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Photovoltaic power station parallel mismatch adjustment method and device

An adjustment method and photovoltaic power station technology, applied in the direction of photovoltaic power generation, single-network parallel feeding arrangement, etc., can solve problems such as parallel mismatch, difficult to find, and difficult to find deeper problems, so as to increase power generation and reduce The Effect of Parallel Mismatch Loss

Active Publication Date: 2020-05-22
HEFEI SUNGROW RENEWABLE ENERGY SCI & TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Due to the complex situation in mountainous areas, it is necessary to improve the space utilization rate as much as possible when building a photovoltaic power station on a mountainous area. When a photovoltaic power station is built, the MPPT of most inverters is connected according to the branch number of the combiner box. If there is a parallel Mismatch problems are hard to spot
[0003] At this stage, the operation and maintenance of photovoltaic power plants mostly use the discrete rate to diagnose and analyze the faults of photovoltaic power plants, or use IV scanning to detect photovoltaic power plants, or use the maximum power point to recombine MPPT under most inverters in photovoltaic power plants. However, none of the above methods can effectively screen out the parallel mismatch problem and give a solution
[0004] Using the discrete rate to analyze the photovoltaic power station can only analyze the difference in the power generation of the photovoltaic power station at the same time or within a period of time, and it is difficult to find deeper problems; because IV scanning is aimed at a certain moment of detection is a transient state value, it is difficult to accurately determine the strings with inconsistent orientations during installation by using IV scanning to detect photovoltaic power plants; different strings have different output characteristics due to differences in the environment and their own parameters, and when the When the string is greater than 1, there must be a parallel mismatch problem
When the orientations are different, or the shaded and unshielded strings are connected to the same MPPT (the same MPPT of the current string inverter is mostly connected to 2 or 3 strings), the parallel mismatch problem is particularly serious. Use The maximum power point recombines the MPPT under most inverters of the photovoltaic power station, and it is difficult to avoid falling into a local optimum, and there will be a phenomenon of constantly adjusting the combination scheme

Method used

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  • Photovoltaic power station parallel mismatch adjustment method and device

Examples

Experimental program
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Effect test

Embodiment 1

[0045] figure 1 It is a flow chart of a method for adjusting the parallel mismatch of photovoltaic power plants provided by Embodiment 1 of the present invention. This embodiment is applicable to the detection and adjustment of parallel mismatch of inverters in photovoltaic power plants. The parallel mismatch adjustment device is implemented, and the device can be implemented in the form of software and / or hardware. Specifically include the following steps:

[0046] S110. Select a typical day of each inverter, and acquire current data of each string of each inverter on the typical day.

[0047] Among them, the selection of a typical day can be determined by determining the group string with the largest daily power generation of the total station inverters of the photovoltaic power station, and determining that the absolute values ​​of the second-order differences are all smaller than the preset daily power generation threshold.

[0048] The current data of each string of the...

Embodiment 2

[0067] figure 2 It is a flow chart of a method for adjusting the parallel mismatch of photovoltaic power plants provided by Embodiment 2 of the present invention. This embodiment is optimized on the basis of the foregoing embodiments.

[0068] Correspondingly, the method in this embodiment specifically includes:

[0069] S210. Select a date when the absolute values ​​of the second-order differences of the strings with the maximum daily power generation of each inverter are smaller than a preset daily power generation threshold as typical days.

[0070] Since the analysis object of the parallel mismatch loss is the actual operating data of the photovoltaic power station, the inverters with real problems can be screened out. In general, it is necessary to find a date or time period with relatively stable irradiance as a typical day. If the irradiance is unstable, fluctuating, and when it changes rapidly, the actual tracking response accuracy of the inverter is different, and ...

Embodiment 3

[0099] image 3 It is a flow chart of a method for adjusting the parallel mismatch of photovoltaic power plants provided by Embodiment 3 of the present invention. The technical solutions of the embodiments of the present invention are further optimized on the basis of the above embodiments. The method of this embodiment specifically includes:

[0100] S310. Select a date when the absolute values ​​of the second-order differences of the strings with the maximum daily power generation of each inverter are smaller than a preset daily power generation threshold as typical days.

[0101] S320. Obtain the current data of each string of each inverter on the typical day, determine the current data of the string with the largest power generation according to the current data, and obtain the current data of the string with the largest power generation according to the current data of the string with the largest power generation The daily dispersion rate of the string current of each i...

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Abstract

The embodiment of the invention discloses a photovoltaic power station parallel mismatch adjustment method and device. The adjustment method comprises: selecting a typical day of each inverter, and acquiring current data of each string of each inverter on the typical day; determining a reference string current curve based on the current data, and determining the string type of the to-be-screened string according to the current peak moment corresponding to the reference string current curve and the current peak moment of the to-be-screened string; and determining to adjust the string access mode of the inverter according to the string access mode of the inverter corresponding to the string type of the string to be screened. According to the technical scheme, the parallel mismatch loss of the photovoltaic power station is reduced, and the generating capacity of the photovoltaic power station is improved.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of photovoltaic power station power generation, and in particular to a method and device for adjusting parallel mismatch of a photovoltaic power station. Background technique [0002] Due to the complex situation in mountainous areas, it is necessary to improve the space utilization rate as much as possible when building a photovoltaic power station on a mountainous area. When a photovoltaic power station is built, the MPPT of most inverters is connected according to the branch number of the combiner box. If there is a parallel Mismatch problems are difficult to find. [0003] At this stage, the operation and maintenance of photovoltaic power plants mostly use the discrete rate to diagnose and analyze the faults of photovoltaic power plants, or use IV scanning to detect photovoltaic power plants, or use the maximum power point to recombine MPPT under most inverters in photovoltaic p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38
CPCY02E10/56
Inventor 张家前
Owner HEFEI SUNGROW RENEWABLE ENERGY SCI & TECH CO LTD
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