18-10-2010, 11:13 AM
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Magneto-optical current transformer technology (MOCT)
INTRODUCTION
An accurate electric current transducer is a key component of
any power system instrumentation. To measure currents power stations
and substations conventionally employ inductive type current
transformers with core and windings. For high voltage applications,
porcelain insulators and oil-impregnated materials have to be used to
produce insulation between the primary bus and the secondary
windings. The insulation structure has to be designed carefully to
avoid electric field stresses, which could eventually cause insulation
breakdown. The electric current path of the primary bus has to be
designed properly to minimize the mechanical forces on the primary
conductors for through faults. The reliability of conventional highvoltage
current transformers have been questioned because of their
violent destructive failures which caused fires and impact damage to
adjacent apparatus in the switchyards, electric damage to relays, and
power service disruptions.