Velitsikakis, Kostas

Grid Strategist, Asset Management, TenneT TSO, Netherlands

Velitsikakis, Kostas

Grid Strategist, Asset Management, TenneT TSO, Netherlands

Biography

Surge Arrester Stresses due to Harmonic Resonance Temporary Overvoltages in Transmission Systems: Case Study of Dutch Grid

Mr. Velitsikakis received his M.Sc. in High Voltage Engineering from the Technical University of Delft in 2013 and works as senior expert in the field of Insulation Coordination and Electromagnetic Transient (EMT) studies for HV and EHV transmission systems. Currently, he is Secretary of the CIGRÉ Working Groups C4.46 ” Evaluation of Temporary Overvoltages in Power Systems due to Low Order Harmonic Resonances” and B1/C4.69 “Insulation Coordination of HVAC Cables”.

HVAC cable systems of significant length are being introduced into grids along with longer cable circuits due to connection with offshore wind generation. The higher capacitance of a cable leads to changes in harmonic impedance profile of the system close to the points of connection and new resonances can be created at low frequencies that can shift close to or at a low harmonic. Such harmonic resonances could be excited under system transient events resulting in temporary overvoltages that can stress components dielectrically and thermally. This presentation explains why arresters need special attention under harmonic resonance TOV conditions and their assessment during electromagnetic transient studies. Results of such a study in the 400 kV Dutch system are also shown.

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