A photovoltaic grid-connected energy efficiency test system

Abstract

The present invention relates to the technical field of electrical digital data processing, and in particular to a photovoltaic grid-connected energy efficiency test system. The system comprises a power grid disturbance simulation module, an island effect detection module, a data acquisition and analysis module, and an on-board centralized control management module. The power grid disturbance simulation module is used to simulate the disturbance in the power grid, the island effect detection module is used to detect and prevent the photovoltaic power station from continuing to operate when the power grid is powered off, the data acquisition and analysis module is responsible for collecting, recording and analyzing the data generated during the photovoltaic power station grid connection process, and the on-board centralized control management module is responsible for the management and coordination of the entire test process; the system can add various disturbance data to the power grid, and test the grid-connected energy efficiency after the disturbance, so as to more intuitively understand the anti-interference ability of the photovoltaic grid connection.

Description

Technical Field

[0001] The invention relates to the technical field of electrical digital data processing, and in particular to a photovoltaic grid-connected energy efficiency testing system. Background Art

[0002] As the global demand for renewable energy continues to increase, photovoltaic power generation, as a clean and sustainable form of energy, has received widespread attention and application. Photovoltaic systems need to be connected to the grid before the generated electricity can be used in actual production and life. The energy efficiency of the grid connection will directly affect the role of the photovoltaic system. Therefore, a system for energy efficiency testing of photovoltaic grid connection is needed to continuously improve the grid connection technology based on the test results.

[0003] The foregoing discussion of the background art is intended only to facilitate an understanding of the present invention. This discussion does not acknowledge or admit that any of the material referred to is part of the common general knowledge.

[0004] Now many photovoltaic grid-connected test systems have been developed. After a lot of searching and reference, it is found that the existing test systems are such as the system disclosed in the publication number CN108710049B. These systems generally include a photovoltaic simulator, a photovoltaic grid-connected inverter, an island simulation load and a power analyzer. The photovoltaic simulator, the photovoltaic grid-connected inverter and the island simulation load are connected in sequence. The power analyzer is respectively connected to the two ends of the island simulation load and the input end of the photovoltaic grid-connected inverter. It is characterized in that the test equipment also includes an anti-backflow load and an AC simulation grid. The input end of the anti-backflow load is connected to the output end of the island simulation load, and the output end is connected to the AC simulation grid. However, this test system cannot simulate the test of the power grid system with disturbances, and cannot obtain energy efficiency test results under various conditions. Summary of the invention

[0005] In view of the above problems existing in the prior art, the present invention is proposed.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a photovoltaic grid-connected energy efficiency test system, comprising: a power grid disturbance simulation module, an islanding effect detection module, a data acquisition and analysis module, and an on-board centralized control management module;

[0007] The grid disturbance simulation module is used to simulate the disturbance in the grid, the islanding effect detection module is used to detect and prevent the photovoltaic power station from continuing to operate when the grid is powered off, the data acquisition and analysis module is responsible for collecting, recording and analyzing the data generated during the photovoltaic power station grid connection process, and the on-board centralized control management module is responsible for the management and coordination of the entire test process;

[0008] The power grid disturbance simulation module includes a voltage disturbance unit, a frequency disturbance unit, a harmonic injection unit and a short-time power outage unit. The voltage disturbance unit is used to simulate voltage fluctuations, the frequency disturbance unit is used to simulate power grid frequency changes, the harmonic injection unit is used to inject harmonics into the power grid, and the short-time power outage unit is used to simulate short-time power outages in the power grid;

[0009] The islanding effect detection module includes a power grid monitoring unit, an islanding protection unit and an automatic reset unit. The power grid monitoring unit is used to monitor the power grid status in real time and detect the power grid power failure. The islanding protection unit is used to disconnect the photovoltaic system when the power grid power failure is detected. The automatic reset unit is used to automatically reconnect the photovoltaic system to the grid when the power grid returns to normal.

