Grid-connected control system and control method in solar photovoltaic power generation system

Abstract

The invention discloses a grid-connected control system and a grid-connected control method in a solar photovoltaic power generation system, and relates to the technical field of photovoltaic power generation control. According to the grid-connected control method for the power grid in the solar photovoltaic power generation system, power generation operation data when the solar photovoltaic power generation system is connected with a target power grid are obtained, feature analysis is performed respectively, a grid-connected evaluation index set when the solar photovoltaic power generation system is connected with the target power grid is obtained, and comprehensive analysis is performed; according to the invention, the preset grid-connected control measures are adopted based on the source-grid cooperative safety index when the solar photovoltaic power generation system is connected with the target power grid, so that dynamic safety evaluation and control in the grid-connected process of the photovoltaic system are realized. Therefore, the photovoltaic system can flexibly adapt to grid connection under different power grid conditions, and the compatibility and the stability of photovoltaic power generation to a power grid operation environment are integrally improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation control, and specifically relates to a grid connection control system and a control method in a solar photovoltaic power generation system. Background Art

[0002] Solar photovoltaic power generation has become one of the key clean energy forms developed in China and globally. Especially in resource-rich areas, the rapid deployment of large-scale centralized photovoltaic power stations and the continuous expansion of grid connection scale have brought higher requirements for the dynamic adaptability and stability of the traditional power grid operation. Centralized photovoltaic power stations often have characteristics such as high installed capacity, large current injection, and long-distance power transmission, which are prone to impact or disturbance on the target power grid. If there is a lack of refined and dynamic grid connection control means, it is easy to cause power quality problems such as local voltage fluctuations, frequency disturbances, and harmonic pollution. In severe cases, it may even lead to power station disconnection or system oscillation. Moreover, existing large-scale photovoltaic grid connection control methods often ignore the overall coupling state between the photovoltaic power station and the target power grid, and only rely on local electrical parameters, making it difficult to reflect the comprehensiveness and dynamic change trend of the current grid connection conditions.

[0003] The prior art, such as a control method for grid-connected operation of a solar photovoltaic power generation system disclosed in a patent application with the publication number of CN105790308B, includes the following steps: First, build a solar photovoltaic power generation experimental system, where the solar photovoltaic power generation experimental system includes four groups of solar photovoltaic power generation devices with DC / DC converters and a common load, and the four groups of solar photovoltaic power generation devices jointly supply power for the load to use; Second, according to physical principles, establish a mathematical model of the solar photovoltaic power generation experimental system, and this mathematical model belongs to an interconnected system with four non-linear subsystems; Finally, based on the mathematical model, design a decentralized sampling event-triggered controller and give a simulation test platform for the system. The grid-connected operation control scheme provided by the present invention can not only ensure the safe and stable operation of the microgrid, but also significantly reduce the communication data between each power generation unit.

[0004] Based on the above scheme, it is found that the limitations of the prior art at least include the following problems: The prior art lacks in-depth analysis of the dynamic adaptability of the power grid and the photovoltaic system during the actual grid connection process, and does not consider the interaction of various complex factors in actual operation. For example, grid equipment may cause uneven power grid load due to external load fluctuations or emergencies, and such situations cannot be timely reflected and optimally controlled in the prior art, which is likely to lead to poor coordination between the photovoltaic system and the power grid, thereby affecting the stability of the power grid and power quality. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a grid connection control system and control method in a solar photovoltaic power generation system, which solves the problems of the prior art lacking dynamic adaptability analysis and not considering various complex factors in actual operation, resulting in poor coordination between photovoltaic and the grid, and further affecting stability and power quality.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A grid connection control method in a solar photovoltaic power generation system includes the following steps: obtaining the power generation operation data when the solar photovoltaic power generation system is connected to the target grid, including grid equipment operation data, photovoltaic power operation data, and source-grid interaction data; respectively performing feature analysis on the power generation operation data when the solar photovoltaic power generation system is connected to the target grid to obtain a grid connection evaluation index set when the solar photovoltaic power generation system is connected to the target grid, including a grid equipment stability index, a photovoltaic operation stability index, and a grid connection adaptability index, and performing comprehensive analysis to obtain a source-grid coordination safety index when the solar photovoltaic power generation system is connected to the target grid; taking preset grid connection control measures based on the source-grid coordination safety index when the solar photovoltaic power generation system is connected to the target grid.

[0007] Further, the specific formula for calculating the source-grid coordination safety index when the solar photovoltaic power generation system is connected to the target grid is as follows: Among them, BwR is the source-grid coordination safety index when the solar photovoltaic power generation system is connected to the target grid, DwH is the grid equipment stability index when the solar photovoltaic power generation system is connected to the target grid, α1 is the equipment stability adjustment coefficient stored in the database, GyW is the photovoltaic operation stability index when the solar photovoltaic power generation system is connected to the target grid, ζ is the photovoltaic operation smoothing coefficient stored in the database, α2 is the photovoltaic operation adjustment coefficient stored in the database, BsY is the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target grid, and α3 is the grid connection adaptation adjustment coefficient stored in the database.

[0008] Further, the grid equipment operation data includes an inverter feedforward steady-state index, a breaker feedforward steady-state index, and a transformer feedforward steady-state index, and the specific steps for obtaining the grid equipment stability index when the solar photovoltaic power generation system is connected to the target grid are as follows: respectively performing comprehensive analysis on the inverter feedforward steady-state index, the breaker feedforward steady-state index, and the transformer feedforward steady-state index when the solar photovoltaic power generation system is connected to the target grid to obtain an initial grid equipment stability index and an equipment interaction correction index when the solar photovoltaic power generation system is connected to the target grid; and performing comprehensive analysis on the initial grid equipment stability index and the equipment interaction correction index when the solar photovoltaic power generation system is connected to the target grid to obtain the grid equipment stability index when the solar photovoltaic power generation system is connected to the target grid.

