Apart from considering the type of transformer you are about to buy, you also need to consider other technical factors like:
- Proper winding material
For windings, Surplec substation transformer always use aluminum or copper. The former units are cheaper and the most cost effective. Copper wound transformers are small in size as copper is a better conductor and it makes the coil stronger. When it comes to choosing between the two, consult a manufacturer who can help you evaluate the best and also some expertise to work with the material that is best suited to your needs.
- Low-loss core material
Core choice is also a factor to consider and core losses must always be determined accurately. Losses that happen because of hysteresis and eddy currents. The magnetic steel of high quality must be used so that these hysteresis losses are brought down, and laminated cores are selected to bring down the eddy current losses.
- Shielding the transformer from extreme conditions
Make sure that the transformer core, coil, accessories and leads are properly protected, particularly when exposed in extreme conditions. Liquid filled transformers must always be kept sealed, automatically protecting the internal parts. Consider stainless steel tanks for highly corrosive cases. When it comes to protecting dry type transformers from extreme environments, consider using cast coil, vacuum pressure encapsulated with a silicone varnish. Unless the dry type transformers are totally sealed, the core or coil and lead assembly should be cleaned on a timely basis, even when the conditions are not extreme, to keep the dust and other contaminant accumulation over time.
- Insulators
Dry type transformers use insulators that are made of fiber glass reinforced polyester molding parts. These insulators are at a rating of 15kV and are meant to be used indoors or within a moisture proof enclosure. Liquid filled transformers use porcelain insulators where the ratings exceed 500kV. Porcelain insulators are track proof, meant to be used outdoors and can be easily cleaned. High voltage porcelain insulators consist of oil impregnated paper insulation that serves as capacitive voltage dividers to deliver uniform voltage gradients.
- Voltage taps
Know that no matter how well you have maintained the equipment, the secondary voltage is subject to change if the incoming voltage changes. When transformers are plugged in to the utility system, when the utility operations change or new loads are plugged, the incoming voltage may change. To compensate with the same, transformers are manufactured with LTCs or NLTCs.
