IS 4201 : 1983 Application Guide for Current Transformer

1 Scope

1.1 This guide covers application of current transformers foruse with both electrical measuring instruments and meters(measuring current transformers) and electrical protective devicesin non-balanced protected equipment, for example, for the operationof overcurrent devices both of the non-directional and directionaltypes and for the operation of earth fault devices with time-lagcharacteristics (protective current transformer).

1.1.1 Reference has been made to the use of current transformersfor the dual purpose of measurement and protection and also for theoperation of those protective devices which are more preciselydependent upon the magnitude and phase relationship of voltage andcurrent, or upon the balance of the current.