Grid access method and device of household light storage and charging integrated equipment, computer equipment and storage medium

Abstract

This application discloses a method, apparatus, computer equipment, and storage medium for grid connection of a home photovoltaic-storage-charging integrated device. The method includes: collecting voltage waveform data of a target power grid; determining the grid system of the target power grid; injecting a disturbance signal at the grid connection point of the target power grid with a disturbance duration less than a preset threshold; determining transformer area characteristic parameters based on feedback from the disturbance signal; calculating a protection threshold based on the grid system and the transformer area characteristic parameters; loading a matching grid connection standard parameter set based on the grid system; and performing grid connection operation within the protection threshold limits using an operating strategy and the grid connection standard parameter set. This application automatically completes grid system identification, transformer area characteristic identification, protection threshold calculation, and loading of a matching grid connection standard parameter set after grid connection. It achieves plug-and-play functionality and automatic grid connection, lowering the installation threshold. It solves the technical problem of cumbersome and error-prone operation procedures when connecting home photovoltaic-storage-charging integrated devices to the user's power grid.

Description

Technical Field

[0001] This application relates to the field of distributed energy grid connection control technology, and in particular to grid connection methods, devices, computer equipment and storage media for integrated photovoltaic, energy storage and charging equipment for home use. Background Technology

[0002] With the increasing prevalence of photovoltaic, energy storage, and electric vehicle charging piles, integrated photovoltaic-energy storage-charging equipment is gradually entering homes. However, the installation and commissioning of such equipment currently heavily relies on professional electricians. Manual configuration is cumbersome; installers must first determine whether the power grid is single-phase or three-phase, the voltage level, and whether the phase sequence is correct, before manually dialing codes or setting equipment parameters via an app. Protection settings need to be customized; different transformer areas have different capacities, grounding methods, and short-circuit capacities. Over / under voltage protection, over / under frequency protection, and anti-islanding protection thresholds require manual calculation and input, which is prone to errors. Coordination of multiple units in parallel is difficult; when multiple photovoltaic-energy storage-charging devices are connected in parallel in the same area, without automatic identification, it may lead to excessive power backflow or improper protection coordination. Although existing technologies have some automatic identification functions, they are limited to simple voltage detection and cannot comprehensively acquire grid characteristic parameters, let alone adaptively configure operating strategies. Therefore, existing technologies suffer from cumbersome and error-prone operation procedures when connecting home integrated photovoltaic-energy storage-charging equipment to the user's power grid. Summary of the Invention

[0003] This application provides a grid connection method, apparatus, computer equipment, and storage medium for integrated home photovoltaic, energy storage, and charging devices, which can solve the technical problem that the operation process of integrated home photovoltaic, energy storage, and charging devices is cumbersome and prone to errors when connected to the user's power grid in the prior art.

[0004] In a first aspect, embodiments of this application provide a grid connection method for a home-use integrated photovoltaic, energy storage, and charging device, including: In response to the grid connection command, the voltage waveform data of the target grid is collected; Based on the voltage waveform data, the grid system of the target power grid is determined by judging the effective voltage value and frequency, wherein the grid system includes voltage level and number of phases of AC power; A disturbance signal is injected into the grid connection point of the target power grid with a disturbance duration less than a preset duration threshold, and the characteristic parameters of the distribution area are determined based on the feedback of the disturbance signal; Based on the power grid system and the characteristic parameters of the distribution area, calculate the protection thresholds corresponding to various protection types in the power grid, wherein each protection type includes at least one of voltage protection, frequency protection and current protection; Based on the power grid system, a matching set of grid connection standard parameters is loaded, and grid connection operation is carried out within the protection threshold limit using the corresponding operating strategy and the set of grid connection standard parameters.

[0005] In some embodiments, the power grid system includes voltage level, number of phases of AC power, phase sequence, and grounding method. Based on the voltage waveform data, the power grid system of the target power grid is determined by judging the effective voltage value and frequency. The power grid system includes voltage level and number of phases of AC power, including: Based on the voltage waveform data, determine the effective voltage value and frequency; The voltage level and the number of phases of the AC power supply of the target power grid are determined based on the effective voltage value and the frequency. If the voltage waveform data indicates that the number of phases of the AC power is three-phase, then the phase sequence is determined to be either positive or negative based on the phase difference of the three-phase voltage. The voltage to ground of each phase of the three-phase voltage is measured respectively, and the grounding mode is determined based on the voltage to ground. If the voltage to ground of all three phases is not zero and is symmetrical, it is determined to be ungrounded. If the voltage to ground of any one phase is 0, it is determined to be grounded.

[0006] In some embodiments, the transformer substation characteristic parameters include line impedance and transformer short-circuit capacity. A disturbance signal is injected into the grid connection point of the target power grid for a disturbance duration less than a preset duration threshold. The transformer substation characteristic parameters are determined based on feedback from the disturbance signal, including: Inject current disturbances at the grid connection point of the target power grid for a disturbance duration less than a preset duration threshold. Detect the voltage change at the grid connection point; Calculate the ratio between the voltage change and the current change corresponding to the current disturbance to obtain the line impedance; Calculate the product of the rated current and the line impedance to obtain the theoretical voltage drop; The transformer short-circuit capacity is calculated based on the rated power and the rated voltage drop.

[0007] In some embodiments, based on the power grid system, a matching set of grid connection standard parameters is loaded, and grid connection operation is performed within the protection threshold limit using the corresponding operating strategy and the set of grid connection standard parameters, including: Based on the effective voltage value and frequency in the power grid system, load the grid connection standard parameter set for the corresponding region; Without injecting disturbance signals, the harmonics of the voltage-current ratio are collected, and a harmonic background library for the transformer area is established. Based on the characteristic parameters of the transformer area and the harmonic background library of the transformer area, select the corresponding operation strategy; Within the protection threshold limit, the operation strategy is executed to perform grid-connected operation using the parameters in the grid-connected standard parameter set.

