Electrical Power & Protection


Better transformer design improves safety

October 2019 Electrical Power & Protection

As electricity utilities and users worldwide look to become more safety conscious and efficient in their use of electrical energy, it is important to leverage the improvements that have been made in the design of transformers.

According to Trafo Power Solutions managing director, David Claassen, there have been considerable strides in technology, surpassing both the efficiency and the reliability of the traditional oil-filled transformers that are predominantly used in power grid systems.

These high efficiency solutions include open-wound transformers (OWTs), vacuum-pressured impregnated transformers (VPIs) and cast resin transformers (CRTs). Traditional oil-filled transformers use paper saturated in oil wrapped around the winding material as an insulation medium. If not maintained correctly, insulation degradation will occur, with the oil posing both a safety and environmental risk.

“OWTs are constructed by dipping preheated windings into a high temperature varnish bath and then baking them,” says Claassen. “This replaces the need for oil and paper, so only a small amount of material is flammable.”

In VPI construction, layers of polyester resin are applied to the windings, which are subjected to interchanging cycles of pressure and vacuum that ensures deeper penetration and reduces the chances of air voids.

“With CRTs, windings are placed in a mould which is filled under vacuum with resin epoxy,” says Claasen. “Fibreglass mesh is used to strengthen the windings, which are cured in a heat-controlled oven. This process also prevents air voids, and the resin in CRTs is non-flammable.”

These designs have also made advances in reduced electrical losses, thereby improving efficiency. The use of OWTs, VPIs and CRTs offer considerable savings in energy costs over their life-spans, which for CRTs averages about 20 years. Despite the slightly higher capital cost (around 20%), these technologies can repay the price differential in just four years.

Claassen concludes that low loss cast resin transformers are being used in many parts of the world including Europe and North America because, although there is an initial premium, the payback period is between two and four years. These are now available for the African market from Trafo Power Solutions.

For more information contact David Claassen, Trafo Power Solutions, +27 11 325 4007, david@trafo.co.za, www.trafo.co.za




Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Power supplies for building automation
June 2020, Phoenix Contact , Electrical Power & Protection
The new Step Power power supplies from Phoenix Contact are specifically tailored to the needs of modern building automation. With their comprehensive approval package, which includes the standard ...

Read more...
Skid-mounted dry-type transformer
June 2020 , Electrical Power & Protection
In a specialised application on a coal mine, Trafo Power Solutions recently supplied a dry-type transformer mounted on a mobile skid. “The harsh environment of a coal mine required us to specially ...

Read more...
Customised transformers for renewables and beyond
June 2020 , Electrical Power & Protection
A focus on application engineering allows Trafo Power Solutions to supply customised dry-type transformers for a range of sectors including renewable energy. “We begin at the proposal stage by engaging ...

Read more...
Electrical certificate of compliance (COC) for instrumentation: non-hazardous installations
June 2020, Everest Equipment & Control , Electrical Power & Protection
An instrument and control installation’s scope of work often never makes a request for a certificate of compliance: it is assumed to be an electrical function and hence many installations are non-compliant. ...

Read more...
Five tips to manage energy use while staying at home
May 2020 , Electrical Power & Protection
Covid-19 continues to impact many aspects of our lives. Many are now required to stay at home in an effort to curb the spread of the pandemic. One of the many implications of staying at home will be the ...

Read more...
Holistic approach to energy security
April 2020 , Electrical Power & Protection
As South Africans settle into the routine and inconvenience of load shedding and planning their activities around shifting electricity supply, it is businesses that are taking the biggest hit through ...

Read more...
Save energy costs with highly-efficient Delta VFDs
April 2020, ElectroMechanica , Electrical Power & Protection
Customers can realise significant savings on their total energy costs by replacing older motor starters with energy-efficient Delta variable frequency drives (VFDs), distributed locally by ElectroMechanica ...

Read more...
Utility made easy
April 2020, Schneider Electric South Africa , Electrical Power & Protection
In recognition of the growing demand for reliable power provision, Schneider Electric strives to assist network operators to deliver electricity safely and efficiently. The company’s Advanced Distribution ...

Read more...
Specialised transformers for renewable energy projects
April 2020, Zest WEG Group , Electrical Power & Protection
Zest WEG’s local transformer manufacturing facility has supplied 36 specialised photovoltaic (PV) transformers to a solar energy generation plant in the Northern Cape. According to sales team leader, ...

Read more...
Meeting the needs of the mining industry
April 2020, Varispeed (Div of Hudaco Trading) , Electrical Power & Protection
Both above and below ground, Varispeed keeps the interests of its customers top of mind, all the time. The company was recently approached by a platinum mine in South Africa to assist with a robust application. ...

Read more...