[0010] The data acquisition and analysis module includes a data acquisition unit, a data recording unit and a data analysis unit. The data acquisition unit is used to measure electrical parameters in the power grid, the data recording unit is used to record all data generated during the grid connection process in real time, and the data analysis unit is used to analyze the collected data to obtain energy efficiency test results.

[0011] As a preferred solution of the photovoltaic grid-connected energy efficiency testing system described in the present invention, the power grid monitoring unit includes a voltage sensing detection processor, a current sensing detection processor and an event triggering processor, the voltage sensing detection processor is used to detect the voltage in the power grid, the current sensing detection processor is used to detect the current in the power grid, and the event triggering processor is used to send a trigger signal to the island protection unit and the automatic reset unit.

[0012] As a preferred solution of the photovoltaic grid-connected energy efficiency testing system described in the present invention, the data analysis unit includes a data screening processor, an energy conversion calculation processor and a stability analysis processor. The data screening processor is used to filter out the collected data corresponding to the disturbance period from the data recording unit as the target data, the energy conversion calculation processor is used to calculate the energy conversion efficiency of the photovoltaic grid-connected, and the stability analysis processor is used to calculate the anti-interference ability of the photovoltaic grid-connected.

[0013] As a preferred solution of a photovoltaic grid-connected energy efficiency test system described in the present invention, wherein: the power generation Ep is calculated according to the energy conversion calculation processor:

[0014]

[0015] Where, Ip(t) is the current output value of the photovoltaic system at time t, Vp(t) is the voltage output value of the photovoltaic system at time t, and t1 is the duration of the target data. Expressed as a time element.

[0016] As a preferred solution of a photovoltaic grid-connected energy efficiency test system described in the present invention, wherein: the power transmission Eo is calculated according to the energy conversion calculation processor:

[0017]

[0018] Wherein, Io(t) is the current value of the power grid at time t, and Vo(t) is the voltage value of the power grid at time t.

[0019] As a preferred solution of a photovoltaic grid-connected energy efficiency test system described in the present invention, wherein: the energy conversion efficiency η is calculated according to the energy conversion calculation processor:

[0020]

[0021] As a preferred solution of the photovoltaic grid-connected energy efficiency test system described in the present invention, the stability analysis processor includes: selecting the voltage peak value Vmax(i) from the target data; calculating the interval time T(i) of each voltage peak;

[0022] Calculate the peak standard deviation δV:

[0023]

[0024] Where n is the number of voltage peaks in the target data, is the peak mean;

[0025] Calculate the standard deviation of the time difference δT:

[0026]

[0027] Calculate the stability index P of the target data:

[0028]

[0029] Among them, k is the relative conversion coefficient and t0 is the time base.

[0030] The beneficial effects of the present invention are as follows: the system can freely add disturbances to the photovoltaic power grid, and test the grid-connected energy efficiency under different disturbance conditions, and can intuitively understand the anti-interference ability of the entire photovoltaic system. The system actively cuts off the power supply to the power grid before testing to detect the islanding effect, and can better protect the operation of the entire system during the actual test process. When analyzing and collecting data, the efficiency and quality of electric energy are analyzed, which can more comprehensively reflect the effect of photovoltaic grid connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0032] Figure 1 A schematic diagram of the overall structural framework of a photovoltaic grid-connected energy efficiency testing system provided by an embodiment of the present invention.

[0033] Figure 2 A schematic diagram of an islanding effect detection module of a wireless transmission micro-electromechanical system of a photovoltaic grid-connected energy efficiency test system provided by an embodiment of the present invention.

[0034] Figure 3 A schematic diagram of the data acquisition and analysis module of a photovoltaic grid-connected energy efficiency test system provided by an embodiment of the present invention.

[0035] Figure 4 A schematic diagram of the structure of a power grid monitoring unit of a photovoltaic grid-connected energy efficiency test system provided by an embodiment of the present invention.

