Phase-modulated fiber-optic current transformer/voltage transformer

Technical Report · Mon Jul 01 04:00:00 EDT 1991

OSTI ID:5572813

Davis, C M ^[1]

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1. Optical Technologies, Inc., Herndon, VA (United States)

This report summarizes the results of an investigation into the use of phase-modulated fiber-optic sensing techniques for the measurement of current and voltage in non-revenue aerial and underground distribution systems. The phase-modulated Fiber-Optic Current Transformer/Voltage Transformers (FOCT/VT) described uses single-mode fiber and conventional telecommunications components. The heart of the FOCT/VT system is a fiber-optic interferometer. The current of voltage signals of interest are converted to phase modulation of the light in the interferometer. This is accomplished with a piezoelectric (PZT) element where optical fiber in one arm of the interferometer is attached. Since the PZT is electrostrictive, an applied voltage results in a change in dimensions of the PZT, thereby straining the optical fiber. The strain in the optical fiber produces a corresponding phase modulation of the light propagating through the fiber. The interferometer converts the phase modulation to intensity modulation proportional to the amplitude of the current or voltage signal. In either case, a detection bandwidth exceeding 1 kHz was achieved. A dynamic range of 90 dB was demonstrated which corresponds to a measurement span of 1.34 to 43,000 Amps and 29 V to 979 kV for the case of the current and voltage sensors, respectively. A compact, clamp-on sensor package suitable for hot-stick installation in the field was designed which houses the current and voltage sensors and their associated optical components. A market investigation was conducted which estimated the market potential of the FOCT/VT and determined that the FOCT/VT has viable applications in distributions automation. 15 figs., 2 tabs.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (United States); Optical Technologies, Inc., Herndon, VA (United States)
• Sponsoring Organization: EPRI; Electric Power Research Inst., Palo Alto, CA (United States)
• OSTI ID: 5572813
• Report Number(s): EPRI-EL-7421
• Country of Publication: United States
• Language: English

Related Subjects

24 POWER TRANSMISSION AND DISTRIBUTION
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47 OTHER INSTRUMENTATION
AUTOMATION
CURRENTS
DESIGN
ELECTRIC CURRENTS
ELECTRIC POTENTIAL
ELECTRICAL EQUIPMENT
ELECTRICITY
EQUIPMENT
FIBER OPTICS
FIBERS
INTERFEROMETERS
MARKET
MEASURING INSTRUMENTS
MODULATION
OPTICAL FIBERS
PIEZOELECTRICITY
POWER TRANSMISSION
POWER TRANSMISSION LINES
STRAINS
TRANSFORMERS