New energy power station grid connection method and system based on satellite time service and synchronous compensation

Abstract

The application discloses a new energy power station grid connection method and system based on Beidou satellite timing and synchronous compensation, and the method comprises the following steps: receiving a Beidou satellite timing signal, generating a unified reference synchronous time, and calculating a reference synchronous phase angle according to the reference synchronous time; taking the reference synchronous phase angle as a control reference, driving a network type inverter to perform a grid connection operation; monitoring a Beidou timing signal integrity index in real time, and when detecting that the Beidou timing signal is abnormal or invalid, starting at least one level of synchronous compensation mechanism according to the abnormal or invalid duration and the system operation state, so as to maintain the phase continuity and frequency stability of the new energy power station grid connection operation.

Description

Technical Field

[0001] This invention belongs to the field of new energy power plant grid connection technology, and more specifically, relates to a new energy power plant grid connection method and system based on satellite timing and synchronization compensation. Background Technology

[0002] The penetration rate of intermittent and random renewable energy sources such as photovoltaics and wind power in the power grid is constantly increasing. This poses a severe challenge to the stability, security, and power quality of the power grid. Renewable energy power plants are connected to the grid through power electronic inverters, which do not possess the rotational inertia and damping characteristics of traditional synchronous generators. This leads to a decrease in the equivalent inertia of the power grid and prominent frequency stability issues.

[0003] The existing technology has the following main drawbacks:

[0004] 1. Time Synchronization Dependence and Uniqueness: Existing virtual synchronizing technologies largely rely on Global Positioning Systems (such as GPS) for time synchronization. This not only poses a technological dependency risk, but also means that when GPS signals are interfered with, blocked, or fail (e.g., due to severe weather, geomagnetic storms, or human interference), the grid-connected units will lose a unified time reference, leading to increased phase synchronization errors and potentially causing grid connection shocks, oscillations, or even grid disconnection.

[0005] 2. Rigid Synchronization Mechanism: Traditional grid-following inverters strictly track grid voltage and frequency, failing to provide inertial and damping support to the grid. Existing virtual synchronous machine technology typically uses fixed parameters when simulating the rotor motion equations of a synchronous machine. Under conditions of rapid grid frequency changes or complex faults, its adaptive capability is insufficient, and its dynamic response characteristics are unsatisfactory.

[0006] 3. Inadequate response to loss of synchronization: Current technical solutions generally lack systematic and coordinated response strategies for situations where satellite timing signals are lost for extended periods. Simply switching to a local crystal oscillator can lead to phase accumulation errors, making it impossible to maintain phase consistency among multiple distributed power stations, which is detrimental to the stability of the regional power grid.

[0007] Therefore, there is an urgent need for a technical solution that can solve the above technical problems. Summary of the Invention

[0008] To address the above technical problems, this invention proposes a grid connection method for new energy power plants based on satellite timing and synchronization compensation, wherein the satellite timing is BeiDou satellite timing, including:

[0009] Receive BeiDou satellite timing signals, generate a unified reference synchronization time, and calculate the reference synchronization phase angle based on the reference synchronization time;

[0010] Using the aforementioned reference synchronization phase angle as the control reference, the grid-connected inverter is driven to perform grid-connected operation;

[0011] The integrity indicators of the BeiDou timing signal are monitored in real time. When an abnormality or failure of the BeiDou timing signal is detected, at least one level of synchronization compensation mechanism is activated based on the duration of the abnormality or failure and the system operating status to maintain the phase continuity and frequency stability of the grid-connected operation of the new energy power plant.

[0012] Furthermore, the integrity indicators of the BeiDou timing signal include at least one BeiDou timing-related indicator, which includes:

[0013] The carrier-to-noise ratio of BeiDou satellite radio frequency signals, the locking status of BeiDou satellite timing calculation, and the duration of interruption of BeiDou satellite timing signals;

[0014] When the carrier-to-noise ratio is lower than the preset carrier-to-noise ratio threshold, it is determined that the timing signal reception quality is abnormal.

[0015] When the time synchronization calculation lock state switches from locked to unlocked, the time synchronization function is determined to be abnormal.

[0016] When the duration of the interruption of the timing signal exceeds a preset time threshold, the timing signal is determined to be invalid.

[0017] Furthermore, when the duration of the anomaly or failure is less than or equal to the first threshold, a first-level synchronization compensation mechanism is activated. The first-level synchronization compensation mechanism includes: switching to a local high-stability timekeeping module, which is used to continuously output the local time during the time synchronization signal anomaly or failure.

[0018] The historical frequency deviation sequence of the local clock relative to BeiDou time was collected and stored during the normal period of BeiDou satellite timing signal.

[0019] Based on the historical frequency deviation sequence, drift prediction and compensation are performed on the local time output by the local high-stability timekeeping module to generate a compensated time;

[0020] The compensation synchronization phase angle is calculated based on the compensation time and used for subsequent grid connection control.

[0021] Furthermore, the drift prediction and compensation for the local time output by the local high-stability timekeeping module includes:

[0022] Trend modeling is performed on historical frequency deviation sequences to obtain frequency drift parameters characterizing the long-term drift characteristics of the local high-stability timekeeping module;

[0023] Exponential smoothing is performed on the historical frequency deviation sequence after trend modeling to obtain the disturbance compensation amount used to compensate for short-term fluctuations.

[0024] During periods of time synchronization signal abnormality or failure, the local time output by the local high-stability timekeeping module is iteratively drift-corrected based on the frequency drift parameters and disturbance compensation amount to generate a compensated time.

[0025] Furthermore, when the duration of the anomaly or failure is less than the first threshold and less than or equal to the second threshold, a secondary synchronization compensation mechanism is activated. The secondary synchronization compensation mechanism includes:

[0026] Within the area of ​​a new energy power plant that meets communication delay and electrical topology constraints, each synchronization control terminal periodically broadcasts synchronization status information including timing status, timekeeping accuracy, and time stability parameters.

