MAGNETO OPTICAL MAGNETO OPTICAL CURRENT CURRENT

TRANSFORMERTRANSFORMER

Presented By:Presented By:

Shivankit BansalShivankit Bansal

12077491207749

Final YearFinal Year

Electrical Deptt.Electrical Deptt.

Drawbacks of Current Drawbacks of Current T/fT/f The insulation structure has to be The insulation structure has to be

designed carefully to avoid designed carefully to avoid breakdown.breakdown.

Electric current path of primary Electric current path of primary bus has to be designed properly bus has to be designed properly to minimize the mechanical to minimize the mechanical forces.forces.

Violent destructive failures.Violent destructive failures.

ABSTRACT:ABSTRACT:

MOCT technology provides solution to MOCT technology provides solution to many of the problems of conventional many of the problems of conventional current transformer.current transformer.

Quite new technology-in research stage.Quite new technology-in research stage. Provides no Electromagnetic Provides no Electromagnetic

Interference.Interference. No need to break the conductor to No need to break the conductor to

enclose the optical path in the current enclose the optical path in the current carrying circuit.carrying circuit.

A TYPICAL MOCT A TYPICAL MOCT

MOCT SYSTEM MOCT SYSTEM CONFIGURATIONCONFIGURATION

What is it?What is it?

Passive optical current transducer Passive optical current transducer which uses light to accurately which uses light to accurately measure current on high voltage measure current on high voltage systems.systems.

Measures current by means of Measures current by means of Faraday’s Effect.Faraday’s Effect.

Determines the rotation angle & Determines the rotation angle & converts into a signal of few volts converts into a signal of few volts proportional to the current.proportional to the current.

COMPONENTS:COMPONENTS:

Sensor head located near the Sensor head located near the current carrying conductor.current carrying conductor.

An Electronic Signal Processing An Electronic Signal Processing Unit.Unit.

Fiber Optical Cables linking these Fiber Optical Cables linking these two parts.two parts.

The sensor head consists of optical The sensor head consists of optical components.components.

The signal is brought down to signal The signal is brought down to signal processing unit by means optical fiber processing unit by means optical fiber cables.cables.

Signal Processing Unit basically converts Signal Processing Unit basically converts the optical signal into suitable electrical the optical signal into suitable electrical form.form.

As no metallic wires are needed therefore As no metallic wires are needed therefore it provides better insulation.it provides better insulation.

MOCT PRINCIPLE:MOCT PRINCIPLE:

Contd.Contd.

A polarizer is used to convert the randomly A polarizer is used to convert the randomly polarized incident light into linearly polarized incident light into linearly polarized light.polarized light.

Orientation rotates an angle Orientation rotates an angle after the light after the light has passed through the magneto-optical has passed through the magneto-optical material because of Faraday Effect.material because of Faraday Effect.

Analyzer converts the orientation variation Analyzer converts the orientation variation of polarized light into intensity variation of polarized light into intensity variation with two outputs.with two outputs.

The outputs are send to photo detectors.The outputs are send to photo detectors.

Proper wrapping of optical path around current Proper wrapping of optical path around current carrying conductor is required.carrying conductor is required.

Can be achieved by folding the optical path by Can be achieved by folding the optical path by means of reflections.means of reflections.

Total Internal Reflections & Metal Reflections are Total Internal Reflections & Metal Reflections are good ways.good ways.

Prisms should be designed to keep the light Prisms should be designed to keep the light linearly polarized.linearly polarized.

Phase shift should be avoided.Phase shift should be avoided. A program in FORTRAN is used for the A program in FORTRAN is used for the

performing the entire operation.performing the entire operation.

Electronic Circuit for Electronic Circuit for MOCTMOCT

APPLICATIONS:APPLICATIONS:

Most suited for outdoor type Most suited for outdoor type applications.applications.

It meets the protection class It meets the protection class accuracy as specified by IEC 60004-accuracy as specified by IEC 60004-8.8.

The optical design enables accurate The optical design enables accurate measurement of fault currents.measurement of fault currents.

Makes the output signal insensitive Makes the output signal insensitive to shock & vibration.to shock & vibration.

ADVANTAGES:ADVANTAGES:

No risks of fires & explosions.No risks of fires & explosions. Simpler insulation structure.Simpler insulation structure. High immunity to Electromagnetic High immunity to Electromagnetic

interferences.interferences. Wide frequency response.Wide frequency response. Larger Dynamic Range.Larger Dynamic Range. Low voltage outputs-compatible with Low voltage outputs-compatible with

the inputs of digital to analog the inputs of digital to analog converters.converters.

DISADVANTAGES:DISADVANTAGES:

Temperature and stress induced Temperature and stress induced linear birefringence in the linear birefringence in the sensing material causes error sensing material causes error and instability.and instability.

The accuracy of MOCT is so far The accuracy of MOCT is so far insufficient for the use in power insufficient for the use in power systems. systems.

CONCLUSION:CONCLUSION:

This magneto optical current transducer eliminates many This magneto optical current transducer eliminates many of the drawbacks of the conventional current of the drawbacks of the conventional current

transformers. In an conventional current transformers, transformers. In an conventional current transformers, there is a chance of saturation of magnetic field under there is a chance of saturation of magnetic field under

high current, complicated insulation and cooling high current, complicated insulation and cooling structure, a chance of electro magnetic interference structure, a chance of electro magnetic interference

etc. etc. By applying Faraday’s principle this transducer By applying Faraday’s principle this transducer

provides an easier and more accurate way of current provides an easier and more accurate way of current measurement. This MOCT is widely used in power measurement. This MOCT is widely used in power

systems and substations nowadays. And a new trend systems and substations nowadays. And a new trend is being introduced, which known as OCP based on is being introduced, which known as OCP based on adaptive theory, which make use of accuracy in the adaptive theory, which make use of accuracy in the steady state of the conventional current transformer steady state of the conventional current transformer and the MOCT with no saturation under fault current and the MOCT with no saturation under fault current

transients. transients.

THANK YOUTHANK YOU