[0008] In some embodiments, based on the power grid system and the distribution area characteristic parameters, protection thresholds corresponding to various protection types in the power grid are calculated, wherein each protection type includes at least one of voltage protection, frequency protection, and current protection, and includes: In response to the presence of other devices connected to the grid in the same distribution area, calculate the remaining load capacity after deducting the load of other devices from the total load of the current distribution area; If the remaining load capacity is less than the protection load capacity corresponding to the protection threshold, the protection load capacity is updated based on the remaining load capacity to obtain a new protection load capacity. Based on the power grid system, a matching set of grid connection standard parameters is loaded, and grid connection operation is carried out within the new protection load capacity limit using the corresponding operating strategy and the set of grid connection standard parameters.

[0009] In some embodiments, the various protection types include at least one of overvoltage protection, undervoltage protection, overfrequency protection, underfrequency protection, and overcurrent protection.

[0010] In some embodiments, the home-use integrated photovoltaic storage and charging device supports plug-and-play functionality.

[0011] Secondly, embodiments of this application also provide a grid connection device for a home photovoltaic-storage-charging integrated device, comprising: The acquisition unit is used to acquire voltage waveform data of the target power grid in response to the power grid access command; The determining unit is used to determine the grid system of the target power grid based on the voltage waveform data by judging the effective voltage value and frequency, wherein the grid system includes voltage level and number of phases of AC power; The disturbance unit is used to inject a disturbance signal at the grid connection point of the target power grid with a disturbance duration of less than a preset duration threshold, and to determine the characteristic parameters of the distribution area based on the feedback of the disturbance signal. The calculation unit is used to calculate the protection thresholds corresponding to various protection types in the power grid based on the power grid system and the distribution area characteristic parameters, wherein each protection type includes at least one of voltage protection, frequency protection and current protection; The grid connection execution unit is used to load a matching set of grid connection standard parameters based on the power grid system, and to perform grid connection operation within the protection threshold limit using the corresponding operation strategy and the set of grid connection standard parameters.

[0012] Thirdly, embodiments of this application also provide a computer device for grid access of a home photovoltaic storage and charging integrated device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-mentioned method.

[0013] Fourthly, embodiments of this application also provide a computer-readable storage medium storing a computer program, the computer program including program instructions that, when executed by a processor, can implement the above-described method.

[0014] This application provides a method, apparatus, computer equipment, and storage medium for grid connection of a home photovoltaic-storage-charging integrated device. The method includes: in response to a grid connection command, acquiring voltage waveform data of a target grid; determining the grid system of the target grid based on the voltage waveform data by judging the effective voltage value and frequency, wherein the grid system includes voltage level and the number of AC phases; injecting a disturbance signal at the grid connection point of the target grid with a disturbance duration less than a preset duration threshold, and determining transformer area characteristic parameters based on feedback from the disturbance signal; calculating protection thresholds corresponding to various protection types in the grid based on the grid system and the transformer area characteristic parameters, wherein each protection type includes at least one of voltage protection, frequency protection, and current protection; loading a matching grid connection standard parameter set based on the grid system, and performing grid connection operation within the protection threshold limits using a corresponding operating strategy and the grid connection standard parameter set. In this application, after grid connection, grid system identification, transformer area characteristic identification, protection threshold determination, and loading of a matching grid connection standard parameter set are automatically completed, achieving plug-and-play functionality and automatic grid connection, reducing installation barriers and labor costs. This solves the technical problem of cumbersome and error-prone operation procedures when connecting home photovoltaic, energy storage and charging integrated equipment to the user's power grid. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic flowchart illustrating the grid connection method for a home photovoltaic-storage-charging integrated device provided in this application embodiment; Figure 2 A schematic block diagram of the grid connection device for a home photovoltaic-storage-charging integrated device provided in the embodiments of this application; Figure 3 A schematic block diagram of a computer device provided in an embodiment of this application. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the stated features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0019] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0020] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0021] With the increasing prevalence of photovoltaic, energy storage, and electric vehicle charging piles, integrated photovoltaic-energy storage-charging equipment is gradually entering homes. However, the installation and commissioning of such equipment currently heavily relies on professional electricians. Manual configuration is cumbersome; installers must first determine whether the power grid is single-phase or three-phase, the voltage level, and whether the phase sequence is correct, before manually dialing codes or setting equipment parameters via an app. Protection settings need to be customized; different transformer areas have different capacities, grounding methods, and short-circuit capacities. Over / undervoltage protection, over / underfrequency protection, and anti-islanding protection thresholds require manual calculation and input, which is prone to errors. Coordination of multiple units in parallel is difficult; when multiple photovoltaic-energy storage-charging devices are connected in parallel in the same area, without automatic identification, it may lead to excessive power backflow or improper protection coordination. Although existing technologies have some automatic identification functions, they are limited to simple voltage detection and cannot comprehensively acquire grid characteristic parameters, let alone adaptively configure operating strategies. Therefore, existing technologies suffer from cumbersome and error-prone operation procedures when connecting home integrated photovoltaic-energy storage-charging equipment to the user's power grid.

[0022] This application provides a grid connection method, device, computer equipment, and storage medium for a home photovoltaic, energy storage, and charging integrated device, aiming to solve the technical problem that the operation process of the existing home photovoltaic, energy storage, and charging integrated device is cumbersome and prone to errors when connected to the user's power grid.

[0023] This application enables the equipment to automatically complete grid system identification, transformer area parameter identification, protection setting configuration, and grid connection protocol matching after being connected to the grid, achieving plug-and-play functionality and automatic grid connection, thereby reducing installation barriers and labor costs.

[0024] Figure 1 This is a schematic flowchart illustrating the grid connection method for a home-use integrated photovoltaic, energy storage, and charging device provided in this application embodiment. The grid connection method for the home-use integrated photovoltaic, energy storage, and charging device is applied to the grid connection equipment for this device. For example... Figure 1 As shown, the method includes the following steps S110-S150:

[0025] S110. In response to the grid connection command, collect voltage waveform data of the target grid; As an example, a home-use photovoltaic-storage-charging integrated device is a 5kW rated power photovoltaic-storage-charging integrated machine, which includes a photovoltaic interface, an energy storage interface, a charging pile interface, and a grid connection interface.

[0026] As an example, the controller of the grid access device of the home photovoltaic storage and charging integrated equipment of this application adopts an ARM Cortex-M4 chip, with built-in voltage / current sampling circuit, relay drive, and PLC communication module.

