Photovoltaic power station energy efficiency optimization method

Abstract

The invention provides a photovoltaic power station energy efficiency optimization method, which comprises the following steps of: A, collecting energy efficiency data of a photovoltaic power station; calculating photoelectric conversion efficiency, inverter output voltage, combiner box direct current-inverter alternating current conversion efficiency, inverter-box transformer substation conversion efficiency, box transformer substation-current collection circuit conversion efficiency, current collection circuit-main transformer conversion efficiency, main transformer conversion efficiency-power grid conversion efficiency, a square array capacitance ratio and a standard square array error; establishing a photovoltaic system energy consumption analysis model according to the calculation result; and step C, obtaining energy efficiency data of the photovoltaic power station monitored in real time, inputting the energy efficiency data into the photovoltaic system energy consumption analysis model to obtain an energy efficiency analysis optimization result, and screening problems of the photovoltaic power station according to the energy efficiency analysis optimization result to adjust a power generation plan.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic power station energy efficiency optimization, and in particular relates to a photovoltaic power station energy efficiency optimization method. Background Art

[0002] Photovoltaic power station is a facility that uses solar energy to generate electricity. It mainly converts solar energy into electrical energy through photovoltaic power generation system. However, there will be a lot of potential energy loss in the conversion process, resulting in energy waste.

[0003] Through energy efficiency analysis of photovoltaic power stations, real-time screening of equipment problems and line problems of photovoltaic components can be achieved, thereby optimizing power generation performance, improving power generation and energy utilization efficiency. Therefore, how to achieve reliable energy efficiency analysis of photovoltaic power stations is the focus of current research. Summary of the invention

[0004] In view of the problems raised by the background technology, the present invention proposes a method for optimizing energy efficiency of a photovoltaic power station.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A method for optimizing energy efficiency of a photovoltaic power station, step A: collecting energy efficiency data of the photovoltaic power station, the energy efficiency data including cumulative solar radiation energy, string energy, combiner box input voltage, combiner box power, combiner box energy, box transformer energy, collector line energy, main transformer energy and grid energy;

[0007] Step B: Based on the energy efficiency data of the photovoltaic power station collected in step A, calculate the photoelectric conversion efficiency, inverter output voltage, combiner box DC-inverter AC conversion efficiency, inverter-box transformer conversion efficiency, box transformer-collector line conversion efficiency, collector line-main transformer conversion efficiency, main transformer conversion efficiency-grid conversion efficiency, array ratio and standard array error;

[0008] According to the above calculation results, a photovoltaic system energy consumption analysis model is established;

[0009] Step C: Obtain the energy efficiency data of the photovoltaic power station monitored in real time and input it into the photovoltaic system energy consumption analysis model to obtain energy efficiency analysis optimization results, and screen the problems of the photovoltaic power station according to the energy efficiency analysis optimization results to adjust the power generation plan.

[0010] Preferably, in the step B, the photoelectric conversion efficiency is calculated according to formula 1 and the inverter output voltage is calculated according to formula 2;

[0011] ω 1 =E zc / E sun --Formula 1;

[0012] in:

[0013] ω 1 It represents the photoelectric conversion efficiency;

[0014] E zc Indicates the string energy;

[0015] E sun Indicates the cumulative solar radiation energy;

[0016] V out =V dc ×α--Formula 2;

[0017] V out Indicates the inverter output voltage;

[0018] V dc Indicates the combiner box input voltage;

[0019] α represents the duty cycle, that is, the high level time of the AC signal accounts for α% of the total cycle time.

[0020] Preferably, in the step B, the conversion efficiency of the combiner box DC power to the inverter AC power is calculated according to Formula 3;

[0021] ω 2 =E hl / E n --Formula 3;

[0022] in:

[0023] ω 2 Indicates the conversion efficiency of combiner box DC power to inverter AC power;

[0024] E hl Indicates the power of the combiner box;

[0025] E n Indicates the energy of the combiner box.

