Method for optimizing the power enhancement of photovoltaic solar plants using smart preventive and predictive maintenance

Abstract

The invention is a method to optimize solar photovoltaic power plant repowering by making use of the smart predictive and preventive maintenance which detects failures in modules or in cells within modules, i.e., aerial inspections by infrared thermography and/or electroluminescence. In the method object of the invention, the detected failed modules are separated in different types of failures: A—irreversible; B—reversible and C—partly reusable. Repowering consists on substituting modules of type A for new, more powerful ones, and re-group them series-connected within the same strings (1). Modules with type B failures are repaired and installed back in their original place, and modules C are either re-grouped in series-strings, or substituted by new, more powerful modules, also series connected in strings (1).

Claims

1. A method to optimize repowering of solar photovoltaic power plants through predictive and preventive maintenance in which: a. in a first step, an aerial thermographic infrared and/or electroluminescent inspection is carried out to detect failed modules; b. during the analysis of the results of said inspection, failed modules are classified in each of the following three types of failure: A—irreversible, B—reversible and C—partly reversible; c. modules with failure type A are substituted by new ones, of more power, which are grouped and series-connected within strings and their power range has a standard deviation lower than ±5%; d. modules with failure type B are repaired and their original power recovered, and, once repaired, they are put back in their original position within the power plant; e. modules with failure type C are either re-grouped according to their new power which is always lower than their original power, in groups within strings, where they are series-connected and their power range has a standard deviation lower than ±5%, or they are destined to other power plants and are substituted by new modules, of higher power, which are grouped within strings, where they are series-connected and their power range has a standard deviation lower than ±5%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows the modules of a solar plant after an inspection, at which a certain number of modules with type A failure (irreversible), another number of type B modules (reversible) and another number of type C modules (partly reversible) have been found, all of which distributed at random along the solar power plant. The rectangles (1) show several module strings inside the plant, wherein the modules are series-connected.

(2) FIG. 2 shows the modules of a solar plant after repowering has been implemented. Modules with type A failures have been substituted for new, more powerful ones, line in the same series-connected string (1), separated from the other strings by parallel connection. Modules with type B failures have been repaired and placed back in their original places, as they have recovered their original power and do not affect the string they were in. And modules with type C failures have been re-grouped within the same series-connected string (1), separated from the other strings by parallel connection.

DESCRIPTION OF EXAMPLE EMBODIMENTS

(3) In one possible, but non-exclusive embodiment, a 10 MWp, ground-mounted solar photovoltaic power plant is formed by 40.000 modules of 250 Wp each, distributed in 1,000 strings of 40 series-connected modules each.

(4) Through an aerial thermography inspection that took place as part of the smart annual predictive and preventive maintenance, the following failed modules were detected: 400 modules with type A failures (irreversible). 240 modules with type B failures (reversible). 160 modules with type C failures, 80 of which lost half their power (thus staying at 125 Wp), and the remaining 80 lost one fifth of their original power (thus staying at 200 Wp).

(5) With the repowering method, in this embodiment, the 400 type A modules are substituted for new generation modules, of 300 Wp each, and are grouped in 10 strings of 40 series-connected modules each.

(6) The 240 type B modules are repaired, gain their original power back and are placed at the same places they occupied before the inspection.

(7) The 160 type C modules are re-grouped and distributed into four strings, two with 40 modules each with new power of 125 Wp per module, and another two of with 40 modules each with new power of 200 Wp per module.

(8) This way, the solar power plant keeps working at its optimum, and a repowering from 10 MWp (nominal power, though it would be less, as 800 modules were not working properly) to 10.006 MWp is achieved.

(9) In another possible, but non-exclusive configuration, with the same number and type distribution of failed modules, those modules with failures of type A and B follow the same procedure, whereas the 160 modules with failures of type C are sold, and substituted in the plant by new ones of 300 Wp each, distributed in four strings (1) of 40 series-connected modules each. The achieved repowering reaches now 10,028 MWp.