Control method, device and equipment of high-voltage direct-current power transmission system and medium

Abstract

The invention relates to the technical field of high-voltage direct-current control, and provides a control method, device and equipment of a high-voltage direct-current power transmission system and a medium, and the method comprises the steps: carrying out the evaluation calculation of a predicted power curve in a preset stable control time window, and obtaining the target effective direct-current power; calculating a filter group number fixed value and a converter transformer tap gear fixed value in a preset stable control time window; calculating a reactive power exchange constant value of the preset converter station and the alternating current system in the preset stable control time window; if the reactive power exchange constant value meets the preset reactive power exchange condition, adjusting the number of filter input groups to be a filter group number constant value, and adjusting the tap gear of the converter transformer to be a tap gear constant value of the converter transformer; and if the reactive power exchange constant value does not meet the preset reactive power exchange condition, recalculating the filter group number constant value and the converter transformer tap gear constant value. According to the invention, the problem that the AC filter and the converter transformer tap need to frequently reciprocate and cannot adapt to the power regulation requirement of the power market can be solved.

Description

Technical Field

[0001] This application relates to the field of high voltage direct current (HVDC) control technology, and in particular to a control method for a HVDC transmission system, a control device for a HVDC transmission system, a corresponding electronic device, and a corresponding computer-readable storage medium. Background Technology

[0002] High-voltage direct current (HVDC) transmission technology has become a core means of cross-regional interconnection of modern power grids due to its significant advantages in long-distance and large-capacity power transmission, and plays an important role in projects such as the West-to-East Power Transmission Project.

[0003] With the deepening of global power market reforms and the high proportion of renewable energy integration, the role of high-voltage direct current (HVDC) transmission projects is undergoing a fundamental transformation. They are gradually evolving from simple "power transmission channels" into market-oriented resources that combine power regulation, frequency support, and reserve sharing. Based on domestic and international market clearing results, HVDC projects need to respond to dispatch commands within minutes or even seconds, and the regulation range has expanded from the traditional ±10% to over ±50% of rated power. The amplitude and frequency of power regulation in HVDC projects have increased significantly, making traditional control strategies insufficient to meet these growing demands. When HVDC projects undertake high-frequency, wide-range power regulation tasks, their classic... The control paradigm reveals structural flaws: Under classical control, the DC voltage remains constant, and the DC power is adjusted by changing the DC current. However, the DC current needs to be adjusted by changing the firing angle of each converter station. Since the firing angle of the converter station has a limited range of variation, when the power range changes significantly, it is necessary to adjust the tap position of the converter transformer to regulate its valve-side voltage, thereby ensuring that the firing angle fluctuation meets the requirements while adjusting the DC power. In addition, when the high-voltage DC power changes, the reactive power consumed and the harmonic current will also change. In order to reduce the impact on the AC system, the number of AC filter banks usually needs to be adjusted accordingly.

[0004] However, frequent and wide-range adjustments to DC power will be accompanied by frequent reciprocating movements of the converter transformer taps and AC filters, which will reduce the service life of the equipment and increase the difficulty of operation and maintenance. Summary of the Invention

[0005] This application provides a control method, device, equipment, and medium for a high-voltage direct current (HVDC) transmission system. It can solve the problem that when the power of a HVDC system is frequently adjusted over a wide range, the AC filter and converter transformer taps need to operate frequently and repeatedly, which makes it unable to adapt to the power regulation requirements of the power market. It can achieve efficient, flexible, and wide-range adjustment of HVDC power and meet the functional requirements of the power market.

[0006] In one aspect, this application provides a control method for a high-voltage direct current transmission system, the method comprising:

[0007] Acquire AC / DC system data and electricity market strategies, and generate predicted power curves based on the AC / DC system data and each of the electricity market strategies;

[0008] The predicted power curve within the preset stable control time window is evaluated and calculated to obtain the target effective DC power; the target effective DC power is used to indicate the power point where the power level lasts for a longer period than the operating time of the converter transformer taps and AC filter bank.

[0009] Based on the target effective DC power, the filter group number set value and the converter transformer tap position set value within the preset stable control time window are calculated.

[0010] Calculate the reactive power exchange setpoints of the preset converter station and AC system within the preset stable control time window;

[0011] If the reactive power exchange setpoint meets the preset reactive power exchange conditions, then the number of filter groups in the high voltage direct current transmission system is adjusted to the filter group number setpoint, and the converter transformer tap position in the high voltage direct current transmission system is adjusted to the converter transformer tap position setpoint.

[0012] If the reactive power exchange setpoint does not meet the preset reactive power exchange condition, then the filter group number setpoint and the converter transformer tap position setpoint are recalculated.

[0013] In some embodiments of this application, the step of calculating the filter bank number setpoint and converter transformer tap position setpoint within the preset stable control time window based on the target effective DC power includes:

[0014] Starting from the actual tap position at the beginning of the preset stable control time window, calculate the filter group number set value and the converter transformer tap position set value based on the target effective DC power.

[0015] If the set value of the converter transformer tap does not meet the preset first condition, the set value of the converter transformer tap will be adjusted step by step.

[0016] If the filter group number setting does not meet the preset second condition, the filter group number setting is adjusted step by step.

[0017] In some embodiments of this application, the stepwise adjustment of the converter transformer tap position setting includes...

[0018] When the rectifier station firing angle and inverter station shutdown angle in the converter angle exceed the minimum allowable range, the converter transformer tap position setting is downgraded based on the preset converter transformer tap pitch.

[0019] When the rectifier station trigger angle in the converter angle is higher than 90°, the converter transformer tap position setting is upgraded based on the preset converter transformer tap distance.

[0020] In some embodiments of this application, the stepwise adjustment of the filter bank number setting includes:

[0021] When the filter group number set value is greater than the upper limit threshold in the preset second condition, the filter group number set value is decremented by one.

[0022] When the filter group number is less than the lower threshold in the preset second condition, the filter group number is incremented by one.

[0023] In some embodiments of this application, the preset first condition is that the converter transformer tap position setting is within the adjustment range of the preset first tap position threshold and the preset second tap position threshold, and the per-unit value of the converter transformer valve side voltage does not exceed the preset allowable threshold.

[0024] The preset second condition is:

[0025]

[0026] Where, N acf Set a value for the number of filter banks within the preset stable control time window; Q con Q represents the reactive power consumed by the converter. acf0 Q represents the reactive power capacity of a filter group at rated voltage. acmin and Q acmax These are the minimum and maximum allowable values ​​for reactive power exchange, respectively; U1 is the per-unit value of AC voltage on the converter transformer side.

[0027] In some embodiments of this application, calculating the reactive power exchange setpoints of the preset converter station and AC system within the preset stable control time window includes:

[0028] Using the predicted power curve, the filter group number setpoint, and the converter transformer tap position setpoint within the preset stable control time window, the preset reactive power exchange setpoint of the converter station and AC system within the preset stable control time window is calculated.

[0029] In some embodiments of this application, after adjusting the number of filter banks in the high-voltage direct current transmission system to the set value of the number of filter banks and adjusting the tap position of the converter transformer in the high-voltage direct current transmission system to the set value of the converter transformer tap position, the method further includes:

[0030] Acquire real-time system data, and calculate the system DC voltage reference value and system current reference value based on the real-time system data;

[0031] The converter angle is calculated based on the system DC voltage reference value and the system current reference value, and then adjusted accordingly.

