Virtual inertia collaborative control method and device for water-light complementary power generation system

Abstract

The application provides a virtual inertia collaborative control method and device of a water-light complementary power generation system, and relates to the technical field of new energy grid connection control. The method comprises the following steps: determining the frequency measurement reliability according to the frequency estimation value of a synchronous measuring device and a photovoltaic inverter phase-locked loop; when the reliability meets the condition, adaptively determining the frequency band decoupling filter coefficient based on the photovoltaic support margin and the water power movable margin; using the coefficient to decompose the grid connection point frequency deviation and the frequency change rate into a high-frequency fast component and a low-frequency sustained component; generating the original photovoltaic power station support instruction with the high-frequency component, and generating the original water turbine unit support instruction with the low-frequency component; and correcting the original instruction through a safety envelope to obtain the final support instruction to control the unit output. The application can adaptively divide the frequency band according to the real-time support capacity of the equipment when the frequency signal is reliable, fully exert the advantages of photovoltaic fast response and water power sustained support, and guarantee the safe operation of the inverter and the water power equipment in the support process.

Description

Technical Field

[0001] This application relates to the field of new energy grid connection control technology, and in particular to a virtual inertia collaborative control method and device for a water-solar hybrid power generation system. Background Technology

[0002] In weakly interconnected power grids, such as those at the ends of long-distance transmission lines, isolated load centers in mountainous areas, and areas with a high proportion of renewable energy integration, the system often exhibits characteristics such as low short-circuit capacity, small equivalent inertia, and severe frequency fluctuations. As the proportion of zero-inertia power sources such as photovoltaics continues to increase, the frequency stability problem of the power grid is becoming increasingly prominent.

[0003] In related technologies, inertia support methods mostly rely on fixed parameter control or simple power coordination. In the case of hydro-solar complementary power generation in weakly connected areas, inertia support strategies are difficult to match with the actual state of the power grid, easily leading to insufficient or excessive support. Furthermore, although hydropower units possess physical inertia, their rapid support capability is limited by hydraulic constraints such as head, flow rate, and guide vane operating speed, making them unsuitable for rapid response with a fixed inertia coefficient. The virtual inertia capability of photovoltaic power generation units originates from inverter control and reserve capacity, and is significantly time-varying and uncertain due to inverter current limiting, irradiance fluctuations, DC-side energy, and reactive power occupation. Existing joint control methods mostly focus on power coordination or economic dispatch, lacking a unified modeling and refined collaborative allocation mechanism for the inertia support capabilities of hydropower and photovoltaic power, leading to problems such as static inertia configuration, coarse allocation, equipment constraints, and unstable response effects in weakly connected areas under disturbance scenarios, making it difficult to effectively improve the transient frequency stability and operational robustness of the power grid in weakly connected areas. Summary of the Invention

[0004] This application aims to at least partially address one of the technical problems in the related art.

[0005] Therefore, the first aspect of this application proposes a virtual inertia cooperative control method for a hydro-solar complementary power generation system, the hydro-solar complementary power generation system including a hydropower unit and a photovoltaic power station, comprising the following steps:

[0006] The reliability of the frequency measurement is determined based on the frequency estimate on the grid side of the hydro-solar hybrid power generation system and the frequency estimate obtained by the phase-locked loop of the photovoltaic inverter in the photovoltaic power station. When the reliability of the frequency measurement is greater than or equal to the preset high reliability threshold, the frequency band decoupling filter coefficient is determined based on the photovoltaic support margin of the photovoltaic power station and the hydropower mobility margin of the hydropower unit. Based on the frequency band decoupling filter coefficients, the frequency deviation and frequency change rate of the hydro-solar hybrid power generation system at the grid connection point are decomposed into the low-frequency continuous component of the frequency deviation, the high-frequency fast component of the frequency deviation, the low-frequency continuous component of the frequency change rate, and the high-frequency fast component of the frequency change rate. The high-frequency virtual inertia original support command for the photovoltaic power station is generated based on the high-frequency fast component of the frequency deviation and the high-frequency fast component of the frequency change rate; the low-frequency inertia damping original support command for the hydropower unit is generated based on the low-frequency continuous component of the frequency deviation and the low-frequency continuous component of the frequency change rate. A safety filter is constructed using the electromagnetic safety envelope on the photovoltaic side and the hydraulic safety envelope on the hydropower side. The original support command for the high-frequency virtual inertia and the original support command for the low-frequency inertia damping are then subjected to safety filtering to obtain the high-frequency virtual inertia support command for controlling the output of the photovoltaic power station and the low-frequency inertia damping support command for controlling the output of the hydropower unit.

[0007] In some embodiments of this application, the frequency measurement reliability is determined using the following formula based on the frequency estimate from the grid side of the hydro-solar hybrid power generation system and the frequency estimate obtained from the phase-locked loop of the photovoltaic inverter in the photovoltaic power station:

[0008] in, To assess the reliability of the frequency measurement, This refers to the frequency estimate on the grid side of the aforementioned hydro-solar hybrid power generation system. The frequency estimate is obtained from the phase-locked loop of the photovoltaic inverter in the photovoltaic power station. The total harmonic distortion (THD) of the grid connection voltage in the aforementioned hydro-solar hybrid power generation system is given. This represents the absolute value of the rate of change of the bus voltage. This refers to the negative sequence voltage component or voltage imbalance. To measure data packet loss rate or data quality anomaly indicators, This is the credibility weighting coefficient.

[0009] In some embodiments of this application, the frequency band decoupling filter coefficients are determined using the following formula based on the photovoltaic support margin of the photovoltaic power station and the hydropower mobility margin of the hydropower unit:

[0010]

[0011] in, These are the frequency band decoupling filter coefficients. To control the cycle, The frequency band boundary time constant, For the amplitude limiting function, This is the hydraulic time-scale adjustment coefficient. For hydraulic start-up time, For the photovoltaic support margin, For power grid strength margin, The aforementioned hydropower mobility margin, This is the lower limit of the time constant for frequency band boundaries. The upper limit of the frequency band boundary time constant, satisfying .

[0012] In some embodiments of this application, the frequency deviation at the grid connection point of the hydro-solar hybrid power generation system is decomposed into a low-frequency continuous component and a high-frequency fast component of the frequency deviation based on the frequency band decoupling filter coefficient using the following formula:

[0013]

[0014] in, For the first The low-frequency continuous component of the frequency deviation per control cycle For the first The low-frequency continuous component of the frequency deviation per control cycle For the first The frequency deviation for each control cycle These are the decoupling filter coefficients for the frequency band. For the first The high-frequency fast component of the frequency deviation of each control cycle; Based on the frequency band decoupling filter coefficients, the frequency change rate at the grid connection point of the hydro-solar hybrid power generation system is decomposed into a low-frequency continuous component and a high-frequency fast component of the frequency change rate using the following formula:

[0015]

[0016] in, For the first The low-frequency continuous component of the frequency change rate per control cycle For the first The low-frequency continuous component of the frequency change rate per control cycle For the first The rate of change of the frequency in each control cycle, These are the decoupling filter coefficients for the frequency band. For the first The high-frequency fast component of the frequency change rate of each control cycle.