[0027] Based on the received synchronization status information, the credibility of the synchronization control terminals within the area is evaluated, and at least one reference terminal is selected.

[0028] The communication delay between the local synchronization control terminal and the reference terminal is measured, and the synchronization phase angle reported by the reference terminal is compensated for the delay to generate a reference synchronization phase angle.

[0029] Calculate the phase deviation between the local synchronization phase angle and the reference synchronization phase angle after delay compensation, and perform multiple rounds of sampling and robust processing on the phase deviation to obtain a robust phase deviation estimate.

[0030] Based on the robust phase deviation estimate, the compensated synchronization phase angle is progressively corrected to achieve phase resynchronization within the region.

[0031] Furthermore, when the duration of the anomaly or failure exceeds the second threshold, a three-level synchronization compensation mechanism is activated. This three-level synchronization compensation mechanism includes:

[0032] Real-time acquisition of grid frequency and grid frequency change rate at the grid connection point, and acquisition of operating status parameters of the local synchronization control terminal;

[0033] The dynamic virtual inertia coefficient is calculated based on the power grid frequency deviation, power grid frequency change rate, operating status parameters, and duration of abnormality or failure.

[0034] Based on the dynamic virtual inertia coefficient, the rate of change of the corrected compensated synchronization phase angle is adjusted so that the synchronization phase angle evolves continuously with the change of the power grid frequency.

[0035] As the duration of anomalies or failures increases, the dynamic virtual inertia coefficient is attenuated to gradually reduce the response strength of the synchronization phase angle to frequency changes.

[0036] The synchronization phase angle is updated based on the rate of change of the adjusted synchronization phase angle for grid connection control.

[0037] This invention also proposes a grid-connected system for new energy power plants based on satellite timing and synchronization compensation, wherein the satellite timing is BeiDou satellite timing, including:

[0038] The timing module is used to receive BeiDou satellite timing signals, generate a unified reference synchronization time, and calculate the reference synchronization phase angle based on the reference synchronization time.

[0039] The grid-connection module is used to drive the grid-connected inverter to perform grid-connection operations based on the reference synchronous phase angle.

[0040] The compensation module is used to monitor the integrity indicators of the BeiDou timing signal in real time. When an abnormality or failure of the BeiDou timing signal is detected, at least one level of synchronization compensation mechanism is activated according to the duration of the abnormality or failure and the system operating status to maintain the phase continuity and frequency stability of the grid-connected operation of the new energy power plant.

[0041] Furthermore, the integrity indicators of the BeiDou timing signal include at least one BeiDou timing-related indicator, which includes:

[0042] The carrier-to-noise ratio of BeiDou satellite radio frequency signals, the locking status of BeiDou satellite timing calculation, and the duration of interruption of BeiDou satellite timing signals;

[0043] When the carrier-to-noise ratio is lower than the preset carrier-to-noise ratio threshold, it is determined that the timing signal reception quality is abnormal.

[0044] When the time synchronization calculation lock state switches from locked to unlocked, the time synchronization function is determined to be abnormal.

[0045] When the duration of the interruption of the timing signal exceeds a preset time threshold, the timing signal is determined to be invalid.

[0046] Furthermore, when the duration of the anomaly or failure is less than or equal to the first threshold, a first-level synchronization compensation mechanism is activated. The first-level synchronization compensation mechanism includes: switching to a local high-stability timekeeping module, which is used to continuously output the local time during the time synchronization signal anomaly or failure.

[0047] The historical frequency deviation sequence of the local clock relative to BeiDou time was collected and stored during the normal period of BeiDou satellite timing signal.

[0048] Based on the historical frequency deviation sequence, drift prediction and compensation are performed on the local time output by the local high-stability timekeeping module to generate a compensated time;

[0049] The compensation synchronization phase angle is calculated based on the compensation time and used for subsequent grid connection control.

[0050] Furthermore, the drift prediction and compensation for the local time output by the local high-stability timekeeping module includes:

[0051] Trend modeling is performed on historical frequency deviation sequences to obtain frequency drift parameters characterizing the long-term drift characteristics of the local high-stability timekeeping module;

[0052] Exponential smoothing is performed on the historical frequency deviation sequence after trend modeling to obtain the disturbance compensation amount used to compensate for short-term fluctuations.

[0053] During periods of time synchronization signal abnormality or failure, the local time output by the local high-stability timekeeping module is iteratively drift-corrected based on the frequency drift parameters and disturbance compensation amount to generate a compensated time.

[0054] In summary, the technical solutions conceived by this invention have the following beneficial effects compared with the prior art:

[0055] 1. High degree of autonomy and security: Completely free from dependence on GPS, it adopts the independently controllable BeiDou system as the core reference. A multi-level compensation mechanism constitutes a quadruple guarantee of "BeiDou as the main system - local timekeeping - regional coordination - inertial maintenance", making the system extremely robust.

[0056] 2. High synchronization accuracy and good consistency: The unified time synchronization based on BeiDou ensures strict initial phase synchronization of all new energy power stations within a wide area. Even after a loss of lock, intelligent compensation can maintain phase consistency among power station groups for a long time, avoiding operational risks caused by accumulated errors.

[0057] 3. True grid construction capability and active support: Deeply integrating BeiDou timing into grid-based control transforms new energy power plants from "followers" to "supporters," providing valuable inertia and primary frequency regulation functions to the power grid, significantly improving the stability of high-proportion new energy power grids.