[0036] Figure 5 A schematic diagram of the structure of a data analysis unit of a photovoltaic grid-connected energy efficiency testing system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0038] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0039] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0040] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0041] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0042] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] Example 1

[0044] Reference Figure 1 , which is the first embodiment of the present invention, and provides a photovoltaic grid-connected energy efficiency test system, including: a grid disturbance simulation module 101, an island effect detection module 102, a data acquisition and analysis module 103 and an on-board centralized control management module 100;

[0045] The grid disturbance simulation module 101 is used to simulate the disturbance situation in the grid, the island effect detection module is used to detect and prevent the photovoltaic power station from continuing to operate when the grid is powered off, the data acquisition and analysis module is responsible for collecting, recording and analyzing the data generated during the photovoltaic power station grid connection process, and the on-board centralized control management module is responsible for the management and coordination of the entire test process;

[0046] The power grid disturbance simulation module 101 includes a voltage disturbance unit, a frequency disturbance unit, a harmonic injection unit and a short-time power outage unit. The voltage disturbance unit is used to simulate voltage fluctuations, the frequency disturbance unit is used to simulate power grid frequency changes, the harmonic injection unit is used to inject harmonics into the power grid, and the short-time power outage unit is used to simulate short-time power outages in the power grid;

[0047] The islanding effect detection module 102 includes a power grid monitoring unit, an islanding protection unit and an automatic reset unit. The power grid monitoring unit is used to monitor the power grid status in real time and detect the power grid power failure. The islanding protection unit is used to disconnect the photovoltaic system when the power grid power failure is detected. The automatic reset unit is used to automatically reconnect the photovoltaic system to the grid when the power grid returns to normal.

[0048] The data acquisition and analysis module includes a data acquisition unit, a data recording unit and a data analysis unit. The data acquisition unit is used to measure the electrical parameters in the power grid. The data recording unit is used to record all data generated during the grid connection process in real time. The data analysis unit is used to analyze the collected data to obtain energy efficiency test results.

[0049] The power grid monitoring unit includes a voltage sensing detection processor, a current sensing detection processor and an event triggering processor, wherein the voltage sensing detection processor is used to detect the voltage in the power grid, the current sensing detection processor is used to detect the current in the power grid, and the event triggering processor is used to send a trigger signal to the island protection unit and the automatic reset unit;

[0050] The data analysis unit includes a data screening processor, an energy conversion calculation processor and a stability analysis processor, wherein the data screening processor is used to filter out the collected data corresponding to the disturbance period from the data recording unit as the target data, the energy conversion calculation processor is used to calculate the energy conversion efficiency of the photovoltaic grid-connected, and the stability analysis processor is used to calculate the anti-interference ability of the photovoltaic grid-connected;

[0051] The energy conversion calculation processor calculates the amount of electricity Ep according to the following formula:

[0052]

[0053] Where, Ip(t) is the current output value of the photovoltaic system at time t, Vp(t) is the voltage output value of the photovoltaic system at time t, and t1 is the duration of the target data;

[0054] The energy conversion calculation processor calculates the transmission amount Eo according to the following formula:

[0055]

[0056] Where, Io(t) is the current value of the power grid at time t, and Vo(t) is the voltage value of the power grid at time t;

[0057] The energy conversion calculation processor calculates the energy conversion efficiency η according to the following formula:

[0058]

[0059] The process of analyzing the target data by the stability analysis processor comprises the following steps:

[0060] Filter out the peak value of the voltage from the target data and record it as Vmax(i);

[0061] Calculate the interval time between each voltage peak, recorded as T(i);

[0062] The peak standard deviation δV is calculated according to the following formula:

[0063]

[0064] Where n is the number of voltage peaks in the target data, is the peak mean;

[0065] The standard deviation of the time difference δT is calculated according to the following formula:

[0066]

[0067] The stability index P of the target data is calculated according to the following formula:

[0068]

[0069] Among them, k is the relative conversion coefficient and t0 is the time base.

