Optimal operation of regional meshed power–gas systems: A tightened conic relaxation based approach

Abstract

Under the reliability consideration of the multi-energy system, more and more regional networks are in meshed topology. This paper presents a novel method for the regional meshed power–gas system based on the reformulated and tightened cone relaxations. The proposed model defines two energy flows, which are relaxed as convex constraints in the optimization. In the power network, considering the phase angle of each node in meshed networks, a series of conic relaxation-based constraints are employed to represent the alternating current power flow. In the gas network, the conic relaxations are imposed with convex hulls and cones to the gas flow, taking the transmission directions and line-pack constraints into account. To enhance the quality of the relaxation, we propose an approach to tighten the feasible region through two steps. The first step is to tighten the lower and upper bounds of the variables through an optimality-based linear program. The second step is to solve the relaxed tightened optimization with new bounds through a mixed-integer second-order cone program. The advantage and applicability of the proposed approach are tested over a real case study, which shows the improvement of solution quality and optimization speed.