Mitigation of ferroresonance in line commutated HVDC converter interconnected with series compensated overhead line transmission system

Ferroresonance is a non-linear resonance which can typically occur when a saturable magnetizing inductance forms a resonance circuit with a capacitor. An example of such a resonance condition can be a system configuration where an overhead transmission line with series compensation terminates into a HVDC converter transformer. Such a configuration may lead to post fault ferroresonance oscillations. Mitigation of ferroresonance using converter controls is a simple and economically attractive solution when compared to other solutions such as installing additional equipment in the network. This paper proposes a damping controller to mitigate ferroresonance oscillations for a HVDC system.