Security-Constrained Unit Commitment With Natural Gas Transmission Constraints

TLDR

The paper develops a security‑based method for short‑term SCUC that incorporates natural gas transmission constraints. The method models the gas network with nonlinear equations, decomposes the SCUC into separate gas and power feasibility subproblems, iteratively adds violated gas constraints to the master UC until convergence, and is validated on a six‑bus and an IEEE 118‑bus test system. The resulting model enables utilities or ISOs to perform short‑term unit commitment and dispatch while respecting natural gas transmission constraints.

Abstract

The contribution of this paper focuses on the development of a security-based methodology for the solution of short-term SCUC when considering the impact of natural gas transmission system. The proposed methodology examines the interdependency of electricity and natural gas in a highly complex transmission system. The natural gas transmission system is modeled as a set of nonlinear equations. The proposed solution applies a decomposition method to separate the natural gas transmission feasibility check subproblem and the power transmission feasibility check subproblem from the hourly unit commitment (UC) in the master problem. Gas contracts are modeled and incorporated in the master UC problem. The natural gas transmission subproblem checks the feasibility of natural gas transmission as well as natural gas transmission security constraints for the commitment and dispatch of gas-fired generating units. If any natural gas transmission violations arise, corresponding energy constraints will be formed and added to the master problem for solving the next iteration of UC. The iterative process will continue until a converged feasible gas transmission solution is found. A six-bus power system with seven-node gas transmission system and the IEEE 118-bus power system with 14-node gas transmission system are analyzed to show the effectiveness of the proposed solution. The proposed model can be used by a vertically integrated utility or the ISO for the short-term commitment and dispatch of generating units with natural gas transmission constraints.