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Transient
Currents in Capacitor Fuses
This DSTAR project develops
guidelines for avoiding nuisance operation of feeder capacitor bank fuses due to
switching transient and lightning duty.
Fuses protecting
capacitors on distribution feeders are subjected to high currents from transient
phenomena such as lightning and switching surges. It is possible for the
transient currents to operate or damage the fuses, even though the protected
capacitors remain undamaged, thus yielding a nuisance fuse operation. Some
utilities report unexplained operations of cutout type fuses protecting feeder
capacitors. Such nuisance fuse operations increase utility operating costs and
also may subject customers to reduced voltage or three-phase voltage imbalance
if only one or two phases have blown fuses in a three-phase capacitor bank.
DSTAR addressed this issue in response to membership’s need for improved
guidelines regarding minimum fuse size needed to avoid nuisance operation due to
routine system voltage transients. |
