The tests of the current transformers must be made according to the standard NBR 6821 – Current transformer – Test method. The tests to be carried out on the transformers are as follows:
– Routine Tests: These tests confer the quality and uniformity of the workmanship and materials used in the manufacture of current transformers. The routine tests required by NBR 6856/81: 111949
– Induced voltage;
– Partial discharges;
– Insulation and capacitance power factor;
– Industrial frequency withstand voltage;
– Mechanical resistance to internal pressure.
– Type Tests: Type tests are made to show whether a particular type or type of transformer is capable of working satisfactorily under the specified conditions:
– Temperature elevation;
– All the tests explained above;
– Winding resistance;
– Atmospheric impulse withstand voltage;
– Maneuver impulse withstand voltage;
– Rated thermal current;
– Radio interference (Vn 145kV);
– Hot sealing.
– Summary Specification: The specification of a current transformer causes prior knowledge of the use of this equipment for measuring or protection service.