Load demands in a power system are randomly and constantly changing over time, leading to the deviation of network frequency from its nominal value (50Hz or 60Hz). Due to the undesired consequences of this deviation, it is very necessary to deal with the load-frequency control (LFC) in order to maintain the nominal working frequency. This study investigates an efficient combination of fuzzy logic controllers based on PD principle and superconducting magnetic energy storage (SMES) devices to solve the problem of LFC. Such PD-based fuzzy logic controllers can damp quickly the deviation of the network frequency, while SMES units can compensate efficiently the variation of load during the operation of a power system. The effectiveness of the proposed controllers as well as SMES devices for LFC strategy compared with conventional PI regulators will be demonstrated in a five-area interconnected power system as a typical case study of a large-scale electric network in reality. Also, various load conditions will be considered in this study to evaluate comprehensively dominant features of the proposed control scheme for LFC problem.