Circuit Breaker Trip Diagnosis Using Temperature and Magnetic Triggers

The patent introduces an intermediary computational model that relates bimetallic strip deformation to current characteristics without requiring direct measurement of the current itself. The model uses the equation d²x/dt² + α(dx/dt) + βx = γI², where the bimetallic strip displacement x and its derivatives serve as intermediaries to infer current intensity and duration, avoiding sensor saturation issues while maintaining diagnostic accuracy.

The patent replaces the electrical measurement system (current sensors) with a mechanical measurement system (bimetallic strip displacement sensors). By measuring the mechanical displacement of the bimetallic strip and its derivatives, the system infers electrical current characteristics without directly measuring the current, thereby avoiding sensor saturation at high currents.

The patent implements a feedback mechanism where the actual bimetallic strip displacement is measured and fed back into the computational model. By continuously monitoring the displacement and its derivatives, the system adjusts its diagnosis to account for real operating conditions, ensuring accurate differentiation between magnetic and thermal tripping regardless of environmental variations from nominal conditions.

The patent performs preliminary characterization of the bimetallic strip behavior by establishing the computational model parameters (α, β, γ) before actual operation. This preliminary action creates a reference framework that accounts for the specific bimetallic strip characteristics, enabling accurate diagnosis under varying real-world conditions by comparing actual measurements against the pre-established model.

The patent applies dynamics by measuring not only the static displacement of the bimetallic strip but also its first derivative (velocity) and second derivative (acceleration). This dynamic measurement approach captures the transient behavior characteristics that differ between magnetic and thermal tripping, enabling reliable differentiation even when both mechanisms operate rapidly.

The patent establishes preliminary thresholds and behavioral patterns for magnetic versus thermal tripping responses before actual operation. By pre-characterizing the expected dynamic response patterns (displacement, velocity, acceleration profiles) for each tripping mechanism, the system can rapidly and reliably differentiate between them during actual switching events.