A reactive disturbance active suppression method, system, device and storage medium

Abstract

The application discloses a kind of reactive disturbance active inhibition method, system, equipment and storage medium, applied to the field of power electronic converter, including obtaining the sub-module voltage reference data of voltage regulation module in target flexible DC transmission system;According to the sub-module voltage reference data, the state of the converter of target flexible DC transmission system is judged, and the fault ride-through state judgment result is obtained;If the fault ride-through state judgment result is that the AC side of the converter is in the fault ride-through state, then the reactive disturbance active inhibition strategy is put in, and the reactive disturbance active inhibition strategy is designed to add an inhibition factor to the bridge arm AC reference wave in the control process.The reactive disturbance active inhibition method of the application can significantly improve the reactive power stability of the flexible DC transmission system during AC fault ride-through, enhance the reliability of the system, and provide a strong guarantee for the safe operation of the power grid.

Description

Technical Field

[0001] This invention relates to the field of power electronic converter technology, and in particular to a method, system, device and medium for active suppression of reactive power disturbances. Background Technology

[0002] With the widespread application of flexible DC transmission technology, the importance of grid-type flexible DC transmission systems in the power grid is becoming increasingly prominent. However, reactive power disturbances during AC fault ride-throughs seriously affect the stability and reliability of the system.

[0003] In existing technologies, during AC fault ride-through in grid-type flexible DC transmission systems, voltage fluctuations in submodules cause the valve-side voltage to deviate from the ideal reference waveform, resulting in an inability to output ideal reactive power and generating significant reactive power disturbances. These disturbances not only affect system stability but may also prolong grid recovery time and even trigger more severe grid faults. Furthermore, existing technologies lack effective methods for suppressing reactive power disturbances, failing to meet the requirements for stable reactive power output during fault ride-through in grid-type flexible DC transmission systems.

[0004] Therefore, how to effectively suppress reactive power disturbances during AC fault ride-through in grid-type flexible DC transmission systems has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] This invention provides a method, system, device, and storage medium for actively suppressing reactive power disturbances in flexible DC transmission systems.

[0006] To address the aforementioned technical problems, embodiments of the present invention provide an active reactive power disturbance suppression method, comprising:

[0007] Obtain voltage reference data for the submodules of the voltage regulation module in the target flexible DC transmission system.

[0008] The converter status of the target flexible DC transmission system is judged based on the voltage reference data of the submodule, and the fault ride-through status judgment result is obtained.

[0009] If the fault ride-through state judgment result indicates that the AC side of the converter is in a fault ride-through state, then the active reactive power disturbance suppression strategy is implemented. The active reactive power disturbance suppression strategy is designed to add a suppression factor to the AC reference wave of the bridge arm during the control process.

[0010] If the fault ride-through status judgment result is that the AC side of the converter is not in a fault ride-through state, then the reactive power disturbance active suppression strategy is exited.

[0011] Furthermore, the voltage regulation module includes a bridge arm module and a valve control module, and the submodule voltage reference data includes the real-time average voltage value of the submodule and the calculated voltage value of the submodule.

[0012] The acquisition of submodule voltage reference data of the voltage regulation module in the target flexible DC transmission system includes:

[0013] Obtain the real-time average voltage values ​​of the sub-modules of each bridge arm module and the calculated voltage values ​​of the sub-modules of the valve control module in the target flexible DC transmission system.

[0014] Furthermore, the calculation process for the submodule voltage value is as follows:

[0015] Determine the rated voltage type of the valve control module. If the rated voltage type is fixed rated voltage, then the calculated voltage value of the submodule is the fixed rated voltage.

[0016] If the rated voltage type is variable rated voltage, the variable rated voltage is dynamically adjusted according to the number of bridge arm sub-modules in the bridge arm module, and the calculated value of the sub-module voltage is the variable rated voltage.

[0017] Further, the step of judging the converter status of the target flexible DC transmission system based on the submodule voltage reference data to obtain the fault ride-through status judgment result includes:

[0018] Calculate the voltage amplitude and absolute value of the three-phase voltage in the three-phase rotating coordinate system based on the voltage reference data of the submodule.

[0019] If the voltage amplitude is less than the preset low voltage setting, or the absolute value of the three-phase voltage is greater than the preset zero-sequence voltage setting, then the AC side of the converter of the target flexible DC transmission system is determined to be in a fault ride-through state; otherwise, the AC side of the converter of the target flexible DC transmission system is determined not to be in a fault ride-through state.

