  This paper proposes a convex optimization based distributed algorithm to
solve multi-period optimal gas-power flow (OGPF) in coupled energy distribution
systems. At the gas distribution system side, the non-convex Weymouth gas flow
equations is convexified as quadratic constraints. The optimal gas flow (OGF)
subproblem is solved by an iterative second-order cone programming 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 non-convex branch flow equations,
and the optimal power flow (OPF) subproblem gives rise to a second order cone
program. Tightness is guaranteed by the radial topology. In the proposed
distributed algorithm, OGF and OPF are solved independently, and coordinated by
the alternating direction multiplier method (ADMM). Numerical results
corroborate significant enhancements on computational robustness and efficiency
compared with existing centralized OGPF methods.
