4Roman H, Pietzsch H. Earth-fauh treatment in medi-um-voltage networks[D]. Contributions 14th International Conference and Exhibition on Electricity Distribution. Part 1. 1997,4:36.
5Sezi T. A new approach for transformer ground differ- ential protection [D]. 1999 IEEE Transmission and Dis- tribution Conference, 1999, 1:394,398.
