Ferroresonance
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The phenomenon of Ferroresonance is the occurrence of an unstable high voltage, typically on 3 phase electrical systems which only occurs under specific conditions. The nature of the overvoltage can cause the failure of equipment.
[edit] Conditions for Ferroresonance
Ferroresonance occurs when an unloaded 3-phase system consisting of an inductive and a capacitive component is interrupted by single phase means. In practice this is typical of a high voltage electrical distribution network of transformers (inductive component) and power cables (capacitive component). If such a network has no load and the applied voltage is then interrupted on a single phase, a ferroresonance may be observed. If the remaining phases are not interrupted and the phenomenon continues, failure of connected components can occur due to the breakdown of insulation due to overvoltage.
The phenomenon can be avoided by maintaining a minimal load on the circuit or by interrupting the applied voltage by a 3-phase interrupting device.
