Stability Requirements for Implementation of Grid Separation Scheme in a Steel Mill with Internal Generation

This paper provides an analysis of the separation philosophy for a large steel mill with internal generation, which is transitioning from net power import to net power export after the addition of two new steam turbine generators. Separation from the utility in the case of a fault is determined by the operation of the protective relay system at the point of separation. The plant has a PLC controlled load shedding, which drops blocks of load, based upon measurement of the amount of load and generation in service. With the addition of new generation, alternatives such as generation rejection and fast turbine valving must be evaluated.