A Two-Stage Combined UC-OPF Model Using Mixed Integer and Semi-Definite Programming

A two-staged combined unit-commitment (UC) andOptimal power flow (OPF) architecture are proposed in this pa-per based on mixed-integer semi-definite programming (MISDP).The MISDP problem is then divided into a mixed-integer linearprogramming problem and a semidefinite programming problemto achieve the solution. Different cases have been studied on 6bus, IEEE 14 bus, and IEEE 118 bus systems to test the efficacyof the proposed method. It has been observed that the proposedtwo-staged combined UC gives very close results (2% differencesin solution differences in comparison with unified approach) forsmaller systems while scalable and feasible for IEEE 118 bussystem where the unified approach fails. The optimal operatingpoint derived from the two-staged approach is comparable withthe unified approach but the proposed approach performs betterin terms of scalability.