Transient Temperature Rise Process of Composite Insulator Under Interface and Surface Heat Sources

The heat source for the abnormal heating of composite insulators is generally located at the mandrel-sheath interface or on the sheath surface. Fiber Bragg gratings are used to measure the transient temperature rise on the mandrel-sheath interface and the sheath surface of the composite insulator under interface and surface heat source. The measurements are performed on a 10 kV composite insulator. The experimental results show that the time constants of interface temperature rise and surface temperature rise under the interface heat source are about 40 s and 115 s, respectively. In comparison, they are 100 s and 7 s respectively under the surface heat source. When the heat source is applied to the mandrel-sheath interface, it takes 15–50 min and 15–35 min respectively, for the interface temperature and surface temperature to stabilize; while it takes 9–18 min and 8–16 min respectively for the interface temperature and the surface temperature to reach stability under surface heating. The rise amplitude of the interface temperature and the surface temperature both show a linear relationship with the applied heat. The difference between the interface and surface temperature increases with increasing applied heat.