[0027] For example, in a typical scenario, a user plugs the power cord of their home photovoltaic, energy storage, and charging integrated device into a wall socket. The wall socket operates on a single-phase 220V voltage, the transformer capacity in the distribution area is 100kVA, and a neighbor has already installed a 3kW photovoltaic system.

[0028] The grid connection device of the home photovoltaic storage and charging integrated equipment collects the voltage waveform of the PCC at the grid connection point through a voltage sensor.

[0029] S120. Based on the voltage waveform data, the power grid system of the target power grid is determined by judging the effective voltage value and frequency, wherein the power grid system includes voltage level and number of phases of AC power. The target power grid's grid standard refers to a set of standard technical parameters adopted by that grid, mainly including three basic elements: rated voltage, rated frequency, and grounding system. Clearly defining the target power grid standard is crucial for the design and equipment selection of residential photovoltaic energy storage and charging systems.

[0030] Different regions have different power grid systems; for example, the power grid system in country A is different from that in country B.

[0031] For household photovoltaic, energy storage, and charging systems, the main power supply standard is the low-voltage distribution network. Residential low-voltage power supply primarily uses two voltage levels: single-phase 220V and three-phase 380 / 220V. Single-phase 220V is suitable for small systems with a capacity not exceeding 8kWp. Three-phase 380 / 220V is suitable when the total power of the equipment exceeds 8kW, requiring three-phase power supply. The rated frequency is uniformly 50Hz. The mainstream grounding system standards are TN-S or TN-CS. Both systems provide independent neutral and protective grounding wires to electrical equipment. The key difference is that in the TN-S system, the neutral and protective grounding wires are completely separated from the transformer onwards; while in the TN-CS system, a single PEN wire is used before entering the house, and then separated into neutral and protective grounding wires after entering the house.

[0032] Common international power grid systems include, for example, a regional power grid system of 230V single-phase or 400V three-phase, with a rated frequency of 50Hz, and the mainstream grounding system systems are TT and TN-S systems.

[0033] The power grid system includes voltage level, number of phases of AC power, phase sequence, and grounding method. S120 includes S1201-S1204: S1201. Based on the voltage waveform data, determine the effective voltage value and frequency; Based on the voltage waveform data, a high sampling rate AC sampling method is used, such as sampling 64 points or more per cycle, and the RMS voltage value and frequency are directly calculated using the root mean square algorithm. Since the waveforms generated by modern inverters are not perfect standard sine waves, measurement equipment supporting the true RMS algorithm should be selected.

[0034] Use high-precision voltage transformers or sensors, and calibrate the analog-to-digital conversion acquisition channels to eliminate system errors.

[0035] As an example, the effective value of the sampled voltage is 223.5V and the frequency is 50.02Hz.

[0036] S1202. Determine the voltage level and the number of phases of the target power grid based on the effective voltage value and the frequency; If the effective value of the sampled voltage is 223.5V and the frequency is 50.02Hz, it is determined to be a single-phase 220V system. The voltage level is 220V, and the number of phases is single-phase.

[0037] S1203. If the voltage waveform data indicates that the number of phases of the AC power is three-phase, then based on the phase difference of the three-phase voltage, determine whether the phase sequence is positive or negative. Three-phase alternating current is a power supply system composed of three single-phase alternating currents with the same frequency, equal amplitude, and a phase difference of 120°, combined in a certain way. It is equivalent to three single-phase voltages that are synchronized but have staggered start times.

[0038] If the voltage waveform is characterized by three sine waves of the same frequency and amplitude, with a phase difference of 120° between adjacent waveforms. For example, phase B lags phase A by 120°, and phase C lags phase B by 120°.

[0039] The waveform of three-phase voltage changes over time, but at any given moment, the sum of the instantaneous values ​​of the three-phase voltages is zero. Three-phase alternating current has high transmission efficiency; for the same power transmission, a three-phase system saves on conductor material compared to a single-phase system. Three-phase equipment generates constant torque, exhibits low vibration and noise, and provides stable instantaneous power. It can simultaneously provide two voltages: industrial line voltage such as 380V and residential phase voltage such as 220V.

[0040] Determining whether a three-phase voltage has a positive or negative phase sequence requires utilizing the known phase difference characteristics between the three phases. In an ideal three-phase system, the phase difference between any two phases is either +120° or -120°, meaning it leads by 120°, depending on the phase sequence.

[0041] If phase B voltage lags phase A by 120° (i.e., the phase difference is -120° or +240°), then verify whether phase C also lags phase B by 120°. If so, the phase sequence is positive, from A to B to C.

[0042] If phase B voltage leads phase A by 120° (i.e., the phase difference is +120° or -240°), and phase C also leads phase B by 120°, i.e., phase C leads phase B by 120°, then the phase sequence is reversed, from A to C to B.

[0043] In some embodiments, the order of the zero-crossing points of the three waveforms is determined on the oscilloscope. A zero-crossing point is a rising zero-crossing point from negative to positive. If the order of the zero-crossing points is A to B to C to A, it is a positive order; if the order of the zero-crossing points is A to C to B to A, it is a reverse order.

[0044] S1204. Measure the voltage to ground of each phase of the three-phase voltage, and determine the grounding method based on the voltage to ground. If the voltage to ground of all three phases is not zero and is symmetrical, it is determined to be ungrounded. If the voltage to ground of any one phase is 0, it is determined to be grounded.

[0045] By measuring the voltage values ​​of the three phases relative to the ground, ungrounded systems and directly grounded systems can be distinguished.

[0046] In low-voltage power distribution systems, based on the relationship between the neutral point and ground, they are classified as follows: In directly grounded systems such as TN or TT, the neutral point of the power supply is directly grounded. During normal operation, the potential of the neutral point to ground is approximately 0V, but the voltage of the phase lines L1 / L2 / L3 to ground is approximately equal to the phase voltage, such as 220V. There will never be a situation where the voltage of any one phase to ground is 0V. In an ungrounded system (IT), the neutral point of the power supply is either ungrounded or grounded through a high impedance. During normal operation, the three-phase lines have distributed capacitance and insulation resistance to ground, and the three-phase voltages to ground are symmetrical and close to the phase voltages. However, occasionally they are not non-zero and symmetrical; in reality, there may be slight differences due to asymmetry in ground parameters.

