Why Do High-voltage Disconnect Switches Not Exhibit Resistance?

High Voltage Disconnect Switch Operation must be performed when the circuit is unloaded. Disconnectors lack arc-extinguishing devices; their contacts are completely exposed to air. The air gap between the disconnecting contacts does not have the ability to generate or extinguish an arc when current is present or a fault current is present. Disconnecting under load will trigger an arc, potentially damaging the contacts or even causing a flashover. This is the fundamental difference between disconnectors and circuit breakers or other switchgear with anti-knock functions.

The moving mechanism and contacts of a disconnector are primarily designed to achieve contact and separation under static circuit conditions. Because it lacks an arc-extinguishing medium, damping mechanism, or energy absorption structure, there is no transient reaction force caused by current interruption during no-load operation. This design results in no anti-knock phenomena being observed in actual operation.