Lehretz, Fabian
Biography
Mr. Lehretz studied composite materials at Hof University and subsequently worked for nine years in the R&D Department at Lapp Insulators. Since 2019, he has been responsible for insulators and corrosion protection at TenneT TSO GmbH, a large power grid operator in Germany. He is Convenor of CIGRE WG B2.80 (Numerical Simulation of Composite Insulator Strings) and IEC 63264 Insulators with integrated optical fibres.
HTV silicone is the preferred material for composite insulators used on overhead lines due to its hydrophobicity, hydrophobicity recovery and hydrophobicity transfer. While these properties have been verified in standardized test procedures, resistance to ageing during operation is also critical since this can lead to insulator failure. TenneT, a cross-border TSO, applies a systematic approach to assess reliability using a ‘Health Index’ for each grid component. This presentation explains how this concept is applied to new lines being equipped with polymer insulators. It also discusses choice of samples as well as assessment of laboratory test results and provides specific examples showing the practicability and reliability of this process.