Abstract
Traditional monitoring methods cannot obtain the overall thermal information for power transformers. To solve this problem, a distributed fiber optic sensor (DFOS) was creatively applied inside an operating 35 kV power transformer by highly integrating with the electromagnetic wires. Then, the transformer prototype with totally global sensing capability was successfully developed and it was qualified for power grid application through the strict ex-factory tests. The as designed optical fiber sensor works stably all the time with a temperature accuracy of ±0.2 °C and spatial positioning accuracy of 0.8 m. Based on the obtained internal temperature distribution, Gaussian convolution was further applied for the signal processing and hereby, the hotspots for all the windings and iron cores could be accurately traced. The hottest points were located at 89.1% (55 °C) of the high voltage winding height and 89.7% (77.5 °C) of the low voltage winding height. The actual precise hotspot location corrected the traditional cognition on the transformer windings and it would serve as an essential reference for the manufactures. This new nondestructive internal sensing and condition monitoring method also exhibits a promising future for the DFOS applying in the high-voltage electrical apparatus industry.
Highlights
Transformer overheating is gradually becoming a common problem due to the rapid growth of power consumption, which directly threatens its life expectancy and the safety of the entire power grid
Thermocouples, fluorescent optical fiber sensors and fiber grating sensors (FBG) are usually used for a multi-point sampling in the direct measurements due to its relatively simple and convenient installation, which leads to a strong operability
For all the windings and the three phase core limbs, the sensing fiber was connected with each other through the optical fiber patch cord on the outer side of the fiber flange
Summary
Transformer overheating is gradually becoming a common problem due to the rapid growth of power consumption, which directly threatens its life expectancy and the safety of the entire power grid. The indirect calculation, as its name suggests, uses a numerical method to solve the transformer temperature field based on a thermal circuit model or a mathematical analysis. It can theoretically achieve a distributed detection [13]. The DFOS wild application in various fields under different tough conditions exhibits its mature and stable performance and shows great potential in solving the power transformer overheating problems. In this contribution, an optical fiber composite winding wire has been designed.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