[0058] 4. Wide applicability: It is particularly suitable for remote areas, islands and new energy power plants that form microgrids with weak communication infrastructure, solving the problem of synchronous control signal source in these scenarios. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the network structure of the present invention;

[0060] Figure 2 This is a flowchart of the method in Embodiment 1 of the present invention;

[0061] Figure 3 This is a system structure diagram of Embodiment 2 of the present invention. Detailed Implementation

[0062] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0063] The method provided by this invention can be implemented in a terminal environment that may include one or more of the following components: a processor, a storage medium, and a display screen. The storage medium stores at least one instruction, which is loaded and executed by the processor to implement the method described in the following embodiments.

[0064] A processor may include one or more processing cores. The processor uses various interfaces and lines to connect various parts of the terminal, and performs various functions and processes data by running or executing instructions, programs, code sets or instruction sets stored in the storage medium, and by calling data stored in the storage medium.

[0065] Storage media can include random access memory (RAM) or read-only memory (ROM). Storage media can be used to store instructions, programs, code, code sets, or instructions.

[0066] The display screen is used to show the user interface of each application.

[0067] In addition, those skilled in the art will understand that the structure of the terminal described above does not constitute a limitation on the terminal. The terminal may include more or fewer components, or combine certain components, or have different component arrangements. For example, the terminal may also include radio frequency circuits, input units, sensors, audio circuits, power supplies, and other components, which will not be described in detail here.

[0068] like Figure 1 As shown, the present invention includes a central coordinator and at least one synchronous control terminal distributed in each new energy power station.

[0069] The synchronization control terminal further includes:

[0070] BeiDou multi-mode timing module: used to receive signals from BeiDou satellites at frequencies such as B1C and B2a, generate high-precision, high-integrity second pulses and standard time information, and calculate integrity indicators such as signal carrier-to-noise ratio and ionospheric delay in real time.

[0071] High-stability timekeeping module: Built-in temperature-controlled crystal oscillator or rubidium atomic clock to provide a local high-precision clock reference during BeiDou signal failure.

[0072] Phase generation unit: Receives timing information and generates a unified reference synchronization phase angle for inverter control. .

[0073] Multi-source information fusion and compensation calculation unit: This unit receives electrical measurement data from the BeiDou timing module, the local power station, and synchronization status information from neighboring power stations transmitted via the communication network. This unit executes the core algorithm of this invention to achieve three-level clock compensation.

[0074] Grid-type inverter controller: Receives the reference phase angle from the phase generation unit, executes grid-type control algorithms such as power-phase angle droop control and voltage-frequency adaptive adjustment, and drives the inverter power switch.

[0075] Power grid status monitoring unit: Real-time monitoring of voltage, frequency, harmonic distortion rate and equivalent impedance of the power grid at the grid connection point.

[0076] The central coordinator is deployed in a regional dispatch center or cloud platform, including:

[0077] Global Status Monitoring Module: Collects the working status, timing quality, and electrical information of all synchronous control terminals and grid connection points.

[0078] Regional synchronization arbitration module: When BeiDou signals fail over a large area, it calculates and distributes the optimal virtual synchronization benchmark for the region based on the accuracy level and historical data of the timekeeping modules of each terminal.

[0079] Coordinated control command generation module: Based on the power grid operation requirements, it issues unified frequency regulation and voltage regulation parameters or power reference values ​​to each terminal.

[0080] Example 1

[0081] like Figure 2 As shown, this embodiment proposes a grid connection method for new energy power plants based on satellite timing and synchronization compensation. The satellite timing is BeiDou satellite timing, including:

[0082] Step 101: Receive the BeiDou satellite timing signal, generate a unified reference synchronization time, and calculate the reference synchronization phase angle based on the reference synchronization time;

[0083] Specifically, by locking onto the BeiDou signal and using BeiDou second pulses and high-precision time information, a unified reference synchronization phase angle that is strictly synchronized with UTC time is generated. ,in The rated frequency (e.g., 50Hz). This is for BeiDou time.

[0084] Step 102: Using the reference synchronous phase angle as the control reference, drive the grid-connected inverter to perform grid-connection operation;

[0085] Specifically, the inverter controller is... Using the phase reference, a grid-based control strategy is implemented to simulate the rotor motion equations of a synchronous generator, outputting active and reactive power. Preferably, the time-frequency signal of the BeiDou system is used as the sole and reliable synchronization basis to drive power electronic equipment to simulate and surpass the grid-based behavior of traditional synchronous generators. This transforms the new energy power station from a passive "generation unit" into an active "grid support unit." The specific strategy is as follows:

[0086] 1) Unified benchmark: The grid control of all power plants is based on the same phase angle. Using a single time origin, the phase accumulation error caused by multi-station parallel operation is fundamentally eliminated.

[0087] 2) Unity of Synchronization and Network Construction: BeiDou not only provides "synchronization" signals, but also... The (BeiDou reference angular velocity) becomes the stable equilibrium point of the network control equations. When the satellite signal is normal, the system is a strictly synchronized network source; after the signal is lost, the three-level compensation mechanism (especially the first-level timekeeping and the third-level inertial maintenance) essentially maintains the estimated value of this equilibrium point to ensure continuous control.

[0088] 3) Provides a carrier for the compensation mechanism: Any phase correction amount generated in the three-level compensation is transmitted through... Or directly to The adjustment of the (virtual rotor angle) is seamlessly integrated into this network control framework, achieving an organic unity of "synchronization" and "power control".

[0089] It serves as a bridge connecting "time synchronization" and "power control": it transforms time information from BeiDou or compensation algorithms into electrical angles usable by the power system to determine the phase of power exchange, and is a key virtual quantity for realizing the transformation of new energy power plants from "following the grid" to "building the grid".

[0090] Step 103: Monitor the integrity index of BeiDou timing signal in real time. When an abnormality or failure of BeiDou timing signal is detected, activate at least one level of synchronization compensation mechanism according to the duration of the abnormality or failure and the system operation status to maintain the phase continuity and frequency stability of the grid-connected operation of new energy power plants.

