Long Tail Withstand Voltage Test (TOV test) on the HVDC Cable and Accessories of the Italy-France Intertie

Abstract

The integration of HVDC VSC systems into the power transmission system raises new questions regarding DC transient fault voltage waveforms and their simulation in the laboratory. Numerical simulations reveal that waveforms not covered by the IEC standards can occur in the event of failures. In the meantime, such waveforms are proposed in the CIGRE TB 852 and 853 for HVDC cable systems. Still, the tolerances are wide, and the comparison of the test results may be difficult. The paper presents an overview about test voltage selection and testing activity performed on a 320 kV XLPE cable (terminations, cable and joints) with a typical length for type test loops, showing tests results. The paper also highlights the good fit between waveforms achieved in laboratory and the one actually happened in the field during operation.