Grid-connected off-grid distributed photovoltaic power generation system

Abstract

The invention belongs to the technical field of photovoltaic power generation, and particularly relates to a grid-connected off-grid distributed photovoltaic power generation system, distributed photovoltaic modules converge into a primary and secondary fusion ring main unit, an intelligent control system monitors the generated power input into the primary and secondary fusion ring main unit, the generated power is matched with the electricity utilization power of a local load, and the power utilization power of the local load is matched with the grid-connected off-grid distributed photovoltaic power generation system. And after matching, the power transmission strategy is optimized to obtain an optimal photovoltaic module calling scheme, so that the equipment calling collaboration at the power generation side is improved. Therefore, the problems caused by poor collaboration among the devices in the prior art can be solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic power generation, and in particular relates to a distributed photovoltaic power generation system that is connected to a grid but not connected to the grid. Background Art

[0002] As the global demand for clean energy continues to increase, photovoltaic power generation has been widely used as a sustainable way of energy utilization. Photovoltaic power generation systems are mainly composed of photovoltaic modules, inverters, brackets, combiner boxes and other equipment. Photovoltaic modules convert solar energy into direct current, and inverters convert direct current into alternating current for use by loads or to be connected to the power grid. Photovoltaic modules are usually installed in sunny places such as roofs of buildings and open ground. Their power generation efficiency is affected by many factors such as light intensity, temperature, and shadows. The inverter not only realizes the conversion from DC to AC, but also has functions such as maximum power point tracking (MPPT) to improve the power generation efficiency of the photovoltaic system.

[0003] The photovoltaic power generation system is connected to the grid but not to the Internet, which is the so-called "self-generation for own use" mode. Its core principle is to ensure that the photovoltaic power generation is completely consumed on the local load side through reasonable system design and control, and no excess power flows to the grid.

[0004] The existing photovoltaic power generation system is connected to the grid but not to the grid. The control system coordinates the distribution of electricity between the photovoltaic power generation system and the load. However, when the photovoltaic power generation is greater than the load power consumption, the control system often controls the inverter to reduce the output power, or adds an additional energy storage system to store the excess electricity generated by the photovoltaic power generation system. This will enable the photovoltaic power generation system to be effectively utilized. In a distributed photovoltaic power generation system, more excess electricity is often generated. When the coordination between the various devices in the photovoltaic power generation system that is connected to the grid but not to the grid is poor, it often affects the system stability and the realization of the offline function. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a distributed photovoltaic power generation system that is connected to the grid but not connected to the grid, so as to solve the problems caused by poor coordination between devices in the prior art.

[0006] The basic solution provided by the present invention is: a distributed photovoltaic power generation system that is connected to the grid but not connected to the grid, comprising a distributed photovoltaic module, a primary and secondary fusion ring network cabinet, an intelligent control system, and an anti-backflow inverter. The output line of the distributed photovoltaic module is connected to the incoming line port of the primary and secondary fusion ring network cabinet; the primary and secondary fusion ring network cabinet is connected to the municipal power grid access point through the anti-backflow inverter;

[0007] The intelligent control system is connected to the primary and secondary integrated ring main unit through communication. The intelligent control system includes a data acquisition module, a photovoltaic system simulation module, and a power transmission control module, wherein:

[0008] The data acquisition module is used to obtain parameter information, structural data and operating data of each device in the distributed photovoltaic components, primary and secondary fusion ring network cabinets, anti-reverse current inverters, municipal power grids and local loads;

[0009] The photovoltaic system simulation module is used to simulate and generate a digital image of a photovoltaic power generation system that is connected to the grid and not connected to the grid according to the parameter information and structural data collected by the data collection module, and to drive the simulation of changes in the digital image of the photovoltaic power generation system according to the operation data;

[0010] The data acquisition module is used to collect the power generation data of the distributed photovoltaic components flowing into the primary and secondary fusion ring network cabinet, the power supply data of the municipal power grid and the power consumption data of the local load in the simulation results of the change of the digital image of the photovoltaic power generation system in real time;

[0011] The power transmission control module is used to determine whether the power generation data of the distributed photovoltaic components meets the power demand based on the local load power consumption data. If so, a power adjustment command is generated to adjust the power transmission strategy of the distributed photovoltaic components connected to the primary and secondary fusion ring network cabinet. If not, a switching command is generated to control the primary and secondary fusion ring network cabinet to switch to the municipal power grid for power supply;

[0012] The photovoltaic system simulation module is also used to receive the power transmission strategy of the anti-backflow control module and simulate the changes in the digital image of the photovoltaic power generation system.