[0032] If the reactive power and harmonics absorbed by the preset converter station do not exceed the standard, then keep the number of filter groups and the tap position of the converter transformer unchanged until the next DC power reference point.

[0033] If the pre-set reactive power and harmonics absorption of the converter station exceed the standard, the filter group number setting and the converter transformer tap position setting will be recalculated.

[0034] On the other hand, this application provides a control device for a high-voltage direct current transmission system, the device comprising:

[0035] The predicted power curve generation module is used to acquire AC / DC system data and electricity market strategies, and generate a predicted power curve based on the AC / DC system data and each of the electricity market strategies.

[0036] The target effective DC power calculation module is used to evaluate and calculate the predicted power curve within a preset stable control time window to obtain the target effective DC power; the target effective DC power is used to indicate the power point where the power level lasts for a longer period than the operating time of the converter transformer taps and AC filter bank.

[0037] The control setpoint calculation module is used to calculate the filter group number setpoint and converter transformer tap position setpoint within the preset stable control time window based on the target effective DC power.

[0038] The reactive power exchange setpoint calculation module is used to calculate the reactive power exchange setpoint of the preset converter station and AC system within the preset stable control time window;

[0039] The control value adjustment module is used to adjust the number of filter groups in the high-voltage direct current transmission system to the filter group number set value and the converter transformer tap position to the converter transformer tap position set value when the reactive power exchange set value meets the preset reactive power exchange conditions; and to recalculate the filter group number set value and the converter transformer tap position set value when the reactive power exchange set value does not meet the preset reactive power exchange conditions.

[0040] In some embodiments of this application, the control setpoint calculation module includes:

[0041] The control setpoint calculation submodule is used to calculate the filter group number setpoint and converter transformer tap position setpoint based on the target effective DC power, starting from the actual tap position at the beginning of the preset stable control time window; if the converter transformer tap position setpoint does not meet the preset first condition, the converter transformer tap position setpoint is adjusted step by step; if the filter group number setpoint does not meet the preset second condition, the filter group number setpoint is adjusted step by step.

[0042] In some embodiments of this application, the control setpoint calculation submodule includes:

[0043] The gear setting adjustment unit is used to downgrade the converter transformer tap gear setting based on a preset converter transformer tap pitch when the rectifier station firing angle and inverter station shutdown angle in the converter angle exceed the minimum allowable range; and to upgrade the converter transformer tap gear setting based on a preset converter transformer tap pitch when the rectifier station firing angle in the converter angle is higher than 90°.

[0044] In some embodiments of this application, the control setpoint calculation submodule includes:

[0045] The filter group number setting adjustment unit is used to decrement the filter group number setting by one when the filter group number setting is greater than the upper limit threshold in the preset second condition; and to increment the filter group number setting by one when the filter group number setting is less than the lower limit threshold in the preset second condition.

[0046] In some embodiments of this application, the preset first condition is that the converter transformer tap position setting is within the adjustment range of the preset first tap position threshold and the preset second tap position threshold, and the per-unit value of the converter transformer valve side voltage does not exceed the preset allowable threshold.

[0047] The preset second condition is:

[0048]

[0049] Where, N acf Set a value for the number of filter banks within the preset stable control time window; Q con Q represents the reactive power consumed by the converter. acf0 Q represents the reactive power capacity of a filter group at rated voltage. acmin and Q acmax These are the minimum and maximum allowable values ​​for reactive power exchange, respectively; U1 is the per-unit value of AC voltage on the converter transformer side.

[0050] In some embodiments of this application, the reactive power exchange setpoint calculation module includes:

[0051] The reactive power exchange setpoint calculation submodule is used to calculate the reactive power exchange setpoint of the preset converter station and AC system within the preset stable control time window by using the predicted power curve, the filter group number setpoint, and the converter transformer tap position setpoint within the preset stable control time window.

[0052] In some embodiments of this application, after adjusting the number of filter banks in the high-voltage direct current transmission system to the set value of the number of filter banks, and adjusting the tap position of the converter transformer in the high-voltage direct current transmission system to the set value of the converter transformer tap position, the device includes:

[0053] The real-time adjustment module is used to acquire real-time system data, calculate the system DC voltage reference value and system current reference value based on the real-time system data, calculate the converter angle based on the system DC voltage reference value and system current reference value, and make corresponding adjustments according to the converter angle; if the preset reactive power absorption and harmonics of the converter station do not exceed the standard, the number of filter groups and the tap position of the converter transformer remain unchanged until the next DC power reference point; if the preset reactive power absorption and harmonics of the converter station exceed the standard, the set value of the number of filter groups and the set value of the tap position of the converter transformer are recalculated.

[0054] In another aspect, this application also provides an electronic device, including: a processor, a memory, and a computer program stored in the memory and capable of running on the processor, wherein the computer program, when executed by the processor, implements the control method of any of the high-voltage direct current transmission systems described in the present application.

[0055] In another aspect, this application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the control method for any of the high-voltage direct current transmission systems described in the present invention.

[0056] In another aspect, this application also provides a computer program product containing instructions that, when run on a computer, cause the computer to perform the control method for the high-voltage direct current transmission system described in the above aspects.

[0057] The control method, apparatus, equipment, and storage medium for high-voltage direct current (HVDC) transmission systems provided in this application, when designing the control of HVDC transmission systems, comprehensively calculate and evaluate the required converter transformer tap positions and AC filter group numbers at the DC power point based on the predicted power curve required by the power market. This yields scientifically reasonable converter transformer tap position settings and filter group number settings, ensuring that the number of converter transformer taps and AC filter groups remains as constant as possible when the DC power is frequently adjusted over a wide range. Furthermore, it ensures that the reactive power exchange between the converter station and the AC system is within the allowable range. This solves the problem that the AC filters and converter transformer taps of the HVDC system need to frequently reciprocate during frequent and wide-range power adjustments, making it unable to adapt to the power market's power adjustment requirements. This achieves efficient, flexible, and wide-range adjustment of HVDC power, meeting the functional needs of the power market. Attached Figure Description

[0058] Figure 1 This is a schematic diagram showing the characteristics of the tap position of the high-voltage DC converter transformer as a function of DC power under conventional control.

[0059] Figure 2 This is a schematic diagram showing the variation of the number of AC filter banks with DC power under conventional control when a high-voltage DC power supply is applied.

[0060] Figure 3 This is a flowchart illustrating the steps of a control method for a high-voltage direct current transmission system provided in an embodiment of this application.

[0061] Figure 4 This is a schematic diagram of the control process of a high-voltage direct current transmission system provided in an embodiment of this application;

[0062] Figure 5 This is a schematic diagram illustrating the calculation process for the lowest tap level provided in an embodiment of this application;

[0063] Figure 6 This is a schematic diagram illustrating the characteristics of the tap position of the high-voltage DC converter transformer as a function of DC power under the control method provided in the embodiments of this application.

[0064] Figure 7 This is a schematic diagram illustrating the variation characteristics of the number of AC filter groups connected to high voltage direct current as a function of DC power under the control method provided in the embodiments of this application.

