Investigations of models and methods for transmission network planning

Based on diverse power flow distribution patterns resulting from the use of FACTS devices and/or different modes of system operation, this paper argues that the transportation model is better suited for the transmission network planning. This viewpoint runs contrary to the conventional practice where the d.c. power flow constraints are widely used. This paper shows that using the transportation model in the transmission planning study can result in less complex formulas, more practical approaches, and, quite possibly, a better result of network planning. In addition, an improved security cuts method is implemented to produce a more secure network expansion. A two-phase planning procedure is also introduced to attain a trade-off between the computational burden and the solution accuracy. IEEE 6-bus system has been tested by the proposed methods. The results are compared with other existing techniques.