“Process Immunity Time” assessment of its practicability in industry

This paper summarizes the research concerning the practicability of a new Power Quality concept, "Process Immunity Time" (PIT). Process Immunity Time has been developed as a new concept by a CIGRE/CIRED/UIE working group, starting from experience with voltage dips in the chemical industry. In order to know if PIT is a generic concept for other industrial sectors, a number of voltage dip sensitive industries have been approached in Europe. The theoretical background of the PIT concept is briefly sketched. The method is illustrated by the worked out example of a process in the chemical industry. Subsequently, its practicability in industry is tested for three other industries. The research shows that PIT is generally applicable in several industrial sectors but that some problems have emerged in its practical implementation. The conclusions also contain some recommendations for the CIGRE/CIRED/UIE working group and suggestions for further research are given.