Environmental states in a limited space mainly include: gas composition, gas concentration, ambient temperature, ambient humidity and ambient wind speed, etc. Environmental state perception mode mainly monitors and analyzes environmental states in a limited space area or restricted part, and has the functions of data analysis and storage. This paper further improves the emergency protection measures for limited space operations, realizes full-time perception, early warning, quick warning, and emergency evacuation, and reduces the risk of blind rescue and stray into dangerous areas, in order to avoid the escalation of the scope and impact of safety accidents, effectively improve the emergency protection capability of power grid limited space operations, and the IoT and intelligent level of emergency protection technology for power grid equipment and facilities.