Autoreclosure is an irreplaceable protective scheme that was initially engineered for power system stability
enhancement especially in areas with high isokeraunic levels. Unsuccessful reclosure on transmission
lines emanating from thermal power plants has been long identified as a potential hazard to the
shafts of the turbine-generators in these power plants. Therefore, the principal focus of this work is to
mitigate the shaft torsional oscillations resulting from unsuccessful reclosure. The main scope of this
study is to utilize a battery energy storage system controlled via fuzzy logic controllers to mitigate shaft
torsional oscillations resulting from unsuccessful reclosure. Additionally, a coordinated operation of
fuzzy based dynamic braking resistor is considered to obtain a superior torsional torque profile. Local
control input signal synthesized from the generator shaft speed is employed in this work for the proposed
controllers. For testing the effectiveness of the proposed scheme, non-linear time-domain simulation
study is performed on a single machine infinite bus and the IEEE 3-machine 9-bus system via
MATLAB/Simulink-based modelling and simulation platform. Comparative simulation studies of the test
systems after being subjected to unsuccessful reclosure of three-phase to ground fault conditions demonstrate
the effectiveness of proposed scheme. From the time domain simulation results, the torsional torque
profiles reach an excellent level due to the implementation of the proposed scheme |
