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Abstract To efficiently reduce the fault currents of active distribution networks (ADNs), this paper proposes a novel methodology for Pareto optimal allocation of resistive‐type fault current limiters (R‐FCLs). The proposed approach enables to simultaneously optimize the number, location, and size of the R‐FCLs in the ADNs with inverter‐interfaced and synchronous distributed generators (DGs). The sensitivity analysis is introduced to rank candidate locations, and a constrained multiobjective function is created to minimize the cost of the R‐FCLs and the fault currents of the ADNs. An improved multiobjective particle swarm optimization (MOPSO) algorithm and a multiobjective artificial bee colony (MOABC) algorithm are designed to obtain the Pareto optimal solution set. The proposed approach is verified using the modified IEEE 33‐node and 69‐node distribution systems, where both centralized and dispersed access of DGs are considered. The numerical results demonstrate that: (a) The fault currents in all nodes of the two testing systems are limited to the permissible levels using the least capital cost of the R‐FCLs, and (b) the improved MOPSO outperforms the MOABC to achieve a better Pareto front and decrease the number of iterative computation. In consequence, the feasibility and superiority of the proposed approach are well validated.

The necessary Low Voltage Ride Through (LVRT) capability is very important to wind turbines. This paper presents a method to enhance LVRT capability of doubly fed induction generators- (DFIGs-) based wind turbine systems with series superconducting magnetic energy storage (SMES) in the rotor side. When grid fault occurs, series SMES in the rotor side is utilized to produce a desired output voltage and absorbs energy. Compared with other methods which enhance LVRT capability with Superconducting Fault-Current Limiter-Magnetic Energy Storage System (SFCL-MESS), this strategy can control the output voltage of SMES to suppress the transient AC voltage component in the rotor directly, which is more effective and rapid. Theoretical study of the DFIG under low voltage fault is developed; the simulation results are operated by MATLAB/Simulink.