Study on the method of evaluating open/closed loop operation modes of electromagnetic loop network based on group decision-making theory

The electromagnetic loop network in power system refers to the annular grid composing of two groups of different voltage grades transmission lines connected by transformers or electromagnetic coupling. The operation of electromagnetic loop network has an important influence on power supply reliability, short-circuit current level, etc. This paper proposes an evaluation method of the open/closed loop operation modes of electromagnetic loop network based on group decision-making theory. Proceeding from reliability and economical efficiency of power grid operation, the method regards bus short-circuit current level, line load rate, transformer load rate, power system static security, power system transient stability and network loss as the indexes to evaluate the different ways of opening electromagnetic loop network. Based on the indexes of expectation curve in the actual operation of power grid, the paper establishes the evaluation formulas of operation indexes with threshold value. Then a new method based on multiple attribute group decision-making is put forward to determine weight parameters of each operational index. The theoretical method considers impacts on the weight parameters with respect to the degree of decision results consistency between experts and expert group during decision-making activities. According to the above evaluation method, advantages and disadvantages can be analyzed by quantitative comparison of different open/closed loop operation modes of electromagnetic loop network. By the comparisons of calculation examples in Nanjing(Jiangsu province, China) power grid, it shows that the methods of getting electromagnetic loop network operation evaluation indexes are practical and effective.