  The integration of a massive number of large-scale wind turbines brought
about urgent technical challenge to power transmission network operators in
terms of secure power supply and energy dispatching optimization. In this
paper, an optimal framework is proposed for transmission expansion planning in
a deregulated power market environment. The level of congestion in the network
is utilized as the driving signal for the need of network expansion. A
compromise between the congestion cost and the investment cost is used to
determine the optimal expansion scheme. The long-term network expansion problem
is formed as the decoupled combination of: 1) the master problem (minimization
of investment costs subject to investment constraints and the Benders cuts
generated by the operational problem (power pool) and 2) the operational
problem, whose solution provides congestion details and associated multipliers.
A proper power-pool model is developed and solved for congestion cost,
congestion revenue, and transmission shadow prices. Also, we proposed to use a
set of metrics to rate the effect of the expansion on the generators, demands,
and the system as a whole. The proposed model is applied to the Garver six-bus
system and to the IEEE 24-bus Reliability Test System.
