Abstract: The secondary equipment in-situ of smart substation meets the requirements of material saving, land saving and energy saving, which is a hot research focus in smart substation construction at present. For the application extension of the construction mode with secondary equipment in-situ in smart substation, this paper summarized the status of protection technology for secondary equipment in-situ in recent years, and studied the interfering mechanism of temperature, humidity and electromagnetic interference on secondary equipment in-situ. Aimed at the deficiency of existing protection technology, a new precast chamber protection scheme was proposed, and the single row and double row configuration methods of holders in chamber were described, which had the characteristics of compact construction, good economics, significant protection effect, precast production inner plant and short construction period, and could effectively improve the construction efficiency of smart substation and reduce the construction area, construction period, investment of smart substation. The secondary equipment in-situ of smart substation will further promote the “standardized design, factory processing, assembling construction” for the smart substation, which has the value of popularization and application.

Key words: smart substation, secondary equipment in-situ, electromagnetic interference, outer chamber, precast chamber