[0013] Furthermore, the photovoltaic system simulation module includes a digital mirror construction unit, a digital mirror simulation unit and a rendering unit. The digital mirror construction unit is used to receive the parameter information and structural data of the distributed photovoltaic components, the primary and secondary fusion ring network cabinets, and the anti-backflow inverter collected by the data acquisition module, and construct the digital mirrors of the interconnected distributed photovoltaic components, the primary and secondary fusion ring network cabinets, and the anti-backflow inverter, and extract the geographical location distribution information of the distributed photovoltaic components, and use the primary and secondary fusion ring network cabinets as the trunk nodes and the geographical location distribution nodes of each photovoltaic component as the branch nodes to generate a tree-like digital mirror of the photovoltaic component; the digital mirror simulation unit is used to simulate the changes of the digital mirror according to the operating data of the distributed photovoltaic components, the primary and secondary fusion ring network cabinets, and the anti-backflow inverter, and the rendering unit is used to render the digital mirror change simulation to generate visualization.

[0014] Furthermore, the power transmission control module includes a power consumption judgment unit, a photovoltaic power generation node optimization unit, and a power supply parameter adjustment unit. The power consumption judgment unit is used to extract the real-time power consumption of the local load power consumption data and the power generation power of the distributed photovoltaic component power generation data, calculate the difference between the real-time power generation power and the real-time power consumption, and judge whether the difference is greater than 0. If so, a power adjustment command is generated;

[0015] The photovoltaic power generation node optimization unit is used to generate power demand according to the power regulation command, and call the optimization strategy according to the preset photovoltaic components according to the power demand, call the corresponding photovoltaic components to perform power transmission operations, and synchronize them to the tree-like digital image of photovoltaic components for visualization;

[0016] The power supply parameter adjustment unit is used to switch to the mains power supply when no power adjustment command is received.

[0017] Furthermore, the photovoltaic component call optimization strategy preset in the photovoltaic power generation node optimization unit is specifically:

[0018] Call the tree-like digital image of photovoltaic components, and generate a photovoltaic component node calling solution set according to the power generation power, layout distance, and power demand parameters in the power regulation command of the photovoltaic components in each node;

[0019] The PV module node calling scheme set is used as the initial population, and the optimized genetic algorithm is called to perform genetic iteration on the initial population. After a preset number of genetic iterations, the transmission cost fitness with power generation and layout distance as parameters is calculated, and the optimal PV module node calling scheme with the smallest transmission cost fitness is retained;

[0020] The photovoltaic component nodes in the optimal calling scheme of the photovoltaic component nodes are loaded and displayed in the digital image of the photovoltaic component, and the photovoltaic component nodes that are not in the optimal calling scheme of the photovoltaic component nodes are eliminated.

[0021] Furthermore, the transmission cost adaptability expression is:

[0022]

[0023] Where n represents n distributed photovoltaic modules, for the i-th photovoltaic module, i = 1, 2, ..., n; d i represents the layout distance from the ith PV module to the primary and secondary integrated ring network cabinet, P theoretical_i represents the theoretical power generation of the ith photovoltaic module; k represents the power loss coefficient, then k×d i represents the power loss of the i-th PV module during power transmission, C1 represents the cost of laying out the PV module line, and C2 represents the economic cost of unit power loss;

[0024] The lower the transmission cost fitness value is, the lower the transmission cost is, and the PV module node calling scheme is optimal.

[0025] Furthermore, the intelligent control system also includes an anti-backflow simulation module and an anti-backflow control module. The anti-backflow simulation module is used to generate in real time the simulation change results of the digital image of the photovoltaic power generation system under the power transmission strategy during the simulation process of the digital image change of the photovoltaic power generation system; the anti-backflow control module is used to control the output voltage parameters of the anti-backflow inverter according to the simulation change results.

[0026] A distributed photovoltaic power generation method that is connected to the grid but not connected to the grid is applied to the above-mentioned distributed photovoltaic power generation system that is connected to the grid but not connected to the grid, comprising:

[0027] S1: A photovoltaic power generation system connected to the grid but not connected to the grid is constructed through distributed photovoltaic modules, primary and secondary integrated ring network cabinets, intelligent control systems, and anti-reverse flow inverters; the photovoltaic power generation system transmits power to local loads;

[0028] S2: Obtain parameter information, structural data and operation data of each device in distributed photovoltaic components, primary and secondary integrated ring network cabinets, anti-reverse current inverters, municipal power grids and local loads;

[0029] S3: Generate a digital image of a photovoltaic power generation system that is connected to the grid and not connected to the grid based on the acquired parameter information and structural data, and drive the simulation of changes in the digital image of the photovoltaic power generation system based on the operation data;

[0030] S4: Extract the power generation data of the distributed photovoltaic components, the city grid power supply data and the local load power consumption data flowing into the primary and secondary integrated ring main unit from the simulation results of the changes in the digital image, and judge whether the power generation data of the distributed photovoltaic components meets the local load power consumption data. If so, generate a power adjustment command to adjust the transmission strategy of the distributed photovoltaic components connected to the primary and secondary integrated ring main unit. If not, generate a switching command to control the primary and secondary integrated ring main unit to switch to the city grid for power supply.

