology as shown in Figure 3 includes a synchronous generator (a device capable of converting mechanical energy into alternating current energy, characterized by a strict synchronization relationship between its rotational speed and the frequency of the alternating current generated), and a generator near the energy storage converter (i.e. parallel converter) connected to the infinite grid through their respective line impedance. When a fault in the power system is detected, the angular frequency measurement of the synchronous generator mainly depends on physical sensors, which often have a large error, which leads to certain difficulties in capturing the frequency deviation during the transient process. In order to overcome this problem, the power angle and angular frequency of the synchronous generator during the power system fault can be accurately calculated based on the topological parameters of the power system and the current output power of the synchronous generator, which are two important parameters for evaluating the dynamic stability of the power system and preventing system collapse.

[0063] The calculation formula is as follows:

[0064]

[0065] where δ is the power angle of the synchronous generator during the power system fault, f is the angular frequency of the synchronous generator during the power system fault, P e is the current output power of the synchronous generator, X is the line equivalent impedance, E is the output voltage of the synchronous generator, and V is the grid voltage.

[0066] In step S102, the rotor acceleration area of the synchronous generator during the power system fault is calculated based on the power angle and angular frequency of the synchronous generator during the power system fault.

[0067] The rotor acceleration area is an indicator reflecting the change of kinetic energy of the synchronous generator rotor, which is closely related to the dynamic behavior of the synchronous generator during the fault.

[0068] Specifically, the power angle curve of the synchronous generator during the power fault can be as shown in Figure 4 , where curve II is the power angle curve when the power system is operating normally, and curve I is the power angle curve after the power system fault. Next, based on the power angle and angular frequency of the synchronous generator during the power system fault, the rotor acceleration area of the synchronous generator during the fault (such as the S1 area shown in Figure 4 ) can be calculated in real time by integration until the fault clearance of the power system is detected.

[0069] That is, the rotor acceleration area of the synchronous generator during the power system fault is:

[0070]

[0071] wherein S1 is the rotor acceleration area of the synchronous generator during the power system fault, δ c is the power angle of the synchronous generator at the time of fault clearing, δ s is the power angle of the synchronous generator at the time of stable operation, P real is the active power reference value of the synchronous generator.

[0072] In step S103, the target rotor deceleration area of the synchronous generator is determined based on the rotor acceleration area, and the converter is controlled to absorb active power based on the target rotor deceleration area until the power angle of the synchronous generator after the power system fault is cleared is in the preset stable state.

[0073] wherein the target rotor deceleration area refers to the kinetic energy area that needs to be consumed by the rotor of the synchronous generator in order to enable the synchronous generator to quickly recover to the stable operation state after the fault is cleared.

[0074] It can be understood that, when the power system fault is cleared, if the local converter does not have a starting action, then the deceleration area (i.e., the initial rotor deceleration area) of the synchronous generator can be represented by the S2 area in the S1 area. In this case, if the area of the S2 area is smaller than the area of the S1 area, then the synchronous generator will have a loss of step phenomenon. Figure 4

[0075] In order to effectively increase the deceleration area of the synchronous generator to prevent the loss of step phenomenon, the embodiments of the present application can determine the target rotor deceleration area S4 of the synchronous generator after the power system fault based on the calculated rotor acceleration area S1 during the power system fault. In order to achieve this goal, the converter can be controlled to absorb the corresponding active power, thereby helping the synchronous generator to slow down the speed until the power angle of the synchronous generator after the power system fault is cleared reaches the preset stable state, so as to ensure the safe and stable operation of the entire power system.

[0076] Next, how to determine the target rotor deceleration area of the synchronous generator based on the rotor acceleration area will be described in detail.

