A Review of Lithium-Ion Battery Models in Techno-economic Analyses of Power Systems

The penetration of the lithium-ion battery energy storage system (BESS) into the power system environment occurs at a colossal rate worldwide. This is mainly because it is considered as one of the major tools to decarbonize, digitalize, and democratize the electricity grid. The economic viability and technical reliability of projects with batteries require appropriate assessment because of high capital expenditures, deterioration in charging/discharging performance and uncertainty with regulatory policies. Most of the power system economic studies employ a simple power-energy representation coupled with an empirical description of degradation to model the lithium-ion battery. This approach to modelling may result in violations of the safe operation and misleading estimates of the economic benefits. Recently, the number of publications on techno-economic analysis of BESS with more details on the lithium-ion battery performance has increased. The aim of this review paper is to explore these publications focused on the grid-scale BESS applications and to discuss the impacts of using more sophisticated modelling approaches. First, an overview of the three most popular battery models is given, followed by a review of the applications of such models. The possible directions of future research of employing detailed battery models in power systems' techno-economic studies are then explored

Sensitivity analysis of a parallel-plate method for measuring the dielectric permittivity of high-voltage insulating materials

Ascertaining the dielectric character of polymeric insulation materials is of particular interest for comparative studies that use accelerated ageing and samples from decommissioned installations. In the case of polymeric samples, the possibility of physical deformation within the sample holder adds additional variability to comparative measurements. Using readily obtainable instrumentation, this study undertakes a systematic sensitivity analysis of a parallel-plate capacitance measurement approach for polymeric materials that only has one capacitance plate in contact with the sample, avoiding issues of sample deformation. The analysis demonstrates that the biggest contributor of uncertainty in the measurement of the relative permittivity and loss tangent is the precision with which the plate–plate and plate–sample separation is determined. The measurements show that the determination of loss tangent can be susceptible to uncertainties arising from electrical noise, but that these can be controlled further by utilising more refined instrumentation