Why is it necessary to use optical fiber for measuring the temperature of oil immersed transformer windings

Optisko šķiedru temperatūras sensors, Inteliģenta uzraudzības sistēma, Izplatīts optisko šķiedru ražotājs Ķīnā

Why do oil immersed transformers need temperature measurement
With the development of transformers towards ultra-high voltage, large capacity, and intelligence, as important electrical equipment in the power system, the safe and reliable operation of transformers is crucial for the power system. The average accident rate of transformers with a voltage of 110kV and above is about 0.69%, among which insulation aging, transformer winding breakdown, and burnout accidents caused by winding overheating account for a considerable proportion.

The lifespan of oil immersed transformers mainly depends on the lifespan of solid insulation (fiber paper), and the main factors that promote insulation aging are temperature, moisture, and oxygen. The thermal effect generated by the increase in winding temperature during transformer operation is the most prominent and decisive factor in transformer aging. Tāpēc, directly measuring the hot spot temperature of transformer windings has become an important development direction to ensure their safe and reliable operation. Accurate and real-time monitoring of the temperature of transformer windings and their insulation oil is a necessary condition to ensure the normal operation of transformers.

Fiber optic temperature measurement of oil immersed transformer winding

Šobrīd, the winding temperature is usually simulated by detecting the top oil layer temperature and load current as a criterion for transformer operating conditions. Tomēr, this technology has the disadvantages of being inaccurate, untimely, and not intuitive. Tāpēc, it is very necessary to adopt new technologies for real-time monitoring of the temperature of transformer windings during operation, reflecting the actual temperature of the windings in a timely manner. The online monitoring system for transformer winding fiber temperature can effectively solve the above problems. The application of fiber optic temperature measurement technology in monitoring the hot spot temperature of transformer windings has the advantages of convenience, accuracy, safety, and reliability. It can timely and accurately detect defects and hidden dangers such as winding overheating, which is of great significance for improving the safety and stable operation of transformers.

The principle of oil to fluorescence optical fiber temperature measurement is to add a fluorescent substance at the end of the optical fiber, and by measuring the attenuation time of the light intensity in the fluorescent substance, the temperature at the measurement point can be converted.

The online monitoring system for transformer winding fiber temperature can directly measure the hot spot temperature of the winding in real time, solving the problems of low temperature measurement accuracy and inability to reflect rapid changes in winding or oil temperature in a timely manner of thermal simulation winding thermometers. And the fiber optic temperature online monitoring system has high temperature measurement accuracy, simple structure, viegla uzstādīšana, high reliability and intelligence level.

During the experiment, key technologies such as temperature measurement accuracy, real-time performance, long-term oil resistance, electrical insulation characteristics of the fiber optic sensor, sensor installation, fiber optic penetration through transformer oil tank wall sealing, and fiber optic signal demodulation were verified; The long-term operation results have proven that the online monitoring system for transformer winding fiber temperature is stable and reliable, meeting the monitoring needs.

Online monitoring of transformer winding fiber temperature

Scientific, advanced, and safe transformer winding temperature monitoring technology has the advantages of high accuracy, small error, fast response, multiple monitoring points, direct monitoring of hotspots, wide application range, and convenient construction compared to other temperature measurement technologies; It can also be used to monitor the temperature of transformer oil passages, structural components, and iron cores.

As one of the components of intelligent transformers, the online monitoring system for transformer winding fiber temperature can not only provide transformer warning and fault analysis, but also perform transformer load and life analysis; Thereby improving the reliability of transformer operation, optimizing the load of transformer operation, and enhancing the level of transformer intelligence.