[0017] In some embodiments of this application, the original high-frequency virtual inertia support command for the photovoltaic power station is generated based on the high-frequency fast component of the frequency deviation and the high-frequency fast component of the frequency change rate using the following formula:

[0018] in, This refers to the original support command for the high-frequency virtual inertia. For photovoltaic virtual inertia gain, The high-frequency fast component of the frequency change rate. For photovoltaic virtual damping gain, For the high-frequency fast component of frequency deviation, To support the coupling gain of photovoltaic voltage, This refers to the bus voltage deviation. The low-frequency inertia damping original support command for the hydroelectric generator is generated based on the low-frequency continuous component of the frequency deviation and the low-frequency continuous component of the frequency change rate using the following formula:

[0019] in, This refers to the original support command for the low-frequency inertia damping. For low-frequency inertia gain in hydropower, The low-frequency continuous component of the rate of change of frequency. For low-frequency damping gain of hydropower, This is the low-frequency continuous component of the frequency deviation. For energy recovery gain, This is due to discrepancies in the photovoltaic energy ledger.

[0020] In some embodiments of this application, the photovoltaic-side electromagnetic safety envelope is represented by the following formula:

[0021] in, This is the electromagnetic safety envelope on the photovoltaic side. This is the command that supports the high-frequency virtual inertia. For the current active power output of photovoltaic power, This represents the maximum power point power under the current irradiance and temperature conditions. This represents the current reactive power output of the photovoltaic system. This refers to the AC side voltage amplitude of the inverter. The maximum allowable AC current for the inverter. This is the DC bus voltage. This is the safe lower limit for DC bus voltage. The equivalent energy available for virtual inertia support on the photovoltaic side. This is the lower limit of the equivalent energy safety for the photovoltaic side. Inverter thermal state indicators This is the upper limit of the allowable thermal state of the inverter. Reserve backup capacity for photovoltaic power. Minimum reserve capacity required to maintain subsequent frequency support; The hydraulic safety envelope on the hydroelectric side is expressed by the following formula:

[0022] in, This is the hydraulic safety envelope on the hydroelectric side. This refers to the low-frequency inertia damping support command. This refers to the current active power output of the hydropower unit. This refers to the minimum permissible active power output of the hydroelectric generator unit. The maximum allowable active power output of the hydropower unit satisfies the following conditions. , The current guide vane opening, To achieve the required guide vane opening correction for additional support power, This is the lower limit of the guide vane opening. The upper limit of the guide vane opening must satisfy... , The rate of change of guide vane opening. This represents the upper limit of the rate of change of guide vane opening. The guide vane opening acceleration, This is the upper limit of the guide vane opening acceleration. For predicting time The pressure in the pipeline at any given time, This refers to the lower limit of the allowable pressure for pressure pipelines. The upper limit of the allowable pressure for pressure pipelines must meet the following requirements. , This is due to the deviation in the speed of the turbine or generator. To allow for speed deviation limits, For unit vibration indicators, This is the upper limit of the unit's permissible vibration. To predict the time step.

[0023] In some embodiments of this application, the objective function of the security filter is expressed as:

[0024]

[0025]

[0026] in, This is the support instruction vector after security filtering. This is the command that supports the high-frequency virtual inertia. This refers to the low-frequency inertia damping support command. This is the original support instruction vector. This refers to the original support command for the high-frequency virtual inertia. This refers to the original support command for the low-frequency inertia damping. As slack variables, This is the instruction deviation weight matrix. The superscript represents the penalty coefficient for slack variables. This is the transpose symbol.

[0027] In some embodiments of this application, when the frequency measurement confidence level is less than the high confidence level threshold and the frequency measurement confidence level is greater than or equal to a preset low confidence level threshold, the photovoltaic inverter reduces its virtual inertia gain and enters a limiting support state. The high confidence level threshold is greater than the low confidence level threshold.

[0028] In some embodiments of this application, when the frequency measurement confidence level is less than the low confidence threshold, the photovoltaic inverter freezes the most recent confidence frequency slope or enters a current-limiting hold state.

[0029] A second aspect of this application provides a virtual inertia cooperative control device for a hydro-solar hybrid power generation system, the hydro-solar hybrid power generation system comprising a hydropower unit and a photovoltaic power station, including: The acquisition module is used to determine the reliability of the frequency measurement based on the frequency estimate on the grid side of the hydro-solar hybrid power generation system and the frequency estimate obtained by the phase-locked loop of the photovoltaic inverter of the photovoltaic power station. The determination module is used to determine the frequency band decoupling filter coefficients based on the photovoltaic support margin of the photovoltaic power station and the hydropower mobility margin of the hydropower unit when the frequency measurement confidence is greater than or equal to a preset high confidence threshold. The decomposition module is used to decompose the frequency deviation and frequency change rate of the hydro-solar hybrid power generation system at the grid connection point into a low-frequency continuous component of the frequency deviation, a high-frequency fast component of the frequency deviation, a low-frequency continuous component of the frequency change rate, and a high-frequency fast component of the frequency change rate, based on the frequency band decoupling filter coefficients. The generation module generates the original high-frequency virtual inertia support command for the photovoltaic power station based on the high-frequency fast component of the frequency deviation and the high-frequency fast component of the frequency change rate, and generates the original low-frequency inertia damping support command for the hydropower unit based on the low-frequency continuous component of the frequency deviation and the low-frequency continuous component of the frequency change rate. The safety filtering module is used to construct a safety filter using the electromagnetic safety envelope of the photovoltaic side and the hydraulic safety envelope of the hydropower side, and to perform safety filtering on the original support command of the high-frequency virtual inertia and the original support command of the low-frequency inertia damping, so as to obtain the high-frequency virtual inertia support command for controlling the output of the photovoltaic power station and the low-frequency inertia damping support command for controlling the output of the hydropower unit.

[0030] The virtual inertia collaborative control method for a hydro-solar hybrid power generation system provided in this application ensures that the photovoltaic inverter only participates in virtual inertia support when the frequency signal at the grid connection point is reliable, based on frequency measurement reliability judgment. This avoids malfunctions caused by phase-locked loop (PLL) loss or voltage distortion. When the frequency signal is reliable, the frequency band decoupling filter coefficient is adaptively determined according to the photovoltaic support margin and the hydropower mobility margin, matching the frequency band allocation with the real-time support capability of the equipment and preventing a disconnect between the support task allocation and the actual available capacity of the equipment. The grid connection point frequency deviation and frequency change rate are decomposed into high-frequency fast components and low-frequency continuous components, allowing the photovoltaic power station to handle the rapidly changing high-frequency components and the hydropower unit to handle the continuously changing low-frequency components, fully leveraging the advantages of fast photovoltaic response and continuous hydropower support. The original support commands are corrected through the electromagnetic safety envelope on the photovoltaic side and the hydraulic safety envelope on the hydropower side, ensuring that the additional support power does not exceed the equipment safety boundaries such as inverter current, DC bus voltage, guide vane operating rate, and pressure pipeline pressure, thereby improving the frequency stability in the weak connection zone while protecting the safety of the power generation equipment.

[0031] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0032] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 A flowchart illustrating a virtual inertia collaborative control method for a water-solar hybrid power generation system provided in this application embodiment; Figure 2 This is a schematic diagram of a virtual inertia collaborative control device for a water-solar hybrid power generation system provided in an embodiment of this application. Detailed Implementation

[0033] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0034] Specifically, the virtual inertia cooperative control method and apparatus for a hydro-solar complementary power generation system according to embodiments of this application are described below with reference to the accompanying drawings. The hydro-solar complementary power generation system includes a hydropower unit and a photovoltaic power station, as well as a corresponding grid side. This application embodiment can select a weakly interconnected power grid in a mountainous area as the application object. This area is connected to the main grid via a long-distance interconnection line, has limited local grid strength, and a high proportion of renewable energy. A hydropower station and a centralized photovoltaic power station can be configured within the area to form a hydro-solar complementary power generation system. The hydropower unit and the photovoltaic power station are connected to the grid through a grid connection point to meet local load power demand and achieve renewable energy consumption.