[0026] Preferably, in the step B, the inverter-box transformer conversion efficiency is calculated according to formula 4;

[0027] ω 3 =E n / E xb --Formula 4;

[0028] in:

[0029] ω 3 Indicates the inverter-box transformer conversion efficiency;

[0030] E xb Indicates the box transformer energy;

[0031] E n Indicates the energy of the combiner box.

[0032] Preferably, in the step B, the conversion efficiency of the box transformer-collector line is calculated according to formula 5;

[0033] ω 4 =E xb / E jd --Formula 5;

[0034] in:

[0035] ω 4 Indicates the conversion efficiency of the box-type transformer-collector line;

[0036] E xb Indicates the box transformer energy;

[0037] E jd Represents the collector line energy.

[0038] Preferably, in the step B, the collector line-main transformer conversion efficiency is calculated according to formula 6;

[0039] ω 5 =E jd / E zb --Formula 6;

[0040] in:

[0041] ω 5 Indicates the collector line-main transformer conversion efficiency;

[0042] E jd Indicates the collector line energy;

[0043] E zb Indicates the main transformer energy.

[0044] Preferably, in the step B, the main transformer conversion efficiency minus the grid conversion efficiency is calculated according to formula 7;

[0046] ω 6 =E zb / E d --Formula 7;

[0047] in:

[0048] ω 6 Indicates the main transformer conversion efficiency - grid conversion efficiency;

[0049] E zb Indicates the main transformer energy;

[0050] E d Represents the grid energy.

[0051] Preferably, in step B, the square array ratio is calculated according to formula eight, and the standard square array error is calculated according to formula nine;

[0052] β i =θ i / μ i --Formula 8;

[0053] γ=E i / β i ×β--Formula 9;

[0054] in:

[0055] β i represents the capacity ratio of the i-th array of the photovoltaic power station;

[0056] θ i represents the string capacity of the i-th array of the photovoltaic power station;

[0057] μ i represents the AC output capacity of the i-th inverter;

[0058] γ represents the standard square matrix error;

[0059] E i represents the AC power generation of the i-th array of the photovoltaic power station;

[0060] β represents the standard lineup ratio.

[0061] Preferably, in step C, screening the problems of the photovoltaic power station according to the energy efficiency analysis optimization result to adjust the power generation plan includes:

[0062] When the photoelectric conversion efficiency is lower than the first preset value, screening whether the photovoltaic module has a local short circuit or a shielding problem;

[0063] When the DC power-inverter AC power conversion efficiency of the combiner box is lower than the second preset value, the combiner box is screened for problems such as excessive cable loss, increased contact resistance, shadowing, surface contamination of the photovoltaic panel, or excessive temperature;

[0064] When the inverter-box transformer conversion efficiency is lower than the third preset value, the inverter is screened to see if there are problems such as low inverter conversion efficiency, unstable or mismatched grid conditions, and damaged connectors and joints;

[0065] When the conversion efficiency between the box transformer and the collector line is lower than the fourth preset value and the conversion efficiency between the collector line and the main transformer is lower than the fifth preset value, the box transformer is screened to see whether there are problems such as reduced box transformer efficiency, improper cable laying method, and severe on-site environmental factors;

[0066] When the main transformer conversion efficiency minus the grid conversion efficiency is lower than the sixth preset value, it is screened whether there is a problem of grid power fluctuation or grid voltage instability.