[0047] Measure the phase-to-ground voltage of each phase. If the phase-to-ground voltage of any phase is close to 0V, it is determined to be a directly grounded system; if the phase-to-ground voltages of all three phases are not zero and are symmetrical, it is determined to be an ungrounded system. This information is used to configure the leakage current protection strategy.

[0048] As an example, the voltage to ground was measured. The live wire was 223V to ground, and the neutral wire was 1.2V to ground, indicating a TN grounding system.

[0049] S130. Inject a disturbance signal at the grid connection point of the target power grid with a disturbance duration less than a preset duration threshold, and determine the characteristic parameters of the distribution area based on the feedback of the disturbance signal. Distribution transformer area characteristic parameters are a series of technical indicators used to quantitatively describe and evaluate the operating status, grid structure and load characteristics of a distribution transformer area and its subordinate low-voltage power grid.

[0050] The method of identifying transformer substation characteristic parameters by injecting short-term disturbance signals with a duration less than a preset threshold, such as tens to hundreds of milliseconds, and analyzing the feedback is essentially an active transformer substation sensing approach, especially suitable for scenarios with large-scale integration of distributed power sources such as photovoltaics and energy storage. It can quickly obtain the equivalent model parameters of the power grid without affecting the normal power supply to users.

[0051] At the grid connection point, a short-duration, controllable disturbance current sequence is actively generated by the energy storage converter or a dedicated signal injection device in the photovoltaic-storage-charging system. This disturbance is superimposed on the normal power frequency current and propagates along the feeder. Its response voltage change includes the frequency or time domain characteristics of the lines, transformers, branches, and even the loads along the route.

[0052] The characteristic parameters of the transformer substation include line impedance and transformer short-circuit capacity, and S130 includes S1301-S1305: S1301. Inject current disturbance at the grid connection point of the target power grid with a disturbance duration less than a preset duration threshold. If the disturbance duration is less than the preset duration threshold, a controllable, short-term current change is actively generated as an excitation signal. The short duration can avoid affecting the normal power supply and not triggering the protection.

[0053] The injected current disturbance is usually a step or a low-frequency square wave, and the measured value is the power frequency equivalent impedance. If a high-frequency harmonic impedance is required, the corresponding frequency must be injected.

[0054] S1302. Detect the voltage change at the grid connection point; Measure the response change of the grid connection point voltage caused by current disturbance, whether transient or steady-state.

[0055] Voltage changes are usually small, so high-resolution synchronous sampling is required to meet the voltage transformer requirements caused by power quality disturbances.

[0056] S1303. Calculate the ratio between the voltage change and the current change corresponding to the current disturbance to obtain the line impedance; According to Ohm's law, an AC system is an impedance modulus or complex impedance, and the equivalent impedance of the system seen from the disturbance point is Z = ΔU / ΔI. This impedance includes the transformer short-circuit impedance, line impedance, and the parallel effect of the load.

[0057] This calculation method applies to both single-phase and three-phase systems. In a three-phase system, the impedance of each phase should be measured separately, or the positive sequence impedance should be calculated.

[0058] As an example, a reactive current disturbance ΔIq is injected into the grid-connected converter for a short period of less than 100ms. The voltage change ΔU at the grid connection point is detected, and the line impedance Zline = ΔU / ΔIq is calculated. This impedance is used to subsequently configure overcurrent protection and active / reactive power support capabilities.

[0059] S1304. Calculate the product of the rated current and the line impedance to obtain the theoretical voltage drop; S1305. Based on the rated power and the rated voltage drop, the short-circuit capacity of the transformer is calculated.

[0060] The process of calculating the transformer short-circuit capacity in this application is actively controllable, independent of natural faults or load switching, and can be measured on demand. Short-term disturbances do not interfere with user equipment, do not cause protection malfunctions, and the calculation is simple, requiring no synchronization phasors or complex signal processing. It is suitable for grid-connected equipment with current source characteristics, such as photovoltaic, energy storage, and charging equipment.

[0061] By monitoring the voltage drop depth before and after the equipment is connected, and combining this with the estimated line impedance, the transformer short-circuit capacity Sk can be calculated.

[0062] Based on the short-circuit capacity range, such as transformer short-circuit capacity Sk < 50kVA being a small-capacity distribution area, and transformer short-circuit capacity Sk > 200kVA being a large-capacity distribution area, the rated output power is automatically limited to prevent overload.

[0063] S140. Based on the power grid system and the characteristic parameters of the distribution area, calculate the protection threshold corresponding to various protection types in the power grid, wherein each protection type includes at least one of voltage protection, frequency protection and current protection. Each type of protection includes at least one of the following: overvoltage protection, undervoltage protection, overfrequency protection, underfrequency protection, and overcurrent protection.

[0064] In power systems, especially in grid-connected inverters such as energy storage converters in photovoltaic-storage-charging systems and user-side power distribution, overvoltage, undervoltage, overfrequency, underfrequency, and overcurrent are the five most basic and core protection functions. Together, they ensure equipment safety, grid stability, and personal safety.

[0065] Overvoltage protection refers to immediately disconnecting the equipment from the power grid or limiting its output when the grid connection point voltage exceeds a set upper limit. This prevents abnormal rises in grid voltage from damaging user equipment and prevents the inverter from injecting excessively high voltage into the grid.

[0066] Undervoltage protection refers to tripping or stopping the circuit breaker when the detected voltage is lower than the set lower limit value, so as to prevent the equipment from being damaged by overheating due to excessive current under low voltage and to prevent voltage collapse accidents from escalating.

[0067] Overfrequency protection refers to immediately disconnecting the grid when the detected grid frequency exceeds the upper limit, preventing generator overspeed, protecting rotating equipment, and preventing excessively high frequencies from disrupting system stability.

[0068] Underfrequency protection refers to tripping or reducing load when the detected frequency is lower than the lower limit, preventing generators and the power grid from entering a frequency collapse, and can also serve as a basis for low-frequency load reduction instructions.