[0020] Furthermore, the addition of a suppression factor to the AC reference wave of the bridge arm during the control process is expressed as follows:

[0021]

[0022]

[0023] Where j = a, b, c; i = p, n; U reffinji For the final bridge arm reference wave, U refji U is the original bridge arm reference wave. dvbia_pro DC bias; Uv avgcal This is the calculated voltage value for the submodule; Uv jiSUM The normal submodule voltage of phase i bridge arm and N; vjiThe number of normal submodules in phase i bridge arm.

[0024] Furthermore, if the fault ride-through state determination result indicates that the AC side of the converter is not in a fault ride-through state, then the reactive power disturbance active suppression strategy is exited, including:

[0025] When the fault ride-through state judgment result indicates that the AC side of the converter is not in a fault ride-through state, timing begins. When the timing duration reaches the preset delay interval, the suppression factor in the AC reference wave of the bridge arm is removed to exit the active reactive power disturbance suppression strategy.

[0026] Furthermore, the calculation process of the suppression factor in the active reactive power disturbance suppression strategy is as follows:

[0027] Based on the submodule voltage reference data, the voltage regulation coefficient of each bridge arm submodule is calculated. The voltage regulation coefficient is the ratio of the calculated submodule voltage value to the real-time average voltage value of each bridge arm submodule.

[0028] The suppression factor is the reciprocal of the voltage regulation coefficient and is used to adjust the AC reference wave of the bridge arm to offset the effect of submodule voltage fluctuations on reactive power output.

[0029] Another embodiment of the present invention provides an active reactive power disturbance suppression system, comprising:

[0030] The data acquisition module is used to acquire voltage reference data of the sub-modules of the voltage regulation module in the target flexible DC transmission system.

[0031] The status judgment module is used to judge the status of the converter of the target flexible DC transmission system based on the voltage reference data of the submodule, and obtain the fault ride-through status judgment result.

[0032] The disturbance suppression module is used to activate the active reactive disturbance suppression strategy if the fault ride-through state judgment result indicates that the AC side of the converter is in a fault ride-through state. The active reactive disturbance suppression strategy is designed to add a suppression factor to the AC reference wave of the bridge arm during the control process.

[0033] The voltage regulation module includes a bridge arm module and a valve control module, and the submodule voltage reference data includes the real-time average voltage value of the submodule and the calculated voltage value of the submodule.

[0034] The data acquisition module is specifically used for:

[0035] Obtain the real-time average voltage values ​​of the sub-modules of each bridge arm module and the calculated voltage values ​​of the sub-modules of the valve control module in the target flexible DC transmission system.

[0036] The calculation process for the submodule voltage value is as follows:

[0037] Determine the rated voltage type of the valve control module. If the rated voltage type is fixed rated voltage, then the calculated voltage value of the submodule is the fixed rated voltage.

[0038] If the rated voltage type is variable rated voltage, the variable rated voltage is dynamically adjusted according to the number of bridge arm sub-modules in the bridge arm module, and the calculated value of the sub-module voltage is the variable rated voltage.

[0039] The status determination module is specifically used for:

[0040] Calculate the voltage amplitude and absolute value of the three-phase voltage in the three-phase rotating coordinate system based on the voltage reference data of the submodule;

[0041] If the voltage amplitude is less than the preset low voltage setting, or the absolute value of the three-phase voltage is greater than the preset zero-sequence voltage setting, then the AC side of the converter of the target flexible DC transmission system is determined to be in a fault ride-through state; otherwise, the AC side of the converter of the target flexible DC transmission system is determined not to be in a fault ride-through state.

[0042] The addition of a suppression factor to the AC reference wave of the bridge arm during the control process is expressed as follows:

[0043]

[0044]

[0045] Where j = a, b, c; i = p, n; U reffinji For the final bridge arm reference wave, U refji U is the original bridge arm reference wave. dvbia_pro DC bias; Uv avgcal This is the calculated voltage value for the submodule; Uv jiSUM The normal submodule voltage of phase i bridge arm and N; vji The number of normal submodules in phase i bridge arm.

[0046] The system also includes an exit suppression module, specifically used for:

[0047] When the fault ride-through state judgment result indicates that the AC side of the converter is not in a fault ride-through state, timing begins. When the timing duration reaches the preset delay interval, the suppression factor in the AC reference wave of the bridge arm is removed to exit the active reactive power disturbance suppression strategy.

[0048] The calculation process for the suppression factor in the active reactive power disturbance suppression strategy is as follows:

[0049] Based on the submodule voltage reference data, calculate the voltage regulation coefficient of each bridge arm submodule. The voltage regulation coefficient is the ratio of the calculated submodule voltage value to the real-time average voltage value of each bridge arm submodule.

[0050] The suppression factor is the reciprocal of the voltage regulation coefficient and is used to adjust the AC reference wave of the bridge arm to offset the effect of submodule voltage fluctuations on reactive power output.