[0067] Compared with the prior art, one of the above technical solutions has the following beneficial effects:

[0068] 1. The present invention collects energy efficiency data of photovoltaic power stations, establishes a photovoltaic system energy consumption analysis model, calculates various conversion efficiencies one by one, and screens out problems existing in photovoltaic power stations based on the conversion efficiencies, thereby optimizing the corresponding photovoltaic component equipment and corresponding lines, thereby achieving the effect of reducing energy consumption losses in photovoltaic power stations;

[0069] 2. The present invention also evaluates the layout quality of the photovoltaic power station by calculating the standard array error of the photovoltaic power station, and determines the difference between the actual layout and the ideal layout of the photovoltaic system, so as to achieve the effect of real-time adjustment of the layout. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 is a flow chart of the photovoltaic power station energy efficiency optimization method of the present invention;

[0071] Figure 2 It is a schematic diagram of the photovoltaic system energy consumption analysis model of the present invention for analyzing the energy efficiency of a photovoltaic power station. DETAILED DESCRIPTION

[0072] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0073] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0074] The terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, device, product or end including a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units inherent to these processes, methods, products or ends.

[0075] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0076] This application proposes a method for optimizing the energy efficiency of a photovoltaic power station, such as Figure 1 As shown, step A: collecting energy efficiency data of the photovoltaic power station, the energy efficiency data includes cumulative solar radiation energy, string energy, combiner box input voltage, combiner box power, combiner box energy, box transformer energy, collection line energy, main transformer energy and grid energy;

[0077] Step B: Based on the energy efficiency data of the photovoltaic power station collected in step A, calculate the photoelectric conversion efficiency, inverter output voltage, combiner box DC-inverter AC conversion efficiency, inverter-box transformer conversion efficiency, box transformer-collector line conversion efficiency, collector line-main transformer conversion efficiency, main transformer conversion efficiency-grid conversion efficiency, array ratio and standard array error;

[0078] According to the above calculation results, a photovoltaic system energy consumption analysis model is established;

[0079] Step C: Obtain the energy efficiency data of the photovoltaic power station monitored in real time and input it into the photovoltaic system energy consumption analysis model to obtain energy efficiency analysis optimization results, and screen the problems of the photovoltaic power station according to the energy efficiency analysis optimization results to adjust the power generation plan.

[0080] In an embodiment of the present application, by collecting energy efficiency data of photovoltaic power stations, a photovoltaic system energy consumption analysis model is established, and various conversion efficiencies are calculated one by one. Problems existing in the photovoltaic power station are screened out based on the conversion efficiency, so as to optimize the corresponding photovoltaic component equipment and the corresponding lines, thereby achieving the effect of reducing the energy consumption loss of the photovoltaic power station.

[0081] Preferably, in the step B, the photoelectric conversion efficiency is calculated according to formula 1 and the inverter output voltage is calculated according to formula 2;

[0082] ω 1 =E zc / E sun --Formula 1;

[0083] in:

[0084] ω 1 It represents the photoelectric conversion efficiency;

[0085] E zc Indicates the string energy;

[0086] Esun Indicates the cumulative solar radiation energy;

[0087] V out =V dc ×α--Formula 2;

[0088] V out Indicates the inverter output voltage;

[0089] V dc Indicates the combiner box input voltage;

[0090] α represents the duty cycle, that is, the high level time of the AC signal accounts for α% of the total cycle time.

[0091] Preferably, in the step B, the conversion efficiency of the combiner box DC power to the inverter AC power is calculated according to Formula 3;

[0092] ω 2 =E hl / E n --Formula 3;

[0093] in:

[0094] ω 2 Indicates the conversion efficiency of combiner box DC power to inverter AC power;

[0095] E hl Indicates the power of the combiner box;

[0096] E n Indicates the energy of the combiner box.

[0097] Preferably, in the step B, the inverter-box transformer conversion efficiency is calculated according to formula 4;

[0098] ω 3 =E n / E xb --Formula 4;

[0099] in:

[0100] ω 3 Indicates the inverter-box transformer conversion efficiency;

[0101] E xb Indicates the box transformer energy;

[0102] E n Indicates the energy of the combiner box.