[0091] Specifically, the integrity indicators of the BeiDou timing signal include at least one BeiDou timing-related indicator, which includes:

[0092] The carrier-to-noise ratio of BeiDou satellite radio frequency signals, the locking status of BeiDou satellite timing calculation, and the duration of interruption of BeiDou satellite timing signals;

[0093] When the carrier-to-noise ratio is lower than the preset carrier-to-noise ratio threshold, it is determined that the timing signal reception quality is abnormal.

[0094] When the time synchronization calculation lock state switches from locked to unlocked, the time synchronization function is determined to be abnormal.

[0095] When the duration of the interruption of the timing signal exceeds a preset time threshold, the timing signal is determined to be invalid.

[0096] Specifically, when the duration of the anomaly or failure is less than or equal to the first threshold, a first-level synchronization compensation mechanism is activated. The first-level synchronization compensation mechanism includes: switching to the local high-stability timekeeping module, which is used to continuously output the local time during the time synchronization signal anomaly or failure.

[0097] The historical frequency deviation sequence of the local clock relative to BeiDou time was collected and stored during the normal period of BeiDou satellite timing signal.

[0098] Based on the historical frequency deviation sequence, drift prediction and compensation are performed on the local time output by the local high-stability timekeeping module to generate a compensated time;

[0099] The compensation synchronization phase angle is calculated based on the compensation time and used for subsequent grid connection control.

[0100] Specifically, the drift prediction and compensation for the local time output by the local high-stability timekeeping module includes:

[0101] Trend modeling is performed on historical frequency deviation sequences to obtain frequency drift parameters characterizing the long-term drift characteristics of the local high-stability timekeeping module;

[0102] Exponential smoothing is performed on the historical frequency deviation sequence after trend modeling to obtain the disturbance compensation amount used to compensate for short-term fluctuations.

[0103] During periods of time synchronization signal abnormality or failure, the local time output by the local high-stability timekeeping module is iteratively drift-corrected based on the frequency drift parameters and disturbance compensation amount to generate a compensated time.

[0104] Preferably, Level 1 compensation (high-precision short-term timekeeping): immediately switch to the local high-stability timekeeping module, and at the same time, call the historical clock drift rate data stored before the signal lost lock, perform short-term offset prediction and compensation for the local clock, and minimize the initial phase jump and accumulated error.

[0105] After losing lock, the local high-stability timekeeping module performs the following steps:

[0106] 1) Historical frequency deviation estimation: During the normal signal period, calculate the historical frequency deviation sequence y(k) of the local clock relative to the BeiDou time according to the period Δt, and save the most recent N samples.

[0107] 2) Model establishment: At time t0, perform linear regression on the y(k) sequence to obtain the trend term. Calculate the residuals and perform exponential smoothing to obtain the fluctuation term. Synthetic predicted value (The predicted value of the relative frequency deviation of the local high-stability clock at any future time t).

[0108] This is a linear prediction model for the frequency drift of locally stable clocks (such as oven-controlled crystal oscillators, OCXOs), used for high-precision timekeeping in first-level compensation. Its specific meaning is as follows:

[0109] a: Linear drift rate (unit: seconds / second² or dimensionless). It quantifies the rate of aging of the clock frequency over time and is an extremely small constant (e.g., 1). e-10 / day). a>0 indicates that the clock is running faster and faster, a<0 ​​indicates that it is running slower and slower. This is the key to predicting medium- to long-term drift.

[0110] t: Time variable. Calculations are usually started from the moment t0 when BeiDou loses lock.

[0111] b: Initial relative frequency deviation (dimensionless) at the moment of loss of lock t0. It represents the slight offset of the local clock frequency relative to the BeiDou standard frequency at that instant t0.

[0112] 3) Time compensation calculation: After the lock is lost, the compensated BeiDou time is calculated iteratively using the following formula:

[0113]

[0114] in, . The time is the BeiDou time after compensation in the i-th calculation cycle; This is the reading of the local high-stability clock during the i-th calculation cycle; In order to be in At this moment, the predicted relative frequency deviation of the local clock; It is the instant of loss of lock ( The last real BeiDou time recorded.

[0115] 4) Phase angle generation: The final output synchronization phase angle is .

[0116] This algorithm can control the synchronization phase angle error within ±0.01 degrees during the T1 period after the lock is lost.

[0117] Specifically, when the duration of an anomaly or failure is less than the first threshold and less than or equal to the second threshold, a secondary synchronization compensation mechanism is activated. The secondary synchronization compensation mechanism includes:

[0118] Within the area of ​​a new energy power plant that meets communication delay and electrical topology constraints, each synchronization control terminal periodically broadcasts synchronization status information including timing status, timekeeping accuracy, and time stability parameters.

[0119] Based on the received synchronization status information, the credibility of the synchronization control terminals within the area is evaluated, and at least one reference terminal is selected.

[0120] The communication delay between the local synchronization control terminal and the reference terminal is measured, and the synchronization phase angle reported by the reference terminal is compensated for the delay to generate a reference synchronization phase angle.

[0121] Calculate the phase deviation between the local synchronization phase angle and the reference synchronization phase angle after delay compensation, and perform multiple rounds of sampling and robust processing on the phase deviation to obtain a robust phase deviation estimate.

[0122] Based on the robust phase deviation estimate, the compensated synchronization phase angle is progressively corrected to achieve phase resynchronization within the region.

[0123] Preferably, secondary compensation (power plant cluster coordinated correction): If the BeiDou signal is not restored after a preset time interval, secondary compensation is initiated. The synchronization control terminal performs phase comparison with one or more "reference terminals" (whose timekeeping module has the highest accuracy or still has a valid BeiDou signal) via a dedicated power fiber optic network or power line carrier communication. Based on the comparison results, a one-time phase correction is performed on the local phase generation unit to achieve phase resynchronization within a region. The region refers to a cluster of new energy power plants with low latency, high reliability communication conditions, and tight electrical connections. The specific implementation process is as follows:

[0124] Step 1: Refer to the terminal discovery and trustworthiness assessment mechanism to calculate time-varying weights based on multi-dimensional state information (lock status, hardware level, historical stability).

