Challenges facing solar South Africa

by Media Xpose

Alternative energy sources have become increasingly popular over the last twenty years in South Africa, with solar in particular taking up a fair share of the public conversation. Power cuts and unreliable electricity supply will remain with us for the foreseeable future, pushing more people to seek ways to generate their own power.

“The renewable energy sector needs infrastructure,” says Allbro managing director Quintin Lamprecht. As the industry grows, the support system around renewable energy generation will need to be put in place to ensure safe and reliable delivery of that energy. There are, however, some safety concerns that are not immediately apparent.

The wiring code and regulations in South Africa have been created for traditional AC systems. This code has not been updated to accommodate renewable energy systems. “There has been a lot of development in solar panel and inverter technology but the infrastructure that supports it remains largely unregulated. The voltages you’re dealing with in your house are usually 220V and in some cases 380VAC. Solar installations typically run at 300V to 1000VDC,” says Lamprecht. PV systems are direct current (DC), which poses its own set of safety challenges.

When a fault condition is created in an alternating current (AC) installation, the protection devices detect and interrupt the fault condition, limiting damage to the installation, the building and more importantly protecting people from serious harm or injury. In a DC system, there is a very real risk of a fault condition manifesting in the form of a DC arc which is more difficult to detect and interrupt.

“Within the PV industry, the risk presented by DC arc faults is gaining significant attention, and for good reason,” writes Marv Dargatz of Enphase Energy Inc. “The DC circuits within a PV installation can generate, and sustain, arcs of considerable intensity. Not only have these arcs started fires, but the intensive energy that generates these arcs also poses a significant risk to firefighters during their efforts to suppress the fire.”

“[A DC arc] is a flame source that can continue for a long time. You need protective housings that do not become a fuel source that helps to propagate a fire,” says Lamprecht. South Africa’s prevailing regulations specify that an electrical system needs to have an isolator, surge protection and short circuit / over current protection. “While fuses remain a preferred solution they are not effective in detecting or interrupting a DC arc which is characteristically similar to the nominal current of the circuit. This allows the arc perpetuate,” warns Lamprecht. He says that even V0 rated plastics are not safe enough. A plastic is rated V0 if it does not continue to burn once the source of fire has been removed. The “self extinguishing” must occur within 10 seconds of the flame source being removed. “A sustained DC arc is a sustained fire so flame retardant plastic, despite being self extinguishing actually becomes a fuel source for the flame. That’s why we’ve really been pushing to have GRP [Glass Reinforced Polyester] to be the material of choice for such circuits.”

“Allbro is designing products that are safe to use when you’re using power that is not historically part of the wiring code,” says Lamprecht. “We design products that are able to support the functional requirements of these installations in a safer way”.

In Australia, Allbro has seen many of their Allbrox® enclosures used to house the main distribution boards on solar installations. The Allbrox® is their Glass Reinforced Polyester answer to the traditional steel boxes but with a 25+ year UV life, an IP66 rating and a greater ability to weather outdoor conditions. Steel enclosures are conductive and present a significant risk as a shock hazed.

Allbro is also seeing some of their snap-flap AllRobust™ enclosures used to house isolator switches for solar installations. Made from GRP, the AllRobust™ solves the problem of housing the isolator switch in an enclosure that does not become a fuel source in cases where a DC arc occurs and perpetuates. Its resilience to the elements allows the housing to be placed outside the home where the fire department would need to isolate the electrical supply before dealing with a fire.

And the future for Africa?

“Mini-grids,” explains Lamprecht. “You can’t run transmission lines to all the remote villages in Africa. A mini-grid that combines diesel power or Battery storage with solar power is the likely solution. As mini-grids begin to populate the countryside and a power line does eventually come through, the mini-grid can be joined to the larger grid.” Allbro’s existing electrical solutions – like metering, monitoring and distribution boards are designed to withstand the harsh sunlight and extreme weather conditions of Africa.

As more and more organisations and households look to leverage the abundant the hours of sunlight we are blessed with, Allbro is busy implementing world-class solutions specifically designed to withstand the particular hazards of more than just a solar installation, we are designing solutions for a solar installation somewhere in Africa.

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