[0069] Overcurrent protection refers to the protection that cuts off the circuit or limits the current when the current flowing through the equipment exceeds the rated value or a set multiple, in order to prevent equipment damage or circuit fire.

[0070] Based on the power grid system and the characteristic parameters of the distribution transformer area, the protection thresholds corresponding to various protection types in the power grid are calculated. The power grid system provides a benchmark for protection settings, while the characteristic parameters of the distribution transformer area determine the sensitivity and selectivity of the protection. The two have different influence mechanisms and correlation dimensions, and together they determine the safety boundary of the system protection.

[0071] The power grid standard serves as a fundamental reference for protection thresholds. All voltage protection thresholds are based on the rated voltage, such as a percentage setting for 220V / 380V. In a single-phase 220V system, the 110% overvoltage threshold is 242V; in a low-voltage 380V system, it corresponds to 418V.

[0072] As an example, the protection thresholds are: overvoltage protection: 220V × 1.1 = 242V; undervoltage protection: 220V × 0.85 = 187V.

[0073] Over-frequency protection: 50Hz + 1Hz = 51Hz; Under-frequency protection: 50Hz - 1Hz = 49Hz; Maximum grid-connected power: 70kVA capacity × safety factor 0.8 = 56kW, but the equipment itself is only 5kW, so it is limited to 5kW.

[0074] The threshold for frequency protection is also set around the rated frequency, such as 50Hz. For over / under frequency protection, a typical setting range is ±2% to ±5% of the rated frequency.

[0075] The grounding system determines the zero-sequence current path, which directly affects the selection of algorithms and logic for single-phase ground fault detection and anti-islanding protection.

[0076] S140 followed by A1-A3: A1. In response to the presence of other devices connected to the grid in the same distribution area, calculate the remaining load capacity after deducting the load of other devices from the total load of the current distribution area; Determine if other devices are connected to the grid in the same distribution area. If other photovoltaic, energy storage, and charging devices are already running in the same distribution area, the newly connected device sends a query frame to the existing devices via power line communication or wireless communication. The existing devices reply with information such as their operating status and current total power.

[0077] The new equipment adjusts its operating mode accordingly: if the total power generation is close to the upper limit of the distribution area capacity, the new equipment automatically limits the grid-connected power; if the existing equipment is in off-grid mode, the new equipment automatically switches to slave mode and synchronizes the voltage phase. If communication fails, the load factor of the distribution area is estimated by detecting the slight deviation of the grid frequency (the existing equipment will have the characteristic of frequency changing with power when using droop control) and the output is adjusted adaptively.

[0078] A1. If the remaining load capacity is less than the protection load capacity corresponding to the protection threshold, the protection load capacity is updated based on the remaining load capacity to obtain a new protection load capacity. As an example, a PLC query revealed that another 5kW photovoltaic device was already connected to the grid at 4kW in the same distribution area. The current total load of the distribution area was 6kW, with a remaining capacity of 2kW. The new device automatically limited its grid-connected power to 2kW and displayed that the distribution area's capacity was nearing its limit, indicating that it was automatically operating with power limiting.

[0079] A1. Based on the power grid system, load a matching set of grid connection standard parameters, and operate the grid connection within the new protection load capacity limit using the corresponding operating strategy and the set of grid connection standard parameters.

[0080] As an example, a query broadcast frame is sent to the power line via a PLC. A nearby grid-connected 3kW photovoltaic (PV) system is of PV type, and its current power output is 2.1kW due to weather conditions.

[0081] It is known that the new device is not yet connected to the grid, with only a neighboring 2.1kW unit available. The total load in the distribution area is unknown, but can be estimated through voltage drops. The new device measures the current voltage at 223.0V, slightly lower than the no-load level, indicating some load. For safety reasons, the new device will not limit its output for now, but will activate real-time monitoring. If the voltage is detected to be below 215V, indicating excessive load, the grid-connected power will be automatically reduced. Simultaneously, the new device will broadcast its 5kW photovoltaic-storage-charging system information to the neighboring unit, which will then update its local device list.

[0082] S150. Based on the power grid system, load the matching grid connection standard parameter set, and perform grid connection operation within the protection threshold limit using the corresponding operation strategy and the grid connection standard parameter set.

[0083] S150 includes S1501-S1504: S1501. Based on the effective voltage value and frequency in the power grid system, load the grid connection standard parameter set for the corresponding region; Different countries and regions have different grid connection standards, such as IEEE1547, VDE-AR-N4105, and GB / T33593, which have different requirements for power factor, harmonics, and reverse power transmission.

[0084] The equipment automatically loads the corresponding grid connection standard parameter set based on the identified voltage / frequency. For example, 220V / 50Hz corresponds to country A or a certain region, and 110V / 60Hz corresponds to country B.

[0085] S1502. When no disturbance signal is injected, collect the harmonics of the voltage-current ratio and establish a harmonic background library for the transformer area. Without injecting disturbance signals, this passive method for monitoring and extracting the harmonic components of voltage and current at the grid connection point is used to calculate their ratio (harmonic impedance) and establish a harmonic background database for the transformer substation. It does not rely on active injection, does not interfere with normal system operation, and is suitable for long-term, continuous establishment of harmonic fingerprints for the transformer substation.

[0086] The voltage-current ratio harmonic pointer calculates the ratio of the voltage harmonic component to the current harmonic component for each harmonic, and obtains the impedance of each harmonic.

[0087] The transformer area harmonic background database is a database containing parameters such as harmonic voltage, harmonic current, harmonic impedance, and total harmonic distortion rate under typical operating conditions of the transformer area. It can also record tag information such as time, load level, and weather.

[0088] Based on the identified transformer capacity and background harmonics, the system automatically selects an operating strategy. If the transformer capacity is large and the background harmonics are low: full-power grid-connected generation is allowed, and the power factor is set to 1.0. If the transformer capacity is small, the maximum grid-connected power is limited to 80% of the transformer capacity, and reactive power compensation is enabled to support the voltage. If the background harmonics are high, the active harmonic suppression algorithm is automatically enabled, and filter parameters are configured according to the detected harmonic spectrum.

