Electricity + Control April 2019

TRANSFORMERS + SUBSTATIONS

Ironing out voltage fluctuations

When a Gauteng-based pharmaceuticals manufacturing facility decided to upgrade its electrical systems, it discovered severe voltage fluctuations on the power line supplying the factory, which could reduce the life and performance of its equipment. Trafo Power Solutions solved this potential problem with an innovative and fast-track installation. Trafo Power Solutions Managing Director, David Claassen ex- plains, “In line with global best practice, the pharmaceutical com- pany had assessed its safety risks and decided to relocate its fac- tory’s substation. With its focus on safety and quality, the company also elected to switch to a dry-type transformer due to this technol- ogy’s high level of safety and low environmental risk.” Because oil is not used in the cooling systems of these cast-res- in transformers they are safe enough to be installed indoors and pose minimal environmental hazard as there is no risk of oil-spills. However, when the electrical consultants responsible for the new substation conducted their regular tests at the factory site, they discovered a concern regarding the power feed. Power meas- urements and data logging indicated that there were large voltage fluctuations on the power line coming into the factory. “We discussed possible remedies with the consultants and – after more analysis and conceptual design work – a decision was taken to include an automatic on-load tap-changer in our transform- er solution,” says Claassen. He explains that a standard transformer is usually fitted with fixed tappings; an arrangement that assumes a consistent supply of a specific voltage into the system. Dealing with voltage fluctu- ations under such conditions usually has to be done manually – a process that is time-consuming and costly in terms of operational disruptions caused by power having to be turned off and on quite often. “An automatic on-line tap-changer, by contrast, can adjust the tap settings itself, while there is load on the incoming line,” Claas-

sen says. “By installing nine different tap settings of 1,875% steps on our transformer, the nominal voltage supplied to the factory re- mained constant throughout a wide range of voltage fluctuations. This enhanced production uptime and minimised the risk of dam- age to the factory’s equipment.” There was significant time pressure on the delivery and instal- lation in this project. Trafo Power Solutions was able to ensure that the transformers and tap-changers were sourced, commissioned and handed over – complete with all the controls – within 10 weeks of the purchase order being presented.

Enquiries: David Claassen at Trafo Power Solutions. Tel. +27 (0)11 325 4007, or email: david@trafo.co.za

The dry-type transformer solution, including an automatic on-line tap chang- er with stepped settings to manage voltage fluctuations in the electricity supply, was fast tracked for this factory substation.

Electricity + Control

APRIL 2019

31