TY - JOUR A1 - Schober, Fabian A1 - Küchler, Andreas A1 - Krause, Christoph T1 - Oil conductivity – an important quantity for the design and the condition assessment of HVDC insulation systems JF - FHWS Science Journal N2 - HVDC (high voltage direct current) transmission is a very effective way of power transmission and it is necessary to supply the worlds growing amount of energy. In HVDC equipment the major insulating materials are oil and pressboard. Oil conductivity is an important quantity for the design, the diagnosis and the condition assessment of HVDC insulation systems. Unfortunately, insulating oil has a strongly nonlinear conductivity which depends on various parameters (field strength, temperature, water content and ageing) and is time-dependent because of charge carrier drift processes. Measuring methods are required to provide the information necessary for the condition assessment of HVDC systems. Therefore, measurements of new and aged oils are compared and taken into account for a diagnosis of oil-filled HVDC insulation systems. Furthermore, today’s standards are analyzed and compared to the so called PDC method. Relations between initial and steady-state conductivities at different temperatures, field strengths and for various oil types are presented and consequences for the condition assessment of insulation systems are discussed. KW - Electromobility KW - Energy Engineering KW - HVDC transmission KW - converter transformer KW - insulation Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:863-opus-463 VL - 1 IS - 2 SP - 59 EP - 78 CY - Würzburg ER -