[0065] Figure 8 This is a schematic diagram illustrating the variation of the number of high-voltage DC input filter groups with DC power under the control method provided in the embodiments of this application;

[0066] Figure 9 This is a structural block diagram of a control device for a high-voltage direct current transmission system provided in an embodiment of this application;

[0067] Figure 10 This is a structural block diagram of an electronic device provided in an embodiment of this application;

[0068] Figure 11 This is a structural block diagram of a computer-readable storage medium provided in an embodiment of this application. Detailed Implementation

[0069] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0070] The main function of a high-voltage direct current (HVDC) system is to achieve efficient and reliable power transmission. Therefore, its system design must adhere to principles of high efficiency and high reliability. Specifically, this means: 1) The DC line voltage must be maintained stably at the rated value to ensure that the line current is minimized under a given power, thereby reducing ohmic losses and improving transmission efficiency; 2) The converter firing angle must be strictly constrained. The operating range of the rectifier side firing angle and the inverter side turn-off angle must be controlled near the rated value, and the fluctuation should generally not exceed 5°. This is to minimize the reactive power exchanged between the converter station and the AC system, reduce disturbances to the grid voltage, and through the coordination of fixed angle control, minimize the switching frequency of the AC filter bank and the adjustment frequency of the converter transformer tap changer, thereby extending the life of key equipment.

[0071] When the high-voltage direct current (HVDC) power changes, its reactive power consumption and harmonic current also change. To minimize the impact on the AC system, the number of AC filter banks typically adjusted accordingly. However, frequent and large-scale adjustments to the DC power will result in frequent reciprocating operations of the converter transformer tap changer and AC filters. For example, under conventional control methods, when the DC power changes, the converter transformer tap positions and the number of filter banks will change significantly. Typical changes may be as follows: Figure 1 and Figure 2 As shown, where, Figure 1 The main feature shown is the characteristic of the tap position of the high-voltage DC converter transformer as a function of DC power under conventional control. Figure 2 This mainly illustrates the characteristics of the number of AC filter banks connected to a high-voltage DC system under conventional control as a function of DC power. When DC power fluctuates frequently, tap positions and filters require frequent switching operations, which reduces the lifespan of the equipment and increases the difficulty of operation and maintenance. In addition, the long response time of tap changer operation and filter switching will affect the frequency and amplitude of power adjustment to some extent. For example, after an AC filter is disconnected, it takes about ten minutes to discharge before it can be put back into use, which creates a certain power adjustment blind spot and affects the flexibility of power adjustment.

[0072] Based on the changing functional roles of high-voltage direct current (HVDC) projects, this application's embodiments shift the design philosophy of HVDC from prioritizing transmission efficiency to a comprehensive optimization design that balances efficiency and flexibility. Specifically, considering that when power needs frequent and wide-range adjustments, the transmitted power of HVDC is already significantly lower than the rated transmission capacity, sacrificing adjustment flexibility to ensure stringent transmission efficiency targets has limited impact on improving overall system efficiency. This application's embodiments can appropriately relax transmission efficiency requirements, i.e., loosen the hard constraint of DC voltage being at the rated voltage, proactively widen the voltage control range during power regulation, establish a dynamic voltage allowable range, and obtain power change trend prediction information from the electricity market to pre-lock the converter transformer tap positions and AC filter groups in optimal positions for continuous operation, reducing the number of operations, improving equipment lifespan and power regulation flexibility, and thus proposing a power-flexible and equipment-lifespan-friendly HVDC control architecture that adapts to the needs of the electricity market.

[0073] Specifically, during the control design of a high-voltage direct current (HVDC) transmission system, the required converter transformer tap positions and the number of AC filter banks at the DC power point can be comprehensively calculated and evaluated based on the predicted power curve demanded by the power market. This yields scientifically reasonable converter transformer tap position settings and filter bank settings, ensuring that the number of converter transformer taps and AC filter banks remains as constant as possible when the DC power is frequently adjusted over a wide range. Furthermore, the reactive power exchange between the converter station and the AC system is pre-set within allowable limits. This addresses the issue of the AC filters and converter transformer taps needing to frequently reciprocate during frequent and large-scale power adjustments in the HVDC system, which would otherwise be unable to adapt to the power market. Addressing the issue of power regulation requirements, enhancing the power regulation capabilities of high-voltage direct current (HVDC) transmission systems, especially when DC power needs to be adjusted frequently and over a wide range, allows AC filter circuit breakers and converter transformer taps to remain constant. This not only reduces the number of switching operations, lowers equipment maintenance costs, and extends equipment lifespan, but also saves time on converter transformer tap and circuit breaker operations and AC filter discharge during frequent power adjustments. The speed and flexibility of HVDC power regulation are significantly improved, significantly enhancing the ability of HVDC projects to adapt to frequent and drastic power adjustments in the spot electricity market, further expanding the functional role of HVDC, and strengthening the overall power regulation capabilities of the power grid and the capacity for renewable energy absorption.

[0074] Reference Figure 3 The diagram illustrates a flowchart of the control method for a high-voltage direct current transmission system according to an embodiment of this application, which may specifically include the following steps:

[0075] Step S301: Obtain AC / DC system data and electricity market strategies, and generate predicted power curves based on the AC / DC system data and various electricity market strategies.

[0076] The acquired AC / DC system data may include AC system voltage data, converter transformer ratio, short-circuit impedance, preset converter transformer tap spacing, upper and lower limits of converter transformer taps, DC rated voltage, DC rated current, AC filter type and number of groups, etc.

[0077] To clarify electricity market requirements, this embodiment of the application generates a projected power curve for a future period based on AC / DC system data and various electricity market strategies. This projected power curve can serve as input for assessing future power fluctuation levels, enabling a comprehensive calculation and evaluation of the converter transformer tap positions and AC filter group deployment requirements of the HVDC transmission system at the DC power point. It should be noted that this embodiment of the application does not limit the specific process for generating the projected power curve.

[0078] Step S302: Evaluate and calculate the predicted power curve within the preset stable control time window to obtain the target effective DC power.

[0079] For the assessment of demand for high-voltage direct current transmission systems, the first step is to evaluate and calculate the predicted power curve within a preset stable control time window to obtain the target effective DC power.

[0080] Within the preset stable control time window T, the high-voltage direct current can adopt the control method provided in the embodiments of this application to ensure the stable operation of the DC transmission system during power adjustment based on subsequent steps, while the converter transformer taps and AC filters remain unchanged.

[0081] Optionally, the preset stable control time window T can be determined based on actual conditions. For example, it can be set based on historical experience. If the DC power fluctuates drastically and regularly within a certain time period each day, this time period can be set as the preset stable control time window T. For instance, if the DC power fluctuates drastically and frequently within a certain two-hour period each day, the preset stable control time window T can be set to the aforementioned two-hour period. As another example, if the daily DC power fluctuations are irregular, but the confidence period for power prediction is within the next two hours, the preset stable control time window T can also be set to two hours, and then calculated and adjusted every two hours. As yet another example, from an equipment management perspective, assuming the maintenance unit expects the DC transmission system's filters and converter transformer taps to operate a maximum of six times a day, the preset stable control time window T can be set to four hours. In other words, the preset stable control time window T can be adjusted and set according to actual needs to meet different technical and management requirements, and this application does not impose any limitations on this.