[0070] Example 2

[0071] refer to Figure 2-Figure 5 , a second embodiment of the present invention provides a photovoltaic grid-connected energy efficiency test system, including a grid disturbance simulation module, an islanding effect detection module, a data acquisition and analysis module, and an on-board centralized control management module;

[0072] The grid disturbance simulation module is used to simulate the disturbance in the grid, the islanding effect detection module is used to detect and prevent the photovoltaic power station from continuing to operate when the grid is powered off, the data acquisition and analysis module is responsible for collecting, recording and analyzing the data generated during the photovoltaic power station grid connection process, and the on-board centralized control management module is responsible for the management and coordination of the entire test process;

[0073] The power grid disturbance simulation module includes a voltage disturbance unit, a frequency disturbance unit, a harmonic injection unit and a short-time power outage unit. The voltage disturbance unit is used to simulate voltage fluctuations, the frequency disturbance unit is used to simulate power grid frequency changes, the harmonic injection unit is used to inject harmonics into the power grid, and the short-time power outage unit is used to simulate short-time power outages in the power grid;

[0074] Combination Figure 2The islanding detection module 102 includes a power grid monitoring unit 201, an islanding protection unit 202 and an automatic reset unit 203. The power grid monitoring unit 201 is used to monitor the power grid status in real time and detect power outages in the power grid. The islanding protection unit 202 is used to disconnect the photovoltaic system when a power outage is detected. The automatic reset unit 203 is used to automatically reconnect the photovoltaic system to the grid when the power grid returns to normal.

[0075] Combination Figure 3 The data acquisition and analysis module 103 includes a data acquisition unit 301, a data recording unit 302 and a data analysis unit 303. The data acquisition unit 301 is used to measure electrical parameters in the power grid. The data recording unit 302 is used to record all data generated during the grid connection process in real time. The data analysis unit 303 is used to analyze the collected data to obtain energy efficiency test results.

[0076] The vehicle-mounted centralized control management module includes a process control unit, a parameter setting unit and an information display unit, wherein the process control unit is used to manage and control the test process, the parameter setting unit is used to set and adjust the disturbance parameters, and the information display unit is used to display the test results;

[0077] The testing process of the photovoltaic grid-connected energy efficiency of the system includes the following steps:

[0078] S1, the short-time power failure unit simulates a power failure;

[0079] S2, the power grid monitoring unit detects a power outage;

[0080] S3, the island protection unit disconnects the photovoltaic system;

[0081] S4, the automatic reset unit waits for the grid to recover and then reconnects the photovoltaic system to the grid;

[0082] S5, the voltage disturbance unit, the frequency disturbance unit, and the harmonic injection unit disturb the power grid in sequence;

[0083] S6. The data acquisition unit collects the parameters of the power grid after the disturbance;

[0084] S7, the data analysis unit performs energy efficiency analysis on the collected data;

[0085] S8, the energy efficiency analysis result is sent to the information display unit for display;

[0086] The above test process is controlled by the process control unit sending instructions to the corresponding units;

[0087] The voltage disturbance unit includes a voltage control processor, a voltage regulation processor and a voltage transformation processor, wherein the voltage control processor is used to receive disturbance parameters and control the voltage regulation processor and the voltage transformation processor to execute disturbance instructions, the voltage regulation processor is used to adjust the voltage amplitude, and the voltage transformation processor is used to convert the voltage adjusted by the voltage regulation processor into a target voltage range;

[0088] The frequency disturbance unit includes a frequency control processor, a frequency conversion processor and a frequency adjustment processor, wherein the frequency control processor is used to receive disturbance parameters and control the frequency conversion processor and the frequency adjustment processor to execute disturbance instructions, the frequency conversion processor is used to convert the frequency of the alternating current, and the frequency adjustment processor is used to make more subtle adjustments to the converted alternating current frequency;

[0089] The harmonic injection unit includes a harmonic control processor, a harmonic generation processor and an interface injection processor, wherein the harmonic control processor is used to receive disturbance parameters and control the harmonic generation processor and the interface injection processor to execute disturbance instructions, the harmonic generation processor is used to generate a harmonic signal, and the interface injection processor is used to inject the generated harmonic signal into the power grid;

[0090] The short-time power-off unit comprises a power-off control processor and a timing processor, wherein the power-off control processor is used to control the power-off state of the power grid, and the timing processor is used to set the power-off time;

