Arc Behavior Analysis and Fractional Decomposition of Voltage Rise of High-Current Air Arc Affected by Deion Plates

Typical molded-case circuit breakers have deion plates to limit and interrupt the fault currents by increasing arc voltage. The rise in the arc voltage by deion plates is considered to result from the following two phenomena: (1) the elongation of an arc length and (2) the generation of an electrode fall voltage of the arc split up between deion plates. In order to clarify the contribution of deion plates in molded-case circuit breakers, an arc voltage was measured for different arrangement of deion plates. In this experiment, optical observation of the arc behavior was also made to find out the arc length and the number of the deion plates dividing the arc. By using the expression of the arc voltage derived in terms of the arc length, the number of deion plates dividing the arc and the arc current, the rise in the arc voltage was successfully decomposed into arc column voltage and electrode fall voltages near the electrodes and the deion plates.