[0077] As a possible implementation manner, in some embodiments, determining the target rotor deceleration area of the synchronous generator based on the rotor acceleration area includes: judging whether the fault of the power system is cleared; in the case that the fault of the power system is cleared, obtaining the initial rotor deceleration area of the synchronous generator; judging whether the rotor acceleration area is greater than or equal to the initial rotor deceleration area; in the case that the rotor acceleration area is greater than or equal to the initial rotor deceleration area, determining the target rotor deceleration area of the synchronous generator based on the rotor acceleration area.

[0078] ​Specifically, firstly, it can be judged whether the fault of the power system has been successfully cleared. In the case of confirming that the fault of the power system is cleared, the initial rotor deceleration area S2 of the synchronous generator at the fault clearing moment can be obtained. Based on the rotor acceleration area S1 and the initial rotor deceleration area S2, further analysis and calculation can be carried out, that is, the rotor acceleration area S1 and the initial rotor deceleration area S2 are compared, if the rotor acceleration area S1 is greater than or equal to the initial rotor deceleration area S2, then the target rotor deceleration area S4 of the synchronous generator can be determined according to the rotor acceleration area S1. In order to prevent the occurrence of step-out, the target rotor deceleration area S4 of the synchronous generator needs to be greater than or equal to the rotor acceleration area S1.

[0079] Next, how to control the active power absorbed by the converter based on the target rotor deceleration area is described in detail.

[0080] As a possible implementation manner, in some embodiments, the method of controlling the active power absorbed by the converter based on the target rotor deceleration area comprises: determining a rotor deceleration area increase amount based on the target rotor deceleration area and the initial rotor deceleration area; adjusting the current state of the converter to a preset active regulation mode, and controlling the active power absorbed by the converter based on the rotor deceleration area increase amount by using a variable-coefficient droop control strategy.

[0081] Specifically, in order to realize that the target rotor deceleration area S4 is greater than or equal to the rotor acceleration area S1, the rotor deceleration area increase amount (that is, S4-S2) can be determined based on the target rotor deceleration area S4 and the initial rotor deceleration area S2. Subsequently, the current working state of the converter is adjusted to convert to a preset active regulation mode, and the active power absorbed by the converter is controlled according to the rotor deceleration area increase amount by using a variable-coefficient droop control strategy, so as to ensure the stable operation of the whole system.

[0082] In order to realize this adjustment, an adaptive expression is used in the embodiments of the present application to calculate the amount of active power that the converter should absorb, and the expression is as follows:

[0083] P ref =g(f,δ s ,δ,S2,S4); (4)

[0084] Wherein, P ref is the active power reference value of the converter, that is, the active power that the converter should absorb.

[0085] Further, the active power that the converter should absorb can also be expressed as:

[0086]

[0087] Wherein, when f=f0, δ=δs P ref = 0. When P ref is positive, it indicates that the converter absorbs active power. S4 is the target rotor deceleration area, S2 is the initial rotor deceleration area, δ u is the power angle corresponding to the unstable equilibrium point of the synchronous generator, δ S is the power angle corresponding to the stable equilibrium point of the synchronous generator, f is the frequency of the synchronous generator, f0 is the power frequency, and a and b are undetermined coefficients.

[0088] If P ref > P max , then P ref = P max , where P max is the maximum active power allowed to be absorbed by the converter.

[0089] According to the active power reference value of the converter, the converter is adjusted, and under the action of the converter, the actual rotor deceleration area of the synchronous generator can be increased as shown in the S3 area of Figure 4 It is worth noting that in this case, the equivalent power angle curve III does not necessarily exhibit the standard sinusoidal waveform characteristics, but converges to the dynamic change curve of δ u During this dynamic change, the area represented by S2+S3 can still be calculated by real-time integration, that is:

[0090]

[0091] The maximum deceleration area of the synchronous generator (i.e., the maximum target rotor deceleration area) can be represented as:

[0092]

[0093] In theory, when the following expression is satisfied, the transient synchronous stability of the synchronous generator can be ensured, that is:

[0094] S1≤max(S2+S3) (8)

[0095] However, in actual operation, when formula (9) is satisfied, the transient synchronous stability of the synchronous generator can be ensured, that is:

[0096] S1≤S2+S3 (9)

[0097] In theory, the actual rotor deceleration area S3 can be completely controlled by the capacity and power of the energy storage converter. This means that as long as the capacity of the energy storage converter is large enough, the synchronous generator can always be kept in a state of synchronous stability during the transient process by applying the above formula.

