186 / 2024-04-15 19:43:25

Experimental Determination of Black-Box Model Parameters for Free Burning Arcs in Air and CO2

SF6 alternatives,Black-Box Arc Models,eco-friendly switchgear

To investigate the suitability of SF6 alternative arc-quenching gases, free burning arc experiments are performed in air and CO2 at pressures from 1 to 5 bar and an arc length of 45 mm. Currents are produced with the flexible pulsed current source, a high-voltage, modular buck converter, enabling the determination of conductance-dependent black-box arc parameters for currents ranging from 100 A to 5000 A. Arc parameter fitting is performed with an optimization method, enabling inherent validation of the model-predicted arc voltage with measurements. Each of the 110 performed arc experiments yields dozens of arc parameter fits, resulting in thousands of arc parameter fits in total. This allows a detailed and model-function independent analysis of the arc properties for varying gas type, gas pressure and current amplitude. It is shown that arc time parameters of CO2 are much lower than those of air for similar arc conductance and same pressure, underlining the better suitability of CO2 for current interruption and thus for replacing SF6 in switching devices.