Creativity knows no bounds, and inventions abound in instrumentation. Today, we'd like to introduce a national invention patent— a fiber optic temperature sensor . This patent was applied for by Toshiba Mitsubishi Electric Industrial Systems Co., Ltd., and was granted authorization on November 16, 2016.
Content Description
This invention relates to an optical fiber temperature sensor for real-time monitoring of temperature anomalies in various components such as busbars or bolts inside electrical components.
Background of the Invention
In recent years, high-speed switching operations in inverter panels have led to increased switching surge voltages caused by the inductance of the busbars within the inverter panel. Therefore, mitigating these surge voltages is crucial. An effective method to reduce inductance is to employ a sandwich busbar, in which the busbar that allows switching current to flow to one end of the load control circuit faces the busbar that allows switching current to flow out of the other end of the switching circuit, separated by an electrically insulating material.
However, short circuits and other faults can sometimes occur due to aging of the sandwich busbar or deterioration of the insulation properties of the interlayer insulation material. Traditional methods cannot prevent such faults.
Furthermore, even fastening bolts used to connect busbars can loosen due to aging, vibration, or impact. This can lead to localized overheating. Therefore, monitoring is necessary to prevent sudden failures within the inverter and other electrical components.
One method for monitoring temperature anomalies is a temperature monitoring device using optical fibers. This type of temperature monitoring device has been applied in various fields, including tunnel disaster prevention equipment.
Summary of the Invention
Traditional fiber optic temperature monitoring devices are well-suited for large structural components and linear structures. However, they cannot be used in confined spaces or small areas, such as those found in frequency converter panels. In particular, they cannot monitor significant anomalies such as busbar overheating.
The purpose of this invention is to provide a fiber optic temperature sensor that enables frequent monitoring of temperature at multiple desired locations within a narrow area.
The figure shows an example of the fiber optic temperature sensor according to Embodiment 1 of the present invention.
To achieve the above objectives, the fiber optic temperature sensor of the present invention is a fiber optic temperature sensor with temperature monitoring function installed on the interlayer insulation material of the sandwich busbar. Its characteristic is that it is formed by housing an optical cable within a frame made of an ultra-thin sheet. The ultra-thin sheet uses an insulating material of equal or higher quality than the interlayer insulation material of the sandwich busbar. Multiple ultra-thin cylinders made of the same material as the frame are housed at multiple locations within the frame. The optical cable is wound onto each of these ultra-thin cylinders to a length equivalent to or greater than the distance resolution capability, without being fixed, thereby forming multiple sensing coils. The temperature of the multiple locations is measured through these multiple sensing coils. The side surface of the frame is sealed with a silicone sealant, and the entire surface of the frame is sealed with a sealing member made of a silicone-based liquid insulating material.
This invention is also applicable to sealed distribution panel type high-voltage power distribution equipment that may malfunction due to harsh environments such as typhoons, heavy rain, dust, or induced magnetic fields.
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