<p>SF6-gas is widely used in medium and high voltage<br />switchgear today because of its excellent insulation and<br />current interruption capabilities. However, due to its<br />high global warming potential, there is a political<br />pressure to replace it wherever possible, resulting in a<br />need for new solutions in the design of compact lowcost<br />switchgear. An evident response is to review and<br />further develop the technologies that were promising<br />before the entry of SF6. One of these was the application<br />of gas-emitting insulation materials, in a process of<br />ablation.<br />This paper reviews the range of commercial breaker<br />designs that have taken advantage of ablation in the<br />interruption process from the 1930s until today. The<br />main designs and developments are outlined and some<br />important parameters are explained, such as the steady<br />state ablation-dominated arc, arc quenching and<br />dielectric recovery in the presence of ablation material.<br />The ratings of the mentioned products, as well as more<br />recent experiments, indicate that there is a design limit<br />for simple ablation-assisted breakers at around 20 kV,<br />but the reasons for the apparent limit are not thoroughly<br />studied or explained.<br />Reviving the knowledge of ablation breakers, and<br />combining this with new knowledge and new tools<br />could prove valuable to the development of SF6-free<br />MV switchgear.</p>
Experiments on Capacitive Current Interruption with Air-Break High Voltage Disconnectors
