3.1 Conceptual Discussion and Background
Apart from VRT capability, another key requirement associated with the integration of wind generation technology into the transmission grid has been the need for reactive power support. As in the case of VRT capability requirements, the increasing penetration of WGRs has resulted in the regional reliability organizations and/or utilities mandating a certain level of reactive power support requirements from interconnecting wind farms. While the potential reactive power support that could be obtained from WGRs was relatively limited during low penetration levels, the same is not the case with transmission systems possessing 10-12% penetration of WGRs. While utilities could rely on tripping wind farms that consumed VARs during periods of temporary voltage dips to prevent the situation from getting exacerbated, the same is not possible today. On the contrary, utilities and regional reliability organizations expect WGRs to contribute to the grid support during periods of voltage dips and/or reactive power deficiency.
To that effect, numerous transmission system grids require WGRs to exhibit the ability to meet a pre-specified reactive power capability irrespective of the active power output. Additionally, the WGRs interconnecting to the transmission grid need to meet the reactive power and/or power factor requirements from a steady state and dynamic standpoint. While numerous technology based advancements have been made by turbine vendors to offer varying packages that provide
different levels of reactive power compensation, transmission planners and utility engineers have limited information associated with testing these capabilities in the planning environment. The discussion presented in this section focuses on certain techniques associated with assessing the ability of WGRs to meet pre-specified reactive power and/or power factor requirements outlined by the regional reliability organization and/or local utility.