George, Jean-Marie

Scientific Director, Sediver, France

George, Jean-Marie

Scientific Director, Sediver, France

Biography

1. Silicone Coating of Insulators: Latest Technical Knowledge Based on Field Performance & Laboratory Testing
2. AC & DC Pollution Testing Methods: Accuracy & Limitations
3. Simulation of Electric Field: What & What Not to Expect

Mr. George received his Electrical Eng. Degree from the HEI School in France and joined Sediver as Research Engineer in 1986. After working as Production Manager for the Composite Insulator Division and Quality Mgr. and Technical Dir. for North America, he is now Scientific Director, with responsibilities covering R&D and technical assistance worldwide. His cross-functional positions with more than 30 years of experience have given him expertise in insulator performance as well as research and development. He has published and co-authored extensively on overhead lines, with 40 papers and articles and he is also author/co-author of patents and utility models. He is a member of CIGRE, IEEE, NEMA, ANSI and CSA as well as 2018 recipient of the Claude de Tourreil Memorial Award for Lifetime Achievement in Electrical Insulators.

1. Substituting polymer insulators with a hydrophobic surface over glass has substantially impacted selection of insulators for polluted environments as well as for certain HVDC applications. Today many suppliers offer glass or porcelain insulators with coatings applied either in the factory or on site. This presentation will explain the key requirement of coating adherence. It will also review a unique field experience that brings light to the possible performance limits of coated insulators under extreme service conditions that go far beyond the pollution classifications within IEC TS60815.

2. Pollution performance of insulator strings is key in design of towers for overhead lines and even more pressing with silicone hydrophobic surfaces whose properties respond differently to various service conditions. This presentation summarizes relevant observations and test details when evaluating insulator strings under such conditions. It also explains why the testing of hydrophobic surfaces requires further work, as now underway in IEC, and why the issue of heavy and very heavy pollution conditions remains an open question. Finally, it seeks to demonstrate how DC glass insulators with appropriate shape can outperform the USCD expected from the IEC Guide.

3. Numerical simulations are required for composite insulators to ascertain electric field on the grading ring and end fittings, on the housing surface and at the triple point where air and housing meet end fitting. The purpose is to assess risk of erosion related to water drop corona. The situation is different for toughened glass cap & pin insulators where the characteristic to consider is visible corona inception voltage related to electric field in the air surrounding a string and to voltage grading along the string. This presentation discusses use of Finite Element Analysis to validate design of insulator strings up to complete assemblies with hardware and fittings and provides examples for AC O/H lines.

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