About the Authors... Narain G. Hingorani is credited with originating the concepts ofFACTS and Custom Power. He is a retired vice president ofElectrical Systems at EPRI and provides consulting services thathelp utilities plan and purchase power electronics technology. Dr.Hingorani has published widely on HVDC and ac transmission and iscoauthor of High Voltage Direct Current Power Transmission (GarawayLtd., 1960). Dr. Hingorani is the recipient of the 1985 Uno LammMedal of the IEEE Power Engineering Society for outstandingcontributions to High Voltage Direct Current Technology and the1995 IEEE Lamme Medal for leadership and pioneering contributionsto the transmission and distribution of electric power. He is aFellow of the IEEE and in 1988 he was elected to the NationalAcademy of Engineering. Laszlo Gyugyi is technical director at Siemens FACTS & PowerQuality Division in Orlando, Florida. His research covers a broadrange of power electronic circuits and systems. In collaborationwith B. R. Pelly, Dr. Gyugyi established the theoreticalfoundations of ac to ac switching converters in Static PowerFrequency Changers (John Wiley & Sons, 1976). Subsequently, hehas focused on the development of new power electronic technologiesfor electric transmission and distribution systems, and haspioneered the converter-based approach for FACTS. Dr. Gyugyi haspublished more than 50 papers in the field and holds 76 U.S.patents. He is the recipient of the 1992 Westinghouse Order ofMerit, the 1994 William E. Newell Power Electronics Award of theIEEE Power Electronics Society, and the first Flexible ACTransmission System (FACTS) Award given by the IEEE PowerEngineering Society in 1999. He is a Fellow of the IEE.