Ferro resonance in Distribution Systems:-
Ferro resonance is a complex and rare phenomenon that can occur in electrical distribution systems, particularly in networks with transformers and power cables.
• The event cause by opening one or two phases, either intentionally or accidentally .
• The situation is established by the commonplace UD cable service drop from an overhead line.
• The cable system either light load or no load.
• The transformers were not permanently damaged.
• Damage did occur to load side equipment.
Corrective measures include:
• Use three-phase switchgear instead of fuses, this is not economical in many cases.
• Open or close all three cutouts as simultaneously as possible.
• Ensure the transformer is loaded while being switched.
• Eliminate fuses. Rely on feeder breaker for fault interruption.
• Various measures to prevent inadvertent fuse operation.
Obviously, each of these measures have certain costs associated with them. Distribution engineers may simply choose to accept the risk or adapt operating procedures to minimize it. There may be no economical way of dealing with certain accidental occurrences.
