Reliability-constrained distributionally robust expansion planning of integrated electricity-gas distribution system with demand response

With the rapid development of integrated electricity-gas systems at distribution level (IEGS-D), their reliability is receiving more and more attention. To balance the economy and reliability in the planning process, a distributionally robust expansion planning of IEGS-D with explicit reliability evaluations is proposed. The paper considers the upgrade of electricity lines and pipelines, the investment of distributed generators (DGs), power-to-gas equipment (P2G), gas storage facilities, and the installation of electricity and gas demand response (DR) services. To cope with the uncertainty of wind generation and electricity/natural gas loads, a distributionally robust optimization (DRO) based coordinated planning of the IEGS is derived. In addition, system average interruption frequency index (SAIFI) for electricity and natural gas distribution system is proposed, where the reliability indices are formulated as a group of mixed-integer linear constraints. Finally, the effectiveness of the proposed model is verified by the modified IEEE 33-node power system and the Belgian high-calorific 20-node natural gas system.