[0051] Another embodiment of the present invention provides a computer device including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor executes the computer program to implement the active reactive power disturbance suppression method as described above.

[0052] In another embodiment of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing a computer program, wherein when the device containing the computer-readable storage medium executes the computer program, the reactive power disturbance active suppression method described above is implemented.

[0053] Compared with the prior art, the beneficial effects of the embodiments of the present invention are at least one of the following:

[0054] By adding a suppression factor to the AC reference waveform of the bridge arm, the impact of submodule voltage fluctuations on reactive power output can be effectively offset. During AC fault ride-through, the converter can be guaranteed to output ideal reactive power, thereby maintaining the stable operation of the power grid. By dynamically adjusting the suppression factor, it can adapt to different fault types and voltage fluctuations, ensuring effective suppression of reactive power disturbances under various complex operating conditions. This invention's active reactive power disturbance suppression method can significantly improve the reactive power stability of flexible DC transmission systems during AC fault ride-through, enhance system reliability, and provide strong protection for the safe operation of the power grid. Attached Figure Description

[0055] Figure 1 This is a flowchart of the active suppression method for reactive power disturbance in one embodiment of the present invention;

[0056] Figure 2 This is a flow control diagram of an active reactive disturbance suppression method in one embodiment of the present invention;

[0057] Figure 3 This is a structural block diagram of an active reactive disturbance suppression device in one embodiment of the present invention;

[0058] Figure 4 This is a comparison diagram of the effectiveness of the active suppression method for reactive power disturbance in one embodiment of the present invention;

[0059] Figure 5This is a structural block diagram of an active reactive disturbance suppression system in one embodiment of the present invention;

[0060] Figure 6 A structural diagram of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0061] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0062] In the description of this application, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0063] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. The terms "vertical," "horizontal," "left," "right," "upper," "lower," and similar expressions used herein are for illustrative purposes only and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0064] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing specific embodiments only and is not intended to limit the invention. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0065] One embodiment of the present invention provides an active suppression method for reactive power disturbances. For details, please refer to [link to relevant documentation]. Figure 1-2 , Figure 1 The diagram shown is a flowchart illustrating the steps of an active reactive power disturbance suppression method according to one embodiment of the present invention. Figure 2 The diagram shown is a flow control diagram of an active reactive disturbance suppression method according to one embodiment of the present invention.

[0066] like Figure 1 As shown, the active reactive power disturbance suppression method of this embodiment includes steps S11-S13:

[0067] Step S11: Obtain the sub-module voltage reference data of the voltage regulation module in the target flexible DC transmission system.

[0068] In flexible DC transmission systems, the voltage regulation module is a crucial component for achieving stable system operation, enabling precise monitoring and regulation of submodule voltages. To achieve effective control of the flexible DC transmission system and enhance its fault ride-through capability, it is necessary to obtain reference voltage data for the submodules within the voltage regulation module.

[0069] The voltage regulation module mainly consists of bridge arm modules and valve control modules. Bridge arm modules are crucial structures in flexible DC transmission systems, connecting sections with different potentials and handling current transmission and voltage distribution. The valve control module is responsible for calculating and controlling the voltage of the submodules to ensure stable system operation. Submodule voltage reference data is the core data for the voltage regulation module's operation, primarily including the real-time average voltage value and the calculated voltage value. The real-time average voltage value reflects the actual voltage level of the submodule and directly represents the system's real-time operating status; while the calculated voltage value is the desired voltage value calculated based on the system's control objectives and operational requirements, guiding the system's voltage regulation of the submodules.

[0070] To obtain reference voltage data for the submodules of the voltage regulation module in the target flexible DC transmission system, corresponding data needs to be acquired from each bridge arm module and valve control module. Specifically, the real-time average voltage value of the submodule needs to be obtained from each bridge arm module. This real-time value reflects the actual voltage status of the submodule in the current bridge arm module, providing basic data for real-time monitoring and control of the system. Simultaneously, the calculated voltage value of the submodule needs to be obtained from the valve control module. This calculated value is the desired voltage value obtained through complex calculations based on the system's control strategy and operational requirements, used to guide the system's regulation and control of the submodule voltage. Step S12: Based on the submodule voltage reference data, the converter status of the target flexible DC transmission system is judged to obtain the fault ride-through status judgment result.

[0071] In flexible DC transmission systems, the state of the converter is crucial to the stable operation of the system. To accurately determine whether the converter is in a fault ride-through state, analysis based on submodule voltage reference data is necessary. This data includes real-time average submodule voltage values ​​and calculated submodule voltage values, which reflect the voltage state of the converter under different operating conditions.

