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and sheathed, although covered by SANS 1507 [2], is not a standard
design used in South Africa. This need has, however, emerged in the
last couple of years through the renewable power projects launched
by government.
Solar PV cables produced in South Africa have, therefore, been
designed and manufactured to the SANS 1507 [2] standard by leading
players in the sector in either a reduced halogen emission xlpe/pvc
(LH) or halogen free xlpe/eva single core flame retardant, UV stable
designs. Local legislation does not require the use of halogen free
cable designs for fixed installations, but current standards do ensure
that cables are prevented from releasing harmful halogens, toxins or
significant volumes of smoke if they do burn during a fire.
Solar cables make use of flexible Class 5 tinned conductors for
flexibility and require compatibility testing in order to ensure that insu-
lation and sheathing compounds do not mutually affect one another
during operation. UV resistance testing is carried out in accordance
with the American standard, UL 1581 [6], which utilises the American
Society of Testing and Materials method (ASTM G155-00 [7]).
The IEC TC20 Working Group (WG) 17 is currently in the process
of drafting a new standard for solar PV cables (IEC 62930 [8]) with
participation from the Association of Electric Cable Manufacturers
of South Africa (AECMSA). The chairman of the AECMSA Technical
Sub-Committee will lead the committee on a proposal to the SABS
for the introduction of a new part to SANS 1507 [2], which will cover
solar PV design and performance requirements specifically.
Future outlook
Solar PV cables are required for rooftop PV systems and it is envisaged
that the current power situation in South Africa will lead to some
homeowners and businesses wanting to be self-sufficient during
power outages or able to make energy cost savings during the day
when the sun is up. This will lead to an increase in the demand for PV
cables from a residential and corporate perspective.
Further to this, with the onset of future smart homes, smart
businesses and smart energy projects, cables could take on multiple
roles, providing solar and grid energy as well as broadband access.
Cables in renewable energy plants could then communicate the status
of energy generation more effectively and ensure the efficient, remote
control of grids and systems.
More and more renewable power generating plants are being con-
structed or planned on the African continent and it is envisaged that
South African consulting engineers, with the experience gained
in local renewable projects, will specify cables compliant with
the SANS standards for use in these projects. This will lead
to cross-border opportunities for local cable manufacturers.
Even though aluminium, which is being used more
and more in renewable energy cables, is less attractive
to thieves (from a value perceptive),
cable theft is likely to remain an issue
going forward.
Themarking of cables with unique
identifiers, so rightful owners can be
identified, and other mitigation meth-
ods should not be discounted.
Conclusion
A recent report by the Council for Scientific and Industrial Research
(CSIR) states that solar and wind projects in South Africa generated
an R8,3 billion benefit for the country from January to June this year.
Opportunities are rife for local cable manufacturers who are able
to meet the demand for quality, durability and sustainability. South
Africa’s local environmental conditions drive the need for innovation
in cable design, ensuring protection against water, UV and ozone
exposure as well as flexibility.
Stricter standards will soon come to the fore, with low halogen
or halogen free cables becoming more prevalent. Cables will not only
have a significant role to play in transmitting much needed renewable
energy to where it is required most, but will also feature in the smart
homes and smart grids of the future.
References
[1] SANS 1339. 2010. Electric cables - Cross-linked polyethylene
(XLPE) insulated cables for rated voltages 3,8/6,6 kV to 19/33 kV.
[2] SANS1507. Electric cables with extruded solid dielectric ini
insulation for fixed installations (300/500 V to 1 900/3 300 V).
[3] SANS 97. 1999. Electric cables impregnated paper insulated
metal sheathed cables for rated voltages 3,3/3,3 kV to 19/33 kV.
[4] IEC 60502-1. 2004. Power cables with extruded insulation and
their accessories for rated voltages from 1 kV (Um = 1,2 kV) up
to 30 kV (Um = 36 kV). Part 1: Cables for rated voltages of 1 kV
((Um = 1,2 kV) and 3 kV (Um = 3,6 kV).
[5] IEC 60055. 2005. Paper-insulated metal-sheathed cables for rated
voltages up to 18/30 kV (with copper or aluminium conductors
and excluding gas-pressure and oil-filled cables).
[6] IEC 60502-2. 2005. Power cables with extruded insulation and
their accessories for rated voltages from 1 kV (Um = 1,2 kV) up
to 30 kV (Um = 36 kV). Part 2: Cables for rated voltages from
6 kV (Um = 7,2 kV) up to 30 kV (Um = 36 kV).
[7] ASTM G155-00 (superseded by ASTM G155-13). Standard
practice for operating Xenon Arc Light apparatus for exposure
of non-metallic materials.
[8] IEC 62930. Electric cables for Photovoltaic systems.
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ENERGY EFFICIENCY MADE SIMPLE 2015