Speaker
Description
Development of vacuum circuit breakers for medium- and high-voltage applications leads to continuous basic research in the field of vacuum arcs. The diagnostics of the electrode surface plays an important role for understanding of basic phenomena and parameter optimization for corresponding applications since the electrodes provide the material for the arc plasma. It is well known that the anode activity has a distinct impact on contact erosion and interrupting capability, because it leads to injection of atomic vapour into the inter-electrode gap causing the lowering of dielectric strength. Therefore, the knowledge about spatiotemporal distribution of the anode surface temperature is of high interest for qualification of electrode materials.
The contribution presents the results for temperature distribution on the anode surface made of CuCr alloy obtained by optical measurements. Several methods, which are applicable during the arcing and after the current interruption, have been applied for quantitative characterisation: NIR spectroscopy, pyrometry and high-speed camera techniques enhanced by narrow-band filters. Advantages and drawbacks of each method will be discussed. The arc was ignited by contact separation during the current flow. The driving current pulse was supplied by a high-current generator that produces an AC waveform at 50 Hz at several kA magnitude. The temporal evolution of the surface temperature for different anode modes will be presented and discussed.
