# Optimal Placement of Multiple Feeder Terminal Units Using Intelligent Algorithms  
Dan Lin  
School of Electric Power, South China University of Technology, Guangzhou 510640, China; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (Q.L. ); [EMAIL_ADDRESS] (F.L. ); [EMAIL_ADDRESS] (Z.W. ); [EMAIL_ADDRESS] (G.Z. ); [EMAIL_ADDRESS] (Y.C.) Qianjin Liu  
School of Electric Power, South China University of Technology, Guangzhou 510640, China; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (Q.L. ); [EMAIL_ADDRESS] (F.L. ); [EMAIL_ADDRESS] (Z.W. ); [EMAIL_ADDRESS] (G.Z. ); [EMAIL_ADDRESS] (Y.C.) Yusheng Li  
School of Electric Power, South China University of Technology, Guangzhou 510640, China; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (Q.L. ); [EMAIL_ADDRESS] (F.L. ); [EMAIL_ADDRESS] (Z.W. ); [EMAIL_ADDRESS] (G.Z. ); [EMAIL_ADDRESS] (Y.C.) Yusheng Li  
School of Electric Power, South China University of Technology, Guangzhou 510640, China; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (Q.L. ); [EMAIL_ADDRESS] (F.L. ); [EMAIL_ADDRESS] (Z.W. ); [EMAIL_ADDRESS] (G.Z. ); [EMAIL_ADDRESS] (Y.C.) Yusheng Li  
School of Electric Power, South China University of Technology, Guangzhou 510640, China; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (Q.L. ); lifiusheng0208@foxmail. feeder manually, it is considered that this terminal unit meets the meaning of \"remote\" in Chinese. The numbers \"one\", \"two\", and \"three\" can be understood as describing the level of automation this terminal unit brings to the distribution network, which can be sensed through the roles of the three types of FTUs in the fault management. The \"One remote\" terminal unit can indicate at the feeder site whether the fault current flows through the corresponding switch, and can help maintenance operators find the fault quickly when they are patrolling the feeder. The \"Two remote\" terminal unit can measure the current and voltage of the corresponding switch. Therefore, it can identify whether the fault current has flowed through the switch. If it is, it will communicate this information to the master station, which can help the operators in the master station to determine the feeder segment where the fault may exist remotely. On the basis of the \"two remote\" terminal unit, the \"three remote\" terminal unit has an additional function: the operators in the master station are able to remotely control the corresponding switch, reducing the time to isolate the fault. To be more concise, we call the sectionalizing switch (SS) with a \"one remote\"/\"two remote\"/\"three remote\" terminal unit as a type A/B/C switch, and call the SS without any FTU as a type D switch. The number and location of FTUs directly affect the reliability, investment, and operation and maintenance costs of the distribution network. In the China Southern Power Grid Company Limited (CSG, one of the two major power grid companies in China), the planning technical guidelines lack targeted guidance for the placement problem of FTUs, in which it is advised to divide the electricity supply areas according to the load density and equip them with the same type of FTUs for the SSes. However, in order to meet the reliability requirements, guidelines often suggest excessive placement of the \"three remote\" terminal units, resulting in extremely high investment cost. In this context, significant and urgent investigation is needed to obtain a better trade-off between reliability and economical placement of FTU. Various papers have been published about optimal placement of SS or remote control switch (RCS). Related models and algorithms have been extensively studied, with SS and RCS formulated in nearly a same way (described as type C switch in this paper). [PERSON] presented a tree-structure based algorithm to compute performance indexes when the positions of SSes are given, and applied it to the radial distribution networks [1]. [PERSON] et al. studied the same problem from the perspective of multi-objective optimization [2]. When [PERSON] et al.