[0031] The principle and advantage of the present invention are as follows: In the present application, the problem of poor coordination between devices in the existing photovoltaic power generation system that is connected to the grid but not connected to the grid is mainly due to the fact that the photovoltaic modules are distributed. Therefore, when photovoltaic modules in different locations want to converge electric energy into the primary and secondary fusion ring network cabinet, the power losses generated are different. In the best theoretical case, the electric energy generated by all photovoltaic modules minus the loss of their transmission just meets the power demand of the local load. However, this is not the case in actual situations. Often, the actual electric energy generated by distributed photovoltaic modules is higher than the power demand of the local load in order to ensure the power stability of the local load. At this time, how to coordinate the power transmission scheme between distributed photovoltaic modules is the key point to solve the poor coordination between the devices.

[0032] In this regard, in this scheme, for the transmission strategy using distributed photovoltaic components, on the one hand, a digital mirror of the entire photovoltaic power generation system is constructed. The digital mirror is a simulation modeling model that truly restores the operation of the photovoltaic power generation system and is constructed using digital twin technology. In this scheme, the digital mirror of the photovoltaic component is constructed in a tree shape. The longer the layout distance, the longer the branch length in the tree-like digital mirror of the photovoltaic component; then, according to the power demand in the local load power consumption data, according to the power generation power and layout distance of each photovoltaic component, a photovoltaic component node calling scheme is generated, and the scheme is genetically iterated through a genetic algorithm. The transmission cost fitness function is constructed with the power generation power and layout distance as parameters. Finally, the one with the smallest transmission cost fitness is obtained, which is the optimal calling scheme for the photovoltaic component node. The corresponding photovoltaic component nodes in the scheme are then displayed in the digital mirror. During the display process, the remaining photovoltaic component nodes that are not in the scheme are eliminated, so that in the subsequent transmission change simulation process of the digital mirror, the system calls fewer computing resources and the user visualization effect is optimal.

[0033] Therefore, in this solution, the coordinated calls between distributed photovoltaic components are optimized to enhance the synergy between devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a functional block diagram of an embodiment of the present invention;

[0035] Figure 2 4 is a functional block diagram of an intelligent control system in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following is further described in detail through specific implementation methods:

[0037] The embodiment is basically as follows Figure 1 and Figure 2 As shown: a distributed photovoltaic power generation system that is connected to the grid but not connected to the grid, comprising distributed photovoltaic components, a primary and secondary fusion ring network cabinet, an intelligent control system, and an anti-reverse flow inverter, wherein the output line of the distributed photovoltaic components is connected to the incoming line port of the primary and secondary fusion ring network cabinet, and the primary and secondary fusion ring network cabinet is connected to the municipal power grid access point through the anti-reverse flow inverter;

[0038] In this embodiment, the photovoltaic modules adopt polycrystalline silicon photovoltaic modules and are distributedly arranged according to factors such as the lighting conditions and available area of ​​the selected site. In the photovoltaic modules, each photovoltaic module string is connected through a multi-channel input port set in the DC junction box, and each input port is equipped with an overcurrent protection fuse. At the same time, a DC voltage monitoring device and a lightning protection module are installed in the DC junction box. The DC voltage monitoring device monitors the output voltage of the photovoltaic module in real time. When the voltage is abnormal, the signal is transmitted to the intelligent control system; the lightning protection module is used to prevent lightning surges from damaging the photovoltaic modules and the system.

[0039] The DC combiner box in the photovoltaic module is then connected to the primary and secondary integrated ring main unit. The primary and secondary integrated ring main unit includes primary equipment and secondary equipment. The primary equipment includes circuit breakers, disconnectors, load switches, etc., and its rated voltage and rated current are determined according to the output voltage and power of the photovoltaic system and the requirements of the local load. In this solution, the insulation material of the primary equipment uses high-performance insulation materials to meet the insulation requirements in a high-voltage environment and prevent electrical breakdown and leakage.

