An Analysis of the Fuzzy Logic Controlled Braking Resistor for Transient Stability Improvement in Multi-Machine Power System

This paper presents the results of analyses about transient stability augmentation by the fuzzy logic controlled braking resistor in a Multi-Machine power system. Following a major disturbance in electric power system, variable rotor speed of the generator is measured, and then the current through the braking resistor is controlled by the firing-angle of the thyristor switch which is controlled by the fuzzy logic. Thus the braking resistor controls the accelerating power in generators and makes the system transiently stable. Simulations are performed by using EMTP (Electro-Magnetic Transients Program). Through the simulation results of both balanced (3LG: Three-phase-to-ground) and unbalanced (1LG: Single-line-to ground, 2LG: Double-line-to ground and 2LS: Line-to-line) faults at different points in the IEEJ West-10 machines system model, the effectiveness of the proposed fuzzy logic controlled braking resistor is demonstrated and the optimal conductance value of the braking resistor in enhancing the transient stability is investigated. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved