OPEN CIRCUIT IN SECONDARY WINDING PROTECTION FOR CURRENT TRANSFORMERS

摘要

Apparatus for continuously protecting current transformers from hazardous voltages due to open circuit in a secondary winding, which comprises solid state non-linear elements with voltage dependent conductivity, connected in parallel to the secondary winding output terminal of said current transformer. The conducting voltage of said solid state non-linear elements is configured to be more than the maximal operating voltage of the secondary winding and less than a hazardous voltage. A normally-open thermo-bimetal switch is placed with good thermal contact on the solid state non-linear elements. The operating temperature (switching ON) of the thermo-bimetal switch is configured to be more than the maximal ambient temperature at the relevant location, and the resetting temperature (switching OFF) of the thermo-bimetal switch is configured to be less than the minimal ambient temperature.