[0040] Secondary equipment includes relay protection devices, measurement and control devices, communication devices, etc. The relay protection devices have multiple protection functions such as overcurrent, overvoltage, undervoltage, short circuit, grounding, etc. The protection setting value can be flexibly set according to system parameters and operating requirements. When a system failure occurs, the relay protection device can act quickly and accurately to cut off the fault circuit and protect the safety of equipment and personnel. The measurement and control device monitors the operating parameters of the primary equipment (such as voltage, current, switch status, etc.) in real time and transmits the data to the intelligent control and monitoring unit. The communication device adopts a variety of communication protocols (such as Ethernet, RS-485, wireless communication, etc.) to realize communication with intelligent control units, anti-reverse current inverters and other equipment to ensure real-time interaction and remote monitoring of system information.

[0041] The anti-reverse flow inverter uses an anti-reverse flow control algorithm to achieve high-precision power control based on real-time grid voltage, frequency, phase, local load power and photovoltaic system power generation information. Therefore, in the photovoltaic power generation system that is connected to the grid but not connected to the grid in this scheme, the anti-reverse flow inverter monitors the power flow between the inverter output end and the access point at the municipal grid in real time. When a trend of outputting power to the grid is detected, the output voltage amplitude, frequency or phase of the inverter is adjusted through the anti-reverse flow control algorithm to match the output power with the local load power, ensuring that the electric energy is consumed only on the local load side and avoiding reverse flow to the municipal grid.

[0042] Therefore, under the support of the above-mentioned existing grid-connected but not online technology, there is still the problem of poor coordination between devices. The reason is that the distributed photovoltaic components located on the power supply side often actually operate in a situation where the power supply required is greater than the power consumption. In this case, the call of each distributed photovoltaic component is very important. On the one hand, it is not possible to call only photovoltaic components of a fixed number of nodes each time, and on the other hand, it is not possible to call photovoltaic components in sequence, which will cause a waste of resources. In this regard, the solution adopted by this application is:

[0043] First, in the intelligent control system, it includes a data acquisition module, a photovoltaic system simulation module and a power transmission control module. The data acquisition module is used to obtain parameter information, structural data and operating data of each device in the distributed photovoltaic components, primary and secondary fusion ring network cabinets, anti-reverse current inverters, municipal power grids and local loads; for example, the parameter information of distributed photovoltaic components includes electrical parameters, physical parameters, thermal parameters, etc., the structural data includes the type of battery cells, the arrangement of battery cells, packaging materials, frame materials, junction boxes, etc., and the operating data includes real-time power generation, cumulative power generation, power generation efficiency, temperature, light intensity, etc.;

[0044] The parameter information of the primary and secondary integrated ring main cabinet includes electrical parameters, mechanical parameters, environmental parameters, etc. The structural data includes cabinet structure, component configuration, connection method, etc. The operating data includes electrical operating data, equipment status data, communication and monitoring data, etc.; as for the anti-reverse current inverter, similar to the above parameter information, structural data, and operating data, for the municipal power grid and local loads, in order to improve the smoothness of the subsequent modeling digital mirror, the municipal power grid and local loads are in the form of digital blocks, their external structure data are blurred, and the parameter information and operating data are retained.

[0045] After the data acquisition module completes the collection, the photovoltaic system simulation module simulates and generates a digital image of the photovoltaic power generation system that is connected to the grid but not connected to the grid according to the collected parameter information and structural data. Specifically, the photovoltaic system simulation module includes a digital image construction unit, a digital image simulation unit and a rendering unit. The digital image construction unit first analyzes and processes the collected parameter information and structural data, and removes and associates duplicate data and scene-related data. For example, in the data of the photovoltaic components, the geographical location of each distributed photovoltaic component, the distribution structure of each photovoltaic panel, the corresponding operating time and other data are associated to serve as the modeling information of the digital image of the photovoltaic component at that location; then, the digital model of the photovoltaic power generation system that is connected to the grid but not connected to the grid is constructed for the parameter information and structural data that have been analyzed and processed, so as to obtain a digital image of the photovoltaic power generation system that is connected to the grid but not connected to the grid.

[0046] After the digital image is constructed, the digital image simulation unit drives the change simulation of the digital image of the photovoltaic power generation system according to the collected operation data. Specifically, the change simulation of the digital image of the photovoltaic power generation system includes the operation simulation of the equipment components in the photovoltaic power generation system and the change simulation of the environment in which the photovoltaic power generation system is located. For the operation simulation of the equipment components, the operation data of each equipment component is collected by sensors to simulate the operation process of the digital image of the equipment component; for the simulation of environmental changes, weather changes are simulated by reading meteorological station data, and the presence of people, animals, foreign objects, etc. in the environment of each device in the photovoltaic power generation system is identified by monitoring cameras, and environmental object changes are simulated. The rendering unit then renders the digital image change simulation to generate visualization. In this way, the real scene of the photovoltaic power generation system can be restored as much as possible, and the authenticity of the digital image change simulation can be improved.

