Pre-disaster preventive dispatch for urban power grids considering frequency support from hydrogen energy systems

With the increasing frequency of extreme weather disasters, urban power grids are vulnerable to topology disruptions and to the frequency-security risks associated with weather-induced line outages and post-contingency operating disturbances. To enhance frequency support in pre-disaster preventive dispatch, this paper proposes a method for pre-disaster preventive dispatch in urban power grids considering frequency support from hydrogen energy systems. First, considering the virtual inertia control and primary frequency regulation characteristics of fuel cells and electrolyzers, a system frequency dynamic response model is constructed, and constraints on the maximum rate of change of frequency, maximum frequency deviation, and quasi-steady-state frequency deviation are established. Second, with the objective of minimizing the cost of pre-disaster preventive dispatch and the expected load-shedding loss under fault scenarios, an optimization model is developed by considering generator output adjustments, hydrogen energy system operation, preventive load shedding, and frequency-regulation reserve allocation. Finally, the problem is formulated as a Markov decision process and solved using the Soft Actor–Critic (SAC) algorithm. Case studies on the modified IEEE 39-bus and IEEE 118-bus systems show that the proposed method can reduce load-shedding loss, improve online decision speed and promote compliance with the prescribed frequency-security limits under the investigated scenarios and evaluation protocol.