[0009] Further, the specific steps for obtaining the pre-inversion feedforward steady-state index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Obtain the inverting steady-current adaptation index, inverting current harmonic distortion index, inverting voltage harmonic distortion index, inverting resonance impedance index, and inverting temperature value when the solar photovoltaic power generation system is connected to the target power grid, and perform standardization processing; comprehensively analyze the inverting steady-current adaptation index, inverting current harmonic distortion index, inverting voltage harmonic distortion index, inverting resonance impedance index, and inverting temperature value after standardization processing when the solar photovoltaic power generation system is connected to the target power grid to obtain the pre-inversion feedforward steady-state index when the solar photovoltaic power generation system is connected to the target power grid.

[0010] Further, the photovoltaic power operation data includes the string current dispersion index, backplane temperature gradient index, and photovoltaic power quality index. The specific steps for obtaining the photovoltaic operation stability index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Obtain the light intensity value, ambient temperature value, and radiation reflectivity value when the solar photovoltaic power generation system is connected to the target power grid, combine with the backplane temperature gradient index, and perform comprehensive analysis to obtain the photovoltaic operation correction factor when the solar photovoltaic power generation system is connected to the target power grid; comprehensively analyze the photovoltaic operation correction factor, string current dispersion index, and photovoltaic power quality index when the solar photovoltaic power generation system is connected to the target power grid to obtain the photovoltaic operation stability index when the solar photovoltaic power generation system is connected to the target power grid.

[0011] Further, the specific steps for obtaining the photovoltaic power quality index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Obtain the voltage deviation value, current deviation value, power offset value, and three-phase balance index when the solar photovoltaic power generation system is connected to the target power grid, and perform standardization processing; comprehensively analyze the voltage deviation value, current deviation value, power offset value, and three-phase balance index after standardization processing when the solar photovoltaic power generation system is connected to the target power grid to obtain the photovoltaic power quality index when the solar photovoltaic power generation system is connected to the target power grid.

[0012] Further, the source-grid interaction data includes the coupling drive index, source-grid symmetry coordination index, supply-demand current adaptation index, and grid-side carrying capacity index. The specific steps for obtaining the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Normalize the coupling drive index, source-grid symmetry coordination index, supply-demand current adaptation index, and grid-side carrying capacity index of the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid; and comprehensively analyze the coupling drive index, source-grid symmetry coordination index, supply-demand current adaptation index, and grid-side carrying capacity index of the grid connection adaptability index after normalization processing when the solar photovoltaic power generation system is connected to the target power grid to obtain the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid.

[0013] Furthermore, the specific formula for calculating the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid is as follows: Among them, BsY is the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid, YwX′ is the source-grid symmetry coordination index after normalization when the solar photovoltaic power generation system is connected to the target power grid, μ1 is the symmetry adjustment coefficient stored in the database, GxP′ is the supply-demand current adaptation index after normalization when the solar photovoltaic power generation system is connected to the target power grid, μ2 is the adaptation adjustment coefficient stored in the database, WsG′ is the grid-side carrying capacity index after normalization when the solar photovoltaic power generation system is connected to the target power grid, μ3 is the carrying adjustment coefficient stored in the database, DqS′ is the coupling drive index after normalization when the solar photovoltaic power generation system is connected to the target power grid, μ4 is the drive adjustment coefficient stored in the database, μ5 is the drive adaptation adjustment coefficient stored in the database, and μ6 is the smoothing adjustment coefficient stored in the database.

[0014] Furthermore, the specific steps of the grid connection control measure preset based on the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Judge and analyze the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid and the preset source-grid collaborative security index threshold; if the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid is lower than or equal to the preset source-grid collaborative security index threshold, take the first grid connection control measure; if the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid is higher than the preset source-grid collaborative security index threshold, take the second grid connection control measure.

[0015] A grid connection control system in a solar photovoltaic power generation system includes: a data acquisition module for acquiring the power generation operation data when the solar photovoltaic power generation system is connected to the target power grid, including grid equipment operation data, photovoltaic power operation data, and source-grid interaction data; a feature extraction module for respectively performing feature analysis on the power generation operation data when the solar photovoltaic power generation system is connected to the target power grid to obtain a grid connection evaluation index set when the solar photovoltaic power generation system is connected to the target power grid, including a grid equipment stability index, a photovoltaic operation stability index, and a grid connection adaptability index; a comprehensive analysis module for comprehensively analyzing the grid connection evaluation index set when the solar photovoltaic power generation system is connected to the target power grid to obtain the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid; and a grid connection control module for taking a preset grid connection control measure based on the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid.

[0016] The present invention has the following beneficial effects:

[0017] (1) The grid connection control method in this solar photovoltaic power generation system obtains power generation operation data and conducts multi-dimensional analysis to obtain the source-grid collaborative security index, thereby realizing dynamic safety assessment and control during the grid connection process of the photovoltaic system. Furthermore, it ensures that the photovoltaic system can flexibly adapt to grid connection under different grid conditions, avoiding grid instability or power quality problems. For example, if the grid load suddenly increases, the output power of the photovoltaic system is adjusted to avoid grid voltage fluctuations and ensure that photovoltaic power generation does not impose an additional burden on the grid, thus enhancing the stability of photovoltaic grid connection and the security of grid operation.

[0018] (2) The grid connection control method in this solar photovoltaic power generation system realizes precise assessment of the operating states of key grid equipment such as inverters, circuit breakers, and transformers by refining the analysis process of the grid equipment stability maintenance index. Specifically, the pre-inversion feedforward steady-state index, pre-circuit-breaker feedforward steady-state index, and pre-transformer feedforward steady-state index are used to comprehensively reflect key physical factors such as current, voltage harmonic distortion, temperature change, and resonant impedance during equipment operation, thereby making a rapid response to the real-time stability of the equipment. For example, when the temperature of the inverter is too high or the harmonic distortion is severe, the photovoltaic power generation system can promptly reduce the output power to effectively prevent the negative impacts on the grid caused by equipment overload and resonance, and further significantly reduce the maintenance costs and power outage risks caused by equipment failures.

