| High Voltage Switchgear is a paramount control equipment in electrical power system which plays an important role in security and reliability. As it always works in high voltage, heavy current and high-intensity magnetic field environment, the temperature is far more likely to increase and it even more serious leads to equipment failure. Therefore, it is necessary to keep monitoring of temperature variation. In recent years, the optical fiber sensing technology develops rapidly, and the various temperature measuring equipments which apply this technology are increasingly mature. In many areas, the equipments of fiber temperature measurement have been used for real time monitoring the temperature of high voltage switchgear. However, they have not been widely used in power grid of Tangshan. For this reason, in terms of multi users, heavy workload and equipments are easy heating in this area, it is necessary to design the fiber temperature measurement system to achieve monitoring the sensitive position temperature of high voltage switchgear online.This paper is to analyse the function of early warning system of high voltage switchgear optical fiber temperature measurement in detail, in addition, propose the overall designing scheme. To begin with, it is to analyse the principle of laser Raman scattering temperature measurement in fiber and the method of orientation which applying the principle of Optical Time Domain Reflectometry (OTDR). Moreover, it is to design the hardware of system which is based on above analysis. In order to optimization, this design adopts a new technology and advanced material. For example,355nm solid laser is applied to the system signal source, dielectric filter is used to optical wavelength division multiplexing (OWDM) system, the new material carborundum is employed in avalanche diode. Furthermore, the software of SQL database design system is appled,based on windows system, in the background. This software strives for conciseness, visualize, especially hommization and compatibility. It is equipped with auto alarm module. When the temperature of observation point exceed the threshold value, the auto alarm starts sending signals. What’s more, it could comparison with historical data and conduct the intelligent analysis so that the staff could master the current condition of sensitive spot and developing tendency of temperature, deal with the potential risk promptly. Additional, according to field apparatus, electronic map is drew. Alarm point is reflected directly in order to equipment maintenance. Finally, this paper illustrates the probational condition of distributed fiber temperature measurement system in110kV Dong Huangtuo transformer substation of Tang Shan.In high voltage switchgear, the electric tension is high, electromagnetic interference is huge and a large number of monitoring points. Moreover, the location of some hot position are covert which are difficult to observe. It is impossible to comprehensive survelliance by general infared temperature measurement, however, adopting this system, it could achieve the real-time monitoring for temperature field in multi-zone and multi sensitive position. It is provided with such characteristic including flame proof,corrosion resistance, high pressure resistant, anti-electromagnetic interference and other outstanding advantages. In practice, this system achieves on-line monitoring and alarm, potential risk analysis, condition based maintenance which proves that the design is reasonable, practical and validity. |
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