ABSTRACT
Instrument transformers are generally connected into a power circuit through an auxiliary connection for measuring the circuit’s current and voltage, besides being used for its control and protection. They are widely used for several applications in switchgears, control gear assembly and switch yards. Their basic purpose is to transform the high voltage and current levels in a power system to a relatively lower value so that the voltage and current levels can be measured comfortably by conventional voltmeters and ammeters. Chapter 4 deals with the various aspects of instrument transformers in detail. Basic connections and complex vector diagrams and design aspects are discussed to strengthen the knowledge base of the professionals dealing in instrument transformers. Ratio and phase angle errors are also discussed in detail with the help of derivations. A few solved examples are also presented in order to give better insight about problem solving.