[0035] Figure 1 This is a flowchart illustrating a virtual inertia cooperative control method for a water-solar hybrid power generation system provided in an embodiment of this application. Figure 1 As shown, the virtual inertia cooperative control method for this water-solar hybrid power generation system may include the following steps: Step 101: Determine the reliability of the frequency measurement based on the frequency estimate on the grid side of the hydro-solar hybrid power generation system and the frequency estimate obtained from the phase-locked loop of the photovoltaic inverter in the photovoltaic power station.

[0036] In some embodiments of this application, the operating status quantities of the grid connection point, grid interconnection lines, hydropower units, and photovoltaic power generation units can be pre-synchronously collected to form a timestamped multi-source state vector. The operating status quantities may include grid connection point frequency, frequency change rate, bus voltage, bus voltage change rate, interconnection line active power, interconnection line reactive power, hydropower unit active power, guide vane opening, guide vane opening change rate, pressure pipeline pressure, head, flow rate, turbine speed, unit vibration, photovoltaic active power, photovoltaic reactive power, maximum power point power, DC bus voltage, DC side available energy, reserved reserve capacity, inverter AC current, inverter temperature, low voltage ride-through status, phase-locked loop status, and irradiance. Constructing a multi-source state vector model unifies the grid status, hydropower unit status, photovoltaic power station unit status, and interconnection line status into a single control data structure, facilitating real-time judgment and control by the station-level coordination controller.

[0037] Among them, the first The system state vector for each control cycle can be represented as:

[0038] in, For the first The system state vector for each control cycle To control the cycle number, the value is a non-negative integer, i.e. Let the power grid state vector be... Let be the state vector of the hydroelectric generator unit. This represents the state vector of a photovoltaic power plant's power generation unit. For the state vector of the power grid tie line, the superscript is... This is the transpose symbol.

[0039] The power grid state vector can be represented as:

[0040] in, For the first The grid connection point frequency for each control cycle, in Hz, with a value greater than 0. The frequency deviation is expressed in Hz and satisfies the following conditions. This is the rated frequency, measured in Hz, typically taken as 50Hz. This is the rate of change of frequency, expressed in Hz / s. This refers to the bus voltage at the grid connection point, expressed in kV or per-unit value, and is greater than 0. This represents the rate of change of bus voltage, expressed in kV / s or per-unit value per second. The short-circuit ratio is a value greater than 0 and is used to characterize the strength of the power grid in weakly connected areas.

[0041] The state vector of a hydroelectric generator unit can be represented as:

[0042] in, This represents the current active power output of the hydropower unit, measured in MW. The value range is determined by the unit's minimum and maximum output. The guide vane opening has a range of values. It can also be normalized to This represents the rate of change of guide vane opening, expressed as a percentage per second. This refers to the guide vane opening acceleration, expressed in seconds per second or as a percentage of seconds per second. This refers to the pressure in the pressure pipeline, expressed in MPa, with a range of values. This represents the current water head, in meters (m), and a value greater than 0. This represents the turbine flow rate, expressed in m³ / s, and its value is not less than 0. This represents the rotational speed of the turbine or generator, expressed in rad / s or per-unit value, and is greater than 0. This is the unit vibration index, and its value should not be less than 0.

[0043] The state vector of a photovoltaic power plant's power generation unit can be represented as:

[0044] in, This represents the current active power output of the photovoltaic system, expressed in MW, and its value is not less than 0. This represents the current reactive power output of the photovoltaic system, in Mvar. This represents the maximum power point power under the current irradiance and temperature conditions, expressed in MW, and its value is not less than 0. This represents the DC bus voltage of the photovoltaic inverter, expressed in V or kV, and a value greater than 0. This represents the equivalent energy available for rapid support on the photovoltaic side, expressed in MJ or MWh, and its value is not less than 0. This represents the AC side current of the inverter, expressed in amperes (A) or per-unit values, and must be no less than 0. This is an inverter thermal state index, and its value can be normalized to... Where 0 indicates no thermal stress and 1 indicates that the thermal limit has been reached. Reserved capacity for photovoltaic power generation, in MW, with a value not less than 0. This is a low-voltage ride-through status indicator, which can be 0, 1, 2, or 3. 0 indicates normal operation, 1 indicates low-voltage ride-through, 2 indicates current limiting and holding, and 3 indicates recovery phase.

[0045] The state vector of the tie line is represented as:

[0046] in, The active power of the tie line is expressed in MW. The reactive power of the tie line is expressed in Mvar. This represents the change in active power of the tie line, expressed in MW.

[0047] In some embodiments of this application, the reliability of frequency measurement can be determined using the following formula based on the frequency estimate from the grid side of the hydro-solar hybrid power generation system and the frequency estimate obtained from the phase-locked loop of the photovoltaic inverter in the photovoltaic power station:

[0048] in, The value ranges from (0,1) to indicate the reliability of the frequency measurement. The closer the value is to 1, the more reliable the frequency measurement. This is an estimated frequency on the grid side of a hydro-solar hybrid power generation system, in Hz. The frequency estimate is obtained from the phase-locked loop of the photovoltaic inverter in a photovoltaic power plant, in Hz. The deviation between the two frequency estimates is not less than 0. The total harmonic distortion (THD) of the grid connection voltage in a hydro-solar hybrid power generation system is defined as a value not less than 0 when using per-unit values; in engineering practice, it is typically limited to a value of [missing value]. , The absolute value of the rate of change of the bus voltage, which is not less than 0. For negative sequence voltage components or voltage imbalance, the value should be no less than 0 when using per-unit values. To measure data packet loss rate or data quality anomaly indicators, the value range is: , This is the credibility weighting coefficient, and all values ​​are no less than 0.

[0049] Optionally, a high confidence threshold can be set. and low confidence threshold : .

[0050] When the reliability of frequency measurement is greater than or equal to the high reliability threshold The photovoltaic inverter controls the output according to normal virtual inertia. When the frequency measurement confidence level is less than the high confidence level threshold, and the frequency measurement confidence level is greater than or equal to the preset low confidence level threshold. The photovoltaic inverter reduces the virtual inertia gain and enters a limiting support state; When the reliability of frequency measurement is less than the low reliability threshold The photovoltaic inverter can freeze the most recent reliable frequency slope or enter a current-limiting hold state.

[0051] Step 102: When the frequency measurement confidence level is greater than or equal to the preset high confidence level threshold, determine the frequency band decoupling filter coefficient based on the photovoltaic support margin of the photovoltaic power station and the hydropower mobility margin of the hydropower unit.

[0052] Optionally, in some embodiments of this application, a photovoltaic support margin model and a hydropower mobility margin model can be pre-constructed. The photovoltaic support margin represents the photovoltaic system's current ability to provide high-frequency, rapid support. A larger photovoltaic support margin indicates that the photovoltaic system is more suitable for undertaking more high-frequency support tasks during the initial stages of disturbances.

