Voltage stability of large-scale wind plants integrated in weak networks: An ERCOT case study

Voltage instability caused by integrating large-scale wind generation into a weak system is a well-known challenge. The ERCOT 2012 Long Term System Assessment report indicated that a voltage stability limit will constrain wind power delivery to the rest of the ERCOT system if the northwestern-most portion of the ERCOT Panhandle CREZ system becomes over-subscribed. To identify the system upgrades necessary to accommodate future wind generation, ERCOT transmission planning performed the Panhandle study. In this study, the ability of several compensation devices to improve voltage stability was investigated, including the static var compensator (SVC), the synchronous condenser and the variable frequency transformer. This paper presents both the static and dynamic voltage stability issues associated with the integration of large-scale wind plants in weak grids.