Wet Leakage Current Test: Ensuring Electrical Safety in PV Modules
The Wet Leakage Current Test is a critical electrical safety assessment conducted on photovoltaic (PV) modules to evaluate their insulation integrity and ability to withstand moisture penetration under various environmental conditions.
This test is particularly pertinent for PV modules installed outdoors, where exposure to rain, morning dew, fog, or melted snow can compromise the module’s electrical isolation and lead to potential safety hazards.
Methodology of Wet Leakage Current Testing:–
The Wet Leakage Current Test involves submerging the PV module in a shallow tank filled with a water bath solution, ensuring that the entire module surface is covered, except for cable entries or MC4 connections of junction boxes not designed for water immersion (less than IPX7).
A testing voltage is then applied across the output connectors, which are shorted, and the water bath solution.
The voltage is incrementally increased up to the module’s system maximum voltage and maintained for a duration of two minutes.
The insulation resistance is measured, and it should not exceed 40 MΩ per square meter of the module’s surface area, provided the module has an area greater than 0.1 m².
Significance of Wet Leakage Current Testing
The primary purpose of the Wet Leakage :-
Current Test is to assess the PV module’s insulation against moisture penetration, which can lead to:
1. Corrosion: Moisture ingress can cause corrosion of metallic components, compromising the module’s structural integrity and electrical performance.
2. Ground Fault: Moisture penetration can lead to electrical shorts and ground faults, posing a significant safety risk.
3. Electric Shock Hazard: Inadequate insulation can result in electric shock hazards, particularly in wet environmental conditions.
Causes of PV Module Failure in Wet Leakage Current Testing PV modules may fail the Wet Leakage Current Test due to various reasons, including:
1. Poor Lamination: Inadequate lamination can lead to moisture penetration and compromise the module’s insulation.
2. Inadequate Edge Sealing: Poor edge sealing can allow moisture to ingress, causing electrical safety issues.
3. Connector-Related Issues: Connector problems can also contribute to test failure.
Wet Leakage Current Testing and IEC 61215 The Wet Leakage Current Test is an integral part of the IEC 61215 standard, which outlines the qualification requirements for PV modules.
This test is conducted after the insulation test and repeated at the end of the quality tests, ensuring that the PV module meets the requisite safety and performance standards.
By conducting the Wet Leakage Current Test, manufacturers can ensure that their PV modules meet the necessary safety and performance requirements, providing a reliable and safe product for consumers