Frequency-constrained optimal power-gas flow with fast frequency response from power-to-gas units

• A frequency-constrained optimal power-gas flow incorporating frequency support from P2Gs and line-pack is proposed. • The dynamic behaviors of the P2Gs and line-pack during frequency regulation are depicted. • A mixed-integer linear programming-based global optimization algorithm is developed to solve the proposed model. • Fast frequency response provided by P2Gs outperforms primary frequency response from generators. The substantial increase in renewable energy integration has resulted in a reduction in inertia and frequency regulation resources within the power system. This reduction poses significant challenges to maintaining system frequency stability, prompting further investigation into the rapid adjustment capabilities of gas-fired units (GFUs) and power-to-gas (P2G) units, which in turn drives the advancement of integrated electricity-gas systems (IEGSs). The coupling between the power system and natural gas system presents both considerable frequency regulation resources for the power system and the frequency stability problem for IEGSs. In this context, this paper investigates the frequency-constrained optimal power-gas flow (FC-OPGF) problem from the perspective of an IEGS. The frequency regulation behaviors of P2Gs and line-pack are formulated considering their frequency support capability. To obtain the global optimum of the FC-OPGF problem, a mixed-integer linear programming-based global optimization algorithm is developed. Case studies highlight the necessity of incorporating frequency constraints in IEGS operation, alongside demonstrating the high solving efficiency and calculation accuracy of the proposed global optimization algorithm.