[0072] In flexible DC transmission systems, the rated voltage type of the valve control module is one of the key factors in determining the converter's status. Rated voltage types are generally divided into two categories: fixed rated voltage and variable rated voltage. When the valve control module uses a fixed rated voltage, it means that the calculated voltage value of the submodule will remain at a constant level. In this case, the calculated voltage value of the submodule is directly equal to the fixed rated voltage value. Fixed rated voltage is typically used in situations where the system operating conditions are relatively stable and frequent voltage adjustments are not required.

[0073] The situation becomes more complex when the valve control module uses a variable rated voltage. A variable rated voltage means that the calculated voltage value of the submodule is dynamically adjusted according to the system's operating status. Specifically, this adjustment is based on the number of bridge arm submodules within the bridge arm module. In flexible DC transmission systems, the number of bridge arm submodules can vary due to faults or other changes in operating conditions. Therefore, by dynamically adjusting the variable rated voltage, it is possible to better adapt to system changes and ensure the stable operation of the converter under different operating conditions. In this case, the calculated voltage value of the submodule will be equal to the dynamically adjusted variable rated voltage value. This dynamic adjustment mechanism can effectively cope with voltage fluctuations in the system, especially during fault ride-through, by adjusting the calculated voltage value in real time, it can better maintain the stability and reliability of the system.

[0074] Step S13: If the fault ride-through state judgment result is that the AC side of the converter is in a fault ride-through state, then the active reactive power disturbance suppression strategy is activated. The active reactive power disturbance suppression strategy is designed to add a suppression factor to the AC reference wave of the bridge arm during the control process.

[0075] When the AC side of the converter is determined to be in a fault ride-through state based on the submodule voltage reference data, an active reactive power disturbance suppression strategy needs to be immediately implemented to effectively suppress reactive power disturbances and ensure stable system operation. The core of this strategy is to add a suppression factor to the arm AC reference waveform during the control process. In this way, the arm reference waveform can be dynamically adjusted to offset the impact of submodule voltage fluctuations on reactive power output, ensuring that the converter can stably output the required reactive power during fault ride-through.

[0076] The calculation process for the suppression factor in the active reactive power disturbance suppression strategy is as follows:

[0077] Based on the submodule voltage reference data, calculate the voltage regulation coefficient of each bridge arm submodule. The voltage regulation coefficient is the ratio of the calculated submodule voltage value to the real-time average voltage value of each bridge arm submodule.

[0078] The suppression factor is the reciprocal of the voltage regulation coefficient and is used to adjust the AC reference wave of the bridge arm to offset the effect of submodule voltage fluctuations on reactive power output.

[0079] The suppression factor added to the AC reference wave of the bridge arm during the control process is represented as follows:

[0080]

[0081]

[0082] Where j = a, b, c; i = p, n; U reffinji For the final bridge arm reference wave, U refji U is the original bridge arm reference wave. dvbia_pro DC bias; Uv avgcal This is the calculated voltage value for the submodule; Uv jiSUM The normal submodule voltage of phase i bridge arm and N; vji The number of normal submodules in phase i bridge arm.

[0083] To accurately determine whether the AC side of the converter is in a fault ride-through state, a detailed voltage analysis is required using submodule voltage reference data. Specifically, in this embodiment, the real-time average voltage value and the calculated voltage value of the submodule are converted to a three-phase rotating coordinate system to calculate the voltage amplitude. Simultaneously, the absolute values ​​of the three-phase voltages also need to be calculated.

[0084] When determining fault ride-through status, two key voltage thresholds are required: the low-voltage setpoint and the zero-sequence voltage setpoint. These thresholds are pre-set based on the system's operating characteristics and design requirements. When the calculated voltage amplitude in the three-phase rotating coordinate system is less than the low-voltage setpoint, it indicates a significant drop in system voltage, possibly due to an AC-side fault. Similarly, when the absolute value of the three-phase voltage is greater than the zero-sequence voltage setpoint, it indicates the presence of a zero-sequence voltage component in the system, which is usually a sign of a fault. Therefore, when either of these conditions is met, the AC side of the converter in the target flexible DC transmission system can be determined to be in a fault ride-through state. Conversely, if neither of these conditions is met, the AC side of the converter can be determined not to be in a fault ride-through state.

[0085] In addition, this embodiment also includes step S14: if the fault ride-through state judgment result is that the AC side of the converter is not in the fault ride-through state, then the active suppression strategy for reactive power disturbance is exited.

[0086] When the voltage reference data from the submodule indicates that the AC side of the converter is not in a fault ride-through state, it means that the system's operating conditions have returned to normal, and the active reactive power disturbance suppression strategy is no longer needed to maintain stable system operation. Therefore, this strategy needs to be phased out in a timely manner to avoid unnecessary control intervention and ensure that the system can operate efficiently and stably under normal operating conditions.

