Soft open point(SOP)is a new kind of flexible equipment which is installed in some key interconnection points of the distribution network to replace a few traditional tie switches. The application of SOP will improve the safety

reliability and flexibility of distribution network and promote the configuration of distribution network in future. In this paper

the working principles of SOP are briefly described firstly

and its characteristics are analyzed compared with distribution flexible AC transmission system(DFACTS)equipment. Then

considering the structure

principle and function of SOP

this paper discusses the topological structure

operation optimization

control protection strategy and system connection techniques of SOP. Finally

after a brief review on some related demonstration projects

some potential research points on the equipment development

control strategy and system connection techniques of SOP are proposed.