Are there any common methods to model optimizations of power transmission expansion planning (TNEP) in a DC model using GAMS?

I'm trying to find a way to optimize power transmission expansion planning in a given network topology. The problem is to be programmed in GAMS with the simplified DC model approach where the optimal power plant dispatch is also optimized.
Expansions of the transmission network could be either the adding of circuits of existing lines or the voltage upgrade of existing lines.