Tag Archives: Trafo Power Solutions

Trafo helps power up DRC copper-zinc mine expansion

Base metals, Mine operation news, Mineral project development, Mining equipment, Mining services, Power supply for mines, , ,

Trafo Power Solutions says it is supplying three mini-substations and two transformers to a copper-zinc mine in the Democratic Republic of the Congo as part of an expansion at the operation.

David Claassen, Managing Director of Trafo Power Solutions, says the pressure was on from early in the planning stages to ensure this critical equipment would be available on time – to facilitate the continued mine expansion. From the date of the contract award, the company will deliver the units to the mine site within just four months – despite most of South African industry having taken an annual December break.

“We have conducted projects previously with the end client and the engineering, procurement and construction (EPC) contractor, so have a good understanding of their requirements,” Claassen explains. “This experience – combined with our history in the DRC and in the mining sector – gave us the edge in expediting the whole process.”

The order was for two 2,000 kVA transformers to step down the electricity supply from 6.6 kV to 550 V, as well as three dry-type miniature substations. Two of the mini-substations are rated 315 kVA and 6.6 kV to 400 V, while the third is a 630 kVA unit which also steps down from 6.6 kV to 400 V.

“This equipment is an important part of the mine’s electrical infrastructure upgrade,” Claassen says. “Of particular interest were the dry-type mini-substations, which were quite unique in certain respects.”

As a specialist in dry-type transformer applications, Trafo Power Solutions designed the mini-substations in an IP54 configuration – ensuring that the units are completely sealed from dust and water. This level of insulation usually requires a forced air solution to ensure adequate air movement for cooling.

“For this application, the requirement was for natural air cooling – so the installation would not include external fans and related control instrumentation,” Claassen says. “This option enhances simplicity and further reduces any chance of ancillary equipment needing attention.”

The design of the enclosure and the transformer therefore took account of this configuration, allowing enough natural cooling despite the high ambient day time temperatures in the region. Another demanding aspect of the contract was that the two 2,000 kVA transformers are to replace units in the mine’s existing substation. This required innovative design to ensure that the new equipment fits into the available space.

“Our replacement units have a higher power rating than the ones they will replace, so the design was customised to ensure the mine does not have to re-engineer the space,” Claassen says. “This highlights our flexibility in designing solutions to optimise ease of installation.”

Delivery to site will take place after a factory acceptance test (FAT) has been conducted. While the functional commissioning of the units is not part of Trafo Power Solutions’ scope of supply on this contract, the company offers a standard commissioning and assistance service. This is part of its value-add to any of its contracts.

“The rapid pace of this project indicates a growing trend not only in mining but in other sectors, towards fast tracking new developments and expansions,” Claassen notes. “Clients are expecting their supply partners to deliver on shorter timelines, so one of our key strategies is to learn from each project and apply those lessons going forward.”

This keeps Trafo Power Solutions at the forefront of efficient project execution, focusing actively on quality and communication. This ensures first-time accuracy and customised designs, so that no time is lost by unnecessarily revisiting aspects of the project as it progresses.

“Our non-corporate approach means that we can take decisions and act quickly on matters commercial and technical,” Claassen says. “Our proven skill is in achieving these goals without compromising on quality.”

Trafo Power Solutions bolsters dry-type transformer contingent at Alphamin’s Bisie mine

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Five years since Trafo Power Solutions supplied Alphamin’s Bisie tin mine in the Democratic Republic of Congo with two dry-type transformers, the mining company has now ordered another three of these modular substations equipped with dry-type transformers to keep up with the mine’s expansion.

“This latest order is testament to the operational performance of our dry-type transformers at Bisie mine over the past five years,” David Claassen, Managing Director of Trafo Power Solutions, said. “There were numerous challenges that our design had to accommodate, not least of which is a very arduous section of road in the journey to the mine.”

The mine’s location in the Walikale Territory of DRC is remote, being about 180 km northwest of Goma. Like the initial order, the three 3,000 kVA, 400 V/11 kV substations will be supplied in standard 6 m containers to facilitate transportation. However, specialised steel bracing is required – to withstand the challenging road conditions, especially over the last part the journey.

“These conditions make the road almost impassable by any vehicle other than a six-wheeled Unimog,” Claassen says. “There is intense vibration and tilting of the cargo on these trailers, so our design and bracing is done with this in mind.”

