Tag Archives: Trafo Power Solutions

DRY-TYPE TRANSFORMERS FROM TRAFO IDEAL FOR COAL MINE

Trafo Power Solutions has customised two dry-type transformers for a coal mine in South Africa’s Limpopo province, allowing the units to be fitted into existing enclosures while meeting the customer’s demanding duty requirements.

“While we would normally supply the transformer together with its enclosure, we are also able to design the solution according to the dimensions available on site,” says David Claassen, managing director of Trafo Power Solutions. 

This required one of the transformers – a specialised 3900kVA unit – to be copper-wound to achieve a smaller footprint suitable to the space constraints without compromising the technical performance. With 11kV capacity on the primary windings, this transformer included four separate secondary windings – for 1810V, 1515V, 1360V and 1210V output respectively. 

“Being located outdoors on a coal mine, the transformer had to be well protected from fine dust and moisture, requiring a specially designed IP54 enclosure,” says Claassen. “At the same time, the transformer’s large size meant substantial heat loss, which needed to be extracted from the enclosure. The design therefore included an air-to-air heat exchanger to recycle cool air in a closed loop.”

The second transformer supplied to the mine was a 1600kVA unit for indoor application, stepping down from 11kV to 550V. Working closely with transformer repair experts Koratech Services, who applied certain modifications to the enclosure, Trafo Power Solutions was able to meet the dimensional and electrical requirement of the application – complete with control and protection system.

“Underground mining often presents space constraints which have to be considered in the design of the transformer or the miniature substation,” he says. “With our expertise and our strategic partnership with leading Italy-based manufacturer TMC Transformers, we can readily cater for these conditions.”

He notes that Trafo Power Solutions also supplies dry-type transformers to the marine industry, which requires not only that transformers can be safely employed indoors, but that they often be accommodated in cramped spaces. This experience enhances the company’s technical capability in underground mines. 

Claassen highlights that both transformers were ordered during the tight Level 5 Covid-19 lockdown in South Africa. Despite similar restrictions in Italy, TMC Transformers proceeded with manufacturing, running a 24-hour, three shift operation to ensure the required social distancing. 

“The high level of collaboration with our strategic partner allowed us to design, build and supply the transformers despite the Covid-19 disruption in 2020,” he says. 

Claassen says the dry-type transformer is ideal for both hazardous and non-hazardous areas of coal mines, as the absence of oil as a coolant makes the solution much safer. There is also much less maintenance required on dry-type transformers.  

GROWING NICHE FOR DRY-TYPE TRANSFORMERS IN OIL, GAS PROJECTS

Demanding safety requirements in the oil and gas sector are being met by custom-designed dry-type transformers from specialist company Trafo Power Solutions.

“We are seeing growing success in the application of dry-type transformer technology in this industry, where all equipment must be safe to use in hazardous areas,” says David Claassen, Trafo Power Solution’s managing director. “Being air-cooled, these transformers are a safe alternative to conventional transformers, which generally use oil as their coolant medium.”

Oil presents risks of explosion, fire and environmental damage while dry-type transformers, by contrast, can be installed indoors, in confined spaces and in proximity to operational areas where people are present. 

“Through our strategic partnership with leading transformer manufacturer TMC Transformers in Italy, we can design, supply and install fit-for-purpose solutions for hazardous areas,” says Claassen. “TMC’s facilities include state-of-the-art technology and capability, and allow us to compete with the best quality and range available globally.”

In one of Trafo Power Solution’s largest projects to date, it is partnering with TMC Transformers to supply the world-class Mozambique liquid natural gas (LNG) project in that country’s northern Cabo Delgado province. Eighteen dry-type transformers are already on site, inside modular substations for the project’s first construction camp of about 9,500 contractors. 

Also being supplied are 20 specialised dry-type transformers for the project’s gas plant, delivering features that only a few players in the global transformer sector could deliver. 

“These 400 kVA to 1600 kVA transformers will be housed in IP56 enclosures, equipping them for high levels of ingress protection,” he says.

SPECIALISED TRANSFORMERS FROM TRAFO FOR LNG PLANT

Twenty custom-designed transformers are being prepared by dry-type transformer specialists Trafo Power Solutions for a liquified natural gas (LNG) plant being constructed in northern Mozambique. 