[0019] (3) The grid connection control method in this solar photovoltaic power generation system constructs a grid connection adaptability index for source-grid interaction characteristics and conducts comprehensive analysis using multi-dimensional parameters to effectively address the coordination problems during the interaction between the photovoltaic power generation system and the grid, especially solving the adaptability problems in complex operating scenarios such as grid voltage disturbances, current imbalance, and load fluctuations. For example, when the grid load fluctuates significantly, by promptly monitoring the source-grid symmetry coordination index and the supply-demand current adaptation index, the photovoltaic power generation system can actively adjust the photovoltaic output power and power factor to avoid additional disturbances to the grid caused by current mismatch or phase asymmetry, thereby significantly enhancing the robustness and flexible adaptation ability of the photovoltaic system when connecting to the grid, and further improving the overall compatibility and stability of photovoltaic power generation with the grid operating environment.

[0020] (4) The grid-connected control system in the solar photovoltaic power generation system realizes the automation and intelligent management of the grid-connected control of the solar photovoltaic power generation system by constructing a system architecture that combines a data acquisition module, a feature extraction module, a comprehensive analysis module and a grid-connected control module. Specifically, the data acquisition module collects multi-dimensional operating data in real time during the grid-connected process, the feature extraction module analyzes the operating characteristics of the power grid, the photovoltaic system and the source-grid interaction in detail, and the comprehensive analysis module accurately outputs the source-grid collaborative safety index, thereby realizing automatic risk assessment and early warning. The grid-connected control module independently judges and executes corresponding control measures based on the safety index, such as automatically enabling reactive power compensation or dynamically adjusting the output power, significantly reducing the need for human intervention and decision-making delays, thereby improving the system's response speed and processing efficiency, and enabling the solar photovoltaic power generation system to adapt to grid fluctuations more intelligently, thereby reducing operation and maintenance costs and enhancing system safety and reliability.

[0021] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention is a flow chart of a grid connection control method in a solar photovoltaic power generation system.

[0023] Figure 2 The present invention is a flowchart of the specific steps of obtaining a grid-connection adaptability index when a solar photovoltaic power generation system is connected to a target grid in a grid-connection control method in a solar photovoltaic power generation system.

[0024] Figure 3 This is an example diagram of source-grid interaction data after normalization processing in a grid connection control method in a solar photovoltaic power generation system of the present invention.

[0025] Figure 4 The present invention is a block diagram of a grid-connected control system in a solar photovoltaic power generation system. DETAILED DESCRIPTION

[0026] See also Figure 1, an embodiment of the present invention provides a technical solution: a grid connection control method for a solar photovoltaic power generation system, including the following steps: obtaining the power generation operation data when the solar photovoltaic power generation system is connected to the target grid (i.e., grid connection), including grid equipment operation data, photovoltaic power operation data, and source-grid interaction data; respectively performing feature analysis on the power generation operation data when the solar photovoltaic power generation system is connected to the target grid to obtain a grid connection evaluation index set when the solar photovoltaic power generation system is connected to the target grid, including a grid equipment stability index, a photovoltaic operation stability index, and a grid connection adaptability index, and performing comprehensive analysis to obtain a source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target grid (used to measure the security when the solar photovoltaic power generation system is connected to the target grid); taking a preset grid connection control measure based on the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target grid.

[0027] The specific formula for calculating the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target grid is as follows: Among them, BwR is the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target grid, DwH is the grid equipment stability index when the solar photovoltaic power generation system is connected to the target grid, α1 is the equipment stability adjustment coefficient stored in the database, GyW is the photovoltaic operation stability index when the solar photovoltaic power generation system is connected to the target grid, ζ is the photovoltaic operation smoothing coefficient stored in the database, α2 is the photovoltaic operation adjustment coefficient stored in the database, BsY is the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target grid, and α3 is the grid connection adaptation adjustment coefficient stored in the database.

[0028] It should be explained that α1, α2, and α3 can be obtained through the following steps: using historical data, combining the grid equipment stability index, the photovoltaic operation stability index, and the grid connection adaptability index, performing statistical regression analysis to quantify the specific impact of each factor on the source-grid collaborative security index, thereby fitting the initial weight values. Secondly, using the sensitivity analysis method, adjusting the value range of each coefficient, observing its impact on the source-grid collaborative security evaluation result, ensuring the stability and rationality of the model, and based on the characteristics of solar photovoltaic power generation and the actual situation, correcting and optimizing the initially fitted coefficients, and finally determining the coefficient values applicable to solar photovoltaic power generation.

[0029] ζ can be obtained through the following steps: obtaining the historical photovoltaic operation stability indices at several historical time points and performing mean processing to obtain the photovoltaic operation smoothing coefficient.

[0030] Specifically, the operation data of grid equipment includes the pre-inversion feedforward steady-state index (used to measure the stability of the inverter in a solar photovoltaic power generation system), the pre-opening feedforward steady-state index, and the pre-voltage transformation feedforward steady-state index (used to measure the stability of the transformer in a solar photovoltaic power generation system). The specific steps to obtain the grid equipment stability maintenance index when the solar photovoltaic power generation system is connected to the target grid are as follows: comprehensively analyze the pre-inversion feedforward steady-state index, the pre-opening feedforward steady-state index, and the pre-voltage transformation feedforward steady-state index when the solar photovoltaic power generation system is connected to the target grid to obtain the initial grid equipment stability maintenance index when the solar photovoltaic power generation system is connected to the target grid (i.e., perform a weighted process on the pre-inversion feedforward steady-state index, the pre-opening feedforward steady-state index, and the pre-voltage transformation feedforward steady-state index) and the equipment interaction correction index (i.e., perform an interaction process on the pre-inversion feedforward steady-state index, the pre-opening feedforward steady-state index, and the pre-voltage transformation feedforward steady-state index); and comprehensively analyze the initial grid equipment stability maintenance index and the equipment interaction correction index when the solar photovoltaic power generation system is connected to the target grid to obtain the grid equipment stability maintenance index when the solar photovoltaic power generation system is connected to the target grid.

