Transformers of conventional distribution are manufactured in powers from 5 kVA to 167 kVA single-phase and from 15 kVA to 500 kVA three-phase, complying with the NTC, ANSI, IEC standards or customer´s specifications.
The single-phase transformers can have one or two bushings in the high voltage to be connected in E1GrdY / E or E / E1GrdY systems respectively, where E is the phase-neutral voltage and E1 is the voltage between phases. At low voltage there are 2E / E or E / 2E configurations, the latter are generally used to form three-phase banks.
The three-phase transformers configuration is made according to the connection requested by the standard or by the client, being the most used Dyn5 and Yyn0.
Conventional distribution transformers are commonly used for residential service loads and occasionally for both commercial and industrial light loads.
This type of transformer does not contain any protection accessory, therefore the lightning rods and protections against over-voltage and over-load must be supplied by the buyer.