In general, the objective of electric transmission expansion planning (TEP) is to
specify addition of transmission facilities that provide adequate capacity and in the
mean time maintain operating performance of electric transmission system [5]. To
achieve effective plan, exact location, capacity, timing and type of new transmission
equipment must be thoroughly determined to meet demand growth, generation
addition and increased power flow. However, cost-effective transmission expansion
planning becomes one of the major challenges in power system optimisation due to
the nature of the problem that is complex, large-scale, difficult and nonlinear.
Meanwhile, mixed integer nature of TEP results in an exponentially increased
number of possible solutions when system size is enlarged.