[0053] The photovoltaic support margin can be expressed as:

[0054] in, The value range is the photovoltaic support margin. This represents the DC bus voltage margin, with a value range of [value range missing]. To reserve a margin of spare capacity, the value range is: This is the inverter current margin, with a value range of [value range missing]. This represents the DC-side equivalent energy margin, with a value range of [value range missing]. These are weighting coefficients, and their values ​​range from [value range missing]. and satisfy .

[0055] DC bus voltage margin is expressed as:

[0056] in, This represents the DC bus voltage margin, with a value range of [value range missing]. This represents the current DC bus voltage, and its value is greater than 0. This is the lower safety limit for DC bus voltage, and its value is greater than 0. This is the reference value for the DC bus voltage, which satisfies... .

[0057] Reserved spare capacity margin is expressed as follows:

[0058] in, To reserve a margin of spare capacity, the value range is: Reserved standby capacity for photovoltaic power generation, with a value not less than 0. This is a reference value for photovoltaic backup capacity, and the value is greater than 0.

[0059] Inverter current margin is expressed as:

[0060] in, This is the inverter current margin, with a value range of [value range missing]. This represents the maximum allowable AC current for the inverter, and its value is greater than 0. This represents the current AC side current of the inverter, and its value is not less than 0.

[0061] The DC-side equivalent energy margin is expressed as:

[0062] in, This represents the DC-side equivalent energy margin, with a value range of [value range missing]. This represents the equivalent energy currently available for rapid support on the photovoltaic side, and its value is not less than 0. This is the lower limit for the safety of equivalent energy on the photovoltaic side, and its value is not less than 0. This is the reference value for the equivalent energy on the photovoltaic side, satisfying... .

[0063] Hydropower availability margin indicates the current capacity of hydropower units to undertake low-frequency continuous support and takeover tasks. The larger the hydropower availability margin, the more suitable the hydropower is for taking over the rapid support tasks of photovoltaic power earlier.

[0064] The dynamic margin of hydropower can be expressed as:

[0065] in, The dynamic margin for hydropower is defined as follows: This is the guide vane rate margin, with a value range of [value missing]. This refers to the pressure margin of the pressure pipeline, with a value range of [value range missing]. This is the speed deviation margin, and its value range is... The vibration margin of the unit, with a value range of [value range missing]. These are weighting coefficients, and their values ​​range from [value range missing]. and satisfy .

[0066] The guide vane rate margin is expressed as:

[0067] in, This is the guide vane rate margin, with a value range of [value missing]. This represents the upper limit of the rate of change of guide vane opening, and is greater than 0. This represents the rate of change of the current guide vane opening.

[0068] Pressure margin in a pressure pipeline is expressed as:

[0069] in, This refers to the pressure margin of the pressure pipeline, with a value range of [value range missing]. This represents the upper limit of the allowable pressure for the pressure pipeline, and its value is greater than 0. The current pressure in the pipeline is greater than 0. For the rated or normal operating pressure of the pressure pipeline, meet the requirements. .

[0070] The speed deviation margin is expressed as:

[0071] in, This is the speed deviation margin, and its value range is... The allowable speed deviation limit is set to a value greater than 0. This represents the current deviation in turbine or generator speed.

[0072] The vibration margin of the unit is expressed as:

[0073] in, The vibration margin of the unit, with a value range of [value range missing]. This represents the upper limit of the unit's permissible vibration, and its value is greater than 0. This is the current vibration index of the unit, and its value should not be less than 0.

[0074] In some embodiments of this application, the frequency band decoupling filter coefficients can be determined using the following formula based on the photovoltaic support margin of the photovoltaic power plant and the hydropower mobility margin of the hydropower unit:

[0075]

[0076] in, These are the frequency band decoupling filter coefficients, with values ​​ranging from... , To control the cycle, the value is greater than 0, preferably 5ms to 100ms, and more preferably 20ms to 50ms. This is the frequency band boundary time constant, with a value greater than 0, and a value range of [value missing]. , This is a limiting function used to restrict calculated values ​​between a lower and an upper limit. This is the hydraulic time-scale adjustment coefficient, with a value greater than 0. This represents the hydraulic start-up time, and its value is greater than 0. To provide a margin for photovoltaic support, For power grid strength margin, The dynamic margin for hydropower is defined as follows: , This is the lower limit of the frequency band boundary time constant, and its value is greater than 0. The upper limit of the frequency band boundary time constant, satisfying .

[0077] Step 103: Based on the frequency band decoupling filter coefficients, decompose the frequency deviation and frequency change rate of the hydro-solar hybrid power generation system at the grid connection point into the low-frequency continuous component of the frequency deviation, the high-frequency fast component of the frequency deviation, the low-frequency continuous component of the frequency change rate, and the high-frequency fast component of the frequency change rate.

[0078] In some embodiments of this application, an adaptive frequency band decoupling model can be constructed to decompose frequency disturbances into high-frequency fast components and low-frequency continuous components, allowing the photovoltaic inverter to handle the rapidly changing portion and the hydropower unit to handle the continuously changing portion. In one implementation, the frequency deviation at the grid connection point of the hydro-photovoltaic complementary power generation system is decomposed into a low-frequency continuous component and a high-frequency fast component of the frequency deviation based on the frequency band decoupling filter coefficient using the following formula:

[0079]

[0080] in, For the first The low-frequency continuous component of the frequency deviation per control cycle, in Hz. For the first The low-frequency continuous component of the frequency deviation per control cycle, in Hz. For the first Frequency deviation per control cycle, in Hz. These are the frequency band decoupling filter coefficients, with values ​​ranging from... , For the first The high-frequency fast component of the frequency deviation of each control cycle, in Hz; Based on the frequency band decoupling filter coefficients, the frequency change rate at the grid connection point of the hydro-solar hybrid power generation system is decomposed into a low-frequency continuous component and a high-frequency fast component of the frequency change rate using the following formula:

[0081]

[0082] in, For the first The low-frequency continuous component of the frequency change rate per control cycle, in Hz / s. For the first The low-frequency continuous component of the frequency change rate per control cycle, in Hz / s. For the first The frequency change rate per control cycle, in Hz / s. These are the frequency band decoupling filter coefficients. For the first The high-frequency fast component of the frequency change rate per control cycle, in Hz / s.

[0083] Step 104: Generate the original support command for the high-frequency virtual inertia of the photovoltaic power station based on the high-frequency fast component of the frequency deviation and the high-frequency fast component of the frequency change rate; and generate the original support command for the low-frequency inertia damping of the hydropower unit based on the low-frequency continuous component of the frequency deviation and the low-frequency continuous component of the frequency change rate.

[0084] The high-frequency virtual inertia original support command and the low-frequency inertia damping original support command are used to represent the expected support power provided by photovoltaic and hydropower based on the frequency disturbance component, without considering the equipment safety boundary.

[0085] In some embodiments of this application, the original high-frequency virtual inertia support command for a photovoltaic power station can be generated based on the high-frequency fast component of the frequency deviation and the high-frequency fast component of the frequency change rate using the following formula:

[0086] in, This is the original support command for high-frequency virtual inertia, in MW. This represents the photovoltaic virtual inertia gain, and its value is not less than 0. The high-frequency fast component is the rate of change of frequency, with units of Hz / s. This represents the photovoltaic virtual damping gain, and its value is not less than 0. This refers to the high-frequency fast component of the frequency deviation, measured in Hz. The voltage-supported coupling gain of the photovoltaic system should be no less than 0. This represents the bus voltage deviation, expressed in kV or per unit value.

