How one “mystery trip” in a thermal power plant led to a new class of DC control relays. When a Control Box Trips “For No Reason” In 2003, a large thermal power plant ran into a problem no operations team wants to see: the local operation box on a high-voltage bay would trip seemingly at random . No breaker failure, no misoperation recorded—just nuisance trips from the control box, often when nearby bays were being operated. The unit was safe, but the operators were not: ev