ESTIMATION OF REACTIVE POWER EXPORT AND IMPORT CAPABILITY FOR NONUTILITY GENERATORS

Non-utility generators (NUG's) are typically required by their electri c power sales agreement to have the capability to supply power to the purchasing utility near unity power factor, With the advent of large c ombustion turbine generators, many NUG's are simple or combined cycle facilities with generating capacities in excess of 100 MW, Utilities a re recognizing that these large NUG facilities can be significant cont ributors to the reactive power [megavars (MVAR's)] flow needed to supp ort system requirements and transmission level grid voltages, NUG's ar e now being dispatched for MVAR export and import activities to meet u tility requirements, The ability of a NUG to export or import MVAR's i s highly dependent on the actual transmission intertie voltage level, Unless plant-specific studies are performed, this capacity can be diff icult to ascertain for the NUG operating and engineering personnel, Th is paper presents a method, based on system load-flow studies, for est imating the capacity of a NUG to export or import MVAR's at a given tr ansmission intertie voltage level, It also explores other key variable s which determine the ability of a NUG to export or import VAR's, This methodology can be used to aid operating personnel at existing facili ties or as a guide during the design of a new facility.