Mobile Substations: Application, Engineering and Structural Dynamics

The current trend in reducing the erection time of substations has driven to the use of pre-mounted assemblies for quick installation in all kind of forms. In such cases the substation components have to be transported mounted in their operation position. Mobile substations are the clearest example. Mobile substations present specific characteristics which make the substation designer to be confronted with problems not affecting to conventional substations (AIS or GIS). The substation equipment must be fixed to a semi-trailer considering the space limitation, insulation distances and not only static but dynamic loads due to transport. The equipment must be fitted in a way to allow a fast installation requiring minimum work. Regular substation components with its support structures have natural frequencies in the normal range of transport motion and then dynamic loads due to vibrations have to be considered. The dynamic forces that occur during transport are of long duration and metal-fatigue has to be taken into account. This paper intends to give an overview of the singular engineering of mobile substations and the special considerations for the application of those substations in the North-American electric network