Series compensation to increase system stability: static and dynamic assessment

In the light of future energy policy objectives, transmission system planners are faced with several challenges. Main concerns are the power systems stability in the event of large power transfers on Extra Hight Voltage (EHV) backbones across critical sections which can result severely loaded when high renewable generation occurs. Furthermore, the identification of cost-effective development options is a key pillar to realize efficient investments in uncertain future energy scenarios. The significant expected growth of variable Renewable Electricity Sources (RES) in the Italian power system foresees potential increasing network congestions in the south-north direction. In this perspective the angle stability constraint and the extension of strategic transmission paths operational limits, becomes relevant to the operation of the power system. In recent studies, benefits in terms of loadability increase and voltage phase shifts mitigation from combining the "5-phases"with the capacitive series compensation have been assessed in static regime. In this paper, dynamic analyses are carried out in a wider pilot network affected by stressful power transfer conditions to test the combined mitigative solutions even in in terms of transient and voltage stability.