[0098] It should be noted that if the rotor acceleration area S1 is less than the initial rotor deceleration area S2, the converter can ensure the synchronous generator to maintain a synchronous stable state in the transient process according to the original low-voltage ride-through mode, that is, after the fault is removed, the converter gradually restores to output the rated active power.

[0099] Further, in some embodiments, after the power angle of the synchronous generator reaches the preset stable state after the power system fault is removed, the method further comprises: controlling the converter to switch from the preset active regulation mode to a preset steady-state regulation mode.

[0100] That is, after the power angle of the synchronous generator reaches the preset stable state after the power system fault is removed (that is, formula (9) is satisfied or the power angle returns to the stable equilibrium point), the parallel converter can be switched from the preset active regulation mode to the preset steady-state regulation mode, that is, the parallel converter is switched from the preset active regulation mode to the steady-state setting state, to ensure the rapid recovery and stable operation of the power system after the fault, and improve the stability and reliability of the entire power system.

[0101] According to the low-voltage ride-through control method of the parallel converter provided in the embodiments of the present application, by analyzing the power system topology and the generator output power, the power angle and the angular frequency of the generator during the fault can be calculated; the rotor acceleration area of the generator during the fault is determined by using these data, and the target rotor deceleration area is set accordingly; by controlling the converter to absorb active power, it is ensured that the generator can recover to the preset stable state after the fault is removed. Therefore, by controlling the converter to absorb active power after the fault is removed according to the acceleration area information of the generator rotor at the moment of fault removal, the problem of poor power angle stability of the generator caused by the low-voltage ride-through mode of the existing parallel converter is solved, accurate control of the power angle stability of the synchronous generator is realized, and the stability and reliability of the power system are further improved.

[0102] Secondly, the low-voltage ride-through control device of the parallel converter according to the embodiments of the present application is described with reference to the accompanying drawings.

[0103] Figure 5 is a block schematic diagram of the low-voltage ride-through control device of the parallel converter according to an embodiment of the present application.

[0104] As shown in Figure 5 , the low-voltage ride-through control device 10 of the parallel converter comprises a first calculation module 100, a second calculation module 200 and a control module 300.

[0105] The first calculation module 100 is configured to obtain the topology parameters of the power system and the current output power of the synchronous generator, and calculate the power angle and the angular frequency of the synchronous generator during the fault of the power system based on the topology parameters and the current output power.

[0106] The second calculation module 200 is configured to calculate a rotor acceleration area of the synchronous generator during the power system fault based on the power angle and the angular frequency of the synchronous generator during the power system fault.

[0107] The control module 300 is configured to determine a target rotor deceleration area of the synchronous generator based on the rotor acceleration area, and control the converter to absorb active power based on the target rotor deceleration area until the power angle of the synchronous generator after the power system fault is cleared is in a preset stable state.

[0108] Further, in some embodiments, the control module 300 is specifically configured to:

[0109] determine whether the fault of the power system is cleared;

[0110] in a case where the fault of the power system is cleared, obtain an initial rotor deceleration area of the synchronous generator;

[0111] determine whether the rotor acceleration area is greater than or equal to the initial rotor deceleration area;

[0112] in a case where the rotor acceleration area is greater than or equal to the initial rotor deceleration area, determine the target rotor deceleration area of the synchronous generator based on the rotor acceleration area.

