Nanodielectrics for use in HVDC power systems and their structure-property relationships using Chemometric methods

G.C. Stevens, N.A. Freebody, A.S. Vaughan, F. Perrot
Gnosys Global,
United Kingdom

Keywords: nanoparticle, nanodielectric, HVDC, HVAC, multi variate statistical analysis

Summary:

There is a need to develop materials with controlled electrical resistivity, reduced space charge accumulation, higher thermal conductivity, higher dielectric strength, enhanced voltage endurance and surface discharging erosion resistance to cope with DC stresses in High Voltage Direct Current (HVDC) transmission systems in addition to supporting HVAC requirements. If the balance of properties, performance and process requirements are achieved this may lead to HVDC insulation systems and equipment having a reduced footprint, larger power densities, and greater multi-stress resilience with longer service lifetimes This paper deals with the development and process scaling of new thermoset based nanocomposite electrical insulation materials for HVDC power transmission applications based on epoxide functionalized nanosilica and boron nitride based composites Some of the results such as increased electrical breakdown strength and reduced electrical conductivity for reactively surface functionalized nanosilica, and increased thermal conductivity for nano boron nitride, and their significance in regard to the wider application of these electrical insulation materials is also discussed. With sufficient understanding of these properties, their trade-offs and process requirements it is possible to obtain balanced materials for specific use in HVAC or HVDC components. To provide material development and quality assurance use was made of FTIR and NIR spectroscopy in conjunction with multivariate statistical analysis. This paper also demonstrates the potential of MVSA methods to determine structure-property relationships central to establishing materials design and process rules. Further, with additional factored measurements linked to specific process conditions it will be possible to expand the knowledge base to include structure-process-property relationships and use these in process optimization leading to process design rules. The potential exists to obtain quantitative metrics but this would require more extensive work in the acquisition of full data sets regarding property measurements. The careful consideration of all property measurements is required when developing a new material for use in HV applications be they HVDC or HVAC. With full and balanced consideration of nanofiller type, loading, reactive surface treatment, and the application of MVSA modelling to confirm property relationships to these controllable factors, optimized materials can be produced. Achieving this will be of immense benefit to power equipment manufacturers and network operators that use this equipment, particularly in the context of renewable generation integration, the move to develop Smart Grid and Low Carbon Networks and also to network upgrading and reinforcement of existing networks.