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A method of counteracting torsional interactions in series compensated power systems is described. This method involves the measurement of the transmission system currents from which the subsynchronous components which produce torsional interactions are extracted. A method of accomplishing this is described in the paper. Once extracted, these signals are subsequently amplified by a controllable current source and injected into the generator bus so as to cancel the original subsynchronous components which would otherwise produce torsional interactions. The IEEE first benchmark system is used to investigate the effectiveness of this approach. A small displacement (eigenvalue) analysis of this system is provided in which it is shown that torsional interactions are prevented. Additionally, the generalized Nyquist method is used to characterize phase and gain margins associated with the feedback circuitry. Finally, the time domain behavior of the benchmark system is investigated by computer simulation.