[0031] Among them, the pre-opening feedforward steady-state index is used to measure the stability of the circuit breaker in the solar photovoltaic power generation system. It can be obtained by acquiring the circuit breaker contact temperature value (which can be obtained through a thermocouple temperature sensor), the circuit breaker contact resistance (respectively acquire the voltage value and current value of the circuit breaker contact through a voltage sensor and a current sensor, and analyze the circuit breaker contact resistance based on Ohm's law), the electromagnetic field distribution index (the distribution of the external electromagnetic field of the circuit breaker), and the contact vibration amplitude value (which can be obtained through a vibration sensor), and performing a standardization process, and performing a weighted process based on the standardization process result. The obtained result is the pre-opening feedforward steady-state index.

[0032] And the electromagnetic field distribution index can be obtained by using a Hall effect sensor to acquire the electromagnetic fields in multiple directions outside the circuit breaker and performing a standard deviation process.

[0033] The pre-voltage transformation feedforward steady-state index is used to measure the stability of the transformer in the solar photovoltaic power generation system. It can be obtained by acquiring the transformer load rate value, the transformer insulation resistance value (reflecting the health status of the internal insulation layer of the transformer, obtained through an insulation resistance measuring instrument), the transformer core temperature value (reflecting the temperature of the transformer core, and too high a temperature rise is likely to cause the core to saturate and affect the working performance of the transformer, which can be obtained through a core temperature sensor), and the transformer excitation current (the excitation current is the current required by the transformer during the magnetization process and has a direct impact on the efficiency of the transformer, which can be obtained through a current sensor), and performing a standardization process, and performing a weighted process based on the standardization process result. The obtained result is the pre-voltage transformation feedforward steady-state index.

[0034] And the transformer load rate value is the ratio of the load current (output current, obtained through a current sensor) to the rated current (obtained through the technical specification of the transformer stored in the database).

[0035] The transformer current balance index is the balance degree among the three-phase currents, which is used to reflect the symmetry of the three-phase currents in terms of amplitude and phase. It can easily lead to an additional burden on the transformer and unstable operation. It can be obtained by using three-phase current sensors to respectively acquire the current values of each phase, performing mean processing to obtain the current mean value, simultaneously counting the maximum and minimum current values, and then calculating and analyzing to get, that is, (maximum current - minimum current) / current mean value.

[0036] The specific formula for calculating the grid equipment stability index when the solar photovoltaic power generation system is connected to the target grid is as follows: DwH = CsW β1 *[β2 * ln(1 + JhY)]; where DwH is the grid equipment stability index when the solar photovoltaic power generation system is connected to the target grid, CsW is the initial grid equipment stability index when the solar photovoltaic power generation system is connected to the target grid, β1 is the initial adjustment coefficient stored in the database, JhY is the equipment interaction correction index when the solar photovoltaic power generation system is connected to the target grid, and β2 is the interaction adjustment coefficient stored in the database.

[0037] It should be explained that β1 and β2 can be obtained through the following steps: Based on historical data, determine the initial influence weights of each variable (initial grid equipment stability index, equipment interaction correction index) on the grid equipment stability index through statistical regression analysis. Then, use the sensitivity analysis method to adjust the value range of the coefficients to evaluate the stability and applicability of these parameters to the formula output. Next, further fit the weights through model optimization (such as machine learning algorithms) to ensure that the formula can accurately reflect the stability of the actual grid equipment.

[0038] In this implementation scheme, by precisely constructing key indicators such as the inverter feedforward steady-state index, circuit breaker feedforward steady-state index, and transformer feedforward steady-state index, the accurate and real-time evaluation and monitoring of the stability of three core grid devices, namely inverters, circuit breakers, and transformers, in a solar photovoltaic power generation system are achieved. Secondly, multi-dimensional characteristics such as the contact temperature, resistance, electromagnetic field, and vibration amplitude of the circuit breaker, as well as the load rate, insulation resistance, core temperature, and exciting current of the transformer, are comprehensively measured, and a standardized and weighted processing method is adopted to form a comprehensive and highly sensitive equipment stability evaluation system. In addition, the initial adjustment coefficient and interaction adjustment coefficient are dynamically calibrated through methods such as historical data statistics, sensitivity analysis, and machine learning optimization, enabling the evaluation formula to continuously fit the actual on-site situation. Finally, through a comprehensive, precise, and dynamic construction method of the equipment stability maintenance index, the photovoltaic system has higher anti-disturbance ability and operation reliability under complex working conditions, thereby effectively reducing the equipment failure risk and operation and maintenance costs.

[0039] Specifically, the specific steps to obtain the inverter feedforward steady-state index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Obtain the inverter steady-current adaptation index, inverter current harmonic distortion index, inverter voltage harmonic distortion index, inverter resonance impedance index, and inverter temperature value when the solar photovoltaic power generation system is connected to the target power grid, and perform standardization processing; comprehensively analyze the standardized inverter steady-current adaptation index, inverter current harmonic distortion index, inverter voltage harmonic distortion index, inverter resonance impedance index, and inverter temperature value when the solar photovoltaic power generation system is connected to the target power grid (based on the information entropy theory, calculate the uncertainty weights of the inverter steady-current adaptation index, inverter current harmonic distortion index, inverter voltage harmonic distortion index, inverter resonance impedance index, and inverter temperature value in real time, multiply them by the corresponding weights, and then add them up) to obtain the inverter feedforward steady-state index when the solar photovoltaic power generation system is connected to the target power grid.