He notes that the mine had considerable foresight in specifying the first dry-type transformers, especially given the relative novelty of this option at the time. At that stage, it tended to be standard practice to use oil-filled transformers for this type of application. Apart from the logistics, the substation solution also had to withstand the equatorial climate and frequent lightning strikes.

“The region where the mine is located is ranked in the top five most vulnerable to lightning strikes, so there is a high risk of damage to equipment related to electrical surge,” Claassen says. “We therefore designed robust surge protection solutions on both the medium voltage and low voltage sides of the substations, and for the transformers.”

Given the warm climate, Trafo Power Solutions designed a fully redundant N+2 cooling system for the transformers; this means that each transformer is cooled by two fans, with another two fans on standby. Among the advantages of dry-type transformers in this climate is that the MV winding is completely cast in resin, so is highly resistant to humidity.

Trafo Power Solutions overcomes design challenges to fulfil UG gold mine order

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Dry-type transformer specialist Trafo Power Solutions has recently been given a ‘hill to climb’ in terms of design and logistics with a request to supply three units to an underground gold mine in South Africa.

The mine required the transformers to operate in the usual demanding conditions of dust, moisture and heat, according to Trafo Power Solutions Managing Director, David Claassen. However, there were a range of other challenges – not least the weight and height restrictions of a deep mine. While two of the transformers are relatively small – 250 kVA and 630 kVA – the third is a substantial 3,150 kVA.

“The transformers are to operate at about 1 km below surface, and will have to be transported through both an incline shaft and vertical shaft,” Claassen says. “Especially with the larger unit, we had to work very closely with our Italian technology partner TMC to reach a design that could be moved within these constraints.”

Trafo Power Solutions also designed the enclosures locally in a manner that would allow them to be transported in manageable components before being re-assembled underground. The enclosure design had to ensure that, while dust and moisture were kept out, there was still enough air circulation to cool the unit. The dry-type transformers will be supplying loads for a refrigeration plant.

“Trafo Power Solutions conducted the complete designs, which were then verified and vetted by TMC,” Claassen says. “This quality control is central to our approach in ensuring fit-for-purpose solutions.”

He emphasised that the design and manufacture of the units was carried out according to schedule and they are on track to be supplied within the customer’s required timeframes.

“On-time supply is an increasingly important aspect of success for mining companies,” he says. “Mines’ capital expenditure is planned according to the expected returns on any project, and supplier delays can undermine these forecasts.”

Trafo Power Solutions also designed the specialised skid bases for the transformers, to facilitate moving the units to their operating destination. These accommodate the considerable weight of the units, particularly the 10-t mass of the large 3,150 kVA unit.

Delivery of the transformers is expected to take place by the end of the year, with Trafo Power Solutions supervising the installation and commissioning process.

Trafo Power Solutions helps sustain iron ore exports at Saldanha Bay

Bulk handling, Mineral project development, Mining equipment, Mining project news, Mining services, Steel and iron ore, , , , , ,

Trafo Power Solutions recently supplied specialised transformers for the Tippler 3 project at the iron ore load-out station at the port of Saldanha Bay, in South Africa, as part of an upgrade Transnet is currently conducting at the facility.

The construction of a third tippler at the Saldanha Bay port is to sustain iron ore export volumes of 60 Mt/y when the existing tipplers are refurbished in the future. It will integrate with the rail system bringing ore via the 860 km line from mines in the Northern Cape of the country.

Key aspects of the new infrastructure comprise the 285 t tippler itself, a loading vault below ground and a conveyor tunnel. New buildings, service roads, bridges, railway lines, conveyors, lighting and bulk electrical supply infrastructure are also part of Transnet’s upgrade project, according to Trafo.

Factory-acceptance testing of the dry-type transformers were completed in December 2019, according to Trafo Power Solutions Managing Director, David Claassen, with delivery to site taking place in February.

Trafo Power Solutions’ contract was for the design, supply and commissioning of five dry-type transformers. There are two 1,000 kVA units and a 3,150 kVA unit, both stepping down from 11 kV to 400 V, the company said. The other two units are 3,500 kVA and 4,500 kVA capacity, respectively, taking 11 kV to 3.3 kV.

To resist the corrosive sea air, all the transformer enclosures were manufactured from the 3CR12 grade of stainless steel, according to Trafo. The enclosures are also IP33-rated to ensure a high level of ingress protection against moisture and dust.