[0103] Preferably, in the step B, the conversion efficiency of the box transformer-collector line is calculated according to formula 5;

[0104] ω 4 =E xb / Ejd --Formula 5;

[0105] in:

[0106] ω 4 Indicates the conversion efficiency of the box-type transformer-collector line;

[0107] E xb Indicates the box transformer energy;

[0108] E jd Indicates the collector line energy.

[0109] Preferably, in the step B, the collector line-main transformer conversion efficiency is calculated according to formula 6;

[0110] ω 5 =E jd / E zb --Formula 6;

[0111] in:

[0112] ω 5 Indicates the collector line-main transformer conversion efficiency;

[0113] E jd Indicates the collector line energy;

[0114] E zb Indicates the main transformer energy.

[0115] Preferably, in the step B, the main transformer conversion efficiency minus the grid conversion efficiency is calculated according to formula 7;

[0117] ω 6 =E zb / E d --Formula 7;

[0118] in:

[0119] ω 6 Indicates the main transformer conversion efficiency - grid conversion efficiency;

[0120] E zb Indicates the main transformer energy;

[0121] E d Represents the grid energy.

[0122] Preferably, in step B, the square array ratio is calculated according to formula eight, and the standard square array error is calculated according to formula nine;

[0123] β i =θ i / μ i --Formula 8;

[0124] γ=Ei / β i ×β--Formula 9;

[0125] in:

[0126] β i represents the capacity ratio of the i-th array of the photovoltaic power station;

[0127] θ i represents the string capacity of the i-th array of the photovoltaic power station;

[0128] μ i represents the AC output capacity of the i-th inverter;

[0129] γ represents the standard square matrix error;

[0130] E i represents the AC power generation of the i-th array of the photovoltaic power station;

[0131] β represents the standard lineup ratio.

[0132] In one embodiment of the present application, β indicates that the standard array ratio is the selected standard array ratio, and the significance of calculating the standard array error is to evaluate the layout quality of the photovoltaic system and help determine whether the layout of the photovoltaic components meets the design requirements. A smaller standard array error means that the difference between the actual layout and the ideal layout is small, indicating that the layout of the system is relatively accurate. A larger standard array error may mean that there are certain problems with the layout, which may affect the power generation efficiency of the photovoltaic system.

[0133] Preferably, Figure 2 As shown, in step C, screening the problems of the photovoltaic power station according to the energy efficiency analysis optimization result to adjust the power generation plan includes:

[0134] When the photoelectric conversion efficiency is lower than the first preset value, screening whether the photovoltaic module has a local short circuit or a shielding problem;

[0135] In one embodiment of the present application, the official standard photoelectric conversion efficiency of photovoltaic modules is 20.7%, the power attenuation in the first year is less than 2%, and the power attenuation is 0.45% per year for 2-30 years. The present invention calculates the photoelectric conversion efficiency of sunlight to the group string. When the calculated photoelectric conversion efficiency is lower than the official standard photoelectric conversion efficiency by 1.5%, the photovoltaic module may have abnormal conditions such as partial short circuit or shading. Specifically, when calculating the photoelectric conversion efficiency, the conversion efficiency is colored. The coloring standard is that the longer the distance from noon, the lighter the color. The photoelectric conversion efficiency in the morning and afternoon should be close to overlap in theory. If the efficiency is significantly reduced in a short time, it can be considered that there is a shadow obstruction. If the photoelectric conversion efficiency decreases from 11:00 to 14:00 at noon, it means that the temperature exceeds the tolerance range of the group string at this time. Excessive temperature will cause the power generation efficiency of the module to decrease. It is necessary to control the temperature of the module through reasonable module heat dissipation design, shading measures or stop power generation. When the photoelectric conversion efficiency is always lower than the critical point, it can be considered that the surface of the photovoltaic module is covered with dust. It is necessary to clean the dust, dirt and snow on the surface of the photovoltaic module to ensure the transmittance of light and the power generation efficiency of the photovoltaic module.