[0087] The low-frequency inertia damping initial support command for the hydroelectric generator can be generated using the following formula based on the low-frequency continuous component of the frequency deviation and the low-frequency continuous component of the frequency change rate:

[0088] in, This is the original support command for low-frequency inertia damping, in MW. For the low-frequency inertia gain of hydropower, the value should not be less than 0. This represents the low-frequency continuous component of the rate of change of frequency, expressed in Hz / s. The low-frequency damping gain for hydropower should be no less than 0. This represents the low-frequency continuous component of the frequency deviation, expressed in Hz. This is the energy recovery gain, and its value is not less than 0. This represents the photovoltaic energy ledger deviation, expressed in MJ, MWh, or equivalent power integral.

[0089] The photovoltaic energy ledger is used to record the supporting energy released by photovoltaics during disturbances, and during the recovery period, hydropower takes on additional active power of the system, so that photovoltaics can gradually recover DC side energy and reserve reserve capacity.

[0090] The photovoltaic energy ledger can be represented as:

[0091] in, For the first The photovoltaic energy ledger value for each control cycle, in MJ or MWh. For the first The photovoltaic energy ledger value for each control cycle, in MJ or MWh. The additional supporting power provided by photovoltaics during disturbances, measured in MW. The power equivalent to the DC-side energy or reserve capacity restored by photovoltaic power during the recovery period, expressed in MW. To control the cycle, the value is greater than 0.

[0092] Photovoltaic energy ledger deviation is expressed as:

[0093] in, For the first Photovoltaic energy ledger deviation for each control cycle, in MJ or MWh. For the first The photovoltaic energy ledger value for each control cycle. This is a reference value for the energy ledger, which can usually be 0, or it can be set according to the photovoltaic backup status before the disturbance.

[0094] The power replenishment during the recovery period is expressed as follows:

[0095] in, This refers to the additional active power supplied by hydropower during the recovery period, measured in MW. This is the energy recovery gain, and its value is not less than 0. This represents the photovoltaic energy ledger deviation, expressed in MJ or MWh.

[0096] The limitations of hydropower replenishment during the recovery period are expressed as follows:

[0097] in, For the first Hydropower replenishment power per control cycle, in MW. For the first Hydropower replenishment power per control cycle, in MW. This represents the upper limit of the hydropower replenishment ramp-up rate during the recovery period, and is a value greater than 0. To control the cycle, the value is greater than 0.

[0098] It should be noted that hydropower replenishment does not mean that hydropower directly charges the photovoltaic DC bus. Rather, it means that hydropower takes on an additional portion of active power at the system level, enabling the photovoltaic system to reduce its external active power transmission, restore the DC bus voltage, restore reserved reserve capacity, or restore the supporting DC energy storage energy.

[0099] Step 105: Construct a safety filter using the electromagnetic safety envelope on the photovoltaic side and the hydraulic safety envelope on the hydropower side. Perform safety filtering on the original support command for high-frequency virtual inertia and the original support command for low-frequency inertia damping to obtain the high-frequency virtual inertia support command for controlling the output of the photovoltaic power station and the low-frequency inertia damping support command for controlling the output of the hydropower unit.

[0100] In some embodiments of this application, a photovoltaic-side electromagnetic safety envelope and a hydroelectric-side hydraulic safety envelope can be pre-constructed. The photovoltaic-side electromagnetic safety envelope is used to determine the range of additional active power support that the photovoltaic inverter can safely provide under current operating conditions. The photovoltaic-side electromagnetic safety envelope can simultaneously consider the maximum photovoltaic power generation, inverter capacity, AC current, reactive power priority, DC bus voltage, DC-side equivalent energy, inverter thermal state, and reserved reserve capacity. For example, the photovoltaic-side electromagnetic safety envelope can be expressed by the following formula:

[0101] in, For the electromagnetic safety envelope on the photovoltaic side, This is a high-frequency virtual inertia support command, measured in MW. This represents the current active power output of photovoltaic systems, in MW. This represents the maximum power point power under the current irradiance and temperature conditions, expressed in MW, and its value is not less than 0. This represents the current reactive power output of the photovoltaic system, in Mvar. This represents the AC side voltage amplitude of the inverter, in kV or per-unit value, and is greater than 0. This represents the maximum allowable AC current for the inverter, and its value is greater than 0. This is the DC bus voltage, and its value is greater than 0. This is the lower safety limit for DC bus voltage, and its value is greater than 0. This represents the equivalent energy available for virtual inertia support on the photovoltaic side, and its value is not less than 0. This is the lower limit for the safety of equivalent energy on the photovoltaic side, and its value is not less than 0. This is an inverter thermal state index, with a normalized value range of [value missing]. This represents the upper limit of the inverter's permissible thermal state; its normalized value range is [value missing]. , Reserved capacity for photovoltaic power generation, in MW, with a value not less than 0. The minimum reserve capacity required to maintain subsequent frequency support, in MW, with a value not less than 0.

[0102] During reactive power priority control or low voltage ride-through, the available active power limit for photovoltaics can be expressed as:

[0103] in, The maximum available active power of photovoltaic power after considering reactive power priority is expressed in MW. This represents the AC side voltage amplitude of the inverter, and its value is greater than 0. This represents the maximum allowable AC current for the inverter, and its value is greater than 0. The reactive power required for low voltage ride-through or voltage support, measured in Mvar, and satisfying the following conditions. .

[0104] The maximum additional active power that photovoltaics can provide is expressed as follows:

[0105] in, This represents the maximum additional active power that photovoltaics can provide, measured in MW. The maximum available active power of photovoltaic power after considering reactive power priority is expressed in MW. This represents the current active power output of photovoltaic systems, measured in MW.

[0106] The equivalent available energy on the photovoltaic side is expressed as:

[0107] in, This represents the equivalent usable energy on the photovoltaic side, expressed in J, MJ, or MWh, and its value is not less than 0. This is the equivalent capacitance of the DC bus, and its value is greater than 0. This represents the current DC bus voltage, and its value is greater than 0. This is the lower safety limit for DC bus voltage, and its value is greater than 0. To support DC energy storage or to provide readily available energy that can be rapidly released from the storage, the value should be no less than 0. This is the equivalent releaseable energy generated by photovoltaic power generation restrictions or reserved reserves, and its value is not less than 0.

[0108] The hydraulic safety envelope on the hydropower side is used to determine the range of additional support power that a hydropower unit can safely provide under current operating conditions. This model not only limits the upper and lower limits of hydropower output but also restricts guide vane movement, pressure in the pressure pipeline, unit speed, and unit vibration. For example, the hydraulic safety envelope on the hydropower side is expressed by the following formula:

[0109] in, For the hydraulic safety envelope on the hydroelectric side, This is a low-frequency inertia damping support command, in MW. The current active power output of the hydropower unit is expressed in MW. This refers to the minimum permissible active power output of a hydroelectric generating unit, measured in MW. The maximum permissible active power output of the hydropower unit, in MW, meets the following requirements. , The current guide vane opening, To achieve the required guide vane opening correction for additional support power, This is the lower limit of the guide vane opening. The upper limit of the guide vane opening must satisfy... When normalizing, one can take , , The rate of change of guide vane opening. This represents the upper limit of the rate of change of guide vane opening, and is greater than 0. The guide vane opening acceleration, This is the upper limit of the guide vane opening acceleration, and its value is greater than 0. For predicting time The pressure in the pipeline at any given time, This represents the lower limit of the allowable pressure for pressure pipelines, and its value is greater than 0. The upper limit of the allowable pressure for pressure pipelines must meet the following requirements. , This is due to the deviation in the speed of the turbine or generator. The allowable speed deviation limit is set to a value greater than 0. The vibration index of the unit should be no less than 0. This represents the upper limit of the unit's permissible vibration, and its value is greater than 0. To predict the time step, the value is greater than 0.

