Series Compensation of an Uprated 230 kV – 50 Hz Backbone in Central Italy: Impact on Fault Quantities

The predominant reason for adding series capacitors in power systems is to increase power transfer capacity enhancing both the voltage and angle stability margins. The resulting decrease in series reactance can determine also undesired effects during faults: the fault current increases in dependence of the compensation degree and of the fault location in the system. This paper investigates the case of an Italian 230 kV – 50 Hz backbone spanning the Centre North – Centre South section, for which re-equipment with high-temperature conductors in conjunction with the installation of 60% capacitive series compensation are being evaluated. The impact of series compensation on faults levels (both phase-to-phase and phase-to-ground) and on the earth fault factors is systematically studied, within the backbone and in the nearby area. A parametric analysis is carried out, considering different generation, load and network scenarios evidencing the impact of series compensation is compatible with present equipment and system operation.