Jännitteenpalautuminen

Jännitteenpalautuminen is a Finnish term that describes the phenomenon of voltage recovery after an electrical arc has been extinguished. This occurs in electrical circuits, particularly in medium and high-voltage systems, when a switch or circuit breaker opens to interrupt a current. As the contacts separate, an arc is formed due to the ionized gas between them. Once the arc is extinguished, the insulating medium between the contacts begins to regain its dielectric strength.

The voltage across the opening contacts, which was zero during the arc, starts to rise again. This rising voltage is known as the restriking voltage. If this restriking voltage exceeds the dielectric strength of the medium between the contacts, the arc may re-ignite, leading to a current interruption failure. Jännitteenpalautuminen is a critical factor in the design and operation of switching devices, as it directly influences their ability to reliably interrupt fault currents.

The rate of voltage rise and the peak value of the restriking voltage depend on various factors, including the inductance and capacitance of the circuit. Electrical engineers must consider these parameters when designing circuit breakers and other protective devices to ensure that the medium between the contacts can withstand the jännitteenpalautuminen and prevent arc restrikes. The study of jännitteenpalautuminen is essential for maintaining the stability and safety of electrical power systems.