ASTM E2481-12
Standard Test Method for Hot Spot Protection Testing of Photovoltaic Modules

Standard No.

ASTM E2481-12

Release Date

2012

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM E2481-12(2018)

Latest

ASTM E2481-12(2023)

Scope

4. Significance and UseTop Bottom

4.1 The design of a photovoltaic module or system intended to provide safe conversion of the sun's radiant energy into useful electricity must take into consideration the possibility of partial shadowing of the module(s) during operation. This test method describes a procedure for verifying that the design and construction of the module provides adequate protection against the potential harmful effects of hot spots during normal installation and use.

4.2 This test method describes a procedure for determining the ability of the module to provide protection from internal defects which could cause loss of electrical insulation or combustion hazards.

4.3 Hot-spot heating occurs in a module when its operating current exceeds the reduced short-circuit current (Isc) of a shadowed or faulty cell or group of cells. When such a condition occurs, the affected cell or group of cells is forced into reverse bias and must dissipate power, which can cause overheating.

Note 1???The correct use of bypass diodes can prevent hot spot damage from occurring.

4.4 Fig. 1 illustrates the hot-spot effect in a module of a series string of cells, one of which, cell Y, is partially shadowed. The amount of electrical power dissipated in Y is equal to the product of the module current and the reverse voltage developed across Y. For any irradiance level, when the reverse voltage across Y is equal to the voltage generated by the remaining ( s-1) cells in the module, power dissipation is at a maximum when the module is short-circuited. This is shown in Fig. 1 by the shaded rectangle constructed at the intersection of the reverse I-V characteristic of Y with the image of the forward I-V characteristic of the (s-1) cells.

FIG. 1 Hot Spot Effect

4.5 By-pass diodes, if present, as shown in Fig. 2, begin conducting when a series-connected string in a module is in reverse bias, thereby limiting the power dissipation in the reduced-output cell.

FIG. 2 Bypass Diode Effect

Note 2???<......

ASTM E2481-12 Referenced Document

• ASTM E1036 Standard Test Methods for Electrical Performance of Nonconcentrator Terrestrial Photovoltaic Modules and Arrays Using Reference Cells
• ASTM E1799 Standard Practice for Visual Inspections of Photovoltaic Modules
• ASTM E1802 Standard Test Methods for Wet Insulation Integrity Testing of Photovoltaic Modules
• ASTM E772 Standard Terminology Relating to Solar Energy Conversion
• ASTM E927 Standard Specification for Solar Simulation for Terrestrial Photovoltaic Testing

ASTM E2481-12 history

• 2023 ASTM E2481-12(2023) Standard Test Method for Hot Spot Protection Testing of Photovoltaic Modules
• 2018 ASTM E2481-12(2018) Standard Test Method for Hot Spot Protection Testing of Photovoltaic Modules
• 2012 ASTM E2481-12 Standard Test Method for Hot Spot Protection Testing of Photovoltaic Modules
• 2008 ASTM E2481-08 Standard Test Method for Hot Spot Protection Testing of Photovoltaic Modules
• 2006 ASTM E2481-06 Standard Test Method for Hot Spot Protection Testing of Photovoltaic Modules