Force safety device for substation with flexible buses

Short-circuit current sets the design loads for substation structure with flexible buses for voltage up to 115 kV and sometimes for higher voltage. Nonrecoverable force safety device (FSD) being included in flexible buses can restrict the transmission of great unwanted forces to substation portals. The device operates similar to a safety fuse of any electrical device while being replaced when tripped. The paper deals with theoretical investigation of FSD usage efficiency. Two mathematical models (one is to verify another) are built. The first model is based on the finite difference equations and the second one uses ANSYS finite elements program. The finite difference equations are derived by linearization of nonlinear equations of buses motion. Both models include bus conductor, insulators, FSD, portals masses, and portals stiffness. Results of actual calculations that show the efficiency of FSD are presented.