[0047] After obtaining the above-mentioned simulation data of the changes in the photovoltaic power generation system that is connected to the grid but not connected to the grid, in order to analyze and deploy the power generation and transmission strategy of the distributed photovoltaic components, the data acquisition module reads and receives the power generation data of the photovoltaic components, the power supply data of the municipal power grid and the local load power consumption data generated in the digital mirror change simulation process, and the collected data is transmitted to the transmission control module for generating the transmission strategy. Specifically, the transmission control module determines whether the power generation data of the distributed photovoltaic components meets the power demand based on the local load power consumption data. Specifically, the local load power consumption data is mainly reflected in the power consumption. The actual power generation data of all photovoltaic components is received through the primary and secondary fusion ring network cabinet, and the total power generation power is aggregated to read whether it meets the power consumption of the local load. If it meets, it means that the power generation data of the photovoltaic components meets the power demand, otherwise it does not meet the power demand. In this solution, the one used It is a photovoltaic power generation system that is connected to the grid but not to the grid. When the electricity demand is not met, it is necessary to switch to the municipal power grid in the primary and secondary integrated ring network cabinet, and the municipal power grid will supply power. When the electricity demand is met, how to allocate the transmission strategy of each distributed photovoltaic component becomes the key to coordinating the synergy of equipment, because the photovoltaic components at each distribution point are usually equipped with an energy storage system to store the electricity generated by the photovoltaic components. When the energy storage system is transmitted to the primary and secondary integrated ring network cabinet, the farther the distribution point is, the more electricity is lost. In the actual power consumption process, it is often not necessary for all photovoltaic components to transmit electricity together, because in actual use, the power generation of all photovoltaic components should be greater than the power consumption. Therefore, when there is a demand for electricity, the photovoltaic components at which distribution points transmit electricity can have higher utilization and higher efficiency. This is the key to solving the synergy between equipment.

[0048] In view of the above problems, in this solution, in order to better present the status of photovoltaic components at each distribution point, the geographical location distribution information of distributed photovoltaic components is extracted in the digital image construction unit in the photovoltaic system simulation module. The positional relationship between the distributed photovoltaic components can be obtained from the geographical location distribution information. In this way, the primary and secondary fusion ring network cabinets that play a confluence role are used as trunk nodes, and each photovoltaic component is a branch node to form a tree-like digital image of the photovoltaic component; in this solution, the generated tree-like digital image of the photovoltaic component can, on the one hand, clearly identify the selected photovoltaic component nodes through the tree structure when selecting photovoltaic components in generating the transmission strategy.

[0049] The power transmission control module also includes a power consumption judgment unit, a photovoltaic power generation node optimization unit and a power supply parameter adjustment unit. Specifically, the power consumption judgment unit calculates the difference between the real-time power generation power and the real-time power consumption power, and determines whether the difference is greater than 0. If so, a power adjustment command is generated. The real-time power generation power in this scheme refers to the available power generation power obtained by deducting the transmission loss power from the theoretical power generation power. Only in this way can it be ensured that the power generation data of the distributed photovoltaic components can meet the power consumption data of the local load. For the generated power adjustment command, the power regulation of both the power supply and power consumption ends is realized through the anti-reverse current inverter. Specifically, the monitoring principle of the power flow direction of the anti-reverse current inverter in this scheme is to install high-precision voltage sensors and current sensors at the output end of the anti-reverse current inverter and the municipal power grid access point respectively, so as to obtain the instantaneous values ​​of voltage and current in real time, and then calculate the power according to the instantaneous voltage and current values ​​through the power calculation formula.

[0050] P=UI cosθ

[0051] To calculate power, in the actual algorithm, digital signal processing technology is used to discretely sample the collected voltage and current signals at a fixed sampling frequency f, and then discrete Fourier transform is used to calculate the voltage and current amplitude, phase and power factor, and then the real-time power is calculated;

[0052] Finally, the output power of the anti-reverse current inverter and the power consumption of the local load are compared to determine whether there is a reverse current phenomenon; if a trend of outputting power to the municipal grid is detected, that is, the output power increases while the power consumption of the local load remains unchanged, the anti-reverse current inverter adjusts the output voltage amplitude, frequency or phase to match the output power with the power consumption of the local load.

