WCA May 2014

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54 Wire & Cable ASIA – May/June 2014
Abstract
Furukawa has developed a cable for photovoltaic power
generation systems, which meets the requirements of
the TÜV 2Pfg1169/2007 standard[1] and the JCS4517
standard[2].
A cable for photovoltaic power generation systems, which
meets the requirements of these standards, requires that
insulating materials and sheath materials be made of
halogen-free materials.
In addition to that, the cable requires vertical
incombustibility, high-temperature heat resistance,
low-temperature characteristics, and acid resistance.
Furthermore, a temperature index is required to be
more than 120ºC, because temperatures in the working
environment range from −40ºC to +90ºC. A temperature
at which an aging residue percentage reaches 50 per cent
after 20,000 hours is required to be higher than 120ºC.
In particular, excellent heat-deterioration characteristics
are required.
At this time, cross-linked polyethylene was used as an
insulator of the cable; highly incombustible cross-linked
polyolefin was used as sheath materials. As a result,
this made it possible to meet the requirements of the
above-mentioned standards.
In addition, it was confirmed that there is no problem
in putting this cable to practical use in terms of peeling
characteristics and bleed characteristics.
Furthermore, it is possible to manufacture this cable
without using special bridging equipment such as
electron-beam irradiation machines.
This cable is very advantageous in terms of costs and
response to mass production.
1 Introduction
In recent years, while there has been a growing interest
in environmental problems all over the world, power
generation activities by using renewable energy such as
wind power generation, photovoltaic power generation and
biomass power generation have become very active.
For photovoltaic power generation, power generation
facilities on the scale of more than 1 megawatt, called
‘mega solar’, have rapidly begun to become widespread.
In the future, demand for the cables to be used in these
power generation facilities is expected to increase.
At present, unique standards are used in each region to
ensure the reliability of electric wires used for these power
generation facilities.
In Europe, there are the TÜV 2Pfg1169 standards while the
UL4703 standards[3] are available in North America.
In recent years, the JCS4517 standards have been
established in Japan on the basis of the TÜV 2Pfg1169
standards. Unique standards were established in each
region, and there is an increasing demand for compatible
cables that meet all standards.
On the other hand, the development of less expensive
cables is called for greater proliferation. At present,
demand for low-cost cables is much higher than demand
for integrated cables.
Against the background of the above-mentioned
circumstances, Furukawa has developed a cable that
meets the requirements of the TÜV standards and the
JCS standards.
2 A Newly Developed Cable for Photo-
voltaic Power Generation
There is a hot-set property as one of the mainly required
properties of a cable for photovoltaic power generation,
which corresponds to the TÜV standards and the JCS
standards. In an incombustible halogen-free electric wire
of polyolefin, electron beams are usually irradiated to
satisfy the standard of hot-set properties.
However, in a future mega solar facility, the capacity of an
electric current will become larger. Namely, the size of a
cable is expected to become larger. There is a limit to the
response by electron-beam irradiation.
In addition, as far as a small size of a low electric current is
concerned, the cost of irradiation equipment itself is high,
and non-electron beam bridging is called for.
Development of the cable
for photovoltaic power
generation systems
By Arifumi Matsumura, Masaki Nishiguchi Shigeru Kubo, Fitel Photonics Laboratory, Furukawa Electric Co Ltd, Japan