[0040] Among them, the inverter constant-current adaptation index measures the stability and adaptation ability of the output current, output voltage, and DC bus voltage, and can be obtained by acquiring the inverter AC output current value (which can be obtained through the current sensor at the inverter AC port), the inverter AC output voltage value (which can be obtained in real time through the voltage sensor at the inverter AC port), the inverter DC bus voltage value (which can be obtained in real time through the voltage sensor at the inverter DC port), the inverter AC output reference current value (obtained from the technical specification of the inverter stored in the database), the inverter AC reference output voltage value (obtained from the standard voltage value of the power grid stored in the database), and the inverter DC bus reference voltage value (i.e., the output voltage of the photovoltaic panel). The difference analysis is performed respectively (such as the absolute value of the difference between the inverter AC output current value and the inverter AC output reference current value), and then the normalization process is carried out. Based on the normalization process, the weighted process is performed, and the obtained result is the inverter constant-current adaptation index.

[0041] The inverter harmonic distortion index is the harmonic content of the inverter output current, which can be obtained through the built-in harmonic analysis module of the inverter, that is, the inverter measures the current waveform through its internal sensor, then calculates the total harmonic distortion based on the fast Fourier transform, and outputs the data.

[0042] The inverter voltage harmonic distortion index is the harmonic content of the inverter output voltage, and its acquisition steps are the same as the logic of the inverter harmonic distortion index.

[0043] The inverter resonance impedance index is the matching between the inverter and the power grid, which can be obtained by acquiring the output impedance amplitude (the proportional relationship between the output voltage and current), the output impedance phase angle, and performing an interaction process, that is, the output impedance amplitude × cos output impedance phase angle. The obtained result is the inverter resonance impedance index, and the output impedance phase angle can perform spectral analysis on the voltage and current waveforms at the inverter output terminal based on the Fourier transform (FFT). The time-domain signals of the voltage and current can be converted to the frequency domain. In the frequency domain, the output voltage and current of the inverter will each have a corresponding phase value (obtained through FFT calculation), and the output impedance phase angle can be obtained by calculating the difference between the voltage and current phases.

[0044] The inverter temperature value is the temperature of the inverter, which can be obtained through a thermocouple temperature sensor.

[0045] In this implementation scheme, by constructing a refined pre-inversion feedforward steady-state index evaluation system, the accurate real-time evaluation and control of the operating state and grid connection quality of the photovoltaic inverter are achieved. Among them, the steady current adaptation index finely quantifies the deviation between the actual operating state and the ideal state of the output current, voltage, and DC bus voltage. The harmonic distortion index comprehensively reflects the potential impact of the inverter output voltage and current on the power grid power quality. The resonance impedance index accurately reveals the impedance matching and coupling degree between the inverter and the power grid. The inverter temperature value monitors the thermal stability status of the inverter in real time. In addition, after these parameters are standardized, the information entropy theory is further used to calculate the uncertainty weights of each parameter in real time, so as to dynamically assign a more reasonable and practical weight distribution to different parameters, enabling the evaluation index to quickly and sensitively capture the small changes in the operating state of the inverter, thereby enhancing the operating safety and lifespan of the inverter. Finally, the deviation and lag of subjective weight assignment are avoided, making the inverter status monitoring more objective and reliable, and improving the stability, robustness, and intelligent management ability of the overall photovoltaic grid-connected system.

[0046] Specifically, the photovoltaic power operation data includes the string current dispersion index, the backplane temperature gradient index, and the photovoltaic power quality index. The specific steps to obtain the photovoltaic operation stability index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Obtain the light intensity value (which can be obtained through a light intensity sensor), the ambient temperature value (which can be obtained through an RTD sensor), and the radiation reflectivity value (which is the proportion of the ground-reflected solar radiation and can be obtained through a reflectivity sensor) when the solar photovoltaic power generation system is connected to the target power grid, and combine them with the backplane temperature gradient index, and conduct comprehensive analysis (first perform standardization processing, and then perform weighted processing based on the standardization processing results) to obtain the photovoltaic operation correction factor when the solar photovoltaic power generation system is connected to the target power grid; conduct comprehensive analysis (first perform standardization processing, and then perform weighted processing based on the standardization processing results) on the photovoltaic operation correction factor, the string current dispersion index, and the photovoltaic power quality index when the solar photovoltaic power generation system is connected to the target power grid to obtain the photovoltaic operation stability index when the solar photovoltaic power generation system is connected to the target power grid.

[0047] Among them, the string current dispersion index is the standard deviation of the string current of each group of DC-side components in the solar photovoltaic power generation system, and the string current of each group of DC-side components can be obtained through a Hall sensor.

[0048] The backplane temperature gradient index is the temperature distribution degree of the backplane of the solar photovoltaic module. Obtain the temperature values at multiple positions on the backplane of the solar photovoltaic module (obtained through an infrared temperature detector), and perform standard deviation processing. The obtained result is the backplane temperature gradient index.

[0049] The specific steps to obtain the photovoltaic power quality index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Obtain the voltage deviation value (the difference between the output voltage and the rated voltage), current deviation value (the difference between the output current and the rated current), power deviation value (the difference between the output power and the rated power), and three-phase balance index when the solar photovoltaic power generation system is connected to the target power grid, and perform standardization processing; Based on the voltage deviation value, current deviation value, power deviation value, and three-phase balance index when the solar photovoltaic power generation system is connected to the target power grid after standardization processing, conduct comprehensive analysis (i.e., weighted processing) to obtain the photovoltaic power quality index when the solar photovoltaic power generation system is connected to the target power grid.

[0050] Among them, the output voltage, output current, and output power are obtained through a voltage sensor, current sensor, and digital power meter in sequence, and the rated voltage, rated current, and rated power can all be obtained through the power grid parameter table stored in the database.