[0053] After the power adjustment command is generated by the power consumption judgment unit, it indicates that the distributed photovoltaic components are needed to supply power. The output power is adjusted according to the local load consumption power in the power adjustment command. In extreme cases, if the local load power consumption requires all distributed photovoltaic components to supply power, the anti-reverse current inverter only needs to output all the power generated by the photovoltaic components to the local load. However, in actual situations, in order to ensure the stable operation of the local load, it is often not necessary for all distributed photovoltaic components to supply power together, but to choose to call the photovoltaic components of several nodes. The principle of calling, the technical means adopted by this scheme is to optimize and iterate by establishing the transmission cost adaptability and optimization algorithm to obtain the optimal photovoltaic component calling strategy, specifically:

[0054] Step 1: Call the tree-like digital image of photovoltaic components, and generate a photovoltaic component node calling plan set according to the power generation power, layout distance and power demand parameters in the power regulation command of the photovoltaic components in each node; among which, the generated photovoltaic component node calling plan set is only the initial population, which serves as a preliminary plan to facilitate subsequent genetic iterative operations.

[0055] Step 2: Take the PV module node calling scheme set as the initial population, call the optimized genetic algorithm to perform genetic iteration on the initial population, and after the preset number of genetic iterations, calculate the transmission cost fitness with power generation and layout distance as parameters, and retain the optimal calling scheme of the PV module node with the smallest transmission cost fitness; in this scheme, the function expression of the transmission cost fitness used is:

[0056]

[0057] Where n represents n distributed photovoltaic modules, for the i-th photovoltaic module, i = 1, 2, ..., n; d i represents the layout distance from the ith PV module to the primary and secondary integrated ring network cabinet, P tjeoretical_i represents the theoretical power generation of the ith photovoltaic module; k represents the power loss coefficient, then k×d i represents the power loss of the i-th PV module during power transmission, C1 represents the cost of laying out the PV module line, and C2 represents the economic cost of unit power loss;

[0058] In view of the above transmission cost adaptability considerations, in this scheme, we first assume that there are n distributed photovoltaic modules, and for the i-th photovoltaic module, i = 1, 2, ..., n; then the following variables can be defined:

[0059] d i : The layout distance from the ith PV module to the primary and secondary integrated ring network cabinet;

[0060] P theoretical_i: represents the theoretical power generation of the i-th photovoltaic module;

[0061] P loss_i : The power loss during the transmission of electric energy from the i-th photovoltaic module. The longer the distance, the greater the loss.

[0062] P actual_i : The actual power generation of the i-th photovoltaic module;

[0063] Then P actual_i =P theoretical_i -P loss_i .

[0064] Among them, P loss_i = k·d i ; k represents the power loss coefficient; so the actual power generation can be expressed as:

[0065] P actual_i =P theoretical_i -k·d i

[0066] Then, the transmission cost fitness function is constructed, and the transmission cost is defined as mainly composed of the line construction cost and the economic loss caused by power loss, such as the reduction in revenue caused by too little power generation. Assuming that the line construction cost is C1 and the economic cost of unit power loss is C2, the transmission cost fitness function is:

[0067]

[0068] In the above transmission cost fitness function, the smaller the function value, the lower the transmission cost. In this way, through the genetic mutation operation, after the preset number of genetic mutations, the transmission cost fitness values ​​of all schemes are calculated, and the scheme with the smallest fitness value is retained as the optimal photovoltaic component calling scheme.

[0069] Step three: Load and display the photovoltaic component nodes in the optimal calling scheme of the photovoltaic component nodes in the digital image of the photovoltaic components, and remove the photovoltaic component nodes that are not in the optimal calling scheme of the photovoltaic component nodes. In this way, in the process of digital image display of many photovoltaic components, the computing power of the system loading simulation is reduced, and the distribution diagram of the called photovoltaic components can be quickly presented.

[0070] When the output power of the anti-reverse current inverter cannot meet the power demand of the local load, the power supply parameter adjustment unit cannot receive the power adjustment command, and then switches to the city grid for power supply to meet the power demand of the local load.

[0071] In addition, the anti-backflow simulation module in the intelligent control system is used to generate in real time the simulation change results of the digital image of the photovoltaic power generation system under the power transmission strategy during the simulation process of the digital image change of the photovoltaic power generation system; the anti-backflow control module is used to control the output voltage parameters of the anti-backflow inverter according to the simulation change results; in this solution, through the anti-backflow simulation module and the anti-backflow control module, simulation can be performed in the digital image until the simulation results meet the requirements, and then operations are performed in the actual photovoltaic power generation system to avoid problems caused by operational errors.