[0082] In some embodiments of this application, the target effective DC power refers to the highest value of the effective DC power within a preset stable control time window, i.e., the highest effective DC power P. dmax Maximum effective DC power P dmax Specifically, it can be used to indicate the power point where the power level lasts longer than the operating time of the converter transformer taps and AC filter banks, so as to comprehensively calculate and evaluate the demand for converter transformer tap positions and the number of AC filter banks to be put into operation in the HVDC transmission system at the DC power point based on the power point.

[0083] Optionally, DC power fluctuates continuously, but not all fluctuations will trigger the taps and filters to operate. These fluctuations need to persist for a certain period. For example, the activation time of a converter transformer tap is typically 10 seconds, which is the duration for which the rectifier station firing angle or inverter station shut-off angle exceeds the allowable range—that is, the converter transformer tap will only activate after 10 seconds. Similarly, the activation time of an AC filter is typically 5 seconds, which is the duration for which the reactive power exchanged between the converter station and the AC system exceeds the allowable range—that is, the AC filter will only activate after 5 seconds. Therefore, the DC power needs to be maintained for at least 5 seconds to trigger the converter transformer taps or AC filter to operate. The highest effective DC power at this point is the highest power level where the DC power persists for more than 5 seconds.

[0084] Step S303: Based on the target effective DC power, calculate the filter group number set value and the converter transformer tap position set value within the preset stable control time window.

[0085] In this embodiment of the application, the target effective DC power P can be used as a reference. dmax A comprehensive calculation and evaluation of the converter transformer tap positions and AC filter activation requirements of the high-voltage direct current transmission system at the DC power point were conducted to obtain a scientifically reasonable converter transformer tap position N. tap Fixed value and number of filter banks N acf The set value ensures that the number of converter transformer taps and AC filter groups remains as constant as possible when the DC power is frequently and extensively adjusted in the future.

[0086] Among them, the calculated number of filter banks N acf Set value and converter transformer tap position N tap The set value is a set of filter groups and converter transformer tap positions that meet all power levels within the preset stable control time window. This ensures that the filters and taps remain constant when the power changes according to the predicted power curve within the preset stable control time window, and that DC voltage, DC current, reactive power, firing angle, and turn-off angle are all within the allowable range.

[0087] It should be noted that the number of filter banks N acf Set value and converter transformer tap position N tapThe set value can be calculated based on the target effective DC power and other AC / DC system conditions. The specific calculation process is not limited in the embodiments of this application.

[0088] Step S304: Calculate the preset reactive power exchange setpoints of the converter station and AC system within the preset stable control time window.

[0089] Furthermore, the reactive power exchange setpoints of the preset converter station and AC system within the preset stable control time window can be calculated using the predicted power curve, the filter bank number setpoint, and the converter transformer tap position setpoint. Specifically, this can be achieved based on the predicted power curve and the filter bank number N within the preset stable control time window T. acf Set value, commutator tap position N tap Using setpoints and other AC / DC system data, the target setpoint for reactive power exchange between the converter station and the AC system within the preset stable control time window is calculated and determined, i.e., the reactive power exchange setpoint Q. acref The system determines whether the reactive power exchange meets the system requirements based on the calculated reactive power exchange setpoint, and further determines whether the calculated filter group number setpoint and converter transformer tap position setpoint can remain unchanged when the DC power is frequently and widely adjusted.

[0090] Step S305: If the reactive power exchange setting meets the preset reactive power exchange conditions, then adjust the number of filter groups in the high voltage direct current transmission system to the filter group number setting, and adjust the converter transformer tap position of the high voltage direct current transmission system to the converter transformer tap position setting.

[0091] In one case, if the reactive power exchange setpoint satisfies Q acref The preset reactive power exchange conditions indicate that the reactive power exchange meets the system requirements, the converter transformer taps and AC filters remain unchanged, and other major electrical parameters are within the allowable range. At this point, the number of filter banks in the HVDC transmission system can be adjusted to N. acf The set value is used to adjust the converter transformer tap position of the high-voltage direct current transmission system to converter transformer tap position N. tap A constant value.

[0092] Among them, the preset reactive power exchange conditions can refer to the preset reactive power exchange between the converter station and the AC system, which meets the minimum and maximum allowable values ​​of reactive power exchange; under the condition that the aforementioned conditions are met, it is determined that there are feasible reactive power exchange settings.

[0093] It should be noted that since adjusting the converter transformer taps and the number of filter banks takes a long time, the AC / DC system can be adjusted to the initial state in advance. This means that the converter transformer tap positions and the number of AC filter banks can be locked in the optimal positions for continuous operation, reducing the number of operations and improving equipment lifespan and power regulation flexibility.

[0094] Step S306: If the reactive power exchange setting does not meet the preset reactive power exchange conditions, then recalculate the filter group number setting and the converter transformer tap position setting.

[0095] In another case, if the reactive power exchange constant Q acref If the preset reactive power exchange condition is not met, then the number of filter banks N can be recalculated. acf Set value and converter transformer tap position N tap A constant value, and thus a reactive power exchange constant value Q. acref The calculation can be specifically represented by exchanging the reactive power constant Q. acref The values ​​can be gradually adjusted upwards to other values. This application does not limit the specific adjustment method.

[0096] It should be noted that when selecting the reactive power exchange setpoint Q... acref When this is the case, it can be preferentially set to the minimum allowable value Q for reactive power exchange. acmin To minimize reactive power consumption by the converter and ensure the highest possible DC voltage under all operating conditions, thereby reducing harmonics and line losses and improving efficiency; additionally, considering the inherent errors in reactive power control and measurement, to prevent filter activation / deactivation due to reactive power exceeding limits, the reactive power exchange setpoint Q is... acref The minimum allowable value Q for reactive power exchange acmin At this time, a certain disturbance removal margin can be added to the set value, such as 5~10MVar. This application does not limit this.

[0097] Optionally, if a single reactive power exchange setpoint cannot meet the requirements of all power levels within a preset stable control time window, it can be set as different setpoint curves segmented according to DC power levels. For example, if the DC power fluctuation range is large within the preset stable control time window T, such as 0.1 to 1.05 pu, then the reactive power exchange setpoint Q can be adjusted. acref With a setting of 5Mvar, the DC power meets the requirements within the range of 0.1~0.8 pu, but the reactive power exchange setpoint Q is insufficient within the range of 0.8~1.05 pu. acref If 5Mvar is used, it will cause the rectifier station firing angle or DC voltage to exceed the allowable value, such as the rectifier station firing angle exceeding 90° or the DC voltage falling below the allowable value. Therefore, the Q value in the 0.8~1.05pu DC power range can be adjusted. acref The value can be set to another value, such as 10Mvar, but this application embodiment does not limit this.

[0098] In this embodiment of the application, after adjusting the number of filter groups in the high-voltage direct current transmission system to the fixed value of the number of filter groups and adjusting the tap position of the converter transformer in the high-voltage direct current transmission system to the fixed value of the converter transformer tap position, the high-voltage direct current transmission system can be monitored and adjusted in real time to further ensure the stable operation of the high-voltage direct current transmission system.