The 20 transformers feature a specialised design that ensures high levels of ingress protection, according to David Claassen, managing director of Trafo Power Solutions. These units – ranging from 400 kVA to 1600 kVA – are housed in IP56 enclosures, for protection from fine dust and water. This solution has been achieved despite the transformers being cooled by air rather than oil.

“By applying world-class technology and expertise, these transformers are designed to operate reliably in humid and dusty outdoor conditions, providing continuous rated power without the use of any forced cooling,” Claassen says. 

The specialised design of the transformers accommodates elements such as temperature rise, losses and insulation systems – suiting each unit for the application and the load it will supply. 

“They will step down voltages from 6,600 V in the medium voltage (MV) network to 420 V required in the plant, and will supply various motor control centres,” he says. “Their specific designs will meet the requirements for various different impedances, voltages and K-factors for non-linear loading.”

This specialised solution is being supplied in a strategic partnership with Italian technology leader TMC Transformers. Together, the companies competed with the world’s leading OEMs for the prized contracts in this LNG mega-project – reportedly the largest-ever single foreign direct investment in Africa.

Trafo Power Solutions will also be supplying dry-type transformers for a Zone 2 hazardous area of the plant, requiring compliance with strict classifications and stringent sign-off from certified professionals. 

Claassen emphasises the safety advantages of dry-type transformers, which do not use oil as a coolant. They therefore pose no hazard in terms of fire, explosion or environmental damage. The transformers also need minimal maintenance, which an important benefit when located on such a remote site. 

DRY-TYPE TRANSFORMERS ENSURE SAFETY AT LNG CAMP

Dry-type transformers supplied by specialist company Trafo Power Solutions are ensuring the safe and reliable operation of substations in a construction camp at a large liquified natural gas (LNG) project in northern Mozambique.

According to David Claassen, managing director of Trafo Power Solutions, 18 dry-type transformers were included in modular substations built in South Africa and shipped to site recently. The company is in a strategic partnership with leading Italian transformer manufacturer TMC Transformers, and is competing at the highest level with other global OEMs.

“These substations are for the project’s first construction camp of about 9,500 contractors,”  Claassen says. “Our transformers have been specially designed for the high ambient temperatures in northern Mozambique.”

Ranging from 500 kVA to 1250 kVA, the temperature of these units will rise to a maximum of only 80⁰C when under full load. With Class-H insulation on both the medium voltage (MV) and low voltage (LV) windings, they will withstand a temperature of 180⁰C. This is considerably more than the potential 40⁰C ambient temperature in the tropics plus the 80⁰C temperature rise. The transformers are also designed for levels of humidity up to 95%.

He highlights that the safety advantages of dry-type transformers allow them to be used in this application. As they do not contain oil – which is the usual coolant in conventional transformers – they pose no fire, explosion or environmental hazard. 

“A transformer containing oil would present a significant risk in a construction camp accommodating thousands of people in close proximity,” he says. “The safety level of dry-type transformers also means that they can be used in enclosed spaces like modular substations. The minimal maintenance required is an added advantage, being located on such a remote site.”

Claassen notes that the global competition to supply this mammoth project has been intense, and points to the vital partnership between the local knowledge and experience of Trafo Power Solutions, and the technology and expertise of TMC Transformers.

TRAFO GAINS GROUND WITH DRY-TYPE TRANSFORMER SOLUTIONS

Dry-type transformer specialist Trafo Power Solutions is growing its footprint in mining and beyond with increased take-up of its safe and reliable technology.

“Our contract pipeline is a clear demonstration of the market’s confidence in dry-type transformers, especially for indoor applications, hazardous areas, remote locations and demanding outdoor environments,” says David Claassen, managing director of Trafo Power Solutions.

Recent orders have included a specialised 3900 kVA unit for a large coal mine in Limpopo province. With a primary voltage of 11 kV, this dry-type transformer delivers through four different secondaries of 1810 V, 1500 V, 1400 V and 1200 V. To operate reliably in the dusty outdoor location, it is installed in an IP54-rated enclosure and cooled using air to air heat exchangers

Even during the Covid-19 lockdown, supply from the company has continued. Two 2000 kVA dry-type transformers were installed in a modular substation for a diamond mine expansion in Sierra Leone.

