Harmonic currents generated by nonlinear loods can cause problems in the power system. Transformer are particularly vulnerable to overheating and premature failure.

A Scott-T transformer (also called a Scott connection) is a type of circuit used to derive two phase (2-φ) current from a three phase (3-φ) source or vice-versa. The Scott connection evenly distributes a balanced load between the phases of the source.

A buck–boost transformer is a type of auto transformer used to make small adjustments to the voltage applied to alternating current equipment. It was developed to supply voltages for two main categories; the first of which is when the local power is consistently not high or low enough to correctly and safely run the equipment at its rated power load.