[0125] Each terminal (denoted as T) i Periodically broadcast its own state vector S i :

[0126] S i ={Terminal_ID: Unique identifier for the terminal,

[0127] Lock_Status: [BeiDou lock, Level 1 timekeeping, ...],

[0128] Clock_Grade: The precision level of the timekeeping module (e.g., OCXO=1, TCXO=2).

[0129] Sigma_t: The standard deviation of its own time bias estimate over a recent period.

[0130] T_last_update: Status update timestamp}

[0131] Each terminal receives S from its neighboring terminals. j And calculate the dynamic credibility weight W for each neighbor. ij :

[0132]

[0133] in: , , The weighting coefficients are adjustable, and + + =1.

[0134] F(·) is the state function: BeiDou lock = 1.0, Level 1 timekeeping = 0.7, others = 0.2.

[0135] G(·) is a rank function: high-stability rubidium clock = 1.0, OCXO = 0.8, TCXO = 0.3.

[0136] This reflects the stability of the terminal's own time; the more stable it is, the higher its weight.

[0137] Terminal T i Weight W ij Above the threshold W th Add all neighbors to its list of valid reference sources R i .

[0138] Step 2: Robust phase alignment and multi-source data fusion: A complete alignment process combining precise delay compensation, multiple rounds of sampling, gross error removal based on median absolute deviation, and weighted averaging.

[0139] 1) Precise delay measurement and compensation:

[0140] A). To T j Send a query message with the exact local send timestamp t_s.

[0141] B).T j Upon receipt, immediately reply with a message containing its receipt timestamp t_r, reply timestamp t_t, and current phase angle θ. j The message.

[0142] C).T i A reply was received at time t_r'.

[0143] D) Calculate the network round-trip delay and estimate the one-way delay:

[0144] RTT = (t_r' - t_s) - (t_t - t_r)

[0145] Assuming the path is symmetric, the propagation delay δ = RTT / 2.

[0146] E). T j The phase angle θ in the report j The impact of compensating for propagation delay:

[0147]

[0148] θ j_corrected (t_r'): The corrected reference phase, representing the phase at the local terminal T. i At the unified time point t_r' of the reception time, the estimated phase value that the reference terminal T_j should have, θ j (t_t): The original phase of the reference terminal, where the reference terminal T is located. j The real-time phase value ω is measured and transmitted at its own clock transmission time t_t. nom δ is the estimated one-way communication delay at the rated angular frequency.

[0149] 2) Local phase difference calculation

[0150] A) At time t_r', terminal T i Its phase is θ i (t_r').

[0151] B) Calculation and Reference Source T j Instantaneous phase difference:

[0152] Δθ ij = θ j_corrected (t_r')-θ i (t_r')

[0153] 3) Multi-round sampling and gross error removal

[0154] A) Repeat step 2) M times (e.g., M=5) to obtain a set of phase difference samples {Δθ}. ij (1), ..., Δθ ij (M)}.

[0155] B) Robust filtering using the median absolute deviation method:

[0156] (a) Calculate the sample median Med.

[0157] (b) Calculate the absolute deviation |Δθ| from the median for each sample. ij (k) - Med|.

[0158] (c) If the absolute deviation of a sample is greater than 3 times the median absolute deviation (MAD), it is considered a gross error and is discarded.

[0159] C) Averaging the remaining L valid samples yields a robust phase difference estimate Δθ. ij_avg .

[0160] Step 3: Adaptive Weighted Phase Correction: Unlike the traditional master-slave one-time hard correction, it adopts a distributed asymptotic approximation synchronization algorithm based on proportional-integral adjustment, namely:

[0161] Terminal T i By combining information from all valid reference sources, a global correction is calculated:

[0162] 1) Calculate the weighted average phase difference:

[0163]

[0164] Δθ i_global Terminal T i The globally weighted average phase deviation represents the terminal T i The deviation between the current phase of the [entity] and the "regional consensus phase" formed by all its trusted reference sources. R i Terminal T i The set of valid reference sources for T. i The phase deviation relative to the entire trusted neighbor network. Wij: Terminal T i Assigning reference source T j The dynamic credibility weight. Δθ ij_avg Terminal T i With reference source T j The robust average phase difference between the two phases after robust processing. Σ{j in R i}: For all valid reference source sets R i The reference terminal j in the middle is summed.

[0165] 2) Determine the necessity of correction:

[0166] If |Δθ i_global If |<ε (ε is a small threshold, such as 0.01 radians), then the local phase is considered to be consistent with the regional network and no correction is required; otherwise, proceed with the correction process.

[0167] 3) Progressive proportional-integral correction:

[0168] a) To avoid phase jumps and power oscillations caused by a large one-time correction, a gradual PI regulator is used:

[0169]

[0170] Where: Correction_Step(k) is the phase correction step size of the kth control cycle, representing the amount of adjustment to be made to the local phase in this cycle; Kp and Ki are the proportional and integral coefficients, respectively; Ki is a very small value to ensure that the steady-state error is eliminated slowly and smoothly; h is the index of the historical control cycle, which traverses all discrete control cycles from the correction start time (or a certain starting point) to the previous cycle of the current cycle k.

[0171] b) Adjust the offset of the local phase generation unit using Correction_Step(k) as the increment:

[0172] θ i_new (t)=θ i_old (t)+Correction_Step(k)

[0173] Where: θ i_new (t): After applying correction, the terminal T i The new phase value over continuous time t. θ i_old (t): Terminal T before correction is applied i The original phase value over continuous time t.

