Eagle Pass back-to-back tie: a dual purpose application of voltage source converter technology

IGBT-based voltage source converters (VSC) connected back-to-back (BTB) is a new technology that can provide reliable interconnection of power systems. At American Electric Power-Central Power and Light\´s (AEP-CPL)-Eagle Pass substation, a 36 MVA VSC based BTB tie, interconnecting AEP-CPL\´s and Comision Federal de Electricidad\´s (CFE) power systems, provides needed reactive power support for dynamic voltage control at the two ends of the BTB tie. At the same time it maintains a controlled bi-directional power transfer between the two power systems. The field tests performed during commissioning have demonstrated the capability of the BTB tie to provide independent control of the voltage at both ends and the real power transfer between AEP-CPL\´s and CFE\´s power systems. Stability of the BTB tie control system is. also demonstrated in normal operation as well as during "black start" of the BTB tie.