Abstract: The electromagnetic loop operation means that the lines with different voltage classes operate parallel which connected together through the electromagnetic circuit by using transformers in the two terminal. The problems existing in the electromagnetic loop operation were analyzed. A series of rules for electromagnetic loop opening was put forward which includes static stability, dynamic stability and economic efficiency etc. The concrete application of synthetical, multilayer fuzzy evaluation method was introduced. The author believes that the electromagnetic loop opening scheme based on synthetical, multilayer fuzzy evaluation is feasible and has practical significance.

Key words: electromagnetic loop operation, open-loop operation, fuzzy evaluation