Dry-type transformers for modular substations
October 2017, Electrical Power & Protection
The introduction of Trafo dry-type transformers to the African market comes just at the time that end-users, in a number of industry sectors, embrace the growing trend towards modularised substations.
“Due to the benefits and the cost-effectiveness of modular substations, dry-type transformers are becoming more popular,” says David Claassen, managing director of Trafo Power Solutions. “The Trafo dry-type transformer is ideally suited to this application as it can be mounted inside a modular structure, which cannot be done with a traditional oil-filled transformer.”
Claassen highlights that safety is the prime concern in the design and construction of substations. Due to its design and the absence of oil as a coolant, the dry-type transformer is simple and safe, allowing extensive test work to be conducted with the modular unit prior to the full solution being sent to site. This in turn reduces the costs associated with site installation, assembly work and commissioning.
Including the dry-type transformer, inside of the modularised substation has the cost-saving benefit of eliminating the need for the civil infrastructure that is needed for oil-filled transformers having to be located outside of the substation for safety reasons. This type of civil work includes foundations and a plinth on which the unit can stand, as well as special purpose bunding walls to contain oil leaks This not only increases the cost of the installation, but lengthens the time frame in which the substation can become operational.
Sourcing dry-type transformers from industry pioneer and leader, Hammond Power Solutions (HPS), gives Trafo Power Solutions the flexibility to meet specific and unusual requirements from customers.
“In a recent E-house application that Trafo Power Solutions provided for a mining project in Sierra Leone, a 2000 kVA dry-type transformer was specified as part of the mobile mining unit,” says Claassen.
“We supplied four dry-type transformers in total: two 800 kVA units, one 1600 kVA unit and one 2000 kVA unit. The unusual voltage levels that were required – 13,2 kV/480 V at 60 Hz – demonstrated our flexibility in meeting specific customer requirements.”
The focus at Trafo Power Solutions is all about finding a solution for the customer, he says, outlining other elements that made this project a success. The scope of supply included temperature control units along with cooling fans. These will be automatically switched on in the event of a failure of the master cooling system and will ensure minimum downtime while the system is repaired.
Another useful function of the cooling fans is to allow the transformer to increase its power output in the event of an overload situation. Surge arrestors for each transformer were supplied as an added protection against the risk of an unstable voltage supply.
Claassen says that because these mobile mining units are transported to site and, in some instances, moved from area to area within a mine, it is critical that the structural integrity meets this type of arduous application. “Trafo transformers are engineered to withstand harsh vibration and are robust in construction, however, where required, it is possible to reinforce the rigidity further.
“We find solutions and offer flexibility through understanding the customer’s specific needs and applying an agile approach,” he says. “Traditionally, this type of equipment would be on the critical path for a project, but we managed to have them manufactured within a five-week window, which allowed for a rapid delivery to the customer.”
Claassen emphasises the high energy efficiency of these transformers, leading not only to lower energy consumption but also to less energy loss through heat; this means less is demanded from the ventilation and cooling systems on these units.
An extra benefit, especially for remote sites such as mines in rural areas of Africa, is that a dry-type transformer is virtually maintenance-free, significantly lowering its operating cost.
For more information contact Trafo Power Solutions, +27 (0)11 325 4007, firstname.lastname@example.org, www.trafo.co.za