Thermochromic insulation composites for prewarning of thermal faults in electrical equipment

Abstract Thermal faults occur in the continuous operation of electrical equipment. This poses a threat to the stable operation of power systems. However, existing detection methods do not apply to large‐scale temperature measurement scenarios due to high cost and poor stability. To solve the above problems, a reversible thermochromic microcapsule is proposed in this work. Silicone rubber composite can be endowed with thermal sensing capability by doping an appropriate amount of thermochromic microcapsules inside the silicone rubber matrix. The test results showed that the color of the obtained thermochromic composites changed sensitively with the change in external temperature. The material undergoes a sudden color change at about 50°C achieving a reversible color change from blue to colorless. The color difference before and after the color change can be up to 37.24. In addition, the color difference shows an exponential decay trend with time. When the dopant concentration of the microcapsules is 1.5 wt%, the composite material shows excellent color‐changing performance, and the insulation strength is increased by 6.92% compared with the pure silicone rubber. Meanwhile, the water contact angle of the composite is 115.3°, which proves that it has good hydrophobicity. Notably, the thermochromic composite also showed excellent weathering properties in thermal aging experiments. The thermochromic microcapsule proposed in this work can realize the visualization of the local overheating state of the electrical equipment, which provides a new idea for the application of thermal fault prewarning of the electrical equipment.