[0174] c) This process continues for several control cycles until Δθ i_global Reduce to within the threshold ε.

[0175] Step 4: Network Consistency Monitoring and Anomaly Isolation: The system has the ability to identify and isolate abnormal nodes, maintaining the overall health and consistency of the regional synchronization network.

[0176] The central coordinator or an elected "master monitoring terminal" collects Δθ from all terminals. i_global Based on the confidence weights, a regional phase consistency matrix is ​​constructed. If a certain terminal T is found... x If a node's phase angle consistently deviates significantly from the network's mainstream value, and its credibility weight is rated low by most of its neighbors, the coordinator can mark it as an "abnormal node" and notify other terminals to temporarily reduce W in the next round of calculation. ix Weights or their reduction from R i Remove from the network to achieve self-healing and isolation.

[0177] Specifically, when the duration of an anomaly or failure exceeds the second threshold, a three-level synchronization compensation mechanism is activated. This mechanism includes:

[0178] Real-time acquisition of grid frequency and grid frequency change rate at the grid connection point, and acquisition of operating status parameters of the local synchronization control terminal;

[0179] The dynamic virtual inertia coefficient is calculated based on the power grid frequency deviation, power grid frequency change rate, operating status parameters, and duration of abnormality or failure.

[0180] Based on the dynamic virtual inertia coefficient, the rate of change of the corrected compensated synchronization phase angle is adjusted so that the synchronization phase angle evolves continuously with the change of the power grid frequency.

[0181] As the duration of anomalies or failures increases, the dynamic virtual inertia coefficient is attenuated to gradually reduce the response strength of the synchronization phase angle to frequency changes.

[0182] The synchronization phase angle is updated based on the rate of change of the adjusted synchronization phase angle for grid connection control.

[0183] The preferred method is three-level compensation (dynamic maintenance of virtual inertia): the fixed virtual inertia coefficient is deepened into a dynamic virtual inertia DVI(t). DVI(t) is calculated in real time through a multi-layer decision model, comprehensively considering the deviation and rate of change of grid frequency (demand layer), local voltage and power safety boundaries (protection layer), and the duration of unlocking (attenuation layer). Based on this dynamic inertia, the system adjusts the phase change rate in real time and introduces frequency change rate feedforward. This mechanism enables new energy power plants to smoothly and safely transition from an active grid support mode to a cautious grid-following mode after long-term unlocking. While providing inertial response, it absolutely ensures the stability of the grid-connected equipment itself, realizing the intelligent unity of synchronization maintenance, grid support, and equipment safety. The specific steps are as follows:

[0184] 1) Dynamic virtual inertia

[0185]

[0186] DVI(t): Dynamic virtual inertia. Δf = f grid -f nom : Grid frequency deviation. δ: Feedforward regulation term, used for rapid response to frequency change rate. Where: Δf: Real-time grid frequency deviation, which is the most critical feedback signal and trigger variable in the entire control system; f grid The actual frequency at the point of common coupling of the power grid, measured in real time by local sensors (such as phase-locked loops); f nom The rated standard frequency of the power grid.

[0187] 2) Quantitative decision model for dynamic virtual inertia DVI(t)

[0188] Determining DVI(t) is a multi-level, serially coupled decision-making process, and its calculation formula is as follows:

[0189]

[0190] (1) Basic Capability Layer K_base

[0191] Definition: Characterizes the maximum theoretical inertial support capability that the inverter hardware and rated capacity can provide; it is a preset constant.

[0192] Quantitative calculation:

[0193] Where: H: the desired virtual inertia time constant (seconds, e.g., 2-6s), representing the rated capacity S n The duration of the power loss compensation. S n Δf: Rated apparent power of the inverter. max The maximum allowable frequency deviation (e.g., ±0.5 Hz) is specified in the design.

[0194] Significance: This layer defines the "ceiling" of inertial support based on the physical limits of the equipment.

[0195] (2) Urgent demand layer α_demand(t)

[0196] Definition: Dynamically assess the urgency of inertial demand based on the degree of deviation and rate of deterioration of the power grid frequency.

[0197] Quantization calculation: α_demand(t) = 1 + +

[0198] Where: k1, k2: weighting coefficients (k1 + k2 ≤ 1.0); tanh(): hyperbolic tangent function, to achieve smooth saturation and avoid over-adjustment; (dΔf / dt) th : is a pre-set threshold representing the "speed of frequency changes that require attention". It is a constant whose value is based on the stability requirements of the power grid and the safety response capability of the equipment (for example, a typical value may be between 0.1 Hz / s and 0.5 Hz / s).

[0199] Significance: When the frequency drops significantly (|Δf| is large) and the drop speed is fast (|dΔf / dt| is large), α_demand(t)>1, actively increasing the virtual inertia and providing stronger support; normally α_demand(t) ≈ 1.

[0200] (3) Safety boundary layer β_safety(t)

[0201] Definition: Based on local operating conditions and grid voltage, inertial support is subject to safety limits to ensure the safety and stability of grid-connected equipment.

[0202] Quantization calculation: If U g nom -ΔU​critical :

[0203] Among them: U g : The magnitude of the grid voltage measured in real time at the grid connection point; U nom The rated voltage of the power grid (e.g., 10kV, 35kV, 110kV, etc.) is a fixed constant, serving as the benchmark target value for voltage regulation. ΔU critical The preset "severely low voltage" critical deviation threshold is a key safety setting value, which defines the boundary for triggering the "safety mode".

[0204] β_safety(t) = 0.5, meaning the voltage is severely low, significantly weakening the inertial support; therefore, prioritizing voltage preservation is crucial.