[0099] In some embodiments of this application, real-time system data, such as power reference value P, can be acquired. dcref Wait, and then you can use real-time system data P dcref And the converter transformer tap position N obtained from the above steps tap Fixed value, number of filter banks N acf Fixed value, reactive power exchange fixed value Q acref From other AC and DC data, the system DC voltage reference value U is calculated. dcref and system current reference value I dcref Then, based on the system DC voltage reference value U... dcref and system current reference value I dcref The converter angle is calculated, which may include the rectifier station firing angle α and the inverter station shutdown angle γ, and adjusted accordingly. At this time, it is possible to monitor and judge in real time whether the reactive power absorption and harmonics of the preset converter station exceed the standard. In one case, if the reactive power absorption and harmonics of the preset converter station do not exceed the standard, the number of filter groups and the tap position of the converter transformer can be kept unchanged, and the system can be stably operated until the next DC power reference point. In another case, if the reactive power absorption and harmonics of the preset converter station exceed the standard, the filter group setting and the converter transformer tap position setting can be recalculated.

[0100] The embodiments of this application can realize flexible, efficient, wide-range and frequent power adjustment of the high voltage direct current system, improve the ability of high voltage direct current to adapt to the frequent and wide-range power adjustment of the power market, expand the functional range of high voltage direct current, and enhance the power regulation and new energy consumption capacity of the large power grid.

[0101] To help those skilled in the art further understand the control method of the high-voltage direct current transmission system provided in the embodiments of this application, the following description is provided in conjunction with the specific control process:

[0102] Reference Figure 4 The diagram illustrates the process of controlling a high-voltage direct current transmission system provided in an embodiment of this application.

[0103] The first step is initialization, which mainly involves inputting AC / DC system data, including AC system voltage data, converter transformer ratio, short-circuit impedance, preset converter transformer tap spacing, converter transformer tap upper and lower limits, DC rated voltage, DC rated current, AC filter type and number of groups, etc.

[0104] The second step is to input the predicted power curve, which can be generated based on AC / DC system data and various electricity market strategies. The generated predicted power curve can serve as an input basis for judging the level of future power fluctuations.

[0105] Step 3 involves inputting a preset stable control time window T, which can be adjusted and set according to actual needs. Within the preset stable control time window T, the high-voltage direct current (HVDC) can employ the control method provided in this application embodiment to ensure stable operation of the DC transmission system during power adjustment, while the converter transformer taps and AC filters remain unchanged, based on subsequent steps.

[0106] Step 4 is to calculate the target effective DC power, i.e., the maximum effective DC power P, within the preset stable control time window T. dmax Specifically, it can refer to the power point where the power level lasts for a period of time exceeding the operating time of the converter transformer taps and AC filter banks.

[0107] Step 5 is to calculate the converter transformer tap position N within the preset smooth control time window T. tap Fixed value and number of filter banks N acf A constant value.

[0108] Specifically, the number of filter banks N can be calculated based on the actual tap position at the start of the preset smooth control time window and the target effective DC power. acf Set value and converter transformer tap position N tap A constant value. Wherein, the number of filter banks N... acf The set value can be determined according to the target effective DC power P within a preset stable control time window T. dmax The number of AC filter banks required to meet the corresponding reactive power balance needs is determined; the number of converter transformer taps N is also determined. tap A fixed value can be obtained by adjusting the lowest tap position N. tapmin The result is obtained by rounding up.

[0109] In some embodiments of this application, if the commutator tap position N tap If the set value does not meet the preset first condition, then the tap position N of the transformer can be swapped. tap The fixed value is adjusted step by step.

[0110] Specifically, when the rectifier station firing angle and inverter station turn-off angle in the converter angle exceed the minimum allowable range (i.e., the firing angle is below 12.5°), the converter transformer tap position setting can be downgraded based on the preset converter transformer tap pitch. This means decreasing the tap position by one based on the preset converter transformer tap pitch for each tap. Conversely, when the rectifier station firing angle in the converter angle is above 90°, the converter transformer tap position setting can be upgraded based on the preset converter transformer tap pitch. This means increasing the tap position by one based on the preset converter transformer tap pitch for each tap. It should be noted that the converter transformer tap position N... tap The adjustment of the set value is generally required to be within the adjustment range of the preset first tap position threshold and the preset second tap position threshold, but this application embodiment does not impose any restrictions on this.

[0111] In some embodiments of this application, if the number of filter banks N acf If the set value does not meet the preset second condition, then the number of filter banks N can be adjusted. acf The fixed value is adjusted step by step.

[0112] Specifically, when the number of filter banks N acf When the set value is greater than the upper threshold in the preset second condition, the number of filter banks N can be adjusted. acf The value is decremented by one; when the number of filter groups N acf When the set value is less than the lower threshold in the preset second condition, the number of filter banks N can be adjusted. acf The constant value is incremented by one. It should be noted that the number of filter banks N... acf The adjustment of the set value is generally required to be within the minimum allowable number of filter groups and the total number of filter groups in the converter station. This application does not impose any restrictions on this.

[0113] Optional, commutator tap position N tap Affecting the voltage U on the converter transformer side v The relationship between the two is shown in the following equation (1):

[0114] (1)

[0115] In the formula, N tap For the commutator tap position, S tep U1 is the preset tap pitch for each tap of the converter transformer, such as 1.25%. U1 is the per-unit value of the AC voltage on the converter transformer grid side. v This is the per-unit value of the AC voltage on the converter transformer side.

[0116] The first preset condition can be that the converter transformer tap setting value is within the adjustment range of the preset first tap setting threshold and the preset second tap setting threshold, and the per-unit value of the converter transformer valve side voltage does not exceed the preset allowable threshold. The preset first tap setting threshold is the lowest tap setting N. tapmin The preset threshold for the second tap level is the highest tap level N. tapmax The preset allowed value is the highest allowed value U. vmax For example, 1.001.

[0117] Optionally, for the preset smooth control time window T, the commutator tap position N tap highest tap position N tapmax The value of N can generally be taken as the highest value in the rheostat tap design. tapmax If the trigger angle is less than the minimum allowable value, such as 5°, then it can be determined in step 5 that there is no feasible Q. acref Jump to step 5 and reduce N by one level. tap Begin a new iterative calculation.

[0118] For the preset stable control time window T, the converter tap position N tap The lowest tap position N tapmin The calculation process can be as follows: Figure 5 As shown, this can be specifically represented by calculating the highest effective grid-side voltage within a preset stable control time window T, i.e., the highest allowable value U, by inputting the predicted voltage curve within the window T. vmax Then, the minimum allowable value of the converter transformer tap position within window T can be calculated, that is, the lowest tap position N. tapmin .

[0119] For example, the lowest tap position N tapmin The specific calculation formula can be shown in the following formula (2):

[0120] (2)

[0121] In this embodiment of the application, the lowest tap position N can be adjusted. tapmin Rounding up gives the commutator tap position N. tap Fixed value. It should be noted that, to cope with additional voltage fluctuations and retain a certain margin, the transformer tap position N should be changed when conditions permit. tap The setpoint can be based on the preset converter transformer tap pitch S for each tap of the converter transformer. tep The embodiments of this application do not limit the possibility of taking one more level up.

