Method and device for determining transmission section in consideration of key branch circuit

The invention discloses a method and a device for determining a transmission section in consideration of a key branch circuit. The method comprises the following steps of: preliminarily determining a transmission section in a system according to a network structure and a tidal current status, and in an analysis process for the limit transmission power of the section, identifying the key branch circuit influencing the transmission capability of the section, and returning the key branch circuit as an actual monitoring object of the section to realize the dynamic regulation of the transmission section. By the transmission section finally determined by the method and the device, the security characteristics of the system can be truly and accurately reflected.