[0110] The relationship between the additional support power of hydropower and the guide vane operation can be expressed as:

[0111] in, Additional supporting power for hydropower, measured in MW. The sensitivity of guide vane opening to hydropower active power; This represents the change in guide vane opening. The sensitivity of water head changes to the active power of hydropower. This represents the change in water head, expressed in meters (m). To assess the sensitivity of hydropower active power to changes in flow rate, This represents the change in flow rate, expressed in m³ / s.

[0112] Over a short timescale, when the water head changes slowly, it can be approximated as:

[0113] in, Additional supporting power for hydropower, measured in MW. The sensitivity of guide vane opening to the active power of hydropower. This represents the change in guide vane opening.

[0114] A security filter is used to modify the original support instructions into executable support instructions that simultaneously satisfy hydropower security, photovoltaic security, and frequency security. For example, the objective function of the security filter can be expressed as:

[0115]

[0116]

[0117] in, This is the support instruction vector after security filtering. This is a command that supports high-frequency virtual inertia. This is a low-frequency inertia damping support command. This is the original support instruction vector. This is the original support command for high-frequency virtual inertia. This is the original support command for low-frequency inertia damping. These are slack variables, and their values ​​are not less than 0. This is the instruction deviation weight matrix, typically a positive semi-definite matrix. This is the slack variable penalty coefficient, which takes a value greater than 0, and is indicated by a superscript. This is the transpose symbol.

[0118] The constraints of the security filter are expressed as follows:

[0119] in, This represents the Cartesian product of two secure envelopes.

[0120] Frequency security prediction constraints are expressed as follows:

[0121] in, For the frequency security prediction constraint coefficient matrix, This is the support instruction vector after security filtering. For frequency security prediction constraint boundary vector, This is a slack variable, and its value is not less than 0. This constraint is used to limit the minimum frequency point and the rate of frequency change to meet safety requirements.

[0122] The control barrier function constraint is expressed as:

[0123] in, For the first The control barrier function corresponding to each security boundary For the first The system state for each control cycle This is the predicted state for the next control cycle. For the first The convergence coefficients of the barrier functions, with values ​​ranging from... The safety boundary number can correspond to the DC bus voltage, pressure pipeline pressure, inverter current, guide vane operation, or lowest frequency point.

[0124] Taking the DC bus voltage as an example, the control barrier function is expressed as:

[0125] in, This is the DC bus voltage barrier function. This represents the current DC bus voltage, and its value is greater than 0. This is the lower safety limit for the DC bus voltage, and its value is greater than 0. When When this occurs, it indicates that the DC bus voltage is higher than the safety lower limit.

[0126] Taking the pressure in a pressure pipeline as an example, the control barrier function is expressed as:

[0127] in, This is the pressure barrier function for pressure pipelines. This represents the upper limit of the allowable pressure for the pressure pipeline, and its value is greater than 0. This represents the current pipeline pressure, and its value is greater than 0. When... When the pressure in the pipeline is below the safe limit, it indicates that the pressure is below the upper limit.

[0128] Taking inverter current as an example, the control barrier function is expressed as:

[0129] in, This is the inverter current barrier function. This represents the maximum allowable AC current for the inverter, and its value is greater than 0. This represents the current AC current of the inverter, and its value is not less than 0. When this occurs, it indicates that the inverter current is below the allowable upper limit.

[0130] Taking the lowest frequency point as an example, the control barrier function is expressed as:

[0131] in, The barrier function at the lowest frequency point. The predicted lowest frequency point, in Hz. This is the lower limit of the permissible frequency, expressed in Hz. When the predicted frequency is lower than the lower limit of the allowed frequency, it indicates that the predicted frequency is lower than the lower limit of the allowed frequency.

[0132] Optionally, in some embodiments of this application, an equivalent frequency dynamic model for weak connection regions can also be constructed to describe the relationship between frequency deviation, frequency change rate and power deficit after disturbance, and to predict whether the current support command is sufficient to reduce the frequency change rate and raise the frequency minimum point.

[0133] The dynamic model of equivalent frequencies in the weakly connected region is expressed as follows:

[0134] in, This is the equivalent inertia of the weakly connected region, and its value is greater than 0. The rated frequency, with a value greater than 0, is typically 50Hz. Frequency deviation, in Hz The frequency deviation rate is expressed in Hz / s. The equivalent damping coefficient for the weakly connected region, with a value not less than 0. Disturbance power deficit, in MW This represents the power variation of the tie line, measured in MW.

[0135] This model is used for frequency security prediction constraints in security filters. When the disturbance power deficit is large and the equivalent inertia is small, the frequency change rate will increase, requiring photovoltaic power to provide rapid support first; when the frequency deviation persists, hydropower is needed to gradually increase low-frequency support.

[0136] Optionally, in some embodiments, a three-stage relay control can be adopted for the hydro-solar hybrid power generation system, including a photovoltaic first support stage, a hydropower takeover stage, and a hydropower replenishment stage.

[0137] For the initial support phase of photovoltaic power generation, the relay control start-up conditions can be expressed as:

[0138] or:

[0139] or:

[0140] in, This is the rate of change of frequency, expressed in Hz / s. The threshold for the rate of change of frequency to initiate virtual inertia relay control is greater than 0. Frequency deviation, in Hz. The frequency deviation threshold for initiating virtual inertia relay control is set to a value greater than 0. This represents the change in active power of the tie line, measured in MW. This is the threshold for power surge in the tie line, and its value is greater than 0.

[0141] During this stage, the photovoltaic inverter provides high-frequency virtual inertia support and fast voltage support based on high-frequency fast components to suppress the rate of frequency change.

[0142] For the hydropower takeover phase, the conditions for switching from the photovoltaic-supported phase to the hydropower takeover phase are expressed as follows:

[0143] or:

[0144] or:

[0145] or:

[0146] in, This is the rate of change of frequency, expressed in Hz / s. The frequency change rate threshold for entering the hydropower connection phase is set to a value greater than 0. This represents the high-frequency fast component of the frequency deviation, measured in Hz. This is the high-frequency component switching threshold, and its value is greater than 0. This represents the current DC bus voltage, and its value is greater than 0. To determine the voltage threshold at which photovoltaic power needs to recover DC-side energy, a value greater than 0 is used. The dynamic margin for hydropower is defined as follows: The minimum allowable margin required for water and electricity connections, with a value range of [value range missing]. .

[0147] During this phase, hydropower units gradually take over the low-frequency continuous power shortage, and photovoltaic power gradually transitions from high-power rapid support to limited support or standby recovery.

[0148] For the hydropower replenishment phase, the conditions for entering the hydropower replenishment phase are expressed as follows:

[0149] and:

[0150] and:

[0151] in, Frequency deviation, in Hz. This is the frequency recovery dead zone threshold, and its value is greater than 0. This is the rate of change of frequency, expressed in Hz / s. The dead zone threshold for frequency change rate recovery is set to a value greater than 0. This refers to the photovoltaic energy ledger value, expressed in MJ or MWh. The energy ledger recovery dead zone threshold is set, and its value is not less than 0.