[0113] Further, in some embodiments, the control module 300 is specifically configured to:

[0114] determine an increase of the rotor deceleration area based on the target rotor deceleration area and the initial rotor deceleration area;

[0115] adjust a current state of the converter to a preset active regulation mode, and control the converter to absorb active power by using a variable-coefficient droop control strategy based on the increase of the rotor deceleration area.

[0116] Further, in some embodiments, the active power is:

[0117]

[0118] wherein, P ref is a reference value of active power of the converter, S4 is the target rotor deceleration area, S2 is the initial rotor deceleration area, δ u is a power angle corresponding to an unstable equilibrium point of the synchronous generator, δ S is a power angle corresponding to a stable equilibrium point of the synchronous generator, f is a frequency of the synchronous generator, f0 is a working frequency, and a and b are to-be-determined coefficients.

[0119] Further, in some embodiments, after the power angle of the synchronous generator after the power system fault is cleared is in the preset stable state, the control module 300 is further configured to:

[0120] The control converter is switched from the preset active regulation mode to the preset steady-state regulation mode.

[0121] It should be noted that the foregoing explanation and description of the parallel converter low voltage ride through control method embodiment also applies to the parallel converter low voltage ride through control device of the embodiment, which will not be described here again.

[0122] The parallel converter low voltage ride through control device provided by the embodiment of the application can calculate the power angle and the angular frequency of the generator during the fault by analyzing the power system topology and the generator output power; the data are used to determine the generator rotor acceleration area at the time of the fault, and the target rotor deceleration area is set accordingly; the active power is absorbed by the control converter to ensure that the generator can recover to the preset steady state after the fault is removed. Therefore, by using the acceleration area information of the generator rotor at the moment of the fault removal, the active power is absorbed by the control converter after the fault removal, the problem of poor power angle stability of the generator caused by the low voltage ride through mode of the existing parallel converter is solved, the precise control of the power angle stability of the synchronous generator is realized, and the stability and reliability of the power system are further improved.

[0123] Figure 6 The structure schematic diagram of the electronic device provided by the embodiment of the application is shown. The electronic device can include:

[0124] The memory 601, the processor 602 and the computer program stored in the memory 601 and executable on the processor 602.

[0125] The processor 602 implements the parallel converter low voltage ride through control method provided in the above embodiments when executing the program.

[0126] Further, the electronic device further includes:

[0127] The communication interface 603 is used for communication between the memory 601 and the processor 602.

[0128] The memory 601 is used to store the computer program executable on the processor 602.

[0129] The memory 601 can include a high-speed RAM (Random Access Memory, Random Access Memory) memory, and can also include a non-volatile memory, such as at least one disk memory.

[0130] If the memory 601, the processor 602 and the communication interface 603 are implemented independently, the communication interface 603, the memory 601 and the processor 602 can be connected with each other through a bus and complete communication between each other. The bus can be an ISA (Industry Standard Architecture, Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect, Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture, Extended Industry Standard Architecture) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, Figure 6 Only one thick line is used in the figure to represent the bus, but it does not mean that there is only one bus or only one type of bus.

[0131] Optionally, in a specific implementation, if the memory 601, the processor 602 and the communication interface 603 are integrated on a chip, the memory 601, the processor 602 and the communication interface 603 can complete communication between each other through an internal interface.

[0132] The processor 602 can be a CPU (Central Processing Unit, Central Processing Unit) or an ASIC (Application Specific Integrated Circuit, Application Specific Integrated Circuit) or one or more integrated circuits configured to implement one or more embodiments of the application.

[0133] The embodiment of the application also provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to implement the parallel current transformer low voltage ride through control method.

[0134] The embodiment of the application also provides a computer program product, which includes a computer program, and the computer program is executed by a processor to implement the parallel current transformer low voltage ride through control method.

[0135] In addition, the terms "first", "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly and specifically limited.

