Monitoring systems and methods for estimating thermal-mechanical fatigue in an electrical fuse

An electrical conductor temperature estimation system for evaluating thermal-mechanical fatigue comprising:

• an electrical fuse including a housing, first and second terminal elements, and a fuse element having a non-linear resistance when connected to an energized electrical power system;
• a controller receiving an ambient temperature input and operable to estimate an operating temperature of the fuse element in the energized electrical power system;
• and
• wherein the estimated operating temperature of the fuse element is estimated based on an addition of an estimated first temperature differential, an estimated second temperature differential, and the ambient temperature;
• wherein the estimated first temperature differential is an estimated temperature differential between a temperature of the fuse element and a temperature of an arc quenching medium surrounding the fuse element, the estimated first temperature differential based on the ambient temperature and a current flowing through the fuse element;
• and
• wherein the estimated second temperature differential is an estimated temperature differential between the temperature of the arc quenching medium and the ambient temperature, the estimated second temperature differential based on the ambient temperature and the current flowing through the fuse element.

A method of estimating a temperature of an electrical conductor in an electrical power system, the method comprising:

• providing an electrical conductor having a non-linear resistance when connected to an electrical power system;
• determining a resistance of the electrical conductor at successive periods of time;
• calculating a current flowing through the electrical conductor based on the determined resistance;
• receiving an ambient temperature input of the electrical conductor;
• and
• iteratively estimating at each period of time a temperature of the electrical conductor based on at least the ambient temperature input and the current flowing through the conductor.