The 10 kV feeder terminal unit（FTU） operates under severe EMI environment

so its reliability and anti-interference ability are very important.In this paper

several typical interference sources in power system were discussed

and their generation mechanisms

spectrum features and coupling paths were analyzed.Moreover

some corresponding anti-interference designs for hardware and software of FTU were provided.The newly designed FTU with high anti-interference ability has operated on a 10 kV line in Linfen

Shanxi Province

demonstrating that the proposed anti-interference methods are effective.