The temperature distribution and deformation of the transformer windings cannot be measured in a distributed manner by the traditional method and failure location cannot be performed. To solve these problems, we present a transformer winding temperature and strain based on a distributed optical fibre sensing detection method. The design of the optical fibre winding composite model is developed and simulated winding temperature rise test and local deformation test distinguish between measuring the winding temperature and the strain curve. The test results show that the distributed optical fibre can transmit wire strain efficiently. Optical fibres, in the process of winding, have a certain pre-stress. Using the Brillouin–Raman joint measuring method, one can effectively extract the optical fibre temperature and strain information and measure the length of the winding direction of the temperature and strain distribution curve to a temperature measurement precision of ±2 °C and strain detection accuracy of ±50 με. The system can carry out local hot spot and deformation localisation, providing new ideas for the transformer winding state monitoring technology.

Winding overheating is a common fault in a transformer. To detect the temperature, the most widely used method is a point-type measurement, but traditional measurement methods cannot obtain the whole temperature distribution in a transformer. Taking this into consideration, a new method with which to measure the temperature of transformer windings was proposed. Based on Raman scattering, a new fibre-optic composite winding model was developed. The feasibility of the model was verified by electrical as well as temperature, field simulation and power frequency resistance testing. To assess the practicality and accuracy of the new model, a distributed optical fibre temperature measurement platform was built, and a series of experiments were designed. According to the data collected, the temperature measurement error based on the method could be limited to 1 °C while the positioning accuracy error was within 1 m, which meant that the new approach can satisfy the requirements of transformer winding temperature measurement and locate hot spots in the winding.

The local overheating fault of power transformer winding threatens the safe, stable operation of a power system. Conventional winding temperature detection methods are point-type temperature measurements, and the hotspot position and the temperature distribution on the winding cannot be accurately obtained. A distributed temperature measurement method of transformer winding based on Raman scattering was thus proposed, and a fiber composite winding model was designed. The influence of fiber on electric field distribution and temperature transfer in oil was simulated, and the insulation performance of fiber composite winding was studied. The distributed optical fiber temperature measurement platform was built, and a temperature sensing test was conducted. The results show that the distributed temperature detection system of transformer winding has high temperature sensing and positioning performance with temperature measurement error less than 1°C and positioning accuracy error within 1.2 m. This means that this method can satisfy the requirements of transformer winding temperature measurement and provide a new, to the best of our knowledge, approach for online monitoring of high-power equipment.