Patent ID: 7030602
Filing Date: 2006-04-18
Classification: G01R

Abstract:
1. A method for testing of a current transformer having a primary winding and a secondary winding without a current circulating through the primary winding comprising: determining an operating burden for the current transformer; determining a resistance value of the secondary winding of the current transformer; determining an input voltage for the current transformer based on the operating burden and the resistance value of the secondary winding; injecting the input voltage to a secondary winding of the current transformer; determining an excitation current flowing through the secondary winding of the current transformer while the input voltage is being injected into the secondary winding of the current transformer; determining an excitation wattage across the secondary winding of the current transformer while the input voltage is being injected into the secondary winding of the current transformer; and determining at least one of a ratio error and a phase angle associated with the current transformer based on the excitation current and the excitation wattage; wherein the current transformer remains in a position adjacent to an electrical apparatus.