Evaluating the Power Quality Impacts of Large-Scale Solar and Wind-Generation Applications on Tennessee Valley Authority’s (TVA) Power System

Over 36 large (greater than 50-MW) inverter-based generation resources are currently being evaluated or already have been evaluated by TVA in recent years. These are primarily solar installations. The locations of these proposed projects are chosen for access to land and other factors not necessarily related to power system interconnection. Because of this, the strength of the transmission system may be less than ideal at the proposed generation sites. TVA's power quality (PQ) staff have assisted the transmission planning group in evaluating issues related to the operations of these facilities: TVA 161-kV capacitor switching and the switching transients affecting the generation's 34.5-kV buses Large transformer banks energizations creating transient voltage sags on 161-kV systems Harmonic flows from renewable energy generation creating resonance with TVA 161-kV capacitors resulting in voltage distortion This paper presents actual case studies and the use of the Electromagnetic Transients Program (EMTP) to evaluate these three major PQ issues. Lessons learned are presented in this paper.