[0072] In another embodiment of the present embodiment, a distributed photovoltaic power generation method that is connected to the grid but not connected to the grid is also included, which is applied to the above-mentioned distributed photovoltaic power generation system that is connected to the grid but not connected to the grid, including:

[0073] S1: A photovoltaic power generation system connected to the grid but not connected to the grid is constructed through distributed photovoltaic modules, primary and secondary integrated ring network cabinets, intelligent control systems, and anti-reverse flow inverters; the photovoltaic power generation system transmits power to local loads;

[0074] S2: Obtain parameter information, structural data and operation data of each device in distributed photovoltaic components, primary and secondary integrated ring network cabinets, anti-reverse current inverters, municipal power grids and local loads;

[0075] S3: Generate a digital image of a photovoltaic power generation system that is connected to the grid and not connected to the grid based on the acquired parameter information and structural data, and drive the simulation of changes in the digital image of the photovoltaic power generation system based on the operation data;

[0076] S4: Extract the power generation data of the distributed photovoltaic components, the city grid power supply data and the local load power consumption data flowing into the primary and secondary integrated ring main unit from the simulation results of the changes in the digital image, and judge whether the power generation data of the distributed photovoltaic components meets the local load power consumption data. If so, generate a power adjustment command to adjust the transmission strategy of the distributed photovoltaic components connected to the primary and secondary integrated ring main unit. If not, generate a switching command to control the primary and secondary integrated ring main unit to switch to the city grid for power supply.

[0077] The above are only embodiments of the present invention. Common knowledge such as the known specific structures and characteristics in the scheme is not described in detail here. Ordinary technicians in the relevant field know all the common technical knowledge in the technical field to which the invention belongs before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply conventional experimental means before that date. Ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A distributed photovoltaic power generation system that is connected to the grid but not connected to the grid, characterized in that: It includes distributed photovoltaic components, primary and secondary fusion ring network cabinets, intelligent control systems, and anti-backflow inverters. The output lines of the distributed photovoltaic components are connected to the incoming line ports of the primary and secondary fusion ring network cabinets; the primary and secondary fusion ring network cabinets are connected to the municipal power grid access point through the anti-backflow inverter; The intelligent control system is connected to the primary and secondary integrated ring main cabinet through communication. The intelligent control system includes a data acquisition module, a photovoltaic system simulation module, and a power transmission control module, wherein: The data acquisition module is used to obtain parameter information, structural data and operating data of each device in the distributed photovoltaic components, primary and secondary fusion ring network cabinets, anti-reverse current inverters, municipal power grids and local loads; The photovoltaic system simulation module is used to simulate and generate a digital image of a photovoltaic power generation system that is connected to the grid and not connected to the grid according to the parameter information and structural data collected by the data collection module, and to drive the simulation of changes in the digital image of the photovoltaic power generation system according to the operation data; The data acquisition module is used to collect the power generation data of the distributed photovoltaic components flowing into the primary and secondary fusion ring network cabinet, the power supply data of the municipal power grid and the power consumption data of the local load in the simulation results of the change of the digital image of the photovoltaic power generation system in real time; The power transmission control module is used to determine whether the power generation data of the distributed photovoltaic components meets the power demand based on the local load power consumption data. If so, a power adjustment command is generated to adjust the power transmission strategy of the distributed photovoltaic components connected to the primary and secondary fusion ring network cabinet. If not, a switching command is generated to control the primary and secondary fusion ring network cabinet to switch to the municipal power grid for power supply; The photovoltaic system simulation module is also used to receive the power transmission strategy of the anti-backflow control module and perform change simulation in the digital mirror image of the photovoltaic power generation system.

2. A distributed photovoltaic power generation system connected to the grid but not connected to the grid according to claim 1, characterized in that: The photovoltaic system simulation module includes a digital image construction unit, a digital image simulation unit and a rendering unit. The digital image construction unit is used to receive the parameter information and structural data of the distributed photovoltaic components, the primary and secondary fusion ring network cabinets, and the anti-backflow inverter collected by the data collection module, and construct the digital images of the interconnected distributed photovoltaic components, the primary and secondary fusion ring network cabinets, and the anti-backflow inverter, and extract the geographical location distribution information of the distributed photovoltaic components, take the primary and secondary fusion ring network cabinets as the trunk nodes, and the geographical location distribution nodes of each photovoltaic component as the branch nodes, and generate a tree-like digital image of the photovoltaic components; The digital mirror simulation unit is used to simulate the changes of the digital mirror according to the operating data of the distributed photovoltaic components, the primary and secondary fusion ring network cabinets, and the anti-backflow inverter, and the rendering unit is used to render and generate visualization of the digital mirror change simulation.

