The transformer is the backbone that keeps operations running. Conventional mining transformers containing mineral oil have traditionally been hardy, but recent technical development has proven a higher safety and environmental benefit. Australian Mining speaks with Exnovo about safer and greener transformers.
CAHORS’ Green, Safe, Maintenance free or GSM transformers have passed all performance tests with regards to site safety, while saving valuable space on site.
The GSM transformers are Factory Mutual (FM) Approved, passing vigorous scientific research and testing to ensure the product meets the highest safety protocol.
As the name suggests, CAHORS’ GSM transformers are more sustainable than their traditional counterparts, using ester fluid, making for safer sites and less maintenance, costing mining companies less in unplanned downtime.
Exnovo distributes CAHORS products in Australia and positions itself between the company and the client to understand industry needs and recommend the best solution for operations.
As Exnovo managing director David Ong explains, the company has in-depth understanding of CAHORS’ products, the FM Approved standards and how they apply to Australian transformer standards.
“Our role in this partnership is to understand and recommend the right product for every scenario so we can create a solution that is both economic and fit for purpose,” Ong tells Australian Mining.
Total cost of Risk
According to a recent presentation by FM Global, over the last 10 years the total loss is over $US900 million ($1.29 billion) due to issues with transformers, with this equating to an annual average loss cost of more than $US90 million.
Transitioning to GSM transformers can greatly reduce insurance costs. In a case study by FM Global, the total estimated loss due to transformer fire, was lowered from $US200 million to $US100,000 by replacing an existing transformer with FM approved equipment.
Lowering the risk of transformer fires on mine sites not only vastly improves safety and productivity, but also capital, as it can take weeks if not months to replace one transformer if damaged, according to Ong.
Benefit of reduced clearance
FM Approved transformers have been tested against high energy faults that cause potential explosive and fire incidents, which means that the transformer unit can be placed next to a building or switch room with distance requirements of only 0.9 metres.
Without this certification, a 1200 litre oil-filled transformer must be placed 7.5 metres away from any combustible surfaces. building, meaning operations with limited space would benefit more from FM Approved transformers as they have a smaller footprint.
The other advantage of using FM Approved transformers is that there are no special construction or fire protection requirements required when installing them, meaning less civil works and a smaller environmental footprint.
FM Approval testing and certification
Having been tested against the harshest of conditions, CAHORS’ GSM transformers provide one of the safest solutions on the market.
“Every type of these transformers is tested against strict criteria and placed into fault event for destructive testing,” Ong explains.
“There are certain criteria they must pass, such – must self-extinguish in case of a failure and the tank body cannot deform after a fault event.
“In one of the criteria, the test evaluates the pressure withstand capability of the transformer.
Conventional transformers withstand only 20 kilopascals whereas FM Approved transformer tanks must withstand 105 kilopascals.”
Rapid pressure relief is the most important factor of avoiding transformer explosion. Rapid pressure relief requirements for conventional transformers are 22 standard cubic feet per minute, while FM Approved transformers are 700 standard cubic feet per minute, for a 1500kVA transformer.
Transformer fluids and environment
The fluid in a transformer serves two main purpose. Firstly, it is an insulator of electricity between live parts. Secondly, it conducts the heat away from the cores and windings to the radiator fans
“The natural ester fluid is not classified as a hydrocarbon (oil),” Ong says. “It is biodegradable and carbon neutral, produced from soybean oil.
The natural ester fluid is environmentally friendly, with 98 per cent of its body biodegrading within 28 days and the remaining 2 per cent within two months, unlike the traditional mineral oil which has a breakdown rate of around 10 per cent in its entire lifetime.
As there are only a few companies making FM Approved natural ester fluid, it can be more expensive option than conventional oils, but according to Ong, it is worth it.
“There is a huge shift into natural ester fluids,” he says. “Despite the fact they have slightly higher initial costs they are much more environmentally friendly compared with mineral oils.
“Mineral oil has a flash point of 160, whereas natural ester fluids have a flash point of 315.”
With the benefits of FM Approved transformers ranging from capital, environmental, performance and lowering risk, Exnovo is bringing a local Australian perspective to the French CAHORS transformers.
This feature also appears in the August edition of Australian Mining.