Frequency-Constrained Dispatching for an Integrated Electricity-Heat Microgrid With Synergic Regulation Resources

Abstract

Given the low-inertia nature of the power grid within the integrated electricity-heat microgrid (IEHM), it is vulnerable to frequency deviations caused by power disturbance. To address this challenge at the operational level, this paper proposes a frequency-constrained dispatching method for IEHMs. This method coordinates synergic resources with diverse dynamic features, including combined heat and power (CHP) unit, wind turbine, and battery energy storage system (BESS), to contribute to primary frequency regulation (PFR). Frequency security, both dynamic and static, is maintained through constraints that account for synergic PFR resources. We employ a distributionally robust (DR) joint chance constraint to manage the wind power uncertainty in IEHMs with a high penetration of wind energy. Based on the above modeling, we develop a frequency-constrained dispatching model for IEHMs. This model integrates the coupled energy sectors to balance the PFR reserves and energy supply while guaranteeing frequency security and minimizing the daily cost of IEHM. To tackle the nonconvex DR joint chance constraint, we adopt a big-M-free reformulation approach based on the Wasserstein-metric ambiguity set, which requires fewer predefined parameters and significantly enhances computational efficiency. Finally, extensive case studies on two test systems validate the effectiveness and scalability of the proposed method. Simulation results also highlight the impact of heat load on PFR in IEHMs.