[0089] S1503. Based on the characteristic parameters of the transformer area and the harmonic background library of the transformer area, select the corresponding operation strategy; S1504. Within the protection threshold limit, the operation strategy is executed to perform grid-connected operation using the parameters in the grid-connected standard parameter set.

[0090] As an example, based on the voltage frequency, the region is identified as country A, the GB / T33593 grid connection standard is loaded, and the power factor is set to exceed 0.95.

[0091] This application provides a method, apparatus, computer equipment, and storage medium for grid connection of a home photovoltaic-storage-charging integrated device. The method includes: in response to a grid connection command, acquiring voltage waveform data of a target grid; determining the grid system of the target grid based on the voltage waveform data by judging the effective voltage value and frequency, wherein the grid system includes voltage level and the number of phases of AC power; injecting a disturbance signal at the grid connection point of the target grid with a disturbance duration less than a preset duration threshold, and determining transformer area characteristic parameters based on the feedback of the disturbance signal; calculating protection thresholds corresponding to various protection types in the grid based on the grid system and the transformer area characteristic parameters, wherein each protection type includes at least one of voltage protection, frequency protection, and current protection; loading a matching grid connection standard parameter set based on the grid system, and performing grid connection operation within the protection threshold limits using a corresponding operating strategy and the grid connection standard parameter set. In this application, after grid connection, grid system identification, transformer area characteristic identification, protection threshold determination, and loading of a matching grid connection standard parameter set are automatically completed. This achieves plug-and-play functionality and automatic grid connection, reducing installation barriers and labor costs. This solves the technical problem of cumbersome and error-prone operation procedures when connecting home photovoltaic, energy storage and charging integrated equipment to the user's power grid.

[0092] Figure 2 This is a schematic block diagram of a grid connection device for a home photovoltaic, energy storage, and charging integrated device provided in an embodiment of this application. Figure 2 As shown, corresponding to the above-described grid connection method for a home photovoltaic-storage-charging integrated device, this application also provides a grid connection device 600 for such a device. This grid connection device 600 includes units for executing the above-described grid connection method for the home photovoltaic-storage-charging integrated device. Specifically, please refer to... Figure 2 The grid connection device 600 for this home photovoltaic-storage-charging integrated device includes a data acquisition unit 601, a determination unit 602, a disturbance unit 603, a calculation unit 604, and a grid connection execution unit 605, wherein: The acquisition unit 601 is used to acquire voltage waveform data of the target power grid in response to the power grid access command; The determining unit 602 is used to determine the grid system of the target power grid based on the voltage waveform data by judging the effective voltage value and frequency, wherein the grid system includes voltage level and number of phases of AC power; The disturbance unit 603 is used to inject a disturbance signal at the grid connection point of the target power grid with a disturbance duration less than a preset duration threshold, and to determine the characteristic parameters of the transformer area based on the feedback of the disturbance signal. The calculation unit 604 is used to calculate the protection thresholds corresponding to various protection types in the power grid based on the power grid system and the distribution area characteristic parameters, wherein each protection type includes at least one of voltage protection, frequency protection and current protection. The grid connection execution unit 605 is used to load a matching set of grid connection standard parameters based on the grid system, and to perform grid connection operation within the protection threshold limit using the corresponding operation strategy and the set of grid connection standard parameters.

[0093] In some embodiments, the power grid system includes voltage level, number of phases of AC power, phase sequence, and grounding method. The determining unit 602, based on the voltage waveform data, determines the power grid system of the target power grid by judging the effective voltage value and frequency. Specifically, the power grid system includes voltage level and number of phases of AC power. Based on the voltage waveform data, determine the effective voltage value and frequency; The voltage level and the number of phases of the AC power supply of the target power grid are determined based on the effective voltage value and the frequency. If the voltage waveform data indicates that the number of phases of the AC power is three-phase, then the phase sequence is determined to be either positive or negative based on the phase difference of the three-phase voltage. The voltage to ground of each phase of the three-phase voltage is measured respectively, and the grounding mode is determined based on the voltage to ground. If the voltage to ground of all three phases is not zero and is symmetrical, it is determined to be ungrounded. If the voltage to ground of any one phase is 0, it is determined to be grounded.

[0094] In some embodiments, the transformer substation characteristic parameters include line impedance and transformer short-circuit capacity. The disturbance unit 603 injects a disturbance signal at the grid connection point of the target power grid for a disturbance duration less than a preset duration threshold. Based on the feedback of the disturbance signal, the transformer substation characteristic parameters are determined, specifically for: Inject current disturbances at the grid connection point of the target power grid for a disturbance duration less than a preset duration threshold. Detect the voltage change at the grid connection point; Calculate the ratio between the voltage change and the current change corresponding to the current disturbance to obtain the line impedance; Calculate the product of the rated current and the line impedance to obtain the theoretical voltage drop; The transformer short-circuit capacity is calculated based on the rated power and the rated voltage drop.

[0095] In some embodiments, the grid connection execution unit 605, based on the power grid system, loads a matching set of grid connection standard parameters and performs grid connection operation within the protection threshold limit using a corresponding operating strategy and the set of grid connection standard parameters, specifically for: Based on the effective voltage value and frequency in the power grid system, load the grid connection standard parameter set for the corresponding region; Without injecting disturbance signals, the harmonics of the voltage-current ratio are collected, and a harmonic background library for the transformer area is established. Based on the characteristic parameters of the transformer area and the harmonic background library of the transformer area, select the corresponding operation strategy; Within the protection threshold limit, the operation strategy is executed to perform grid-connected operation using the parameters in the grid-connected standard parameter set.

[0096] In some embodiments, based on the power grid system and the distribution area characteristic parameters, the protection thresholds corresponding to various protection types in the power grid are calculated, wherein the various protection types include at least one of voltage protection, frequency protection, and current protection. The grid connection execution unit 605 is specifically used for: In response to the presence of other devices connected to the grid in the same distribution area, calculate the remaining load capacity after deducting the load of other devices from the total load of the current distribution area; If the remaining load capacity is less than the protection load capacity corresponding to the protection threshold, the protection load capacity is updated based on the remaining load capacity to obtain a new protection load capacity. Based on the power grid system, a matching set of grid connection standard parameters is loaded, and grid connection operation is carried out within the new protection load capacity limit using the corresponding operating strategy and the set of grid connection standard parameters.

