575 / 2017-05-15 10:50:56

Interruption Characteristics and Reignition Condition of Direct-Current Forced Current Zero

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会场 > DC Switching Technologies

The transient interruption characteristics and reignition conditions of direct-current (DC) forced current zero for vacuum interrupters in 270 V power-supply systems are discussed. Three stages are identified in forced interruption: DC arcing stage, current commutation stage, and voltage recovery stage. During the current commutation stage, the reverse peak current coefficient k, which is a key design factor, is used to calculate the rate of current at zero crossing (di/dt). MATLAB/Simulink simulation models are established to obtain the transient characteristics influenced by the forced commutation branch parameters and the coefficient k. Properly reducing the value of k could reduce the slope of di/dt and lead to better voltage characteristics. Interruption experiments are carried out using the spiral-type contact with diameter of 40 mm and material of CuW80. As the result, the breaking capacitor of vacuum breaker is lower and the value of di/dt is higher with the raise of the forced commutation frequency.