[0136] When the DC power-inverter AC power conversion efficiency of the combiner box is lower than the second preset value, the combiner box is screened for problems such as excessive cable loss, increased contact resistance, shadowing, surface contamination of the photovoltaic panel, or excessive temperature;

[0137] In another embodiment of the present application, when the conversion efficiency from the combiner box to the inverter is too low, assuming that the standard conversion efficiency is 98%, if the efficiency is lower than 98%, it can be suspected that the combiner box has abnormal conditions such as excessive cable loss, increased contact resistance, shadow obstruction, surface contamination of the photovoltaic panel, or excessive temperature.

[0138] When the inverter-box transformer conversion efficiency is lower than the third preset value, the inverter is screened to see if there are problems such as low inverter conversion efficiency, unstable or mismatched grid conditions, and damaged connectors and joints;

[0139] In one embodiment of the present application, when the inverter-to-box transformer conversion efficiency is too low, assuming that the standard conversion efficiency is 98%, if the efficiency is lower than 98%, it can be suspected that there are abnormal conditions such as low conversion efficiency of the inverter itself, unstable or mismatched grid conditions, poor quality or damage of connectors and joints, etc.

[0140] When the conversion efficiency between the box transformer and the collector line is lower than the fourth preset value and the conversion efficiency between the collector line and the main transformer is lower than the fifth preset value, the box transformer is screened to see whether there are problems such as reduced box transformer efficiency, improper cable laying method, and severe on-site environmental factors;

[0141] In one embodiment of the present application, when the conversion efficiency from the box transformer to the collector line and the conversion efficiency from the collector line to the main transformer are too low, assuming that the standard conversion efficiency is 98%, if the efficiency is lower than 98%, it can be suspected that there are abnormal conditions such as low efficiency of the box transformer, improper cable laying method, inappropriate environmental factors such as temperature and humidity, etc.

[0142] When the main transformer conversion efficiency minus the grid conversion efficiency is lower than the sixth preset value, it is screened whether there is a problem of grid power fluctuation or grid voltage instability.

[0143] In one embodiment of the present application, the conversion efficiency from the main transformer to the grid is low. It is suspected that the low efficiency of the main transformer leads to more energy loss during the conversion process, power quality problems of the grid or unstable grid voltage. The grid may have some regulatory requirements for the connected photovoltaic system, such as improper power factor control, grid power fluctuations or instability.

[0144] The technical principle of the present invention is described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific implementations of the present invention without paying creative labor, and these methods will fall within the scope of protection of the present invention.

Claims

1. A method for optimizing energy efficiency of a photovoltaic power station, characterized in that: Step A: Collect energy efficiency data of the photovoltaic power station, including cumulative solar radiation energy, string energy, combiner box input voltage, combiner box power, combiner box energy, box transformer energy, collection line energy, main transformer energy and grid energy; Step B: Based on the energy efficiency data of the photovoltaic power station collected in step A, calculate the photoelectric conversion efficiency, inverter output voltage, combiner box DC-inverter AC conversion efficiency, inverter-box transformer conversion efficiency, box transformer-collector line conversion efficiency, collector line-main transformer conversion efficiency, main transformer conversion efficiency-grid conversion efficiency, array ratio and standard array error; According to the above calculation results, a photovoltaic system energy consumption analysis model is established; Step C: Obtain the energy efficiency data of the photovoltaic power station monitored in real time and input it into the photovoltaic system energy consumption analysis model to obtain energy efficiency analysis optimization results, and screen the problems of the photovoltaic power station according to the energy efficiency analysis optimization results to adjust the power generation plan.

2. A photovoltaic power station energy efficiency optimization method according to claim 1, characterized in that: In the step B, the photoelectric conversion efficiency is calculated according to formula 1 and the inverter output voltage is calculated according to formula 2; ω1=E zc / E sun --Formula 1; in: ω1 represents the photoelectric conversion efficiency; E zc Indicates the string energy; E sun Indicates the cumulative solar radiation energy; V out =V dc ×α--Formula 2; V out Indicates the inverter output voltage; V dc Indicates the combiner box input voltage; α represents the duty cycle, that is, the high level time of the AC signal accounts for α% of the total cycle time.