[0122] Preset smooth control time window T, number of filter groups N acfThe set value can be determined by the reactive power balance and harmonic filtering requirements at various power levels. Generally, the number of filter banks N is... acf The set value can be based on the highest effective DC power P within window T. dmax The number of AC filter banks required for the corresponding reactive power balance is determined.

[0123] Optionally, the reactive power exchanged between the converter station and the AC system is preset to Q. ac It can be calculated based on the reactive power consumed by the converter and the reactive power provided by the AC filter bank pre-installed in the converter station. For example, the specific expression can be shown in the following formula (3):

[0124] (3)

[0125] In the formula, Q con Q represents the reactive power consumed by the converter. acf The reactive power provided by the AC filter bank for the converter station.

[0126] In equation (3), the reactive power consumed by the converter is Q. con It can be calculated based on the target effective DC power, rated DC voltage, and ideal no-load DC voltage of the converter. For example, the specific expression can be shown in the following equation (4):

[0127] (4)

[0128] In the formula, U dc This is the DC voltage, typically taken as the rated DC voltage; U di0 The ideal no-load DC voltage of the converter is given. This ideal no-load DC voltage is calculated based on the rated effective value of the AC line voltage on the valve side, the per-unit value of the AC voltage on the converter transformer network side, the tap position setting of the converter transformer, and the preset tap spacing of each converter transformer tap. For example, the specific expression can be shown in equation (5) below:

[0129] (5)

[0130] In the formula, U 1N This is the rated effective value of the AC line voltage on the valve side.

[0131] In equation (3), the reactive power value Q provided by the AC filter bank at the converter station is... acf It can be calculated based on the number of filter banks, the reactive power capacity of a filter bank at rated voltage, and the per-unit value of the AC voltage on the converter transformer side. For example, the specific expression can be shown in the following equation (6):

[0132] (6)

[0133] In the formula, Q acf0 This represents the reactive power capacity of a set of filters at rated voltage.

[0134] Optionally, based on requirements such as AC system voltage stability, the reactive power exchanged between the converter station and the AC system must satisfy the constraint relationship of equation (7):

[0135] (7)

[0136] In the formula, Q acmin and Q acmax These are the minimum and maximum allowable values ​​for reactive power exchange, respectively.

[0137] From equations (1) to (7), we can obtain the number of filter banks N. acf The pre-defined second condition that the constant value must satisfy can be shown in the following equation (8):

[0138]

[0139] In the formula, N acf The preset number of filter banks within the stable control time window is set to a certain value; Q con Q represents the reactive power consumed by the converter. acf0 Q represents the reactive power capacity of a filter group at rated voltage. acmin and Q acmax These are the minimum and maximum allowable values ​​for reactive power exchange, respectively; U1 is the per-unit value of AC voltage on the converter transformer side.

[0140] Since the converter can absorb inductive reactive power and its value is adjustable, it is generally only necessary to ensure the maximum DC power P. dmax If the reactive power compensation by the AC filter meets the system requirements, then the maximum number of AC filter banks, N, is... acfmax As shown in equation (9):

[0141] (9)

[0142] In the formula, U 1min To preset the minimum effective value of the grid-side voltage within the stable control time window T, Q con If the maximum reactive power consumed by the converter at each power point within the preset stable control time window T is taken, then the final number of AC filter groups N is determined. acf The constant value can be obtained by rounding up according to equation (9).

[0143] Step 6 is to calculate the reactive power exchange setpoint Q between a converter station and the AC system within the preset stable control time window T. acref .

[0144] Step 7 is to determine if there is a feasible reactive power exchange setpoint Q.acref If a feasible reactive power exchange setpoint Q exists acref If no feasible reactive power exchange setpoint Q exists, proceed to the next step sequentially; acref Then proceed to step 5 and adjust the number of filter banks N. acf Set value and converter transformer tap position N tap After setting the value, the reactive power exchange value Q is then set. acref Recalculate.

[0145] Step 8 is to adjust the number of filter banks in the high-voltage direct current transmission system to the number of filter banks N. acf The set value is used to adjust the converter transformer tap position of the high-voltage direct current transmission system to converter transformer tap position N. tap A constant value.

[0146] Step 9 is to acquire real-time system data, such as the power reference value P. dcref wait.

[0147] Step 10 is to calculate the system DC voltage reference value U. dcref and system current reference value I dcref For example, the specific calculation formulas can be shown in equations (10) and (11) below:

[0148] (10)

[0149] (11)

[0150] Step 11 is to calculate and adjust the converter angle, which can be done based on the U value from step 10. dcref and I dcref The rectifier station firing angle α and inverter station turn-off angle γ are calculated from other AC and DC data, and their specific expressions are shown in equations (12) and (13) below:

[0151] (12)

[0152] (13)

[0153] In the formula, I dN Rated DC current; U dci U is the DC voltage of the inverter station. dioNR and U dioNI The rated ideal no-load DC voltage for the two station converters; U dioR and U dioI U represents the actual ideal no-load DC voltage of the two converter stations; t d is the thyristor voltage drop; n is the number of rectifier bridges, d xr d rr d xi dri These represent the inductive voltage drop and resistive voltage drop of the converter transformer at both ends.

[0154] Step 12 involves real-time monitoring to determine if the reactive power and harmonics absorbed by the preset converter station exceed the limits. If the reactive power and harmonics absorbed by the preset converter station do not exceed the limits, step 13 continues sequentially. If the reactive power and harmonics absorbed by the preset converter station exceed the limits, the process jumps to step 5 for cyclical operation. It should be noted that under normal circumstances, this step will not jump to step 5. Jumping to step 5 for recalculation and setting will only occur when there are significant disturbances or changes in the AC / DC system, such as changes in the nearby AC grid causing significant adjustments in AC voltage amplitude or harmonics injected into the converter station, leading to harmonic exceedances or reactive power exceeding limits, rendering the original settings unable to meet the requirements of the new operating conditions. In this case, the process jumps to step 5 for recalculation and setting. That is, under normal circumstances, the number of filter banks N within the preset stable control time window T... acf Set value and converter transformer tap position N tap The fixed value remains unchanged, and this application does not impose any limitations on it in the embodiments.

[0155] Step 13 is to maintain stable operation until the next DC power reference point, i.e., to maintain the number of filter banks N. acf Set value and converter transformer tap position N tap The constant values, and the converter angles α and γ are maintained.

[0156] Step 14 is to determine whether the preset smooth control time window T has ended. If it has ended, proceed to step 15. If it has not ended, jump to step 9 and continue the loop.

[0157] Step 15 ends the current window.

[0158] In this embodiment of the application, the characteristics of the tap position of the high-voltage DC converter transformer changing with DC power under the control method provided in this embodiment of the application can be as follows: Figure 6 As shown; under the control method provided in this application embodiment, the characteristic of the number of AC filter groups connected to the high-voltage DC power supply changing with the DC power can be as follows: Figure 7 As shown; under the control method provided in this application embodiment, the characteristic of the number of high-voltage DC input filter groups changing with DC power can be as follows. Figure 8 As shown, when the DC power changes, the number of converter transformer taps and the number of filter switching groups can remain constant, and the reactive power absorbed by the converter station from the AC system can remain within the operating range.