[0097] In some embodiments, the calculation unit 604 calculates the protection thresholds corresponding to various protection types in the power grid based on the power grid system and the transformer area characteristic parameters, wherein the various protection types include at least one of overvoltage protection, undervoltage protection, overfrequency protection, underfrequency protection and overcurrent protection.

[0098] In summary, the grid access device 600 of the home photovoltaic-storage-charging integrated device in this embodiment of the application collects voltage waveform data of the target power grid in response to the grid access command; based on the voltage waveform data, it determines the grid system of the target power grid by judging the effective voltage value and frequency, wherein the grid system includes voltage level and number of AC phases; it injects a disturbance signal at the grid connection point of the target power grid with a disturbance duration less than a preset duration threshold, and determines the transformer area characteristic parameters based on the feedback of the disturbance signal; based on the grid system and the transformer area characteristic parameters, it calculates the protection thresholds corresponding to various protection types in the power grid, wherein each protection type includes at least one of voltage protection, frequency protection, and current protection; based on the grid system, it loads a matching grid connection standard parameter set, and performs grid connection operation within the protection threshold limits using the corresponding operating strategy and the grid connection standard parameter set. In this application, after grid access, grid system identification, transformer area characteristic identification, protection threshold determination, and loading of a matching grid connection standard parameter set are automatically completed. This achieves plug-and-play functionality and automatic grid connection, reducing installation barriers and labor costs. This solves the technical problem of cumbersome and error-prone operation procedures when connecting home photovoltaic, energy storage and charging integrated equipment to the user's power grid.

[0099] It should be noted that those skilled in the art can clearly understand that the specific implementation process of the grid access device and each unit of the above-mentioned integrated home photovoltaic energy storage and charging equipment can be referred to the corresponding descriptions in the foregoing method embodiments. For the sake of convenience and brevity, they will not be repeated here.

[0100] The grid connection device for the aforementioned integrated home photovoltaic, energy storage, and charging equipment can be implemented as a computer program, which can be used in various ways, such as... Figure 3 It runs on the computer device shown.

[0101] Please see Figure 3 , Figure 3 This is a schematic block diagram of a computer device 700 provided in an embodiment of this application. The computer device 700 can be a terminal or a server. The terminal can be an electronic device with communication functions, such as a smartphone, tablet, laptop, desktop computer, personal digital assistant, or wearable device. The server can be a standalone server or a server cluster composed of multiple servers.

[0102] See Figure 3 The computer device 700 includes a processor 702, a memory, and a network interface 705 connected via a device bus 701. The memory may include a non-volatile storage medium 703 and internal memory 704.

[0103] The non-volatile storage medium 703 may store an operating system 7031 and a computer program 7032. The computer program 7032 includes program instructions that, when executed, cause the processor 702 to perform a grid connection method for a home photovoltaic energy storage and charging integrated device.

[0104] The processor 702 provides computing and control capabilities to support the operation of the entire computer device 700.

[0105] The internal memory 704 provides an environment for the operation of the computer program 7032 in the non-volatile storage medium 703. When the computer program 7032 is executed by the processor 702, the processor 702 can execute a grid connection method for a home photovoltaic storage and charging integrated device.

[0106] This network interface 705 is used for network communication with other devices. Those skilled in the art will understand that... Figure 3 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device 700 to which the present application is applied. The specific computer device 700 may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0107] The processor 702 is used to run the computer program 7032 stored in the memory to perform the following steps: In response to the grid connection command, the voltage waveform data of the target grid is collected; Based on the voltage waveform data, the grid system of the target power grid is determined by judging the effective voltage value and frequency, wherein the grid system includes voltage level and number of phases of AC power; A disturbance signal is injected into the grid connection point of the target power grid with a disturbance duration less than a preset duration threshold, and the characteristic parameters of the distribution area are determined based on the feedback of the disturbance signal; Based on the power grid system and the characteristic parameters of the distribution area, calculate the protection thresholds corresponding to various protection types in the power grid, wherein each protection type includes at least one of voltage protection, frequency protection and current protection; Based on the power grid system, a matching set of grid connection standard parameters is loaded, and grid connection operation is carried out within the protection threshold limit using the corresponding operating strategy and the set of grid connection standard parameters.

[0108] It should be understood that in the embodiments of this application, the processor 702 may be a central processing unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0109] It will be understood by those skilled in the art that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program includes program instructions and can be stored in a storage medium, which is a computer-readable storage medium. The program instructions are executed by at least one processor in the computer device to implement the process steps of the embodiments of the above methods.

[0110] Therefore, this application also provides a storage medium. This storage medium can be a computer-readable storage medium. The storage medium stores a computer program, wherein the computer program includes program instructions. When executed by a processor, the program instructions cause the processor to perform the following steps: In response to the grid connection command, the voltage waveform data of the target grid is collected; Based on the voltage waveform data, the grid system of the target power grid is determined by judging the effective voltage value and frequency, wherein the grid system includes voltage level and number of phases of AC power; A disturbance signal is injected into the grid connection point of the target power grid with a disturbance duration less than a preset duration threshold, and the characteristic parameters of the distribution area are determined based on the feedback of the disturbance signal; Based on the power grid system and the characteristic parameters of the distribution area, calculate the protection thresholds corresponding to various protection types in the power grid, wherein each protection type includes at least one of voltage protection, frequency protection and current protection; Based on the power grid system, a matching set of grid connection standard parameters is loaded, and grid connection operation is carried out within the protection threshold limit using the corresponding operating strategy and the set of grid connection standard parameters.

[0111] The storage medium can be any computer-readable storage medium that can store program code, such as a USB flash drive, external hard drive, read-only memory (ROM), disk, or optical disc.

[0112] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0113] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For example, the division of the various units is merely a logical functional division, and other division methods may be used in actual implementation. For example, multiple units or components may be combined or integrated into another apparatus, or some features may be omitted or not performed.

[0114] The steps in the methods of this application embodiment can be adjusted, merged, or deleted according to actual needs. The units in the apparatus of this application embodiment can be merged, divided, or deleted according to actual needs. In addition, the functional units in the various embodiments of this application 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.

