The invention provides a maximum sag modeling method of a substation flexible conductor on the basis of a
catenary. The method includes the steps of firstly, dividing the substation flexible conductor into a
strain insulator string and a flexible
bus, and determining structure parameters and material parameters; secondly, establishing an X-
Y coordinate system with a hanging point of the
strain insulator string as an original point, establishing the spatial coordinate equation of the
strain insulator string assuming that the hanging point bearing reaction force RA and the horizontal tension T0 are known, and obtaining the
horizontal projection length and the perpendicular projection length of the strain insulator string; thirdly, establishing an x-
y coordinate system with an end point of the flexible
bus as an original point, and obtaining the flexible
bus catenary equation on the basis of a
catenary theory; fourthly, converting the flexible bus from the x-
y coordinate system to the X-
Y coordinate system through coordinate conversion, obtaining the substation flexible
conductor sag expression through the combination of the spatial coordinate equation of the strain insulator string, and then obtaining the maximum sag value of the flexible conductor. On the basis of the known structure parameters and the known material parameters, the accurate maximum sag value is directly obtained according to any design stress of a substation, the sag control is facilitated, and quite high application value is obtained.