Trafo Power Solutions also recently supplied Africa’s largest liquified natural gas (LNG) project, under construction in northern Mozambique. Eighteen dry-type transformers are already on site, inside modular substations for the project’s first construction camp of about 9,500 contractors. Also being supplied are 20 specialised dry-type transformers for the project’s gas plant.

“We have been active in many other industries too, such as telecommunications, health, food and beverages, and commercial buildings,” says Claassen. “Our strategic partnership with a leading global player, TMC Transformers in Italy, allows us to leverage world-class technology and expertise for application in Africa.”

He highlights Trafo Power Solutions’ responsiveness to specific customer requirements, and its experience in custom engineering solutions that are fit for purpose. Backing up these offerings is a flexible, 24/7 support service from technicians in South Africa, who are ready to provide interventions on site where necessary. The company also provides customers further access to the engineering expertise at TMC Transformers’ state-of-the-art design and manufacturing facilities.

BENEFITS OF DRY-TYPE TRANSFORMERS EMBRACED IN AFRICA

The steady uptake of dry-type transformers in the African market is being driven by the range of advantages offered by this technology, argues David Claassen, managing director of dry-type transformer specialist Trafo Power Solutions.

“We have seen wider application of dry-type transformers in Africa, as they move from niche products to more universal use,” says Claassen. “The reasons are not hard to find, and include safety, reliability and low installation costs.”

A key differentiator is that the electrical core and coils in a dry-type unit are cooled by normal air ventilation. By contrast, liquid-filled transformers are cooled by oil, silicone or other liquid. The risk of this liquid spilling is one of the main factors behind the increased use of dry-type transformers. The latter has higher levels of safety and does not present an environmental hazard.

“This makes dry-type units more suitable for indoor use, and also for underground and marine applications,” he says. “At the same time, they are also resilient enough for hostile outdoor environments.”

To insulate the windings and protect them from dirt, moisture, corrosive fumes and conductive dust, special treatment techniques are applied. Depending on the application, one of three main types of insulation is used: open-wound, vacuum pressure impregnated (VPI) or cast coil.

Among their safety benefits is their low fire hazard, with their transformer insulation made up of epoxy resin and eco-friendly quartz powder, the winding is flame-retardant. This also means it will not generate toxic gases when arcing occurs. The cost implication is that costly fire extinguishing equipment is rendered unnecessary.

“When locations are remote, as they often are in African applications, the installation of dry-type transformers makes good sense,” Claassen says. “This is because they are reliable and need little maintenance, while being easier and more economical to install.”

Without the risk of oil spillage, no concrete bund wall or significant civils works is required – saving time and money. Using only air for cooling, liquid testing is not required. At the same time, the smooth coil surface eliminates the build-up of heavy dirt. Designed to meet Class E2 environmental requirements, the units resist condensation and heavy pollution.

“In terms of high reliability, cast resin transformers typically have a service life of over 25 years and the failure rate has been shown to be very low,” concludes Claassen.

DRY TYPE REACTOR FROM TRAFO SAVES POWER FOR SA BANK

When a specialised dry type reactor failed after many years of service in a major banking company’s backup power generating system, Trafo Power Solutions was there to leverage its expertise and applications knowledge.

Trafo Power Solutions supplied and assisted with the installation of a replacement reactor, providing a fit-for-purpose design that accommodated the limited space and awkward position in which the components had to fit.

“The reactor – or inductor – is a key part of the bank’s backup system that feeds a number of buildings in the central business district of Johannesburg,” says Aaron Rost, contracts and proposals engineer at Trafo Power Solutions. “This vital component serves as a link between the utility power, the backup generator and the buildings’ supply.”

Rost explains that the reactor is important for a number of reasons. Among the most important are reducing the bank’s electricity costs, raising the system’s efficiency and contributing to the stability of the municipal power grid.

With its vast data centres, the bank must constantly idle its standby generators online, so that the switchover between utility power and standby power is seamless in the event of a power failure. He notes that to make better use of the fuel consumed by this continuous operation, diesel generators can be repurposed to help alleviate the data centre’s reactive power requirements.