[0115] 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 storage medium. Based on this understanding, the technical solution of this application, the part that essentially 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, terminal, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application.

[0116] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and such modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for grid connection of a home-use integrated photovoltaic, energy storage, and charging device, characterized in that, The method includes: In response to the grid connection command, the voltage waveform data of the target grid is collected; Based on the voltage waveform data, the grid system of the target power grid is determined by judging the effective voltage value and frequency, wherein the grid system includes voltage level and number of phases of AC power; A disturbance signal is injected into the grid connection point of the target power grid with a disturbance duration less than a preset duration threshold, and the characteristic parameters of the distribution area are determined based on the feedback of the disturbance signal; Based on the power grid system and the characteristic parameters of the distribution area, calculate the protection thresholds corresponding to various protection types in the power grid, wherein each protection type includes at least one of voltage protection, frequency protection and current protection; Based on the power grid system, a matching set of grid connection standard parameters is loaded, and grid connection operation is performed within the protection threshold using the corresponding operating strategy and the set of grid connection standard parameters.

2. The method according to claim 1, characterized in that, The power grid system includes voltage level, number of phases of AC power, phase sequence, and grounding method. Based on the voltage waveform data, the power grid system of the target power grid is determined, including: Based on the voltage waveform data, determine the effective voltage value and frequency; The voltage level and the number of phases of the AC power supply of the target power grid are determined based on the effective voltage value and the frequency. If the voltage waveform data indicates that the number of phases of the AC power is three-phase, then the phase sequence is determined to be either positive or negative based on the phase difference of the three-phase voltage. The voltage to ground of each phase of the three-phase voltage is measured respectively, and the grounding mode is determined based on the voltage to ground. If the voltage to ground of all three phases is not zero and is symmetrical, it is determined to be ungrounded. If the voltage to ground of any one phase is 0, it is determined to be grounded.

3. The method according to claim 1, characterized in that, The transformer substation characteristic parameters include line impedance and transformer short-circuit capacity. A disturbance signal is injected into the grid connection point of the target power grid with a disturbance duration less than a preset duration threshold. The transformer substation characteristic parameters are determined based on feedback from the disturbance signal, including: Inject current disturbances at the grid connection point of the target power grid for a disturbance duration less than a preset duration threshold. Detect the voltage change at the grid connection point; Calculate the ratio between the voltage change and the current change corresponding to the current disturbance to obtain the line impedance; Calculate the product of the rated current and the line impedance to obtain the theoretical voltage drop; The transformer short-circuit capacity is calculated based on the rated power and rated voltage drop.

4. The method according to claim 1, characterized in that, Based on the power grid system, a matching set of grid connection standard parameters is loaded, and grid connection operation is performed within the protection threshold using the corresponding operating strategy and the set of grid connection standard parameters, including: Based on the effective voltage value and frequency in the power grid system, load the grid connection standard parameter set for the corresponding region; Without injecting disturbance signals, the harmonics of the voltage-current ratio are collected, and a harmonic background library for the transformer area is established. Based on the characteristic parameters of the transformer area and the harmonic background library of the transformer area, select the corresponding operation strategy; Within the protection threshold, the operation strategy is executed to perform grid-connected operation using the parameters in the grid-connected standard parameter set.

5. The method according to claim 1, characterized in that, Based on the power grid system and the characteristic parameters of the distribution area, the protection thresholds corresponding to various protection types in the power grid are calculated. Each protection type includes at least one of voltage protection, frequency protection, and current protection, and includes: In response to the presence of other devices connected to the grid in the same distribution area, calculate the remaining load capacity after deducting the load of other devices from the total load of the current distribution area; If the remaining load capacity is less than the protection load capacity corresponding to the protection threshold, the protection load capacity is updated based on the remaining load capacity to obtain a new protection load capacity. Based on the power grid system, a matching set of grid connection standard parameters is loaded, and grid connection operation is carried out within the new protection load capacity using the corresponding operating strategy and the set of grid connection standard parameters.

6. The method according to claim 1, characterized in that, Each type of protection includes at least one of the following: overvoltage protection, undervoltage protection, overfrequency protection, underfrequency protection, and overcurrent protection.

7. The method according to claim 1, characterized in that, The home-use integrated photovoltaic, energy storage, and charging device supports plug-and-play functionality.

8. A grid connection device for a household integrated photovoltaic, energy storage, and charging system, characterized in that, The device includes: The acquisition unit is used to acquire voltage waveform data of the target power grid in response to the power grid access command; The determining unit is used to determine the grid system of the target power grid based on the voltage waveform data by judging the effective voltage value and frequency, wherein the grid system includes voltage level and number of phases of AC power; The disturbance unit is used to inject a disturbance signal at the grid connection point of the target power grid with a disturbance duration of less than a preset duration threshold, and to determine the characteristic parameters of the distribution area based on the feedback of the disturbance signal. The calculation unit is used to calculate the protection thresholds corresponding to various protection types in the power grid based on the power grid system and the distribution area characteristic parameters, wherein each protection type includes at least one of voltage protection, frequency protection and current protection; The grid connection execution unit is used to load a matching set of grid connection standard parameters based on the power grid system, and to perform grid connection operation within the protection threshold using the corresponding operation strategy and the set of grid connection standard parameters.

9. A computer device for grid connection of a home-use integrated photovoltaic, energy storage, and charging system, characterized in that, The device includes a memory, a processor, and a grid connection program for a home photovoltaic, energy storage, and charging integrated device stored in the memory and executable on the processor. The processor executes the grid connection program for the home photovoltaic, energy storage, and charging integrated device to implement the steps of the grid connection method for the home photovoltaic, energy storage, and charging integrated device as described in any one of claims 1 to 7.

10. A storage medium, characterized in that, The storage medium stores a program for implementing a grid connection method for a home photovoltaic, energy storage and charging integrated device. The program for implementing the grid connection method for a home photovoltaic, energy storage and charging integrated device is executed by a processor to implement the steps of the grid connection method for a home photovoltaic, energy storage and charging integrated device as described in any one of claims 1 to 7.

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