“The enclosure design also incorporates cable boxes and Type C totally enclosed plug-in bushings for the terminations,” Claassen says. “This provides a boot covering, which is touch-potential safe, and also provides for efficient plug-and-play installation.”

This is a significant improvement on the regular lug and bolt copper connection, which would just be shrouded by a heat-shrunk material, according to the company. The special terminations also facilitate easier maintenance or removal.

“The units will provide the medium-voltage supply for the Tippler 3 project and its associated infrastructure, including equipment like conveyors,” he says. “All the transformers will be supplying non-linear load to a certain extent, so they have been designed with a K-factor of four.”

The K-factor is a measure of a transformer’s ability to withstand the heating effects of non-sinusoidal harmonic currents created by electronic equipment, Trafo explained. “The higher the K-factor, the greater the harmonic heating effects,” the company said.

As dry-type transformers are cooled without the use of oil, these units will receive forced ventilation when a pre-set temperature is reached. This ventilation is provided from a row of fans which Trafo designed to be bolted below the location of the transformers.

Designed locally in South Africa by Trafo Power Solutions, these dry-type transformers are manufactured in Italy by strategic partners TMC Transformers, which focus on cast resin transformer technology. All products are routinely factory-tested according to IEC standards, but type-testing and special testing can also be conducted, according to the company.

“The standard applicable to dry-type power transformers is IEC 60076-11,” Claassen says. “TMC’s advanced laboratory facilities allow us to conduct the full range of tests in-house, in accordance with what these standards and whatever other requirements are designated by the customer.”

At Saldanha, Trafo is also responsible for building auxiliary protection and control panels, which it locates remotely from the transformers. These include temperature control sensors that communicate with the port’s broader control and monitoring network.

Trafo devises mobile dry-type power solution for coal mine

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In a specialised application on a coal mine, Trafo Power Solutions has supplied a dry-type transformer mounted on a mobile skid.

David Claassen, Managing Director at Trafo Power Solutions, said: “The harsh environment of a coal mine required us to specially design a fit-for-purpose solution.

“The cast-resin dry-type transformer is ideal for the mobile arrangement as it is cooled without oil,” he explained. The absence of oil makes it a safer option in terms of fire hazards, especially on a coal mine.

It is also more environmentally-friendly, as there is no chance of an oil spill, according to the company. The 1,250 kVA dual-MV configuration supplied to this mine allows the unit to be linked up to either 11 kV or 6.6 kV supply.

“The unit was designed for a compact enclosure, while still allowing for sufficient air movement for cooling,” Claassen said. “We provided a unique solution of a cast-resin transformer with Class H insulation rating for both the medium voltage and the low voltage windings.”

This insulation standard ensures the transformer can withstand temperatures of up to 180°C, according to Trafo, with Claassen noting that the enclosure design had to accommodate these heat factors while also preventing the ingress of dust or water.

Special engineering was also applied to building a high level of mechanical rigidity into the transformer itself, as demanded by the regular relocation of the mobile skid. This movement means vibration and other forces must be borne by the equipment without affecting its performance.

Claassen emphasises that Trafo Power Solutions is experienced in providing dry-type transformers in a range of enclosed formats to suit customers’ needs. The inherent safety of these transformers also allows them to be installed in underground mining locations.

“We can provide various dry-type transformer enclosed solutions with a mobile skid, which is a versatile format for a range of mining applications,” he says.

Trafo Power Solution’s track record in cast-resin transformers is based on its local expertise and design capacity, combined with the high quality manufacture of the units by Italy-based TMC Transformers.

Trafo powers through at Mpumalanga coal mine

Coal technology, Environmental, Mining services, Power supply for mines, , , , ,

Trafo Power Solutions says it has recently completed a dry-type transformer contract as part of a significant upgrade at a coal mine, in Mpumalanga, South Africa.

This involved the design, supply and installation of two 200 kVA – 22 kV-400 V – dry-type transformers, according to Trafo Power Solutions Managing Director, David Claassen. Housed in specialised IP42-rated ingress protected enclosures, the units were specified by a design house on behalf of the end-customer, the dry-type transformer leader said.

“The contract demonstrated our application engineering capability and our experience in co-ordinating our solution within a larger project,” Claassen said. “This included meeting detailed specifications, and ensuring that our design for the transformers and their enclosures matched the requirements and constraints of the site.”

