A Comparative Analysis of Transmission System Planning for Overhead and Underground Power Systems using AC and DC Power Flow

This paper investigates and compares the results of a transmission system planning approach when both underground and overhead conductors are individually considered. Instead of using a transmission expansion planning of an existing grid, a two-stage transmission planning approach to design a completely new power system is proposed. In addition, the power system is planned by introducing the compulsory N-1 security constraint. Both a relaxed conic AC and a DC power flow models are used and compared. For the purpose of making a comparative analysis of the underground and the overhead transmission system planning, a synthetic test case of the power system of Singapore is used.