Ablation-assisted current interruption in medium voltage switchgear – Development and prospect

Abstract

SF 6 -gas is widely used in medium and high voltage switchgear today because of its excellent insulation and current interruption capabilities. However, due to its high global warming potential, there is a political pressure to replace it wherever possible, resulting in a need for new solutions in the design of compact lowcost switchgear. An evident response is to review and further develop the technologies that were promising before the entry of SF 6 . One of these was the application of gas-emitting insulation materials, in a process of ablation. This paper reviews the range of commercial breaker designs that have taken advantage of ablation in the interruption process from the 1930s until today. The main designs and developments are outlined and some important parameters are explained, such as the steady state ablation-dominated arc, arc quenching and dielectric recovery in the presence of ablation material. The ratings of the mentioned products, as well as more recent experiments, indicate that there is a design limit for simple ablation-assisted breakers at around 20 kV, but the reasons for the apparent limit are not thoroughly studied or explained. Reviving the knowledge of ablation breakers, and combining this with new knowledge and new tools could prove valuable to the development of SF 6 -free MV switchgear.

Consistent Calculation from Particle Composition to Arc Simulation for Arc Ignition Process in Polymer Ablated Arcs

“…Controlling ablation from solid materials in nozzles can be of great interest and key role, as is searching for alternative gas with high arc-extinguishing capabilities. In general, polymer ablation is expected to have effects such as local pressure rise and cooling by blowing ablated polymer vapor onto the arc plasma [3,4]. As a result, the characteristics of the arc plasma are dominated by the entrained polymer vapor.…”

Numerical prediction on arc characteristics for various polymer materials during polymer‐ablated arc ignition process

“…Polymer ablation is used to improve interrupting performance of low-voltage circuit breakers and switches operated in the air under atmospheric pressure. [1][2][3][4] Ablation of polymer materials and evaporation of electrodes is initiated when high-temperature arc plasma contacts arcextinction chamber and electrodes. In so doing, one can expect a number of effects such as a complex flow field and contraction of arc plasma due to high-speed jet, cooling of arc plasma due to decomposition of molecular gas, pressure rise inside the arc-extinction chamber, 5,6 and so forth.…”

“…Polymer ablation is used to improve interrupting performance of low‐voltage circuit breakers and switches operated in the air under atmospheric pressure 1–4 . Ablation of polymer materials and evaporation of electrodes is initiated when high‐temperature arc plasma contacts arc‐extinction chamber and electrodes.…”

Self-Blast Current Interruption and Adaption to Medium-Voltage Load Current Switching

“…By studying the past products and published research, it is clear that the presence of certain ablation materials can improve current interruption [1], [2], but a comprehensive understanding of the processes leading to a successful interruption in these MV switches does not exist. On the other hand, extensive research has been carried out for low [2], [3] and high voltage circuit breakers [4], [5], and much of this can be relevant for First submitted on September 10, 2018.…”