Robust decentralized frequency stabilizers design for SMES taking into consideration system uncertainties

This paper proposes a new robust decentralized design of frequency stabilizers installed with superconducting magnetic energy storages (SMESs) by taking system uncertainties into consideration. To stabilize system frequency oscillations due to large load disturbances, the active power controlled by SMES can be exploited. The multiplicative uncertainty which is used to represent system uncertainties such as variations of system parameters, system non-linearities etc., is incorporated in system modeling. As a result, the system robust stability can be easily guaranteed in terms of the multiplicative stability margin (MSM). The frequency stabilizer is practically based on a second-order lead/lag compensator. To improve MSM, control parameters of frequency stabilizers are automatically optimized by a micro genetic algorithm. Simulation studies exhibit the high robustness of frequency stabilizers against uncertainties. Moreover, small MW/MJ capacities of SMESs are required for frequency stabilization.