Optical-Acoustic Arc Flash Sensor with Diaphragm
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Solution Overview
Problem
Existing arc flash detection methods suffer from slow response times and high false alarm rates due to reliance on single parameter detection, such as light or pressure, which are not effective in accurately and quickly identifying arc flash events.
Innovation Solution
A sensor system that simultaneously detects both light and acoustic waves using a diaphragm within an optical fiber, allowing for the simultaneous capture and processing of both signals to generate an arc fault signal, thereby minimizing false alarms and enabling early detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If optical sensors are used to detect light from arc flash, then detection speed is improved, but false alarm rate increases due to stray light detection
Solution Approach 1:
The patent combines optical detection and acoustic detection into a single sensor system. The optical component detects light from the arc flash while the acoustic component detects pressure waves, and both signals are processed together to confirm arc flash events, reducing false alarms caused by stray light alone.
Solution Approach 2:
The system uses feedback from multiple detection channels (optical and acoustic) to validate arc flash detection. When both optical and acoustic signals indicate an arc flash event, the system confirms the detection, providing a feedback mechanism that reduces false positives from stray light detection.
2Reliability
If pressure sensors are used to detect arc flash induced pressure changes, then false alarms are reduced, but detection time increases due to pressure build-up delay
Solution Approach 1:
The patent merges optical detection (fast response) with acoustic detection (reliable confirmation). The optical sensor provides immediate detection of light from the arc flash, while the acoustic sensor confirms the event by detecting pressure waves, combining the speed of optical detection with the reliability of acoustic detection.
Solution Approach 2:
The system performs preliminary detection using the optical sensor which responds immediately to arc flash light, before the pressure build-up completes. This preliminary action allows the system to detect the arc flash event as soon as light is emitted, rather than waiting for pressure changes.
3Device complexity
If standard fuses and circuit breakers are used for arc flash mitigation, then device complexity is reduced, but response time is too slow to mitigate arc flash effectively
Solution Approach 1:
The patent replaces traditional mechanical protection devices (fuses and circuit breakers) with an integrated optical-acoustic sensor system that provides much faster detection and triggering of arc flash mitigation. The sensor system detects arc flash events in microseconds and can trigger protective devices immediately, rather than waiting for thermal or magnetic trip mechanisms.
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 integrated detection of light and acoustic waves provides a unique signature for rapid and accurate identification of arc flash events, reducing false alarms and enabling timely mitigation.
Implementation Method 1
a diaphragm configured to vibrate upon incidence of sound (acoustic waves) from an arc flash and reflect light from a laser beam into the fiber core
Implementation Method 2
an optical fiber configured to transmit light from the diaphragm
Implementation Method 3
A sensor system that simultaneously detects both light and acoustic waves
Data Source
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AI summary
A sensor to simultaneously detect light and acoustic waves is presented. The sensor includes one or more optical fibers and a diaphragm disposed near one end of at least one of the one or more optical fibers. The diaphragm is configured to vibrate upon incidence of acoustic waves from an arc flash and reflect a light beam into at least the one of the one or more of the optical fibers. A semi-transparent region is disposed around the one or more optical fibers to diffuse light originating from the arc flash into at least one of the one or more optical fibers.