IEEE Guide for Field Testing of Relaying Current Transformers

A description is given of field-test methods that will ensure that the current transformers used as a source of relay input current are connected properly, are of marked ratio and polarity, and are in condition to perform as designed both initially and after a period of service. The standard covers safety considerations; current transformer types and construction and the effect of these on test methods; insulation resistance tests; ratio tests; polarity check; winding and lead resistance (internal resistance); excitation tests; burden measurements; and specialized situations.