“While active power refers to that element of the power supply that actually does the work – such as driving motors or powering lights – the reactive power is essentially useless power that is being wasted,” he says. “This reactive power effectively draws more current from a grid than what is really required.”

Rost highlights that the reactor stops any of this reactive power from being used from the power grid, This reactor also allows only the active power to be supplied from the grid, and in so doing helps create a more efficient system.

The importance of the reactor’s role in this power system is two-fold, he argues. Firstly, it reduces the bank’s electricity bill, as local municipalities charge a premium rate for the reactive power consumed.

“The reactive power raises the tariff that the client ends up paying at the end of the day,” he says. “By preventing the use of reactive power by the grid, the reactor allows the client to save directly on their overall energy costs.”

The second contribution that the reactor makes is that the local municipality does not have to deal with a ‘troublesome’ load, as this type of loading increases the amount of current being drawn.

“This then leads to additional heating in cables, transformers and switchgear, which erodes the life span of this equipment and can potentially lead to premature failure,” he says. “On a grid which is currently in a fragile state, any failed equipment can have massive implications for the equipment that is attached.”

Rost points out that the reactor also serves as a voltage regulator and filter on the utility power being supplied, allowing a more stable power supply to the building. This delivers a further benefit – in the event of a fault, the reactor can help to limit the fault current, making it less likely that costly utility equipment will be damaged.

DRY TYPE REACTOR FROM TRAFO SAVES POWER FOR SA BANK

When a specialised dry type reactor failed after many years of service in a major banking company’s backup power generating system, Trafo Power Solutions was there to leverage its expertise and applications knowledge.

Trafo Power Solutions supplied and assisted with the installation of a replacement reactor, providing a fit-for-purpose design that accommodated the limited space and awkward position in which the components had to fit.

“The reactor – or inductor – is a key part of the bank’s backup system that feeds a number of buildings in the central business district of Johannesburg,” says Aaron Rost, contracts and proposals engineer at Trafo Power Solutions. “This vital component serves as a link between the utility power, the backup generator and the buildings’ supply.”

Rost explains that the reactor is important for a number of reasons. Among the most important are reducing the bank’s electricity costs, raising the system’s efficiency and contributing to the stability of the municipal power grid.

With its vast data centres, the bank must constantly idle its standby generators online, so that the switchover between utility power and standby power is seamless in the event of a power failure. He notes that to make better use of the fuel consumed by this continuous operation, diesel generators can be repurposed to help alleviate the data centre’s reactive power requirements.

“While active power refers to that element of the power supply that actually does the work – such as driving motors or powering lights – the reactive power is essentially useless power that is being wasted,” he says. “This reactive power effectively draws more current from a grid than what is really required.”

Rost highlights that the reactor stops any of this reactive power from being used from the power grid, This reactor also allows only the active power to be supplied from the grid, and in so doing helps create a more efficient system.

The importance of the reactor’s role in this power system is two-fold, he argues. Firstly, it reduces the bank’s electricity bill, as local municipalities charge a premium rate for the reactive power consumed.

“The reactive power raises the tariff that the client ends up paying at the end of the day,” he says. “By preventing the use of reactive power by the grid, the reactor allows the client to save directly on their overall energy costs.”

The second contribution that the reactor makes is that the local municipality does not have to deal with a ‘troublesome’ load, as this type of loading increases the amount of current being drawn.

“This then leads to additional heating in cables, transformers and switchgear, which erodes the life span of this equipment and can potentially lead to premature failure,” he says. “On a grid which is currently in a fragile state, any failed equipment can have massive implications for the equipment that is attached.”

Rost points out that the reactor also serves as a voltage regulator and filter on the utility power being supplied, allowing a more stable power supply to the building. This delivers a further benefit – in the event of a fault, the reactor can help to limit the fault current, making it less likely that costly utility equipment will be damaged.

MINES REDUCE FIRE HAZARD WITH DRY-TYPE TRANSFORMERS

Underground mines in southern, central, and west Africa have been seeing the safety benefits of dry-type transformers from Johannesburg-based Trafo Power Solutions.

