Convex Optimization Based Distributed Optimal Gas-Power Flow Calculation

This paper proposes a convex optimization based distributed algorithm to solve the multi-period optimal gas-power flow (OGPF) problem in coupled energy distribution systems. At the gas distribution system side, the nonconvex Weymouth gas flow equations are convexified as quadratic constraints. Then, the optimal gas flow (OGF) subproblem is solved by an iterative second-order cone programming (SOCP) procedure, whose efficiency is two orders of magnitudes higher than traditional nonlinear methods. A convex quadratic program based initiation scheme is suggested, which helps to find a high-quality starting point. At the power distribution system side, convex relaxation is performed on the nonconvex branch flow equations, and the optimal power flow (OPF) subproblem gives rise to an SOCP. Tightness is guaranteed by the radial topology. In the proposed distributed algorithm, the OGF problem and the OPF problem are solved independently, and coordinated by the alternating direction multiplier method. Numerical results corroborate significant enhancements on computational robustness and efficiency compared with existing OGPF calculation methods.