Testing of current transformers

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.