Special applications in power systems (related to your previous questions) In substations and power plants, tubular electric heaters play the role of a "guardian", preventing equipment failures due to low temperature or humidity: Transformer/bushing respirator heating: prevents silica gel from becoming damp and failing, avoiding moisture entering the oil conservator. Mechanism box/terminal box moisture removal: during the rainy season or in high humidity environments, heaters are activated to reduce relative humidity inside the box, preventing secondary circuit short circuits or corrosion. Circuit breaker/SF6 equipment heat tracing: in cold regions, prevents SF6 gas liquefaction or freezing of operating mechanism lubricating oil, ensuring reliable switch operation. Cable terminal heating: prevents frost heave from damaging cables or moisture ingress into terminal heads. 4. Key testing and maintenance (combined with your previous instruments) Although tubular electric heaters have a simple structure, their electrical safety is crucial. During operation and maintenance, the instruments you mentioned earlier are often used for testing: Cold-state DC resistance measurement (using a DC resistance tester): Purpose: to determine if the resistance wire is broken (infinite) or has inter-turn short circuits (resistance too low). Calculate power: based on