[0087] After confirming that the AC side of the converter is not in a fault ride-through state, the system will start a timer. This timer ensures that the system does not immediately exit the active reactive power disturbance suppression strategy after confirming the fault condition has been cleared, but instead waits for a preset delay interval. This delay interval is set to prevent frequent strategy switching due to instantaneous voltage fluctuations or misjudgments, ensuring system stability and reliability. When the preset delay interval is reached, the system will remove the suppression factor from the AC reference waveform of the bridge arm. After removing the suppression factor, the AC reference waveform of the bridge arm will return to its original state, and the active reactive power disturbance suppression strategy will exit.

[0088] like Figure 2 As shown in Figure 101, the real-time average voltage value Uv of each bridge arm submodule of the flexible DC converter is obtained. avgap UV avgan UV avgbp UV avgbn UV avgcp UV avgcn The calculated voltage value Uv of the submodule of the valve control module avgcal .

[0089] Among the real-time average voltage values ​​of the six sub-modules, abc represents three phases, p represents the upper bridge arm, and n represents the lower bridge arm.

[0090] The real-time average voltage value Uv of each bridge arm submodule of the flexible DC converter is obtained. avgap UV avgan UV avgbp UV avgbn UV avgcp UV avgcn The value is derived from the valve control module and is obtained as follows:

[0091]

[0092] Where j = a, b, c; i = p, n, then Uv jiSUM The normal submodule voltage of phase i bridge arm and N; vji The number of normal submodules in phase i bridge arm.

[0093] The obtained calculated value Uv of the submodule voltage of the valve control module avgcalThe value comes from the valve control module, and there are two ways to determine it, depending on whether the submodule uses a fixed rated voltage or a variable rated voltage:

[0094] Method a1: When the valve control module uses a fixed rated voltage Uv avgN When calculating the number of bridge arm submodules deployed, UV avgcal use .

[0095] Method a2: When the valve control module uses a variable rated voltage Uv avgNC When calculating the number of bridge arm submodules to be deployed, the number of bridge arm submodules with the most failures, Ns, is used as the basis. m_bad Dynamically adjust UV avgNC Uv avgcal use U dcN N is the rated DC voltage of the flexible DC converter. sm This represents the total number of individual bridge arm submodules.

[0096] like Figure 2 As shown in Figures 102, 103, and 104, if the AC side of the converter is in a fault ride-through state, the flag bit B is activated. o When the value changes to 1, an active reactive power disturbance suppression strategy is immediately implemented.

[0097] The method for determining whether the AC side of the converter is in fault ride-through state is as follows: Determine whether the AC fault ride-through state has been entered based on electrical quantities.

[0098] When the voltage amplitude U in the three-phase rotating coordinate system dqm Less than the low voltage setting u dqmlow Or the absolute value U of the sum of the three-phase voltages abcsum Greater than the zero-sequence voltage setting u 0max It is believed that the flexible DC converter has entered an AC fault ride-through state. Among them: , ,u a u b u c This represents the real-time value of the three-phase AC voltage, u. posd u posq This refers to the real-time value of the AC voltage in the dq coordinate system, typically u. dqmlow Take 0.5,u 0max Take 0.1.

[0099] like Figure 2 As shown in Figure 105, the active suppression strategy for reactive power disturbances multiplies each of the original AC reference waves of each bridge arm by an additional coefficient.

[0100] like Figure 2As shown in Figures 103, 102, and 106, if the AC side of the converter exits the fault ride-through state, the time delay T1 flag bit B... o When the change value is 0, the reactive power disturbance active suppression strategy is discontinued.

[0101] The method for determining whether the AC side of the converter has exited fault ride-through status is as follows:

[0102] When the voltage amplitude U in the three-phase rotating coordinate system dqm Greater than the reset voltage setpoint u dqmfg Or the absolute value U of the sum of the three-phase voltages abcsum Less than the asymmetrical fault reset voltage setting u 0fg It is believed that the flexible DC converter has entered an AC fault ride-through state. Wherein: generally u dqmfg Take 0.8,u 0fg Take 0.05.

[0103] like Figure 2 As shown in Figure 105, when the active suppression strategy for reactive power disturbance is implemented, the additional AC reference wave coefficient of each bridge arm is adjusted by using the ratio of the calculated voltage value of the sub-module to the real-time average voltage value of the sub-module after filtering.

[0104] The final reference waveform for each bridge arm is:

[0105]

[0106]

[0107] Where j = a, b, c; i = p, n, U reffinji For the final bridge arm reference wave, U refji U is the original bridge arm reference wave. dvbia_pro DC bias.

