An Interval Computation Approach for Power Components Overload Protection in the presence of Data Uncertainty

The embedding of microprocessor-based relays in power components enables improved overload protection because of higher computational resources, adaptiveness and flexibility. The increased computing power that is now embedded in power component devices makes possible the real-time simulation of built-in thermal models. However, the use of model-based protective systems is exposed to the uncertainty affecting some model components. The effect of these uncertainties could compromise the overall protective function reliability. To address this problem, we use Affine Arithmetic (AA). In particular, AA can be used to calculate the component’s hot spot temperature by solving a thermal dynamic model where parameters are imprecise, and the uncertainty is represented by affine forms. The proposed solution method is implemented on a microcontroller-based unit to develop a prototype thermal relay equipped with robust tools for uncertainty data management. Various experimental results are presented and discussed.