3. A photovoltaic power station energy efficiency optimization method according to claim 1, characterized in that: In the step B, the conversion efficiency of the combiner box DC power to the inverter AC power is calculated according to formula 3; ω2=E hl / E n --Formula 3; in: ω2 represents the conversion efficiency of combiner box DC power to inverter AC power; E hl Indicates the power of the combiner box; E n Indicates the energy of the combiner box.

4. A photovoltaic power station energy efficiency optimization method according to claim 1, characterized in that: In the step B, the inverter-box transformer conversion efficiency is calculated according to formula 4; ω3=E n / E xb --Formula 4; in: ω3 represents the inverter-box transformer conversion efficiency; E xb Indicates the box transformer energy; E n Indicates the energy of the combiner box.

5. A photovoltaic power station energy efficiency optimization method according to claim 1, characterized in that: In the step B, the conversion efficiency of the box transformer-collector line is calculated according to formula 5; ω4=E xb / E jd --Formula 5; in: ω4 represents the conversion efficiency of the box transformer-collector line; E xb Indicates the box transformer energy; E jd Indicates the collector line energy.

6. A photovoltaic power station energy efficiency optimization method according to claim 1, characterized in that: In the step B, the collector line-main transformer conversion efficiency is calculated according to formula 6; ω5=E jd / E zb --Formula 6; in: ω5 represents the collector line-main transformer conversion efficiency; E jd Indicates the collector line energy; E zb Indicates the main transformer energy.

7. A photovoltaic power station energy efficiency optimization method according to claim 1, characterized in that: In the step B, it includes calculating the main transformer conversion efficiency - grid conversion efficiency according to formula 7; ω6=E zb / E d --Formula 7; in: ω6 represents the main transformer conversion efficiency minus the grid conversion efficiency; E zb Indicates the main transformer energy; E d Represents the grid energy.

8. A photovoltaic power station energy efficiency optimization method according to claim 1, characterized in that: In the step B, the square array ratio is calculated according to formula eight, and the standard square array error is calculated according to formula nine; β i =θ i / μ i --Formula 8; γ=E i / β i ×β--Formula 9; in: β i represents the capacity ratio of the i-th array of the photovoltaic power station; θ i represents the string capacity of the i-th array of the photovoltaic power station; μ i represents the AC output capacity of the i-th inverter; γ represents the standard square matrix error; E i represents the AC power generation of the i-th array of the photovoltaic power station; β represents the standard lineup ratio.

9. A photovoltaic power station energy efficiency optimization method according to claim 1, characterized in that: In step C, screening the problems of the photovoltaic power station according to the energy efficiency analysis optimization results to adjust the power generation plan includes: When the photoelectric conversion efficiency is lower than the first preset value, screening whether the photovoltaic module has a local short circuit or a shielding problem; When the DC power-inverter AC power conversion efficiency of the combiner box is lower than the second preset value, the combiner box is screened for problems such as excessive cable loss, increased contact resistance, shadowing, surface contamination of the photovoltaic panel, or excessive temperature; When the inverter-box transformer conversion efficiency is lower than the third preset value, the inverter is screened to see if there are problems such as low inverter conversion efficiency, unstable or mismatched grid conditions, and damaged connectors and joints; When the conversion efficiency between the box transformer and the collector line is lower than the fourth preset value and the conversion efficiency between the collector line and the main transformer is lower than the fifth preset value, the box transformer is screened to see whether there are problems such as reduced box transformer efficiency, improper cable laying method, and severe on-site environmental factors; When the main transformer conversion efficiency minus the grid conversion efficiency is lower than the sixth preset value, it is screened whether there is a problem of grid power fluctuation or grid voltage instability.

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