Can you directly the transformer to the generator and avoid inrush by allowing the generator's AVR to bring the voltage up gently? If you switch on the other (HV? LV?) side of the transformer then you avoid inrush due to the transformer and make life easier for your generator. If you do this you should consider extending the generator's zone protection out to cover the transformer too.
Damping of transformer inrush oscillations can be done with either a load connected to the transformer secondary or the primary. The idea is for energy that returns from the transformer during the inrush period has a place to go. There will also be a voltage overshoot when the voltage regulator tries to compensate for the inrush current.
Also, voltage regulators and speed governors are more stable when they have a load. First Energy's Eastlake and Avon Lake power plants have customers connected directly to the 13,200 volt generator buses as well as some 138 KV distribution substations that run directly off of the power plant. For instance, Brunswick, Ohio still had power on 14 August 2003 because their 138 KV was tapped in between Avon Lake's stepup transformers and the Fowler switchyard. When recovering from the blackout First Energy turned on some customers early partly to stabilize the generators, partly to absorb the charging current of the lines, and partly to absorb the bump that occurs when synchronizing to adjacent utilites.