[0051] The three-phase balance index is the balance degree between the three-phase currents, which is used to reflect the symmetry of the three-phase currents in terms of amplitude and phase. It can be obtained by using a three-phase current sensor to separately obtain the current value of each phase, and performing mean processing to obtain the current mean value. At the same time, the maximum and minimum current values are statistically counted, and then calculated and analyzed to obtain, that is, (maximum current - minimum current) / current mean value.

[0052] In this implementation plan, by establishing a detailed photovoltaic operation stability index evaluation system, the operation status and power generation performance of photovoltaic modules are accurately monitored. Secondly, based on multi-dimensional characteristic indicators such as the string current dispersion index, backplane temperature gradient index, and photovoltaic power quality index, the current balance situation inside the photovoltaic system, the backplane temperature distribution characteristics of the modules, and the output power quality fluctuations can be comprehensively reflected. In addition, combined with environmental parameters (light intensity, ambient temperature, and radiation reflectivity), through standardization and weighted processing, a photovoltaic operation correction factor is obtained, thereby significantly improving the sensitivity and adaptability of the stability index to environmental changes. For example, when the ambient temperature suddenly changes or local hot spots appear abnormally on the backplane of the module, the photovoltaic system can quickly capture these subtle changes and make real-time adjustments, thereby effectively avoiding the long-term impact of local overheating or unbalanced operation of the modules on the power generation performance, effectively improving the photovoltaic power generation efficiency, extending the life of the photovoltaic modules, and reducing the long-term operation and maintenance costs.

[0053] Specifically, such as Figure 2As shown in the figure, the source-grid interaction data includes the coupling drive index, the source-grid symmetry coordination index, the supply-demand current adaptation index, and the grid-side carrying capacity index. The specific steps to obtain the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target grid are as follows: Normalize the coupling drive index, the source-grid symmetry coordination index, the supply-demand current adaptation index, and the grid-side carrying capacity index of the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target grid; and comprehensively analyze the normalized coupling drive index, the source-grid symmetry coordination index, the supply-demand current adaptation index, and the grid-side carrying capacity index of the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target grid to obtain the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target grid.

[0054] Among them, the coupling drive index is the dynamic coupling degree of power disturbance under voltage and interface conduction conditions. It can be obtained by acquiring the active power value (which can be obtained through a power meter), the output voltage value (which can be obtained through a Hall voltage sensor), and the interface conductivity value (acquire the output voltage value and current value, and calculate and analyze to obtain, that is, output current / output voltage value), and then comprehensively analyze (that is, first perform standardization processing, and then perform weighted processing based on the standardization processing result). The obtained result is the coupling drive index.

[0055] The source-grid symmetry coordination index represents the symmetry and consistency degree of the three-phase electricity on the source side (photovoltaic power generation) and the grid side (target grid). It can be obtained by acquiring the three-phase current and voltage on the source side (sequentially through a voltage transformer and a Hall current sensor) and the three-phase current and voltage on the grid side (sequentially through a voltage transformer and a Hall current sensor), and then comprehensively analyze respectively (that is, perform difference processing on each current in the three-phase current on the source side and the corresponding phase current in the three-phase current on the grid side, perform the same processing on the three-phase voltage on the source side and the three-phase voltage on the grid side, and then perform standardization processing), and perform weighted processing based on the comprehensive analysis result. The obtained result is the source-grid symmetry coordination index.

[0056] The supply-demand current adaptation index is the ratio of the output current capacity on the source side (by acquiring the three-phase current on the source side and performing mean processing) to the current required by the load on the grid side (acquired through a current transformer).

[0057] The grid-side carrying capacity index is the absorption capacity of the power grid. It can be obtained by acquiring the three-phase voltage value on the grid side and performing mean processing, acquiring the three-phase current value on the grid side and performing mean processing, and then multiplying, that is, (√3)×grid-side three-phase current mean×grid-side three-phase voltage mean.

[0058] The specific formula for calculating the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target grid is as follows: Among them, BsY is the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid, YwX′ is the source-grid symmetry coordination index after normalization when the solar photovoltaic power generation system is connected to the target power grid, μ1 is the symmetry adjustment coefficient stored in the database, GxP′ is the supply-demand current adaptation index after normalization when the solar photovoltaic power generation system is connected to the target power grid, μ2 is the adaptation adjustment coefficient stored in the database, WsG′ is the grid-side carrying capacity index after normalization when the solar photovoltaic power generation system is connected to the target power grid, μ3 is the carrying adjustment coefficient stored in the database, DqS′ is the coupling drive index after normalization when the solar photovoltaic power generation system is connected to the target power grid, μ4 is the drive adjustment coefficient stored in the database, μ5 is the drive adaptation adjustment coefficient stored in the database, and μ6 is the smoothing adjustment coefficient stored in the database.

[0059] It should be explained that the expression form of the Tanh function is e is the natural constant, and its value is 2.71 in this embodiment, and the domain is (-∞, +∞), and the range is (-1, 1).

[0060] In the formula This term is used to adjust the inhibitory effect on grid connection adaptability under the double blow of disturbance and incoordination.

[0061] μ1, μ2, μ3, μ4, μ5, μ6 can be obtained through the following steps: Based on historical data, determine the initial influence weights of each variable (source-grid symmetry coordination index, supply-demand current adaptation index, grid-side carrying capacity index, coupling drive index) on the grid connection adaptability index through statistical regression analysis. Then, use the sensitivity analysis method to adjust the value range of the coefficients to evaluate the stability and applicability of these parameters to the formula output. Next, further fit the weights through model optimization (such as multi-objective optimization) to ensure that the formula can accurately reflect the actual grid connection adaptability.