[0091] Combination Figure 4 , the power grid monitoring unit 201 includes a voltage sensing detection processor 401, a current sensing detection processor 402 and an event triggering processor 403, wherein the voltage sensing detection processor 401 is used to detect the voltage in the power grid, the current sensing detection processor 402 is used to detect the current in the power grid, and the event triggering processor 403 is used to send a trigger signal to the island protection unit and the automatic reset unit;

[0092] When the voltage and current signals cannot be detected at the same time, the event trigger processor sends a protection signal to the island protection unit; when the voltage and current signals are detected again, the event trigger processor sends a reset signal to the automatic reset unit;

[0093] The voltage sensing detection processor and the current sensing detection processor are connected to necessary parts of the power grid. The necessary parts refer to the necessary parts that must be in operation when the power grid is running. When the voltage sensing detection processor and the current sensing detection processor cannot detect the electrical signal at the same time, it means that the necessary parts are in operation and the power grid is in a power-off state. The island protection unit closes the switch device connecting the photovoltaic power generation system and the power grid system after receiving the protection signal, thereby protecting the power grid system. When the voltage sensing detection processor and the current sensing detection processor detect the electrical signal at the same time, it means that the power grid system resumes operation. The automatic reset unit reopens the switch device connecting the photovoltaic power generation system and the power grid system after receiving the reset signal.

[0094] Both the island protection unit and the automatic reset unit are used to perform status control on the switchgear;

[0095] The data acquisition unit includes a photovoltaic acquisition processor and an output acquisition processor, wherein the photovoltaic acquisition processor is used to acquire energy information generated by the photovoltaic system, and the output acquisition processor is used to acquire energy information output by the power grid after being connected to the grid;

[0096] Combination Figure 5 , the data analysis unit 303 includes a data screening processor 501, an energy conversion calculation processor 502 and a stability analysis processor 503, the data screening processor 501 is used to filter out the collected data corresponding to the disturbance period from the data recording unit as the target data, the energy conversion calculation processor 502 is used to calculate the energy conversion efficiency of the photovoltaic grid, and the stability analysis processor 503 is used to calculate the anti-interference ability of the photovoltaic grid;

[0097] The energy conversion calculation processor calculates the amount of electricity Ep according to the following formula:

[0098]

[0099] Where, Ip(t) is the current output value of the photovoltaic system at time t, Vp(t) is the voltage output value of the photovoltaic system at time t, and t1 is the duration of the target data;

[0100] The energy conversion calculation processor calculates the transmission amount Eo according to the following formula:

[0101]

[0102] Where, Io(t) is the current value of the power grid at time t, and Vo(t) is the voltage value of the power grid at time t;

[0103] The energy conversion calculation processor calculates the energy conversion efficiency η according to the following formula:

[0104]

[0105] The process of analyzing the target data by the stability analysis processor comprises the following steps:

[0106] Filter out the peak value of the voltage from the target data and record it as {Vmax(i)};

[0107] Calculate the time interval between each voltage peak, recorded as {T(i)};

[0108] The peak standard deviation δV is calculated according to the following formula:

[0109]

[0110] Where n is the number of voltage peaks in the target data, is the peak mean;

[0111] The standard deviation of the time difference δT is calculated according to the following formula:

[0112]

[0113] The stability index P of the target data is calculated according to the following formula:

[0114]

[0115] Among them, k is the relative conversion coefficient, and t0 is the time base;

[0116] The smaller the stability index is, the more stable the output is and the stronger the anti-interference ability is. The relative conversion coefficient and time base are pre-set by the staff according to the actual situation.

[0117] The information display unit includes a data pairing processor and a result display processor, wherein the data pairing processor is used to obtain disturbance parameters and test results and perform pairing processing, and the result display processor produces corresponding charts for displaying the paired data;

[0118] The i appearing in the above text is an ordinal number used to indicate a sequence number.