3. A distributed photovoltaic power generation system connected to the grid but not connected to the grid according to claim 2, characterized in that: The power transmission control module includes a power consumption judgment unit, a photovoltaic power generation node optimization unit, and a power supply parameter adjustment unit. The power consumption judgment unit is used to extract the real-time power consumption of the local load power consumption data and the power generation power of the distributed photovoltaic component power generation data, calculate the difference between the real-time power generation power and the real-time power consumption, and judge whether the difference is greater than 0. If so, a power adjustment command is generated; The photovoltaic power generation node optimization unit is used to generate power demand according to the power regulation command, and call the optimization strategy according to the preset photovoltaic components according to the power demand, call the corresponding photovoltaic components to perform power transmission operations, and synchronize them to the tree-like digital image of photovoltaic components for visualization; The power supply parameter adjustment unit is used to switch to the mains power supply when no power adjustment command is received.

4. A distributed photovoltaic power generation system connected to the grid but not connected to the grid according to claim 3, characterized in that: The photovoltaic component call optimization strategy preset in the photovoltaic power generation node optimization unit is specifically: Call the tree-like digital image of photovoltaic components, and generate a photovoltaic component node calling solution set according to the power generation power, layout distance, and power demand parameters in the power regulation command of the photovoltaic components in each node; The PV module node calling scheme set is used as the initial population, and the optimized genetic algorithm is called to perform genetic iteration on the initial population. After a preset number of genetic iterations, the transmission cost fitness with power generation and layout distance as parameters is calculated, and the optimal PV module node calling scheme with the smallest transmission cost fitness is retained; The photovoltaic component nodes in the optimal calling scheme of the photovoltaic component nodes are loaded and displayed in the digital image of the photovoltaic component, and the photovoltaic component nodes that are not in the optimal calling scheme of the photovoltaic component nodes are eliminated.

5. A distributed photovoltaic power generation system connected to the grid but not connected to the grid according to claim 4, characterized in that: The transmission cost adaptability expression is: Where n represents n distributed photovoltaic modules, for the i-th photovoltaic module, i = 1, 2, ..., n; d i represents the layout distance from the ith PV module to the primary and secondary integrated ring network cabinet, P theoretical_i represents the theoretical power generation of the ith photovoltaic module; k represents the power loss coefficient, then k×d i represents the power loss of the i-th PV module during power transmission, C1 represents the cost of laying out the PV module line, and C2 represents the economic cost of unit power loss; The lower the transmission cost fitness value is, the lower the transmission cost is, and the PV module node calling scheme is optimal.

6. A distributed photovoltaic power generation system connected to the grid but not connected to the grid according to claim 5, characterized in that: The intelligent control system also includes an anti-backflow simulation module and an anti-backflow control module. The anti-backflow simulation module is used to generate in real time the simulation change results of the digital image of the photovoltaic power generation system under the power transmission strategy during the simulation process of the digital image change of the photovoltaic power generation system; the anti-backflow control module is used to control the output voltage parameters of the anti-backflow inverter according to the simulation change results.

7. A distributed photovoltaic power generation method that is connected to the grid but not connected to the grid, applied to a distributed photovoltaic power generation system that is connected to the grid but not connected to the grid as claimed in any one of claims 1 to 6 above, characterized in that: include: S1: A photovoltaic power generation system connected to the grid but not connected to the grid is constructed through distributed photovoltaic modules, primary and secondary integrated ring network cabinets, intelligent control systems, and anti-reverse flow inverters; the photovoltaic power generation system transmits power to local loads; S2: Obtain parameter information, structural data and operation data of each device in distributed photovoltaic components, primary and secondary integrated ring network cabinets, anti-reverse current inverters, municipal power grids and local loads; S3: Generate a digital image of a photovoltaic power generation system that is connected to the grid and not connected to the grid based on the acquired parameter information and structural data, and drive the simulation of changes in the digital image of the photovoltaic power generation system based on the operation data; S4: Extract the power generation data of the distributed photovoltaic components, the city grid power supply data and the local load power consumption data flowing into the primary and secondary integrated ring main unit from the simulation results of the changes in the digital image, and judge whether the power generation data of the distributed photovoltaic components meets the local load power consumption data. If so, generate a power adjustment command to adjust the transmission strategy of the distributed photovoltaic components connected to the primary and secondary integrated ring main unit. If not, generate a switching command to control the primary and secondary integrated ring main unit to switch to the city grid for power supply.

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