According to Trafo Power Solutions managing director David Claassen, this clientele even includes collieries, where the strictest safety regulations apply with regard to fire hazards.

“The high risk of fire in underground coal mining environments has led to a high demand for dry-type transformers,” says Claassen. “Among the fire risks that coal mines face are transformer short-circuits as well as fires reaching the transformer.”

He notes that dry-type transformer technology is rated Class F1 in terms of fire protection, ensuring that transformers supplied by Trafo Power Solutions are flame-retardant.

“Oil-cooled transformers, on the other hand, are a fire risk due to the oil they contain to cool the windings,” he says. “The risk is heightened by the harsh operating conditions in which many transformers must function on mines.”

These transformers also require regular attention and maintenance. Oil samples must be taken at prescribed intervals, and these must be tested at a laboratory with the appropriate accreditation. Testing must be conducted to ensure that oil purity is within bounds, and to check for gas levels and pressure build-up in the oil tank.

“This maintenance can present challenges and added costs if the equipment is located on a remote mine far from a source of expertise and the right equipment,” says Claassen. “With dry-type transformers, it is really only the temperature that requires monitoring. The equipment comprises limited componentry, so generally requires servicing only twice a year.”

He highlights that these regular inspections are brief and simple, taking just a couple of hours. Key aspects to be checked are the physical termination connections – which must be tightened to the right torque – and any dust that has gathered around the core and windings must be cleaned away.

Trafo Power Solutions has in recent years supplied dry-type transformers – along with ancillary power equipment such as low and medium voltage switchgear – to mines in South Africa, Mozambique, Zambia, the Democratic Republic of Congo (DRC), Ghana and Sierra Leone. In addition to coal, there are gold and base metal producers included in this clientele.

TRAFO CUSTOMISES TRANSFORMERS FOR RENEWABLES AND BEYOND

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 closely with the customer about the exact application and electrical load,” says David Claassen, managing director of Trafo Power Solutions. “This means that every project gets its own transformer design, so that it is fit for purpose.”

In the case of renewable energy applications, for example, there are some very specific demands that need to be accommodated. A solar power generating plant presents a situation in which a transformer will be energised from zero to 100% on a daily basis.

“This leads to wide fluctuations in temperature inside the transformer which, in turn, causes the resin around the windings to expand and contract considerably,” says Claassen. The windings in dry-type transformers are insulated in a cast resin or epoxy material, rather than oil, and rely on air movement for cooling.

“Such fluctuations could result in the resin cracking, so the design must specify the appropriate class of insulation to cope with these conditions,” he says. “We can design our windings for either a Class F or a Class H insulation. In addition,  the mixture of the resin is specially formulated to accommodate the duty cycle specific to renewable energy applications.”

The standard design – using Class F – can deal with temperatures up to 155 degrees Celsius. For many of Trafo Power Solutions’ low voltage and high voltage installations around Africa, the design includes a resin mix to Class H specifications. This gives it the capacity to withstand temperatures of up to 180 degrees Celsius.

Another aspect that needs to be considered for renewable energy applications is the non-linear load that inverters add to the mix. The transformers need to be designed with a K-Factor much higher than used for standard distribution type loads as well as the addition of an electrostatic shield between the primary and secondary windings, to eliminate potentially damaging leakage currents.  

Claassen notes that dry-type transformers are being increasingly specified for demanding applications such as renewable energy plants, instead of conventional oil transformers.

“With an oil-cooled unit, the temperature fluctuation arising from these rapid and regular energising and de-energising cycles brings its own challenges,” he says. “In particular, it causes more gases to be emitted within the transformer tank, which leads to a variety of problems.”

The cast resin material used in Trafo’s dry-type transformers meets the specifications of the International Electrotechnical Commission (IEC) for fire class F1. The units therefore present minimal fire risk, allowing them to be used indoors safely, and without environmental protection like bund walls for potential oil spills.

Claassen says dry-type distribution transformers are fast becoming a more suitable alternative to oil transformers, especially in the distribution power range between 50 kVA size and 10 MVA, although Trafo Power Solutions is able to supply dry type transformers up to a power rating of 25MVA