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US 2003/0117126 A1Published application
Optical electric field or voltage sensing system
AssigneeNxtPhase Corporation
InventorFarnoosh Rahmatian
Life of this patent
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Abstract
An electric field sensing system is characterized so that a signal processor may derive an output representative of an electric field intended to be measured, particularly established by high voltage on a power line, with enhanced accuracy. Characterizing parameters may be derived from signals representative of a pair of light waves derived from a light wave exiting an optical electric field sensing element in a electric field sensing head spatially positioned in the high voltage environment.
Claims5
An self-monitoring optical electric field sensing system for measuring an electric field comprising:
- a light source for generating a light wave having of finite intensity;
- first and second photodetectors for providing first and second electrical detector output signals, respectively, in response to any light
- impinging thereon, respectively;
- an electric field optical sensing head having,
- an optical sensing element that exhibits an electro-optic effect where transit time of light waves of differing polarizations are affected differently in response to an electric field;
- an input optical circuit responsive to said light wave for coupling first and second light wave components to said optical sensing element, where said first and second light wave components are of differing polarization and having a phase separation, φo, and
- an output optical circuit coupled to said optical sensing element for splitting light exiting therefrom into third and fourth output light waves derived from said first and second light wave components, and directing said third and fourth light waves to impinge upon said first and second photodetectors, respectively;
- and
- a signal processor for deriving sensing system specific characterization parameters K and φo as a function of a pair of resultant signals a and b,
- where,
- signal a and b are derived from the photodetector output signals of the electric field sensing system, including both optical and electrical signal losses along the way from the output of the optical electric field sensing element,
- φo is the intrinsic phase shift between the first and second light wave components, and
- K is equal to the ratio KA/KB, where KA and KB are characteristic loss factors of the specific electric field sensing system, X, associated with said signals a and b.
10 more elements
An optical electric field sensing system for measuring an electric field comprising:
- a light source for generating a light wave having finite intensity;
- first and second photodetectors for providing first and second electrical detector output signals, respectively, in response to any light impinging thereon, respectively;
- an electric field optical sensing head having,
- an optical sensing element that exhibits an electro-optic effect where transit time of light waves of differing polarizations are affected differently in response to an electric field;
- an input optical circuit responsive to said light wave for coupling first and second light wave components to said optical sensing element, where said first and second light wave components are of differing polarization, and
- an output optical circuit coupled to said optical sensing element for splitting light exiting therefrom into third and fourth output light waves derived from said first and second light wave components, and directing said third and fourth light waves to impinge upon said first and second photodetectors, respectively;
- and
- a signal processor for deriving a processor output signal, E, representative of the electric field intended to be measured as a sensing system specific, X, characterized function, Gx, mathematically described by:
- E=Gx{a,b,Eπ, φo, K,α}
- where,
- a and b represent resultant signal processor input signals derived from the photodetector output signals of the electric field sensing system, including both optical and electrical signal losses along the way from the output of the optical sensing element,
- Eπ is a sensing system specific parameter being substantially the average electric field required to create a π radian phase shift between optical polarization components traveling from the input to the output of said optical sensing element in response to an electric field,
- φo is the intrinsic phase shift between the first and second light wave components,
- α is a number between 0 and 1 that characterizes the goodness of the specific electric field sensing system, X, and
- K is equal to the ratio KA/KB, where KA and KB are characteristic loss factors of the specific electric field sensing system, X, associated with said first and second processor input signals, respectively.
12 more elements
Dependencies are inferred from the claim text.