[0136] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms is not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0137] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and the person skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A low-voltage ride-through control method for a parallel converter, characterized in that, Includes the following steps: Obtain the topology parameters of the power system and the current output power of the synchronous generator, and calculate the power angle and angular frequency of the synchronous generator during a power system fault based on the topology parameters and the current output power; Based on the power angle and angular frequency of the synchronous generator during the power system fault, calculate the rotor acceleration area of ​​the synchronous generator during the power system fault. The target rotor deceleration area of ​​the synchronous generator is determined based on the rotor acceleration area, and the converter is controlled to absorb active power based on the target rotor deceleration area until the power angle of the synchronous generator is in a preset stable state after the power system fault is cleared. The active power is: in, This is a reference value for the active power of the converter. The target rotor deceleration area is... This represents the initial rotor deceleration area. The power angle corresponding to the unstable equilibrium point of the synchronous generator. The power angle corresponding to the stable equilibrium point of the synchronous generator. For synchronous generator frequency, For power frequency, , All are undetermined coefficients.

2. The method according to claim 1, characterized in that, Determining the target rotor deceleration area of ​​the synchronous generator based on the rotor acceleration area includes: Determine whether the fault in the power system has been cleared; In the event of a fault clearing in the power system, the initial rotor reduction area of ​​the synchronous generator is obtained; Determine whether the rotor acceleration area is greater than or equal to the initial rotor deceleration area; If the rotor acceleration area is greater than or equal to the initial rotor deceleration area, the target rotor deceleration area of ​​the synchronous generator is determined based on the rotor acceleration area.

3. The method according to claim 2, characterized in that, The active power absorption of the converter based on the target rotor reduction area includes: Based on the target rotor reduction area and the initial rotor reduction area, determine the increase in rotor reduction area; The current state of the converter is adjusted to a preset active power regulation mode, and based on the increase in rotor deceleration area, a droop control strategy with a variable coefficient is used to control the converter to absorb active power.

4. The method according to claim 1, characterized in that, After the synchronous generator reaches the preset stable state in terms of power angle after the power system fault is cleared, the following steps are also included: The converter is controlled to switch from a preset active power regulation mode to a preset steady-state regulation mode.

5. A low-voltage ride-through control device for a parallel converter, characterized in that, include: The first calculation module is used to obtain the topology parameters of the power system and the current output power of the synchronous generator, and to calculate the power angle and angular frequency of the synchronous generator during a power system fault based on the topology parameters and the current output power. The second calculation module is used to calculate the rotor acceleration area of ​​the synchronous generator during the power system fault based on the power angle and the angular frequency of the synchronous generator during the power system fault. The control module is used to determine the target rotor deceleration area of ​​the synchronous generator based on the rotor acceleration area, and to control the converter to absorb active power based on the target rotor deceleration area until the power angle of the synchronous generator is in a preset stable state after the power system fault is cleared. The active power is: in, This is a reference value for the active power of the converter. The target rotor deceleration area is... This represents the initial rotor deceleration area. The power angle corresponding to the unstable equilibrium point of the synchronous generator. The power angle corresponding to the stable equilibrium point of the synchronous generator. For synchronous generator frequency, For power frequency, , All are undetermined coefficients.

6. The apparatus according to claim 5, characterized in that, The control module is specifically used for: Determine whether the fault in the power system has been cleared; In the event of a fault clearing in the power system, the initial rotor reduction area of ​​the synchronous generator is obtained; Determine whether the rotor acceleration area is greater than or equal to the initial rotor deceleration area; If the rotor acceleration area is greater than or equal to the initial rotor deceleration area, the target rotor deceleration area of ​​the synchronous generator is determined based on the rotor acceleration area.

7. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the parallel converter low-voltage ride-through control method as described in any one of claims 1-4.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the low-voltage ride-through control method for parallel converters as described in any one of claims 1-4.

9. A computer program product, characterized in that, Includes a computer program, which, when executed by a processor, is used to implement the low-voltage ride-through control method for parallel converters as described in any one of claims 1-4.

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