[0062] The specific implementation example of calculating the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid is as follows. The following data are available: the coupling drive index, source-grid symmetry coordination index, supply-demand current adaptation index, and grid-side carrying capacity index of the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid, as shown in Table 1:

[0063] Table 1 Example of source-grid interaction data when the solar photovoltaic power generation system is connected to the target power grid

[0064]

[0065] Normalize the data in Table 1 to obtain Table 2, and as Figure 3 shown:

[0066] Example of source-grid interaction data when the solar photovoltaic power generation system after normalization is connected to the target power grid

[0067]

[0068] The symmetric adjustment coefficient μ1 stored in the database is approximately: 0.293;

[0069] The adaptation adjustment coefficient μ2 stored in the database is approximately: 0.538;

[0070] The load-bearing adjustment coefficient μ3 stored in the database is approximately: 0.317;

[0071] The drive adjustment coefficient μ4 stored in the database is approximately: 0.824;

[0072] The drive adaptation adjustment coefficient μ5 stored in the database is approximately: 0.426;

[0073] The smoothing adjustment coefficient μ6 stored in the database is approximately: 0.364;

[0074] Substitute the data in Table 2 and the above adjustment coefficients into the specific formula of the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid for calculation, and obtain:

[0075] The grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid ≈ 0.781.

[0076] In this implementation plan, by accurately constructing the grid connection adaptability index, it deeply reflects the adaptability and stability in the dynamic interaction process between the solar photovoltaic power generation system and the target power grid, and comprehensively considers the coupled driving effect of power disturbance, the symmetry coordination of three-phase electricity on the source side and the grid side, the matching degree of supply and demand current, and the actual power absorption capacity of the power grid. It quantifies various dynamic and static factors in the source-grid interaction process from multiple dimensions, thereby improving the sensitivity and accuracy of grid connection assessment. In addition, through statistical regression analysis, sensitivity analysis and multi-objective optimization methods, the parameter coefficients are continuously adjusted and optimized dynamically, so that the evaluation system continuously fits the actual operating conditions, ensuring real-time response to changes in the grid environment. For example, when adverse factors such as sharp fluctuations in the grid demand load occur, the photovoltaic power generation system can quickly capture the subtle adaptability deviation between the source and the grid and make corresponding control decisions in a timely manner, thus avoiding potential safety risks and grid connection impacts, and effectively ensuring the stable operation of the photovoltaic power generation system after grid connection and the reliability and safety of the overall operation of the power grid.

[0077] Specifically, the specific steps of the grid connection control measures preset based on the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid are as follows: judge and analyze the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid and the preset source-grid collaborative security index threshold; if the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid is lower than or equal to the preset source-grid collaborative security index threshold, then take the first grid connection control measure, which can specifically be reducing the output power (reducing the active power injected into the grid to reduce the impact), enabling reactive power support (supporting the grid voltage by providing reactive power), restricting the power ramp rate (controlling the slope of the output power increase to avoid instantaneous impact), and delaying the grid connection access (postponing the synchronous access time to avoid the peak of the connection point disturbance), to reduce the grid connection disturbance and improve the system stability; if the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid is higher than the preset source-grid collaborative security index threshold, then take the second grid connection control measure, which can specifically be enabling the maximum power output mode (the photovoltaic system performs full power output) and optimizing the power quality (starting the harmonic suppression function in the photovoltaic inverter to ensure that the output current and voltage waveforms meet the power quality standards), to ensure the efficient and safe grid connection operation of the photovoltaic system and provide a stable power output.

[0078] In this implementation plan, by setting a clear source-grid collaborative security index threshold and establishing a corresponding dynamic control mechanism, the adaptive and refined regulation between the solar photovoltaic power generation system and the power grid is realized, and the initiative, security, and stability during the grid connection process are significantly improved. This "dual-mode" dynamic decision-making mechanism greatly improves the response ability of the photovoltaic power generation system to the grid load fluctuation and external environment change, thus achieving a high balance between the grid connection security and the power generation efficiency. At the same time, due to the high degree of automation and real-time response characteristics of the whole process, the risk of delay and misjudgment caused by manual intervention is reduced, and then the grid connection decision-making efficiency is significantly improved, the friendliness of the photovoltaic power generation to the power grid is ensured, and then the overall operation reliability and security of the power grid are enhanced.

[0079] Please refer to Figure 4, an embodiment of the present invention provides a technical solution: a grid connection control system in a solar photovoltaic power generation system, including: a data acquisition module, configured to acquire the power generation operation data when the solar photovoltaic power generation system is connected to the target grid, including grid equipment operation data, photovoltaic power operation data, and source-grid interaction data; a feature extraction module, configured to perform feature analysis on the power generation operation data when the solar photovoltaic power generation system is connected to the target grid respectively, to obtain a grid connection evaluation index set when the solar photovoltaic power generation system is connected to the target grid, including a grid equipment stability index, a photovoltaic operation stability index, and a grid connection adaptability index; a comprehensive analysis module, configured to perform comprehensive analysis on the grid connection evaluation index set when the solar photovoltaic power generation system is connected to the target grid, to obtain a source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target grid; a grid connection control module, configured to take a preset grid connection control measure based on the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target grid.

[0080] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0081] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A grid connection control method for a solar photovoltaic power generation system, characterized in that, The steps include: Obtain the power generation operation data when the solar photovoltaic power generation system is connected to the target power grid, including power grid equipment operation data, photovoltaic power operation data, and source-grid interaction data; Respectively conduct feature analysis on the power generation operation data when the solar photovoltaic power generation system is connected to the target power grid to obtain the grid connection evaluation index set when the solar photovoltaic power generation system is connected to the target power grid, including the grid equipment stability index, photovoltaic operation stability index, and grid connection adaptability index, and conduct comprehensive analysis to obtain the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid; Based on the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid, adopt preset grid connection control measures.

2. The grid connection control method in the solar photovoltaic power generation system according to claim 1, characterized in that, The specific formula for calculating the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid is as follows: Among them, BwR, DwH, GyW, and BsY are the source-grid collaborative security index, grid equipment stability index, photovoltaic operation stability index, and grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid in sequence, α1, α2, and α3 are the equipment stability adjustment coefficient, photovoltaic operation adjustment coefficient, and grid connection adaptation adjustment coefficient stored in the database in sequence, and ζ is the photovoltaic operation smoothing coefficient stored in the database.

