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MAGNETO-OPTICAL CURRENT TRANSFORMER. CONTENTS. CURRENT TRANSFORMER MOCT – principle ,working ,design MOCT BLOCK DIAGRAM APPLICATIONS ADVANTAGES DISADVANTAGES CONCLUSION. CURRENT TRANSFORMER :. CT CONSTRUCTION :
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MAGNETO-OPTICAL CURRENT TRANSFORMER
CONTENTS • CURRENT TRANSFORMER • MOCT – principle ,working ,design • MOCT BLOCK DIAGRAM • APPLICATIONS • ADVANTAGES • DISADVANTAGES • CONCLUSION
CURRENTTRANSFORMER: • CT CONSTRUCTION: • Inductive type transformer with core and primary & secondary windings. • CT WORKING PRINCIPAL: • Step up transformer (voltage), step down transformers (current). • PURPOSE OF CT • It feeds the current coils of indicating ,metering instruments and • protective relays. • Watch over the current’s in the circuit. • DISADVANTAGES OF CT: • The insulation structure has to be designed carefully to avoid • electric field stress, which could eventually cause insulation • breakdown. • Less reliability
MOCT MOCT Measures the electric current by means of FARADAY EFFECT. FARADAY 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. “
Polarization is a property of certain types of waves that describes the orientation of their oscillations.
FARADAY EFFECT By considering the property faraday given two mathematical equations ANGLE=V (INTEGRAL OF B)-------------(1) ANGLE=n*permeability*VI -------------(2)
POLARIZER • MAGNETO-OPTICAL MATERIAL • ANALYZER (POLARIZATION PRISM) • PHOTODIODES
APPLICATION • The MOCT is designed to operate in a transparent manner with modern electronic meters and digital relays, which have been adopted for a low energy analog signal interface.
ADVANTAGES • No risk of fires and explosions. • No need to use metallic wires to transfer the signal. • High immunity to electromagnetic interference. • Larger dynamic range. • Low voltage outputs which are compatible with the inputs of digital to analog converters.
DISADVANTAGES • Due to Temperature and stress induced linear changes in the sensing material causes error and instability. • The accuracy of MOCT is some what less than the conventional transformer. Main cause is temperature drift But the disadvantages can be overcome by implementing the Double closed-loop self-tuning method
CONCLUSION • This paper presents a new kind of current transducer known as magneto optical current transducer. • This MOCT eliminates many of the drawbacks of the conventional current transformers. • By applying Faraday’s principle this transducer provides an easier and more accurate way of current measurement. This MOCT is widely used in power systems and substations nowadays.