Transmission planning with probabilistic modeling of multiple contingencies

Transmission planning is a way of improving reliability and security of the power system. The security can be defined as the ability of the power system to withstand a credible contingency such as loss of a large generating unit or a heavily loaded transmission line. This paper proposes a new probabilistic transmission planning approach which takes into account both security and economic issues. The power system security is modelled using the following three states of power system: (a) steady state equilibrium, (b) transition to new steady state equilibrium and (c) new steady state equilibrium. These three steps present the state of power system before, during, and after a contingency occurred. The transmission expansion plans approved by proposed formulation is applied to the modified IEEE 24-Node reliability test system. Then the expanded system is subjected to several contingencies. The suggested transmission planning schedule is analyzed by comparing the production cost and the generation dispatch schedules. The results show that the proposed probabilistic transmission planning approach can effectively model the multiple contingencies in the transmission planning process.