Gnosys at INSUCON 2017
[15th May, 2017]
These are the abstracts for the papers being presented:
Self-healing electrical insulation systems
[G.C. Stevens, R. Rhodes, S. Basu, I. German]
Self-healing materials should be capable of autonomously repairing minor damage preventing longer term progressive development of faults which could lead to eventual failure. Realising this capability in insulation material systems that could be readily processed and manufactured for engineering applications would be of great value for assets that are either difficult or prohibitively expensive to access. Examples of such assets include underground and subsea cables, generator stators and rotors, and transformers. However, obtaining self-healing mechanisms and materials chemistries that can confer practical self-repair without compromising other performance factors is challenging.
Gnosys has developed a number of materials that show great promise for developing self-repairing cable insulation systems in both extruded polymeric and fluid-filled cables. This will be illustrated by reference to sub-sheath repair materials for extruded polymeric cables which are capable of preventing water incursion through very large sheath defects and can be processed using common cable extrusion techniques. Similarly, we will illustrate the challenges of ensuring that self-healing insulating fluids maintain their electrical and dielectric properties when self-healing chemistries are added to the fluid, resulting in “self-healing fluid” properties that either match or surpass those of commonly used dielectric fluids.
A wide variety of experimental techniques are used to evaluate potential self-healing systems. Self-healing chemistries are examined using chemical analytical techniques to elucidate healing mechanisms and structural change that can support repair. This will be illustrated by reference to both solid and liquid insulation self-healing systems including the use of experimental methods to quantify self-repair function. This includes measurement of key physical properties required to maintain the electrical and fluid properties in self-healing insulating fluids and dielectric, electrical, mechanical and thermal properties in self-healing solids.
Self-healing materials hold promise to improve the performance of high voltage assets, including longer lifetimes, reduced maintenance requirements and greater resilience to common failure modes. However, it is essential that we select appropriate self-healing mechanisms that are activated by conditions that arise when an asset is damaged (e.g. water ingress, partial discharge, surface corona) to ensure that damage can be repaired continuously and the insulation system be maintained.
Rapid evaluation of electrical insulation materials along the supply chain – using Chemometric methods
[H. Herman, N. Freebody, A. Pye, P. Baird and G. C. Stevens]
Chemometrics is the science of applying multivariate mathematical and statistical analysis methods to the extraction of maximum information from complex data sets and the determination of inter-relationships between variables controlling outcomes and properties. While these methods have been widely used in analysing chemical information in chemistry research, chemical engineering and the petrochemicals and pharma industries, to mention a few, they have not been widely used in the development, evaluation and testing of electrical insulation materials.
Gnosys has developed experience and software tools to facilitate the use of these methods for electrical insulation materials in the laboratory, factory and on-site. These developments have particularly made use of spectroscopic measurements for rapid and non-destructive chemical characterisation, measurement of physical properties and performance, establishing structure-property relationships, materials condition assessment and quality assurance. This enables the basic methods and tools to be applied along the supply chain from materials development, production and supply, polymer and composite formulation and testing, insulation system manufacture, condition assessment in the factory and on-site and assessment at end of life.
We will illustrate the applications of these methods to a variety of solid and liquid electrical insulation material systems at different points along the supply chain. This will include examples drawn from the characterisation of polymeric solids and liquids used in both thermoplastic and thermoset based insulation systems, the measurement of physical properties, resin cure behaviour, the assessment of thermal ageing and importantly the measurement of materials condition in service in support of condition assessment for improved asset management. The latter will include examples drawn from transformers, power cables and generators.
The paper will conclude with a view of the future application of these methods in materials research, manufacturing support and distributed spatial condition assessment for improved asset management.