Mitigation technique and measurement of subsynchronous resonance

Due to development in the field of power system, more and more series capacitance compensations have been used in transmission system extensively and because of series capacitance compensation it leads to SSR problems. SSR occurs when a natural frequency of a series compensated transmission system coincides with the complement of one of the torsional modes of the turbine-generator shaft system. Under such circumstances, the turbine-generator shaft system oscillates at a frequency corresponding to the torsional mode frequency and unless corrective action is taken, the torsional oscillations can grow and may result in shaft damage in a few seconds. For mitigating the SSR in transmission system, a mitigation measure based on SVC is introduced[1].