[0152] During this phase, hydropower takes on additional active power of the system based on the deviation of the photovoltaic energy ledger, enabling the photovoltaic system to gradually recover DC-side energy and reserve backup capacity.

[0153] Through the aforementioned three-stage relay control, the photovoltaic rapid support command can be prioritized in the early stage of the disturbance to suppress the frequency change rate; in the middle stage of the disturbance, the hydropower low-frequency continuous support is gradually increased to make the hydropower take over the power deficit; after the frequency is restored, the hydropower takes over the system's active power additionally according to the photovoltaic energy ledger, so that the photovoltaic restores DC side energy and reserves reserve capacity; after the disturbance ends, the control parameters are corrected online according to the lowest frequency point, the maximum frequency change rate, the recovery time and the equipment safety margin.

[0154] By implementing the embodiments of this application, and judging the reliability of frequency measurements, it can be ensured that the photovoltaic inverter only participates in virtual inertia support when the frequency signal at the grid connection point is reliable, avoiding malfunctions caused by phase-locked loop (PLL) loss or voltage distortion. When the frequency signal is reliable, the frequency band decoupling filter coefficient is adaptively determined based on the photovoltaic support margin and the hydropower mobility margin, so that the frequency band division matches the real-time support capability of the equipment, avoiding the disconnect between the support task allocation and the actual available capacity of the equipment. The grid connection point frequency deviation and frequency change rate are decomposed into high-frequency fast components and low-frequency continuous components, so that the photovoltaic power station bears the rapidly changing high-frequency components and the hydropower unit bears the continuously changing low-frequency components, giving full play to the advantages of fast photovoltaic response and continuous hydropower support. The original support command is corrected by the electromagnetic safety envelope on the photovoltaic side and the hydraulic safety envelope on the hydropower side, respectively, to ensure that the additional support power does not exceed the equipment safety boundaries such as inverter current, DC bus voltage, guide vane operating rate, and pressure pipeline pressure, thereby improving the frequency stability in the weak connection area while protecting the safety of the power generation equipment.

[0155] Figure 2 This is a schematic diagram of a virtual inertia cooperative control device for a water-solar hybrid power generation system provided in an embodiment of this application. Figure 2 As shown, the virtual inertia collaborative control device of the water-solar hybrid power generation system may include: an acquisition module 201, a determination module 202, a decomposition module 203, a generation module 204, and a safety filtering module 205.

[0156] The acquisition module 201 is used to determine the reliability of frequency measurement based on the frequency estimate on the grid side of the hydro-solar hybrid power generation system and the frequency estimate obtained by the photovoltaic inverter phase-locked loop of the photovoltaic power station. The determination module 202 is used to determine the frequency band decoupling filter coefficients based on the photovoltaic support margin of the photovoltaic power station and the hydropower mobility margin of the hydropower unit when the frequency measurement confidence is greater than or equal to the preset high confidence threshold. The decomposition module 203 is used to decompose the frequency deviation and frequency change rate of the hydro-solar hybrid power generation system at the grid connection point into the low-frequency continuous component of the frequency deviation, the high-frequency fast component of the frequency deviation, the low-frequency continuous component of the frequency change rate, and the high-frequency fast component of the frequency change rate according to the frequency band decoupling filter coefficient. The generation module 204 generates the original support command for the high-frequency virtual inertia of the photovoltaic power station based on the high-frequency fast component of the frequency deviation and the high-frequency fast component of the frequency change rate, and generates the original support command for the low-frequency inertia damping of the hydropower unit based on the low-frequency continuous component of the frequency deviation and the low-frequency continuous component of the frequency change rate. The safety filtering module 205 is used to construct a safety filter using the electromagnetic safety envelope of the photovoltaic side and the hydraulic safety envelope of the hydropower side, and to perform safety filtering on the original support command of high frequency virtual inertia and the original support command of low frequency inertia damping to obtain the high frequency virtual inertia support command for controlling the output of the photovoltaic power station and the low frequency inertia damping support command for controlling the output of the hydropower unit.

[0157] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0158] To implement the above embodiments, this application also proposes an electronic device, including: a processor and a memory communicatively connected to the processor; the memory stores computer execution instructions; the processor executes the computer execution instructions stored in the memory to implement the method provided in the foregoing embodiments.

[0159] To implement the above embodiments, this application also proposes a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the methods provided in the foregoing embodiments.

[0160] To implement the above embodiments, this application also proposes a computer program product, including a computer program that, when executed by a processor, implements the methods provided in the foregoing embodiments.

[0161] In the foregoing descriptions of the embodiments, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0162] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0163] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0164] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0165] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0166] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0167] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a 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 also be stored in a computer-readable storage medium.

[0168] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A virtual inertia cooperative control method for a hydro-solar hybrid power generation system, wherein the hydro-solar hybrid power generation system includes a hydropower unit and a photovoltaic power station, characterized in that, Includes the following steps: The reliability of the frequency measurement is determined based on the frequency estimate on the grid side of the hydro-solar hybrid power generation system and the frequency estimate obtained from the phase-locked loop of the photovoltaic inverter in the photovoltaic power station. When the reliability of the frequency measurement is greater than or equal to the preset high reliability threshold, the frequency band decoupling filter coefficient is determined based on the photovoltaic support margin of the photovoltaic power station and the hydropower mobility margin of the hydropower unit. Based on the frequency band decoupling filter coefficients, the frequency deviation and frequency change rate of the hydro-solar hybrid power generation system at the grid connection point are decomposed into the low-frequency continuous component of the frequency deviation, the high-frequency fast component of the frequency deviation, the low-frequency continuous component of the frequency change rate, and the high-frequency fast component of the frequency change rate. The high-frequency virtual inertia original support command for the photovoltaic power station is generated based on the high-frequency fast component of the frequency deviation and the high-frequency fast component of the frequency change rate; the low-frequency inertia damping original support command for the hydropower unit is generated based on the low-frequency continuous component of the frequency deviation and the low-frequency continuous component of the frequency change rate. A safety filter is constructed using the electromagnetic safety envelope on the photovoltaic side and the hydraulic safety envelope on the hydropower side. The original support command for the high-frequency virtual inertia and the original support command for the low-frequency inertia damping are then subjected to safety filtering to obtain the high-frequency virtual inertia support command for controlling the output of the photovoltaic power station and the low-frequency inertia damping support command for controlling the output of the hydropower unit.

2. The method according to claim 1, characterized in that, The reliability of the frequency measurement is determined using the following formula based on the frequency estimate from the grid side of the hydro-solar hybrid power generation system and the frequency estimate obtained from the phase-locked loop of the photovoltaic inverter in the photovoltaic power station: in, To assess the reliability of the frequency measurement, This refers to the frequency estimate on the grid side of the aforementioned hydro-solar hybrid power generation system. The frequency estimate is obtained from the phase-locked loop of the photovoltaic inverter in the photovoltaic power station. The total harmonic distortion (THD) of the grid connection voltage in the aforementioned hydro-solar hybrid power generation system is given. This represents the absolute value of the rate of change of the bus voltage. This refers to the negative sequence voltage component or voltage imbalance. To measure data packet loss rate or data quality anomaly indicators, This is the credibility weighting coefficient.