[0108] like Figure 2 As shown in Figure 106, when the active suppression strategy for reactive power disturbance is not implemented or is not implemented, the reference wave coefficient of the additional bridge arm is set to 1.

[0109] The present invention also provides an active suppression device for reactive power disturbance during fault ride in a grid-type flexible DC AC system, comprising: Figure 3 The acquisition unit shown in 201, the judgment unit shown in 203, the active suppression unit for reactive power disturbance shown in 204, and the valve control unit shown in 202 are all included.

[0110] The acquisition unit is used to acquire electrical quantities for AC fault ride-through, such as three-phase AC voltage u. a u b u c Three-phase alternating current i a i b i c.

[0111] The judgment unit is used to determine whether the AC fault ride-through or reset state has been entered, whether the active reactive power disturbance suppression strategy is allowed to be activated, and whether the active reactive power disturbance suppression strategy is allowed to be deactivated, including the flag bit B indicating whether the active reactive power disturbance suppression strategy is allowed to be activated. o Timing of the deployment time T1 for the active suppression strategy of displacement and reactive power disturbance.

[0112] The reactive power disturbance active suppression unit adds an additional bridge arm reference wave coefficient k. Mac The calculation.

[0113] The valve control unit calculates the real-time average voltage value of the submodule and the calculated voltage value Uv of the valve control module. avgcal The calculation.

[0114] The beneficial effect of this invention is that voltage fluctuations in the submodule during AC fault ride-through can cause the valve-side voltage to deviate from the ideal reference waveform, such as... Figure 4 As shown in (a) and 4(b), this will cause reactive power disturbance. Using the bridge arm reference wave additional coefficient method proposed in this invention, the submodule voltage fluctuation can be offset, resulting in an ideal valve-side voltage output, such as... Figure 4 As shown in (a) and 4(c), this enables the grid-type converter to output reactive power with ideal grid characteristics during AC fault ride-through.

[0115] The reactive power disturbance active suppression method of this invention effectively counteracts the impact of submodule voltage fluctuations on reactive power output by adding a suppression factor to the AC reference waveform of the bridge arm. During AC fault ride-through, it ensures that the converter outputs ideal reactive power, thereby maintaining the stable operation of the power grid. By dynamically adjusting the suppression factor, it can adapt to different fault types and voltage fluctuations, ensuring effective suppression of reactive power disturbances under various complex operating conditions. This active reactive power disturbance suppression method significantly improves the reactive power stability of flexible DC transmission systems during AC fault ride-through, enhances system reliability, and provides strong protection for the safe operation of the power grid.

[0116] This invention also provides an active reactive power disturbance suppression system for performing the active reactive power disturbance suppression method described above. Figure 5 This is a block diagram of a reactive power disturbance active suppression system according to an embodiment of the present invention. The system includes:

[0117] The data acquisition module 31 is used to acquire the voltage reference data of the sub-module of the voltage regulation module in the target flexible DC transmission system.

[0118] The status judgment module 32 is used to judge the converter status of the target flexible DC transmission system based on the voltage reference data of the submodule, and obtain the fault ride-through status judgment result.

[0119] The disturbance suppression module 33 is used to activate the active reactive disturbance suppression strategy if the fault ride-through state judgment result is that the AC side of the converter is in the fault ride-through state. The active reactive disturbance suppression strategy is designed to add a suppression factor to the AC reference wave of the bridge arm during the control process.

[0120] The voltage regulation module includes a bridge arm module and a valve control module, and the submodule voltage reference data includes the real-time average voltage value of the submodule and the calculated voltage value of the submodule.

[0121] The data acquisition module is specifically used for:

[0122] Obtain the real-time average voltage values ​​of the sub-modules of each bridge arm module and the calculated voltage values ​​of the sub-modules of the valve control module in the target flexible DC transmission system.

[0123] The calculation process for the submodule voltage value is as follows:

[0124] Determine the rated voltage type of the valve control module. If the rated voltage type is fixed rated voltage, then the calculated voltage value of the submodule is the fixed rated voltage.

[0125] If the rated voltage type is variable rated voltage, the variable rated voltage is dynamically adjusted according to the number of bridge arm sub-modules in the bridge arm module, and the calculated value of the sub-module voltage is the variable rated voltage.

[0126] The status determination module is specifically used for:

[0127] Calculate the voltage amplitude and absolute value of the three-phase voltage in the three-phase rotating coordinate system based on the voltage reference data of the submodule;

[0128] If the voltage amplitude is less than the preset low voltage setting, or the absolute value of the three-phase voltage is greater than the preset zero-sequence voltage setting, then the AC side of the converter of the target flexible DC transmission system is determined to be in a fault ride-through state; otherwise, the AC side of the converter of the target flexible DC transmission system is determined not to be in a fault ride-through state.

