Optical Voltage Sensing With Electro-Optic Crystal Modulation
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Solution Overview
Problem
Conventional capacitive voltage transducer (CVT) technology for voltage sensing in electrical power systems poses safety risks due to high capacitance requirements, environmental hazards from oil or SF6 insulation, and potential for signal distortion and electric shock, especially in high-voltage applications.
Innovation Solution
An optical voltage sensor system using an electro-optic crystal assembly with unpolarized light, which includes a voltage divider, electrodes, and optical components to convert high-voltage signals into intensity-modulated light beams, eliminating the need for high capacitance and reducing safety risks by transmitting signals via optical fiber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CVT technology uses high capacitance voltage dividers to avoid signal corruption, then signal strength is improved, but safety risks and environmental hazards increase due to required oil or SF6 insulation
Solution Approach 1:
The patent replaces the conventional electrical signal transmission system with an optical system. Instead of transmitting electrical signals through high-capacitance voltage dividers requiring oil or SF6 insulation, the invention uses optical fibers to transmit light signals that carry voltage information. This substitution eliminates the need for hazardous insulation materials while maintaining signal integrity over long distances.
Solution Approach 2:
The patent introduces an optical intermediary system between the high-voltage measurement point and the control room. Optical fibers serve as the intermediary medium to carry voltage information, replacing the direct electrical connection that requires hazardous insulation. This intermediary approach allows safe transmission of voltage data without exposing personnel to high voltages or harmful insulating materials.
2Reliability
If 120V signals are transferred by wire across the substation yard, then voltage monitoring is achieved, but safety risk of electric shock increases especially during lightning strikes
Solution Approach 1:
The patent replaces electrical wire transmission with optical fiber transmission. Instead of conducting 120V signals through wires that pose electric shock risks, the system uses light waves to carry voltage information through optical fibers. This eliminates the conductive path that causes electric shock hazards, especially during lightning strikes or fault conditions.
3Reliability
If capacitive voltage transducer technology is used, then voltage sensing is achieved, but device complexity and cost increase due to required high capacitance and specialized insulation
Solution Approach 1:
The patent replaces the complex electrical measurement system with a simpler optical system. Instead of requiring high-capacitance voltage dividers, oil or SF6 insulation, and associated electrical components, the invention uses optical fibers and photodetectors to achieve voltage sensing. This substitution significantly reduces device complexity and eliminates the need for specialized high-voltage insulation materials.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides a safer, more reliable, and cost-effective solution for voltage sensing by eliminating the need for oil or SF6 insulation, reducing signal distortion, and lowering circuitry costs while maintaining sensitivity and stability.
Implementation Method 1
an electro-optic crystal and a plurality of electrodes arranged on the sides of the electro-optic crystal. The electro-optic crystal is connected to receive the LV signal from the voltage divider. In these configurations, an unpolarized light beam is launched through the electro-optic crystal with the plurality of electrodes configured to apply a voltage of the LV signal along the sides of the electro-optic crystal. This arrangement alters the spatial distribution of a portion of the light beam exiting the electro-optic crystal in response to the LV signal.
Data Source
AI summary
An optical voltage sensor system for measuring a high-voltage (HV) signal includes a voltage divider configured to generate a low-voltage (LV) signal representative of the HV signal, an electro-optic crystal, and electrodes arranged on the electro-optic crystal and connected to receive the LV signal from the voltage divider. The electrodes are configured, upon an unpolarized light beam being launched through the electro-optic crystal, to apply a voltage of the LV signal to the electro-optic crystal to alter a spatial distribution of a portion of the light beam exiting the electro-optic crystal in response to the LV signal. The optical voltage sensor system further includes a light collector configured to collect light having an intensity which varies based on the applied voltage, and a light converter configured to convert the collected light into an electronic signal representative of the HV signal.