Trafo Power Solutions also equipped the units with the necessary earth fault protection and surge protection, as well as vibration pads, it said.

“Dry-type transformers are well suited for the coal mining environment, with its hazardous areas and its regulations to mitigate fire risk,” Claassen says. “The dry-type technology uses air to cool the transformers, doing away with the need to use oil as a coolant.”

Claassen emphasised that the absence of oil has advantages for safety, as the oil ignition potential is removed. The units can also be protected against fine airborne coal dust. An added environmental advantage is the lack of oil leaks contaminating the ground or water, too.

Trafo transforms fortunes at KwaZulu-Natal mining operation

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Trafo Power Solutions recently came to the aid of a mining company in KwaZulu-Natal, South, Africa, suffering from a transformer failure.

Following the incident, dry-type transformer specialist, Trafo, designed, built and delivered a non-standard cast-resin replacement for the company – in just five weeks.

David Claassen, Managing Director of Trafo Power Solutions, said: “Once the situation with the old transformer was assessed, it was decided it would be more economical to replace the unit than to embark on major repairs.

“We were able to accommodate the customer’s specifications in our replacement design, and have the unit manufactured by our European partners (the TMC transformers facility, in Italy, pictured) in just four weeks. After that, it took just a week to fly in the transformer and deliver it to the customer.”

Claassen said it is not uncommon for transformer replacements of this scale to take anything from 12 to 14 weeks, with Trafo’s rapid turnaround time highly valued by the customer.

The mine required a 1,600 kVA dry-type DYN11 transformer that stepped 33 kV down to 550 V, with a non-standard tap setting arrangement of seven tap settings instead of the normal five.

Dry-type transformers – also called cast-resin transformers – are growing in popularity as users recognise their safety benefits, as well as their economy and flexibility of placement, according to Trafo. To meet this demand, Trafo works in close collaboration with established and well-resourced manufacturing partners in Europe to source tailored designs that meet customers’ exacting specifications, it said. This comes on top of ongoing after-sales service.

Trafo transforming mobile process plant operations at Sierra Leone mine

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Trafo Power Solutions says four of its dry-type transformers have been proving their worth on a mobile process plant at a Sierra Leone mine since last year.

The dry-type transformers have been so successful in powering the process plant that the customer has ordered six more for its recent phase two upgrade.

Trafo Power Solutions Managing Director, David Claassen, said: “The mine required a solution that would withstand the demanding conditions of a mobile process plant needing to be moved frequently over rugged mining terrain – as often as once a month. They could not risk using a conventional oil-cooled transformer as they needed to avoid any risk of fire or oil leaks. They also needed a product that would require little to no maintenance.”

The second contract was a repeat of the initial order and comprises two 800 kVA units, one 1,600 kVA unit and one 2,000 kVA unit as well as a further two transformers – 1,600 kVA and 800 kVA – which will replace two existing oil filled transformers.

The company said: “Demonstrating its flexibility in meeting specific customer requirements, Trafo Power Solutions designed the solution to cater for the mine’s unusual voltage levels of 13.2 kV/480 V at 60 Hz.”

The transformers are installed in a 6-m-long E-house on the mobile process plant, which is moved around the site on skids as required by the mining plan.

“We were able to customise the design of the transformers for the customer’s specific application,” Claassen said.

“This required a special reinforced frame to accommodate the constant vibration of the working plant, as well as the bumping motion when the skid-mounted plant is dragged to a new location. The design also included anti-vibration damping on the transformer feet, to further mitigate the impact of the vibration.”

The entry of Trafo Power Solutions dry-type transformers to the African market coincides with a growth in the use of modularised sub-stations, according to the company. “Due to the absence of oil as a coolant in dry-type transformers, they are suitable to be used in confined spaces without any of the conventional infrastructure usually necessary to protect the environment from possible oil spillage,” Trafo said.

Claassen said: “Modular and mobile sub-stations are growing in popularity for applications all around Africa, as they can be fully prepared under workshop conditions, reducing the work required on site.

“In terms of the installation of the transformer, for instance, we ensure that the temperature control relays are fully programmed and tested in South Africa, along with the fan system – making it ready for action on site.”

In the unlikely event of any further attention being necessary, Trafo Power Solutions can mobilise service support to any of the sites it supplies, it said.