[0159] It should be noted that the control method for high voltage direct current transmission systems provided in this application is mainly for high voltage direct current transmission systems, but it can also be used in other situations where thyristor converters are required. That is, the application of the solution proposed in this application to other places outside of DC engineering is also considered to be within the scope of protection of this application.

[0160] In this embodiment, by comprehensively calculating and evaluating the required number of converter transformer tap positions and AC filter groups at the DC power point of the high-voltage direct current (HVDC) transmission system based on the predicted power curve required by the electricity market, scientific and reasonable converter transformer tap position settings and filter group settings are obtained. This ensures that the number of converter transformer taps and AC filter groups remains as constant as possible when the DC power of the HVDC is frequently adjusted over a wide range, and that the reactive power exchange between the converter station and the AC system is within the allowable range. This solves the problem that the AC filters and converter transformer taps of the HVDC system need to frequently reciprocate when the power is frequently adjusted over a wide range, making it unable to adapt to the power adjustment requirements of the electricity market. This achieves efficient, flexible, and wide-range adjustment of HVDC power, meeting the functional requirements of the electricity market.

[0161] It should be noted that, for the sake of simplicity, the method embodiments are all described as a series of actions. However, those skilled in the art should understand that the embodiments of this application are not limited to the described order of actions, because according to the embodiments of this application, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of this application.

[0162] Reference Figure 9 This document illustrates a structural block diagram of a control device for a high-voltage direct current transmission system according to an embodiment of this application. Specifically, it may include the following modules:

[0163] The predicted power curve generation module 901 is used to acquire AC / DC system data and power market strategies, and generate predicted power curves based on the AC / DC system data and various power market strategies.

[0164] The target effective DC power calculation module 902 is used to evaluate and calculate the predicted power curve within a preset stable control time window to obtain the target effective DC power; the target effective DC power is used to indicate the power point where the power level lasts for a longer period than the operating time of the converter transformer taps and AC filter bank.

[0165] The control setpoint calculation module 903 is used to calculate the filter group number setpoint and converter transformer tap position setpoint within the preset stable control time window based on the target effective DC power.

[0166] The reactive power exchange setpoint calculation module 904 is used to calculate the preset reactive power exchange setpoints of the converter station and AC system within the preset stable control time window.

[0167] The control value adjustment module 905 is used to adjust the number of filter groups in the high-voltage direct current transmission system to the filter group number set value and the converter transformer tap position to the converter transformer tap position set value when the reactive power exchange set value meets the preset reactive power exchange conditions; when the reactive power exchange set value does not meet the preset reactive power exchange conditions, it recalculates the filter group number set value and the converter transformer tap position set value.

[0168] In some embodiments of this application, the control setpoint calculation module 903 may include the following sub-modules:

[0169] The control setpoint calculation submodule is used to calculate the filter group number setpoint and converter transformer tap position setpoint based on the target effective DC power, starting from the actual tap position at the beginning of the preset stable control time window. If the converter transformer tap position setpoint does not meet the preset first condition, the converter transformer tap position setpoint is adjusted step by step. If the filter group number setpoint does not meet the preset second condition, the filter group number setpoint is adjusted step by step.

[0170] In some embodiments of this application, the control setpoint calculation submodule may include the following units:

[0171] The tap position setting adjustment unit is used to downgrade the converter transformer tap position setting based on the preset converter transformer tap pitch when the rectifier station firing angle and inverter station shut-off angle in the converter angle exceed the minimum allowable range; and to upgrade the converter transformer tap position setting based on the preset converter transformer tap pitch when the rectifier station firing angle in the converter angle is higher than 90°.

[0172] In some embodiments of this application, the control setpoint calculation submodule may include the following units:

[0173] The filter group number setting adjustment unit is used to decrement the filter group number setting by one when the filter group number setting is greater than the upper limit threshold in the preset second condition; and to increment the filter group number setting by one when the filter group number setting is less than the lower limit threshold in the preset second condition.

[0174] In some embodiments of this application, the first preset condition is that the converter transformer tap position setting is within the adjustment range of the preset first tap position threshold and the preset second tap position threshold, and the per-unit value of the converter transformer valve side voltage does not exceed the preset allowable threshold.

[0175] The second condition is preset as follows:

[0176]

[0177] Where, N acf The preset number of filter banks within the stable control time window is set to a certain value; Q con Q represents the reactive power consumed by the converter.acf0 Q represents the reactive power capacity of a filter group at rated voltage. acmin and Q acmax These are the minimum and maximum allowable values ​​for reactive power exchange, respectively; U1 is the per-unit value of AC voltage on the converter transformer side.

[0178] In some embodiments of this application, the reactive power exchange setpoint calculation module 904 may include the following sub-modules:

[0179] The reactive power exchange setpoint calculation submodule is used to calculate the reactive power exchange setpoint of the preset converter station and AC system within the preset stable control time window by using the predicted power curve, filter group number setpoint, and converter transformer tap position setpoint.

[0180] In some embodiments of this application, after adjusting the number of filter banks in the high-voltage direct current transmission system to a fixed value and adjusting the tap positions of the converter transformer in the high-voltage direct current transmission system to a fixed value, the apparatus provided in this application embodiment may further include the following modules:

[0181] The real-time adjustment module is used to acquire real-time system data, calculate the system DC voltage reference value and system current reference value based on the real-time system data, calculate the converter angle based on the system DC voltage reference value and system current reference value, and make corresponding adjustments according to the converter angle; if the preset reactive power absorption and harmonics of the converter station do not exceed the standard, the number of filter groups and the tap position of the converter transformer remain unchanged until the next DC power reference point; if the preset reactive power absorption and harmonics of the converter station exceed the standard, the filter group setting value and the converter transformer tap position setting value are recalculated.

[0182] In this embodiment, by comprehensively calculating and evaluating the required number of converter transformer tap positions and AC filter groups at the DC power point of the high-voltage direct current (HVDC) transmission system based on the predicted power curve required by the electricity market, scientific and reasonable converter transformer tap position settings and filter group settings are obtained. This ensures that the number of converter transformer taps and AC filter groups remains as constant as possible when the DC power of the HVDC is frequently adjusted over a wide range, and that the reactive power exchange between the converter station and the AC system is within the allowable range. This solves the problem that the AC filters and converter transformer taps of the HVDC system need to frequently reciprocate when the power is frequently adjusted over a wide range, making it unable to adapt to the power adjustment requirements of the electricity market. This achieves efficient, flexible, and wide-range adjustment of HVDC power, meeting the functional requirements of the electricity market.

[0183] As the device embodiment is basically similar to the method embodiment, the description is relatively simple, and relevant parts can be found in the description of the method embodiment.

