Open-Phase Resonance in Shunt-Compensated AC Cable Lines

Shunt-compensated ac cable lines (CLs) are a commonly used solution for the connection of renewable energy sources, such as offshore or onshore windfarms. Three phase shunt reactors allow for a cheap and reliable compensation of the surplus reactive power generated by the power cables; however, the interphase magnetic coupling can introduce open phase resonance phenomenon, which is normally not expected to occur in underground CLs, which do not have any electrostatic coupling. Theoretical formulae for evaluating the risk of open-phase resonance in shunt compensated CLs are presented in the paper, as well as steady-state and time domain simulations using detailed cable and shunt reactor models.