18-01-2012, 12:20 PM
Magneto-Optical current transformer
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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.
MOCT-PRINCIPLE
The Magneto-Optical current transformer is based on the
Faradays effect. Michael Faraday discovered that the orientation of
linearly polarized light was rotated under the influence of the magnetic
field when the light propagated in a piece of glass, and the rotation
angle was proportional to the intensity of the magnetic field
MAGNETO-OPTICAL SENSOR
Almost all transparent material exhibits the magneto-optical
effect or Faraday Effect, but the effect of some of the material is very
temperature dependent, and they are not suitable for the sensing
material. The optical glasses are good candidate for the sensing
material, because the Verdet constants are not sensitive to the
temperature changes, and they have good transparency properties.