[0184] This application also provides an electronic device, see embodiments thereof. Figure 10 The provided electronic device 1000 includes a memory 1011, a processor 1020, and a computer program 1011 stored in the memory 1011 and capable of running on the processor 1020. When the computer program 1011 is executed by the processor, it implements the various processes of the control method embodiment of the above-described high voltage direct current transmission system and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0185] This application also provides a computer-readable storage medium, see embodiments thereof. Figure 11 The computer-readable storage medium 1100 provided stores a computer program 1011. When the computer program 1011 is executed by the processor, it implements the various processes of the control method embodiment of the above-described high voltage DC transmission system and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0186] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0187] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of the embodiments of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or modules is not necessarily limited to those steps or modules explicitly listed, but may include other steps or modules not explicitly listed or inherent to these processes, methods, products, or devices. The division of modules in the embodiments of this application is merely a logical division; in actual applications, there may be other division methods. For example, multiple modules may be combined into or integrated into another system, or some features may be ignored or not performed. Additionally, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interface, and the indirect coupling or communication connection between modules may be electrical or other similar forms, none of which are limited in the embodiments of this application. Furthermore, the modules or sub-modules described as separate components may or may not be physically separated, may or may not be physical modules, or may be distributed among multiple circuit modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the embodiments of this application.

[0188] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0189] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and modules described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0190] In the embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, apparatuses, or modules, and may be electrical, mechanical, or other forms.

[0191] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0192] Furthermore, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium.

[0193] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product.

[0194] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0195] This application describes embodiments with reference to flowchart illustrations and / or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0196] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing terminal device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The functions specified in one or more boxes; these computer program instructions may also be loaded onto a computer or other programmable data processing terminal equipment to cause a series of operational steps to be performed on the computer or other programmable terminal equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0197] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0198] Finally, it should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of the relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation portals are provided for users to choose to authorize or refuse.

[0199] The technical solutions provided in the embodiments of this application have been described in detail above. Specific examples have been used in the embodiments of this application to illustrate the principles and implementation methods of the embodiments of this application. The description of the above embodiments is only for the purpose of helping to understand the methods and core ideas of the embodiments of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the embodiments of this application. Therefore, the content of this specification should not be construed as a limitation on the embodiments of this application.

Claims

1. A control method for a high-voltage direct current transmission system, characterized in that, The method includes: Acquire AC / DC system data and electricity market strategies, and generate predicted power curves based on the AC / DC system data and each of the electricity market strategies; The predicted power curve within the preset stable control time window is evaluated and calculated to obtain the target effective DC power; the target effective DC power is used to indicate the power point where the power level lasts for a longer period than the operating time of the converter transformer taps and AC filter bank. Based on the target effective DC power, the filter group number set value and the converter transformer tap position set value within the preset stable control time window are calculated. Calculate the reactive power exchange setpoints of the preset converter station and AC system within the preset stable control time window; If the reactive power exchange setpoint meets the preset reactive power exchange conditions, then the number of filter groups in the high voltage direct current transmission system is adjusted to the filter group number setpoint, and the converter transformer tap position in the high voltage direct current transmission system is adjusted to the converter transformer tap position setpoint. If the reactive power exchange setpoint does not meet the preset reactive power exchange condition, then the filter group number setpoint and the converter transformer tap position setpoint are recalculated.

2. The method according to claim 1, characterized in that, The step of calculating the filter bank number setpoint and converter transformer tap position setpoint within the preset stable control time window based on the target effective DC power includes: Starting from the actual tap position at the beginning of the preset stable control time window, calculate the filter group number set value and the converter transformer tap position set value based on the target effective DC power. If the set value of the converter transformer tap does not meet the preset first condition, the set value of the converter transformer tap will be adjusted step by step. If the filter group number setting does not meet the preset second condition, the filter group number setting is adjusted step by step.

3. The method according to claim 2, characterized in that, The stepwise adjustment of the converter transformer tap position setting includes... When the rectifier station firing angle and inverter station shutdown angle in the converter angle exceed the minimum allowable range, the converter transformer tap position setting is downgraded based on the preset converter transformer tap pitch. When the rectifier station trigger angle in the converter angle is higher than 90°, the converter transformer tap position setting is upgraded based on the preset converter transformer tap distance.

4. The method according to claim 2, characterized in that, The stepwise adjustment of the filter bank number setpoint includes: When the filter group number set value is greater than the upper limit threshold in the preset second condition, the filter group number set value is decremented by one. When the filter group number is less than the lower threshold in the preset second condition, the filter group number is incremented by one.

5. The method according to any one of claims 2 to 4, characterized in that, The preset first condition is that the converter transformer tap position setting is within the adjustment range of the preset first tap position threshold and the preset second tap position threshold, and the per-unit value of the converter transformer valve side voltage does not exceed the preset allowable threshold. The preset second condition is: Where, N acf Set a value for the number of filter banks within the preset stable control time window; Q con Q represents the reactive power consumed by the converter. acf0 Q represents the reactive power capacity of a filter group at rated voltage. acmin and Q acmax These are the minimum and maximum allowable values ​​for reactive power exchange, respectively; U1 is the per-unit value of AC voltage on the converter transformer side.

6. The method according to claim 1, characterized in that, The calculation of the preset reactive power exchange setpoints of the converter station and AC system within the preset stable control time window includes: Using the predicted power curve, the filter group number setpoint, and the converter transformer tap position setpoint within the preset stable control time window, the preset reactive power exchange setpoint of the converter station and AC system within the preset stable control time window is calculated.

7. The method according to claim 1, characterized in that, After adjusting the number of filter banks in the high-voltage direct current transmission system to the set value of the number of filter banks, and adjusting the tap positions of the converter transformers in the high-voltage direct current transmission system to the set values ​​of the converter transformer tap positions, the method further includes: Acquire real-time system data, and calculate the system DC voltage reference value and system current reference value based on the real-time system data; The converter angle is calculated based on the system DC voltage reference value and the system current reference value, and then adjusted accordingly. If the reactive power and harmonics absorbed by the preset converter station do not exceed the standard, then keep the number of filter groups and the tap position of the converter transformer unchanged until the next DC power reference point. If the pre-set reactive power and harmonics absorption of the converter station exceed the standard, the filter group number setting and the converter transformer tap position setting will be recalculated.

8. A control device for a high-voltage direct current transmission system, characterized in that, The device includes: The predicted power curve generation module is used to acquire AC / DC system data and electricity market strategies, and generate a predicted power curve based on the AC / DC system data and each of the electricity market strategies. The target effective DC power calculation module is used to evaluate and calculate the predicted power curve within a preset stable control time window to obtain the target effective DC power; the target effective DC power is used to indicate the power point where the power level lasts for a longer period than the operating time of the converter transformer taps and AC filter bank. The control setpoint calculation module is used to calculate the filter group number setpoint and converter transformer tap position setpoint within the preset stable control time window based on the target effective DC power. The reactive power exchange setpoint calculation module is used to calculate the reactive power exchange setpoint of the preset converter station and AC system within the preset stable control time window; The control value adjustment module is used to adjust the number of filter groups in the high-voltage direct current transmission system to the filter group number set value and the converter transformer tap position to the converter transformer tap position set value when the reactive power exchange set value meets the preset reactive power exchange conditions; and to recalculate the filter group number set value and the converter transformer tap position set value when the reactive power exchange set value does not meet the preset reactive power exchange conditions.

9. An electronic device, characterized in that, include: A processor, a memory, and a computer program stored in the memory and capable of running on the processor, wherein the computer program, when executed by the processor, implements the control method for the high-voltage direct current transmission system as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, which, when executed by a processor, implements the control method for the high-voltage direct current transmission system as described in any one of claims 1 to 7.

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