3. The method according to claim 1, characterized in that, Based on the photovoltaic support margin of the photovoltaic power station and the hydropower mobility margin of the hydropower unit, the frequency band decoupling filter coefficients are determined using the following formula: in, These are the frequency band decoupling filter coefficients. To control the cycle, The frequency band boundary time constant, For the amplitude limiting function, This is the hydraulic time-scale adjustment coefficient. For hydraulic start-up time, For the photovoltaic support margin, For power grid strength margin, The aforementioned hydropower mobility margin, This is the lower limit of the time constant for frequency band boundaries. The upper limit of the frequency band boundary time constant, satisfying .

4. The method according to claim 3, characterized in that, Based on the frequency band decoupling filter coefficients, the frequency deviation at the grid connection point of the hydro-solar hybrid power generation system is decomposed into a low-frequency continuous component and a high-frequency fast component of the frequency deviation using the following formula: in, For the first The low-frequency continuous component of the frequency deviation per control cycle For the first The low-frequency continuous component of the frequency deviation per control cycle For the first The frequency deviation of each control cycle These are the decoupling filter coefficients for the frequency band. For the first The high-frequency fast component of the frequency deviation of each control cycle; Based on the frequency band decoupling filter coefficients, the frequency change rate at the grid connection point of the hydro-solar hybrid power generation system is decomposed into a low-frequency continuous component and a high-frequency fast component of the frequency change rate using the following formula: in, For the first The low-frequency continuous component of the frequency change rate per control cycle For the first The low-frequency continuous component of the frequency change rate per control cycle For the first The rate of change of the frequency in each control cycle, These are the decoupling filter coefficients for the frequency band. For the first The high-frequency fast component of the frequency change rate of each control cycle.

5. The method according to claim 4, characterized in that, The high-frequency virtual inertia original support command for the photovoltaic power station is generated based on the high-frequency fast component of the frequency deviation and the high-frequency fast component of the frequency change rate using the following formula: in, This refers to the original support command for the high-frequency virtual inertia. For photovoltaic virtual inertia gain, The high-frequency fast component of the frequency change rate. For photovoltaic virtual damping gain, For the high-frequency fast component of frequency deviation, To support the coupling gain of photovoltaic voltage, This refers to the bus voltage deviation. The low-frequency inertia damping original support command for the hydroelectric generator is generated based on the low-frequency continuous component of the frequency deviation and the low-frequency continuous component of the frequency change rate using the following formula: in, This refers to the original support command for the low-frequency inertia damping. For low-frequency inertia gain in hydropower, The low-frequency continuous component of the rate of change of frequency. For low-frequency damping gain of hydropower, This is the low-frequency continuous component of the frequency deviation. For energy recovery gain, This is due to discrepancies in the photovoltaic energy ledger.

6. The method according to claim 1, characterized in that, The photovoltaic-side electromagnetic safety envelope is expressed by the following formula: in, This is the electromagnetic safety envelope on the photovoltaic side. This is the command that supports the high-frequency virtual inertia. This represents the current active power output of the photovoltaic system. This represents the maximum power point power under the current irradiance and temperature conditions. This represents the current reactive power output of the photovoltaic system. This refers to the AC side voltage amplitude of the inverter. The maximum allowable AC current for the inverter. This is the DC bus voltage. This is the safe lower limit for DC bus voltage. The equivalent energy available for virtual inertia support on the photovoltaic side. This is the lower limit of the equivalent energy safety for the photovoltaic side. Inverter thermal state indicators This is the upper limit of the allowable thermal state of the inverter. Reserve backup capacity for photovoltaic power. Minimum reserve capacity required to maintain subsequent frequency support; The hydraulic safety envelope on the hydroelectric side is expressed by the following formula: in, This is the hydraulic safety envelope on the hydroelectric side. This refers to the low-frequency inertia damping support command. This refers to the current active power output of the hydroelectric generator unit. This refers to the minimum permissible active power output of the hydroelectric generator unit. The maximum allowable active power output of the hydropower unit satisfies the following conditions. , The current guide vane opening, To achieve the required guide vane opening correction for additional support power, This is the lower limit of the guide vane opening. The upper limit of the guide vane opening must satisfy... , The rate of change of guide vane opening. This represents the upper limit of the rate of change of guide vane opening. The guide vane opening acceleration, This is the upper limit of the guide vane opening acceleration. For predicting time The pressure in the pipeline at any given time, This refers to the lower limit of the allowable pressure for pressure pipelines. The upper limit of the allowable pressure for pressure pipelines must meet the following requirements. , This is due to the deviation in the speed of the turbine or generator. To set the allowable speed deviation limit, For unit vibration indicators, This is the upper limit of the unit's permissible vibration. To predict the time step.

7. The method according to claim 6, characterized in that, The objective function of the security filter is expressed as: in, This is the support instruction vector after security filtering. This is the command that supports the high-frequency virtual inertia. This refers to the low-frequency inertia damping support command. This is the original support command vector. This refers to the original support command for the high-frequency virtual inertia. This refers to the original support command for the low-frequency inertia damping. As slack variables, This is the instruction deviation weight matrix. The superscript represents the penalty coefficient for slack variables. This is the transpose symbol.

8. The method according to claim 1, characterized in that, When the frequency measurement confidence level is less than the high confidence level threshold and the frequency measurement confidence level is greater than or equal to the preset low confidence level threshold, the photovoltaic inverter reduces the virtual inertia gain and enters the limiting support state.

9. The method according to claim 1, characterized in that, When the reliability of the frequency measurement is less than the low reliability threshold, the photovoltaic inverter freezes the slope of the most recent reliable frequency or enters a current-limiting hold state.

10. A virtual inertia cooperative control device for a hydro-solar hybrid power generation system, wherein the hydro-solar hybrid power generation system includes a hydropower unit and a photovoltaic power station, characterized in that, include: The acquisition module is used to determine the reliability of the frequency measurement based on the frequency estimate on the grid side of the hydro-solar hybrid power generation system and the frequency estimate obtained by the phase-locked loop of the photovoltaic inverter of the photovoltaic power station; The determination module is used to determine the frequency band decoupling filter coefficients based on the photovoltaic support margin of the photovoltaic power station and the hydropower mobility margin of the hydropower unit when the frequency measurement confidence is greater than or equal to a preset high confidence threshold. The decomposition module is used to decompose the frequency deviation and frequency change rate of the hydro-solar hybrid power generation system at the grid connection point into a low-frequency continuous component of the frequency deviation, a high-frequency fast component of the frequency deviation, a low-frequency continuous component of the frequency change rate, and a high-frequency fast component of the frequency change rate, based on the frequency band decoupling filter coefficients. The generation module generates the original high-frequency virtual inertia support command for the photovoltaic power station based on the high-frequency fast component of the frequency deviation and the high-frequency fast component of the frequency change rate, and generates the original low-frequency inertia damping support command for the hydropower unit based on the low-frequency continuous component of the frequency deviation and the low-frequency continuous component of the frequency change rate. The safety filtering module is used to construct a safety filter using the electromagnetic safety envelope of the photovoltaic side and the hydraulic safety envelope of the hydropower side, and to perform safety filtering on the original support command of the high-frequency virtual inertia and the original support command of the low-frequency inertia damping, so as to obtain the high-frequency virtual inertia support command for controlling the output of the photovoltaic power station and the low-frequency inertia damping support command for controlling the output of the hydropower unit.

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