[0205] Otherwise, a judgment is made, that is... :

[0206] Where: P dc : Local DC side real-time available power, which is a measured value; P margin : The preset power safety margin, which is a set value, typically 10%-20% of the rated power. out The real-time effective value of the AC output current of the inverter is a measured value; I max The maximum effective value of the output current that the inverter hardware allows for continuous operation.

[0207] Then β_safety(t) = 0.8, which means that the local power reserve is insufficient or the current is close to the limit, so it is moderately limited.

[0208] If not satisfied but:

[0209] β_safety(t) = 1.0, which means that the operating conditions are good and full inertial support is allowed.

[0210] Where: P dc DC-side input power (photovoltaics) or available power (energy storage), P margin Power safety margin.

[0211] Significance: This layer is crucial for ensuring equipment does not disconnect from the grid. When the grid voltage is severely low, it indicates that the system may be in a vulnerable state of insufficient reactive power. If high-power active power support (high inertia) is forcibly provided at this time, it can easily lead to inverter overcurrent disconnection. β_safety(t) realizes the intelligent conversion from "maximum capacity support" to "safe capacity support".

[0212] (4) Attenuation layer γ_decay(t)

[0213] Definition: The time T following the BeiDou lockout lossIncrease and smoothly decay virtual inertia to prevent phase errors accumulated due to long-term lockout from being amplified by the inertial response.

[0214] Quantization calculation: γ_decay(t) = exp(-T) loss / τ)

[0215] Significance: As the uncertainty of the self-owned clock drift increases, the control strategy should gradually shift from "active network construction" to "cautious following". γ_decay(t) ensures the smoothness and stability of this degradation process, avoiding abrupt changes to zero that could trigger secondary disturbances.

[0216] Where τ is the decay time constant (e.g., the total duration of first and second level compensation).

[0217] 3) Dynamic feedforward adjustment of phase change rate

[0218] Based on the DVI(t) decision, a direct feedforward of the frequency change rate dΔf / dt is introduced to form a fast path:

[0219]

[0220] η: Feedforward gain coefficient.

[0221] Function: A negative dΔf / dt indicates that the frequency is accelerating its decline. This function can increase dθ_v / dt in advance before the frequency deviation Δf fully manifests, driving the inverter to provide an increase in active power in advance, thereby suppressing the second derivative of the frequency. This is faster and more advanced than the traditional inertial response (proportional to the first derivative).

[0222] Specifically, this embodiment also includes real-time calculation of the harmonic distortion rate at the grid connection point. When the distortion rate exceeds the limit, the grid-connected inverter controller automatically injects active damping into the control loop to reshape the output impedance and suppress potential high-frequency oscillations.

[0223] Example 2

[0224] like Figure 3 As shown, this invention also proposes a new energy power plant grid connection system based on satellite timing and synchronization compensation, wherein the satellite timing is BeiDou satellite timing, including:

[0225] The timing module is used to receive BeiDou satellite timing signals, generate a unified reference synchronization time, and calculate the reference synchronization phase angle based on the reference synchronization time.

[0226] The grid-connection module is used to drive the grid-connected inverter to perform grid-connection operations based on the reference synchronous phase angle.

[0227] The compensation module is used to monitor the integrity indicators of the BeiDou timing signal in real time. When an abnormality or failure of the BeiDou timing signal is detected, at least one level of synchronization compensation mechanism is activated according to the duration of the abnormality or failure and the system operating status to maintain the phase continuity and frequency stability of the grid-connected operation of the new energy power plant.

[0228] The remaining technical solutions correspond to Embodiment 1, and therefore will not be described in detail.

[0229] In the above embodiments of the present invention, 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.

[0230] In the several embodiments provided by this invention, it should be understood that the disclosed technical content can be implemented in other ways. The system embodiments described above are merely illustrative; for example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units 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 through some interfaces, indirect coupling or communication connection between units or modules, and may be electrical or other forms.

[0231] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0232] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0233] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes: USB flash drives, read-only storage media (ROM), random access storage media (RAM), portable hard drives, magnetic disks, optical disks, and other media capable of storing program code.

[0234] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for grid connection of a new energy power plant based on satellite timing and synchronization compensation, wherein the satellite timing is BeiDou satellite timing, characterized in that, include: Receive BeiDou satellite timing signals, generate a unified reference synchronization time, and calculate the reference synchronization phase angle based on the reference synchronization time; Using the aforementioned reference synchronization phase angle as the control reference, the grid-connected inverter is driven to perform grid-connected operation; Real-time monitoring of the integrity indicators of BeiDou timing signals; when an abnormality or failure of BeiDou timing signals is detected, at least one level of synchronization compensation mechanism is activated based on the duration of the abnormality or failure and the system operating status to maintain the phase continuity and frequency stability of the grid-connected operation of new energy power plants. When the duration of the anomaly or failure is less than or equal to the first threshold, a first-level synchronization compensation mechanism is activated. The first-level synchronization compensation mechanism includes: switching to the local high-stability timekeeping module, which is used to continuously output the local time during the time synchronization signal anomaly or failure. The historical frequency deviation sequence of the local clock relative to BeiDou time was collected and stored during the normal period of BeiDou satellite timing signal. Based on the historical frequency deviation sequence, drift prediction and compensation are performed on the local time output by the local high-stability timekeeping module to generate a compensated time; The compensation synchronization phase angle is calculated based on the compensation time and used for subsequent grid connection control.

2. The grid connection method for new energy power plants based on satellite timing and synchronization compensation as described in claim 1, characterized in that, The integrity indicators of BeiDou timing signals include at least one BeiDou timing-related indicator, which includes: The carrier-to-noise ratio of BeiDou satellite radio frequency signals, the locking status of BeiDou satellite timing calculation, and the duration of interruption of BeiDou satellite timing signals; When the carrier-to-noise ratio is lower than the preset carrier-to-noise ratio threshold, it is determined that the timing signal reception quality is abnormal. When the time synchronization calculation lock state switches from locked to unlocked, the time synchronization function is determined to be abnormal. When the duration of the interruption of the timing signal exceeds a preset time threshold, the timing signal is determined to be invalid.