[0119] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0120] Example 3

[0121] The third embodiment of the present invention is different from the first two embodiments in that:

[0122] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0123] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0124] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0125] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

Claims

1. A photovoltaic grid-connected energy efficiency test system, characterized by: include, Grid disturbance simulation module, islanding effect detection module, data acquisition and analysis module and vehicle-mounted centralized control management module; The grid disturbance simulation module is used to simulate the disturbance in the grid, the islanding effect detection module is used to detect and prevent the photovoltaic power station from continuing to operate when the grid is powered off, the data acquisition and analysis module is responsible for collecting, recording and analyzing the data generated during the photovoltaic power station grid connection process, and the on-board centralized control management module is responsible for the management and coordination of the entire test process; The power grid disturbance simulation module includes a voltage disturbance unit, a frequency disturbance unit, a harmonic injection unit and a short-time power outage unit. The voltage disturbance unit is used to simulate voltage fluctuations, the frequency disturbance unit is used to simulate power grid frequency changes, the harmonic injection unit is used to inject harmonics into the power grid, and the short-time power outage unit is used to simulate short-time power outages in the power grid; The islanding effect detection module includes a power grid monitoring unit, an islanding protection unit and an automatic reset unit. The power grid monitoring unit is used to monitor the power grid status in real time and detect the power grid power failure. The islanding protection unit is used to disconnect the photovoltaic system when the power grid power failure is detected. The automatic reset unit is used to automatically reconnect the photovoltaic system to the grid when the power grid returns to normal. The data acquisition and analysis module includes a data acquisition unit, a data recording unit and a data analysis unit. The data acquisition unit is used to measure electrical parameters in the power grid, the data recording unit is used to record all data generated during the grid connection process in real time, and the data analysis unit is used to analyze the collected data to obtain energy efficiency test results.

2. A photovoltaic grid-connected energy efficiency testing system as claimed in claim 1, characterized in that: The power grid monitoring unit includes a voltage sensing detection processor, a current sensing detection processor and an event triggering processor. The voltage sensing detection processor is used to detect the voltage in the power grid, the current sensing detection processor is used to detect the current in the power grid, and the event triggering processor is used to send a trigger signal to the island protection unit and the automatic reset unit.

3. A photovoltaic grid-connected energy efficiency testing system as claimed in claim 2, characterized in that: The data analysis unit includes a data screening processor, an energy conversion calculation processor and a stability analysis processor. The data screening processor is used to filter out the collected data corresponding to the disturbance period from the data recording unit as target data, the energy conversion calculation processor is used to calculate the energy conversion efficiency of the photovoltaic grid, and the stability analysis processor is used to calculate the anti-interference ability of the photovoltaic grid.

4. A photovoltaic grid-connected energy efficiency testing system as claimed in claim 3, characterized in that: The energy conversion calculation processor calculates the power generation Ep according to: Where, Ip(t) is the current output value of the photovoltaic system at time t, Vp(t) is the voltage output value of the photovoltaic system at time t, and t1 is the duration of the target data. Expressed as a time element.

5. A photovoltaic grid-connected energy efficiency testing system as claimed in claim 4, characterized in that: The energy conversion calculation processor calculates the power transmission Eo according to: Wherein, Io(t) is the current value of the power grid at time t, and Vo(t) is the voltage value of the power grid at time t.

6. A photovoltaic grid-connected energy efficiency testing system as claimed in claim 5, characterized in that: The energy conversion efficiency η is calculated according to the energy conversion calculation processor:

7. A photovoltaic grid-connected energy efficiency testing system as claimed in claim 6, characterized in that: The stability analysis processor includes: selecting the voltage peak value Vmax(i) from the target data; calculating the interval time T(i) between each voltage peak: T(i)=t(i+1)-t(i) Wherein, t(i) represents the i-th voltage peak time point, and t(i+1) represents the i+1-th voltage peak time point; Calculate the peak standard deviation δV: Where n is the number of voltage peaks in the target data, is the peak mean; Calculate the standard deviation of the time difference δT: Calculate the stability index P of the target data: Among them, k is the relative conversion coefficient and t0 is the time base.

Images