3. The grid connection control method in the solar photovoltaic power generation system according to claim 1, characterized in that, The power grid equipment operation data includes the inverter feedforward steady-state index, breaker feedforward steady-state index, and transformer feedforward steady-state index, and the specific steps for obtaining the grid equipment stability index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Respectively conduct comprehensive analysis on the inverter feedforward steady-state index, breaker feedforward steady-state index, and transformer feedforward steady-state index when the solar photovoltaic power generation system is connected to the target power grid to obtain the initial grid equipment stability index and equipment interaction correction index when the solar photovoltaic power generation system is connected to the target power grid; And conduct comprehensive analysis on the initial grid equipment stability index and equipment interaction correction index when the solar photovoltaic power generation system is connected to the target power grid to obtain the grid equipment stability index when the solar photovoltaic power generation system is connected to the target power grid.

4. The grid connection control method in the solar photovoltaic power generation system according to claim 3, characterized in that The specific steps for obtaining the inverter feedforward steady-state index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Obtain the inverter steady current adaptation index, inverter current harmonic distortion index, inverter voltage harmonic distortion index, inverter resonance impedance index, and inverter temperature value when the solar photovoltaic power generation system is connected to the target power grid, and conduct standardization processing; Conduct comprehensive analysis on the standardized inverter steady current adaptation index, inverter current harmonic distortion index, inverter voltage harmonic distortion index, inverter resonance impedance index, and inverter temperature value when the solar photovoltaic power generation system is connected to the target power grid to obtain the inverter feedforward steady-state index when the solar photovoltaic power generation system is connected to the target power grid.

5. The grid connection control method in the solar photovoltaic power generation system according to claim 1, characterized in that, The photovoltaic power operation data includes the series current dispersion index, backplane temperature gradient index, and photovoltaic power quality index. The specific steps for obtaining the photovoltaic operation stability index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Obtain the light intensity value, ambient temperature value, and radiation reflectivity value when the solar photovoltaic power generation system is connected to the target power grid, and combine the backplane temperature gradient index, and conduct a comprehensive analysis to obtain the photovoltaic operation correction factor when the solar photovoltaic power generation system is connected to the target power grid; Conduct a comprehensive analysis of the photovoltaic operation correction factor, string current dispersion index, and photovoltaic power quality index when the solar photovoltaic power generation system is connected to the target power grid to obtain the photovoltaic operation stability index when the solar photovoltaic power generation system is connected to the target power grid.

6. The grid connection control method in the solar photovoltaic power generation system according to claim 5, characterized in that, The specific steps to obtain the photovoltaic power quality index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Obtain the voltage deviation value, current deviation value, power offset value, and three-phase balance index when the solar photovoltaic power generation system is connected to the target power grid, and conduct standardization processing; Based on the voltage deviation value, current deviation value, power offset value, and three-phase balance index when the solar photovoltaic power generation system is connected to the target power grid after standardization processing, conduct a comprehensive analysis to obtain the photovoltaic power quality index when the solar photovoltaic power generation system is connected to the target power grid.

7. The grid connection control method in the solar photovoltaic power generation system according to claim 1, characterized in that The source-grid interaction data includes the coupling drive index, source-grid symmetry coordination index, supply-demand current adaptation index, and grid-side bearing capacity index. The specific steps to obtain the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Normalize the coupling drive index, source-grid symmetry coordination index, supply-demand current adaptation index, and grid-side bearing capacity index of the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid; And conduct a comprehensive analysis of the normalized coupling drive index, source-grid symmetry coordination index, supply-demand current adaptation index, and grid-side bearing capacity index of the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid to obtain the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid.

8. The grid connection control method in the solar photovoltaic power generation system according to claim 7, characterized in that, The specific formula for calculating the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid is as follows: Among them, BsY is the grid connection adaptability index when the solar photovoltaic power generation system is connected to the target power grid, YwX′, GxP′, WsG′, and DqS′ are the source-grid symmetry coordination index, supply-demand current adaptation index, grid-side bearing capacity index, and coupling drive index when the solar photovoltaic power generation system is connected to the target power grid after normalization processing in sequence, and μ1, μ2, μ3, μ4, μ5, and μ6 are the symmetry adjustment coefficient, adaptation adjustment coefficient, bearing adjustment coefficient, drive adjustment coefficient, drive adaptation adjustment coefficient, and smoothing adjustment coefficient stored in the database in sequence.

9. The grid connection control method in the solar photovoltaic power generation system according to claim 1, characterized in that, The specific steps of the grid connection control measures preset based on the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid are as follows: Judge and analyze the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid and the preset source-grid collaborative security index threshold; If the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid is lower than or equal to the preset source-grid collaborative security index threshold, then take the first grid connection control measure; If the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid is higher than the preset source-grid collaborative security index threshold, then the second grid connection control measure is taken.

10. A grid connection control system in a solar photovoltaic power generation system, which applies the grid connection control method for the solar photovoltaic power generation system according to any one of claims 1-9, characterized in that, Including: A data acquisition module, configured to acquire the power generation operation data when the solar photovoltaic power generation system is connected to the target power grid, including grid equipment operation data, photovoltaic power operation data, and source-grid interaction data; A feature extraction module, configured to perform feature analysis on the power generation operation data when the solar photovoltaic power generation system is connected to the target power grid respectively, to obtain a grid connection evaluation index set when the solar photovoltaic power generation system is connected to the target power grid, including a grid equipment stability index, a photovoltaic operation stability index, and a grid connection adaptability index; A comprehensive analysis module, configured to comprehensively analyze the grid connection evaluation index set when the solar photovoltaic power generation system is connected to the target power grid, to obtain the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid; A grid connection control module, configured to take a preset grid connection control measure based on the source-grid collaborative security index when the solar photovoltaic power generation system is connected to the target power grid.

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