[0129] The addition of a suppression factor to the AC reference wave of the bridge arm during the control process is expressed as follows:

[0130]

[0131]

[0132] Where j = a, b, c; i = p, n; U reffinji For the final bridge arm reference wave, U refji U is the original bridge arm reference wave. dvbia_pro DC bias; Uvavgcal This is the calculated voltage value for the submodule; Uv jiSUM The normal submodule voltage of phase i bridge arm and N; vji The number of normal submodules in phase i bridge arm.

[0133] The system also includes an exit suppression module, specifically used for:

[0134] When the fault ride-through state judgment result indicates that the AC side of the converter is not in a fault ride-through state, timing begins. When the timing duration reaches the preset delay interval, the suppression factor in the AC reference wave of the bridge arm is removed to exit the active reactive power disturbance suppression strategy.

[0135] The calculation process for the suppression factor in the active reactive power disturbance suppression strategy is as follows:

[0136] Based on the submodule voltage reference data, calculate the voltage regulation coefficient of each bridge arm submodule. The voltage regulation coefficient is the ratio of the calculated submodule voltage value to the real-time average voltage value of each bridge arm submodule.

[0137] The suppression factor is the reciprocal of the voltage regulation coefficient and is used to adjust the AC reference wave of the bridge arm to offset the effect of submodule voltage fluctuations on reactive power output.

[0138] The technical features and effects of the system proposed in the embodiments of the present invention are the same as those of the method proposed in the embodiments of the present invention, and will not be repeated here. Each module in the above system can be implemented entirely or partially through software, hardware, or a combination thereof. Each module can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0139] See Figure 6 This is a structural block diagram of a computer device provided in an embodiment of the present invention. The computer device provided in this embodiment includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the steps in the active reactive power disturbance suppression method embodiment described above, for example... Figure 1 Steps S11 to S14 as described above; or, when the processor executes the computer program, it implements the functions of each module in the above-described device embodiments, such as modules 31 to 34 of the reactive power disturbance active suppression method system.

[0140] For example, the computer program may be divided into one or more modules, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in the computer device.

[0141] The computer device may include, but is not limited to, a processor and memory. Those skilled in the art will understand that the schematic diagram is merely an example of a computer device and does not constitute a limitation on the computer device. It may include more or fewer components than illustrated, or combine certain components, or different components. For example, the computer device may also include input / output devices, network access devices, buses, etc.

[0142] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the computer device, connecting various parts of the computer device via various interfaces and lines.

[0143] The memory can be used to store the computer programs and / or modules. The processor implements various functions of the computer device by running or executing the computer programs and / or modules stored in the memory and by calling data stored in the memory. The memory may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created according to the use of the mobile phone (such as audio data, phonebook, etc.). In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0144] If the modules integrated into the computer device are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0145] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0146] Accordingly, embodiments of the present invention provide a computer-readable storage medium, the computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to perform steps in the reactive power disturbance active suppression method of the above embodiments, for example... Figure 1 Steps S11 to S14 as described above.

[0147] In summary, compared with the prior art, the active suppression method, system, computer device, and computer-readable storage medium provided by the embodiments of the present invention have the following beneficial effects:

[0148] By adding a suppression factor to the AC reference waveform of the bridge arm, the impact of submodule voltage fluctuations on reactive power output can be effectively offset. During AC fault ride-through, the converter can be guaranteed to output ideal reactive power, thereby maintaining the stable operation of the power grid. By dynamically adjusting the suppression factor, it can adapt to different fault types and voltage fluctuations, ensuring effective suppression of reactive power disturbances under various complex operating conditions. This invention's active reactive power disturbance suppression method can significantly improve the reactive power stability of flexible DC transmission systems during AC fault ride-through, enhance system reliability, and provide strong protection for the safe operation of the power grid.

[0149] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for actively suppressing reactive power disturbances, characterized in that, include: Obtain voltage reference data for sub-modules of the voltage regulation module in the target flexible DC transmission system; The converter status of the target flexible DC transmission system is judged based on the voltage reference data of the submodule, and the fault ride-through status judgment result is obtained. If the fault ride-through state judgment result is that the AC side of the converter is in a fault ride-through state, then the active suppression strategy for reactive power disturbance is put into operation. The active suppression strategy for reactive power disturbance is designed to add a suppression factor to the AC reference wave of the bridge arm during the control process. The addition of a suppression factor to the AC reference wave of the bridge arm during the control process is expressed as follows: in, j = a , b , c ; i = p , n ; U reffinji For the final bridge arm reference wave, U refji The original bridge arm reference wave, U dvbia_pro DC bias; Uv avgcal This is the calculated voltage value for the submodule. Uv jiSUM for j Mutually i The normal submodule voltage of the bridge arm; N vji for j Mutually i The number of normal submodules in the bridge arm; The calculation process of the suppression factor in the active reactive power disturbance suppression strategy is as follows: Based on the submodule voltage reference data, calculate the voltage regulation coefficient of each bridge arm submodule. The voltage regulation coefficient is the ratio of the calculated submodule voltage value to the real-time average voltage value of each bridge arm submodule. The suppression factor is the reciprocal of the voltage regulation coefficient and is used to adjust the AC reference wave of the bridge arm to offset the effect of submodule voltage fluctuations on reactive power output.

