What principle enables an oil switch to effectively break an arc?

The principle that enables an oil switch to effectively break an arc is based on the insulating ability of oil. In an oil switch, the presence of oil serves a crucial function in the interruption of electrical arcs that may occur during the switching process. When the switch is opened, an electric arc can form between the contacts due to the high voltage. The oil surrounding these contacts has excellent dielectric properties, which means it can effectively insulate and suppress the arc.

The insulating ability of oil allows it to cool the arc and absorb the energy generated, preventing the arc from sustaining itself. As the arc is cooled and contained in the oil, it eventually extinguishes, allowing the switch to interrupt the current flow safely. This makes oil switches particularly effective in managing high voltage and providing reliable operation in power systems.

The other options do not specifically address the mechanism of arc suppression in oil switches. While features like the length of switch contacts or the presence of a current transformer may have different roles in the overall performance of electrical systems, they are not directly responsible for the breaking of an arc in the context of an oil switch.