3. The grid connection method for new energy power plants based on satellite timing and synchronization compensation as described in claim 1, characterized in that, The drift prediction and compensation for the local time output by the local high-stability timekeeping module includes: Trend modeling is performed on historical frequency deviation sequences to obtain frequency drift parameters characterizing the long-term drift characteristics of the local high-stability timekeeping module; Exponential smoothing is performed on the historical frequency deviation sequence after trend modeling to obtain the disturbance compensation amount used to compensate for short-term fluctuations. During periods of time synchronization signal abnormality or failure, the local time output by the local high-stability timekeeping module is iteratively drift-corrected based on the frequency drift parameters and disturbance compensation amount to generate a compensated time.

4. The grid connection method for new energy power plants based on satellite timing and synchronization compensation as described in claim 1, characterized in that, When the duration of the anomaly or failure is less than the first threshold and less than or equal to the second threshold, the secondary synchronization compensation mechanism is activated. The secondary synchronization compensation mechanism includes: Within the area of ​​a new energy power plant that meets communication delay and electrical topology constraints, each synchronization control terminal periodically broadcasts synchronization status information including timing status, timekeeping accuracy, and time stability parameters. Based on the received synchronization status information, the credibility of the synchronization control terminals within the area is evaluated, and at least one reference terminal is selected. The communication delay between the local synchronization control terminal and the reference terminal is measured, and the synchronization phase angle reported by the reference terminal is compensated for the delay to generate a reference synchronization phase angle. Calculate the phase deviation between the local synchronization phase angle and the reference synchronization phase angle after delay compensation, and perform multiple rounds of sampling and robust processing on the phase deviation to obtain a robust phase deviation estimate. Based on the robust phase deviation estimate, the compensated synchronization phase angle is progressively corrected to achieve phase resynchronization within the region.

5. The grid connection method for a new energy power plant based on satellite timing and synchronization compensation as described in claim 4, characterized in that, When the duration of an anomaly or failure exceeds the second threshold, a three-level synchronization compensation mechanism is activated. The three-level synchronization compensation mechanism includes: Real-time acquisition of grid frequency and grid frequency change rate at the grid connection point, and acquisition of operating status parameters of the local synchronization control terminal; The dynamic virtual inertia coefficient is calculated based on the power grid frequency deviation, power grid frequency change rate, operating status parameters, and duration of abnormality or failure. Based on the dynamic virtual inertia coefficient, the rate of change of the corrected compensated synchronization phase angle is adjusted so that the synchronization phase angle evolves continuously with the change of the power grid frequency. As the duration of anomalies or failures increases, the dynamic virtual inertia coefficient is attenuated to gradually reduce the response strength of the synchronization phase angle to frequency changes. The synchronization phase angle is updated based on the rate of change of the adjusted synchronization phase angle for grid connection control.

6. A new energy power plant grid-connected system based on satellite timing and synchronization compensation, wherein the satellite timing is BeiDou satellite timing, characterized in that, include: The timing module is used to receive BeiDou satellite timing signals, generate a unified reference synchronization time, and calculate the reference synchronization phase angle based on the reference synchronization time. The grid-connection module is used to drive the grid-connected inverter to perform grid-connection operations based on the reference synchronous phase angle. The compensation module is used to monitor the integrity indicators of the BeiDou timing signal in real time. When an abnormality or failure of the BeiDou timing signal is detected, at least one level of synchronization compensation mechanism is activated according to the duration of the abnormality or failure and the system operating status to maintain the phase continuity and frequency stability of the grid-connected operation of the new energy power plant. When the duration of the anomaly or failure is less than or equal to the first threshold, a first-level synchronization compensation mechanism is activated. The first-level synchronization compensation mechanism includes: switching to the local high-stability timekeeping module, which is used to continuously output the local time during the time synchronization signal anomaly or failure. The historical frequency deviation sequence of the local clock relative to BeiDou time was collected and stored during the normal period of BeiDou satellite timing signal. Based on the historical frequency deviation sequence, drift prediction and compensation are performed on the local time output by the local high-stability timekeeping module to generate a compensated time; The compensation synchronization phase angle is calculated based on the compensation time and used for subsequent grid connection control.

7. A new energy power plant grid connection system based on satellite timing and synchronization compensation as described in claim 6, characterized in that, The integrity indicators of BeiDou timing signals include at least one BeiDou timing-related indicator, which includes: The carrier-to-noise ratio of BeiDou satellite radio frequency signals, the locking status of BeiDou satellite timing calculation, and the duration of interruption of BeiDou satellite timing signals; When the carrier-to-noise ratio is lower than the preset carrier-to-noise ratio threshold, it is determined that the timing signal reception quality is abnormal. When the time synchronization calculation lock state switches from locked to unlocked, the time synchronization function is determined to be abnormal. When the duration of the interruption of the timing signal exceeds a preset time threshold, the timing signal is determined to be invalid.

8. A new energy power plant grid connection system based on satellite timing and synchronization compensation as described in claim 6, characterized in that, The drift prediction and compensation for the local time output by the local high-stability timekeeping module includes: Trend modeling is performed on historical frequency deviation sequences to obtain frequency drift parameters characterizing the long-term drift characteristics of the local high-stability timekeeping module; Exponential smoothing is performed on the historical frequency deviation sequence after trend modeling to obtain the disturbance compensation amount used to compensate for short-term fluctuations. During periods of time synchronization signal abnormality or failure, the local time output by the local high-stability timekeeping module is iteratively drift-corrected based on the frequency drift parameters and disturbance compensation amount to generate a compensated time.

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