Inductive voltage transformers are low power transformers which operate at practicaly no load. They isolate the primary – side rated voltage from the connected instruments and protection circuits and convert the primary voltage into a measurable secondary voltage which is ture in magnitude and phase. Voltage transformers have only one secondary winding.If necassary,single – bushing transformers are provided with a winding for earth – fault detection to the secondary winding i.e.the instrument winding.