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New PV connectors specific for harsh environmental conditions

Operating electrical installations at temperatures over 70°C or at altitudes higher than 6,500 feet make for different requirements for standard installations because of the harsh environmental conditions.

Yet, it is the is in those very areas with such harsh environmental conditions, like deserts and mountain ranges, which offer the large spaces and optimal solar radiation for efficient photovoltaic systems.

The expansion of photovoltaic (PV) installations into every part of the world is giving rise to new areas of application in challenging environmental conditions. About 35% of the Earth’s land surface is covered by deserts.

Thus, a growing push to investigate efficient uses of otherwise unpopulated areas with little economic potential. This is why we are seeing installations of PV solar power plants in hot, dry deserts in South America, Africa, southern Europe and the Middle East.

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Areas at high elevations also show significant potential for solar energy production. Thanks to their high elevation, PV plants in these regions produce about 50% more energy than those at sea level.

The extremely high levels of solar radiation and consistently clear skies provide optimal conditions for high electricity yields. Europe’s high Alpine regions aren’t the only candidate areas for these types of plants. An increasing number of PV plants are being built in the Andes range in South America at altitudes of over 6,500 feet above sea level.

IEC, safety standards at high temperatures

As a result of this market development, the Technical Committee TC82 of the International Electrotechnical Commission (IEC) will more carefully distinguish the requirements for different ambient temperature ranges and prepare the new edition of safety standards for PV modules, IEC 61730-1, for applications at operating temperatures of up to 70°C.

For applications at higher operating temperatures, such as installations in desert regions, the specifications of IEC TS 63126 will apply.

IEC TS 63126 identifies thermal requirements not only for PV modules, but also for added components like PV junction boxes or PV connectors, for two different temperature levels. The two categories for these modules are:

  • Temperature Level 1: greater than or equal to 80°C
  • Temperature Level 2: greater than or equal to 90°C 

Section 6.3 of this technical specification lists the requirements for PV connectors according to IEC 62852 for use at the module temperature levels described above. The connectors’ upper limiting temperatures (ULT) are required to have the following minimum values:

  • ULT for connectors used for installation of Level 1 PV modules: at least 95°C
  • ULT for connectors used for installation of Level 2 PV modules: at least 105°C

Operating in harsh environmental conditions

The requirements for insulation coordination in the safety standards for electrical products are usually designed for applications at altitudes up to 6,500 feet. For applications at higher elevations, the requirements for clearances must be corrected because the lower air pressure reduces the electrical installations’ resistance to voltage flashover across the clearance.

Therefore, the minimum clearance must be multiplied by a correction factor from Table A.2 of IEC 60664-1:2020 or verified with a correspondingly higher test surge voltage.

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Mechatronics solutions provider Stäubli has created a PV connector that meets the requirements for installations in PV systems with module temperature 2, according to the TÜV Rheinland test procedure. This means that Stäubli PV connectors have been successfully tested for PV installations in climate conditions up to at least 105°C. TÜV Rheinland has also verified the suitability of these types for use at elevations of up to at least 4,000m above sea level.

Guido Volberg, Stäubli Renewable Energy’s senior consultant: product regulatory affairs, says: “We’re very pleased to be the world’s first manufacturer of PV connectors to meet this requirement. We can now point to these successful tests when recommending the original MC4 and MC4-Evo connectors to our customers for these forward-looking applications in harsh environmental conditions such as high elevations or hot climate zones.”

Theresa Smith
Theresa Smith is a Content Specialist for ESI Africa.