Frequency is an important technical parameter in evaluating the power quality of the power system and must be maintained within prescribed limits to ensure stable operation of the power system. Therefore, maintaining a stable frequency within the prescribed limits is always the goal of power system designers and operators, based on the analysis of the effects of frequency on the power system, previous domestic and foreign research works, as well as the reality of load shedding being applied in Vietnam today. Research is carried on load shedding methods to restore power system frequency stability on the basis of identifying whether or not load shedding combined with knowledge technology algorithms such as AHP and neural networks. The proposed load shedding method allows to quickly make decisions on choosing a reasonable and effective load shedding strategy to keep the power system frequency stable when a short circuit occurs on the busbars or on the lines of the electrical system. Besides, the proposed load shedding method has less load shedding capacity and faster frequency recovery time than traditional load shedding methods.