Power Quality Management of NASA’s Large, Nonlinear Research Loads

Abstract

The National Aeronautics and Space Administration (NASA) conducts research on aircraft and spacecraft concepts and materials at the Langley Research Center (LaRC) in Hampton, Virginia. In order to match real flight conditions, large, high energy research facilities are used with solid-state power supplies and variable frequency drives to power large motors and arc heaters. Incorporation of this technology introduces nonlinear loads to the electrical power distribution grid and the added consideration of power quality. Because of the resultant harmonic current injection to the line side of these loads, the requirements of IEEE 519 were specified by NASA for each installation in an effort to maintain an acceptable level of power quality across the entire Research Center. Selection of the point of common coupling and minimization of system resonances were design considerations that impacted the cost and performance of the installations. Several of these NASA installations are described here: a 101 MW synchronous machine with Load Commutated Inverter drive, a 9MW synchronous machine with cycloconverter drive, and a 20 MW arc-heater DC power supply. Results of design configurations, harmonic content, operational issues, site layout, and system performance are presented.