2. The active suppression method for reactive power disturbance as described in claim 1, characterized in that, The voltage regulation module includes a bridge arm module and a valve control module, and the submodule voltage reference data includes the real-time average voltage value of the submodule and the calculated voltage value of the submodule. The acquisition of submodule voltage reference data of the voltage regulation module in the target flexible DC transmission system includes: Obtain the real-time average voltage values ​​of the sub-modules of each bridge arm module and the calculated voltage values ​​of the sub-modules of the valve control module in the target flexible DC transmission system.

3. The active suppression method for reactive power disturbance as described in claim 2, characterized in that, The calculation process for the submodule voltage value is as follows: Determine the rated voltage type of the valve control module. If the rated voltage type is fixed rated voltage, then the calculated voltage value of the submodule is the fixed rated voltage. If the rated voltage type is variable rated voltage, the variable rated voltage is dynamically adjusted according to the number of bridge arm sub-modules in the bridge arm module, and the calculated value of the sub-module voltage is the variable rated voltage.

4. The active suppression method for reactive power disturbance as described in claim 1, characterized in that, The step of judging the converter status of the target flexible DC transmission system based on the submodule voltage reference data to obtain the fault ride-through status judgment result includes: Calculate the voltage amplitude and absolute value of the three-phase voltage in the three-phase rotating coordinate system based on the voltage reference data of the submodule; If the voltage amplitude is less than the preset low voltage setting, or the absolute value of the three-phase voltage is greater than the preset zero-sequence voltage setting, then the AC side of the converter of the target flexible DC transmission system is determined to be in a fault ride-through state; otherwise, the AC side of the converter of the target flexible DC transmission system is determined not to be in a fault ride-through state.

5. The active suppression method for reactive power disturbance as described in claim 1, characterized in that, The method further includes: if the fault ride-through state determination result indicates that the AC side of the converter is not in a fault ride-through state, then the reactive power disturbance active suppression strategy is exited. When the fault ride-through state judgment result indicates that the AC side of the converter is not in a fault ride-through state, timing begins. When the timing duration reaches the preset delay interval, the suppression factor in the AC reference wave of the bridge arm is removed to exit the active reactive power disturbance suppression strategy.

6. A reactive power disturbance active suppression system, characterized in that, include: The data acquisition module is used to acquire voltage reference data of the sub-modules of the voltage regulation module in the target flexible DC transmission system; The status judgment module is used to judge the converter status of the target flexible DC transmission system based on the voltage reference data of the submodule, and obtain the fault ride-through status judgment result. The disturbance suppression module is used to activate the active reactive disturbance suppression strategy if the fault ride-through state judgment result is that the AC side of the converter is in the fault ride-through state. The active reactive disturbance suppression strategy is designed to add a suppression factor to the AC reference wave of the bridge arm during the control process. The addition of a suppression factor to the AC reference wave of the bridge arm during the control process is expressed as follows: in, j = a , b , c ; i = p , n ; U reffinji For the final bridge arm reference wave, U refji The original bridge arm reference wave, U dvbia_pro DC bias; Uv avgcal This is the calculated voltage value for the submodule. Uv jiSUM for j Mutually i The normal submodule voltage of the bridge arm; N vji for j Mutually i The number of normal submodules in the bridge arm; The calculation process of the suppression factor in the active reactive power disturbance suppression strategy is as follows: Based on the submodule voltage reference data, calculate the voltage regulation coefficient of each bridge arm submodule. The voltage regulation coefficient is the ratio of the calculated submodule voltage value to the real-time average voltage value of each bridge arm submodule. The suppression factor is the reciprocal of the voltage regulation coefficient and is used to adjust the AC reference wave of the bridge arm to offset the effect of submodule voltage fluctuations on reactive power output.

7. A computer device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor, when executing the computer program, implements the active reactive power disturbance suppression method as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, wherein when the device containing the computer-readable storage medium executes the computer program, it implements the active suppression method for reactive power disturbance as described in any one of claims 1 to 5.

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