Page 7 - Energize June 2022

COVER STORY

insulation material for the transformer. to consult with the manufacturer to ensure there is sufficient natural or forced air flow in
This means that air is used instead of the area with old or new installations.
oil as the cooling medium as well as the Where necessary, CRTs can be built into enclosures suited to a particular application,
insulating medium. This is good news even for outdoors. Should the unit be installed in an area exposed to lightning, suitable
because no oil means no leaks and no lighting arrestors must be installed on the main incoming MV line. Should MV switchgear
fire. be installed close to the CRT, it is highly recommended that surge suppression devices are
Consequently, CRTs can be regarded installed to protect against unwanted switching over voltages.
as a “green technology”, with no fire CRTs are essentially maintenance free. Minor inspections, checks and cleanings are all
hazards due to the self-extinguishing that is needed to successfully maintain these transformers. Transformer manufacturers will
medium used in the CRT, and usually assist with maintenance when requested. Replacing critical parts is easy because all
conformance to other safety, health the CRT’s major parts are accessible.
and environmental (SHE) requirements, Distribution CRTs have been successfully installed and used in Southern Africa in
saving installation costs on a new the last ten years or so in various industries including mining, renewables, municipal,
project. commercial, industrial and telecommunications. These applications often have unique
The fact that there is no oil to specifications according to the needs of the project or client. It is always wise to consult
worry about, also makes life easier as with the manufacturer and provide as much information as possible regarding the
the regular maintenance regarding project, to allow the manufacturer to assess the requirements, and design a CRT to meet
transformer oil is no longer needed. international specifications (such as IEC/SANS 60076-11 : 2020) and your client’s particular
Oil transport and on-site oil filling is no specifications.
longer necessary. Oil bund walls are Consultants are advised to familiarise themselves with the differences in the type test
not needed to contain oil spills. CRTs requirements for CRTs when compared to oil-filled transformers, as specified in
ensure that safety and environmental IEC/SANS 600676-1.
issues which might be regulatory, or
required by specific projects or clients, When considering your next distribution transformer installation, keep the following
are complied with. Insurance costs for advantages of CRTs in mind:
the installation of a CRT in high-risk areas • Environmentally friendly
should be much lower too because of • Fire and flame retardant
the low risk of fire. Typical application • Can easily be designed and installed according to needs
examples include power stations, • Compact dimensions
substations, hospitals, high rise buildings • Ease of maintenance and visual checks
and shopping malls. • CRTs can be recycled if necessary
A CRT’s protection system is based • Low installation cost
on the heat generated by the windings • Low noise levels
during normal operation. This is easily • High efficiency
done with a simple thermal protection • Lower insurance costs
device connected to thermo couples. The • Small installation footprint
thermal protection device is set to the • No contamination as there is no mineral oil used
needed value (according to insulation • No need for oil protection bund walls.
class and manufacture) and can provide • Ease of visual inspections of windings and assembly during manufacture, testing
an alarm and trip signal should these and commissioning.
values be reached. In addition to the
above, fans could be added to the Conclusion
thermal protection device should it be Oil-filled transformers will never be completely replaced in Southern Africa; however,
desirable to control the transformer’s from the above information provided, we hope you will consider CRTs for future projects
temperature. as they have a smaller environmental footprint and many other added advantages. All the
Regarding the installation of a CRT, advantages will save project and maintenance cost in the long run and lead to a greener
there are some key factors to consider. world for future generations.
CRTs are IP 00 with all electrical

connections exposed. Thus, there is Contact Paddy Padayachee,
a risk of environmental exposure and Revive Electrical Transformers,
contact. It is recommended that the Phone 082 560-8953, or
installation area be assessed to ensure Zander van Rooyen,
that all necessary ventilation and safety Phone 076 751-3386,
requirements are met. As the CRT uses sales.revive@ret.co.za, R E V I V E

natural air as cooling, it is very important https://ret.co.za REVIVE ELECTRICAL TRANSFORMERS (PTY) LTD

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