Tennessee Valley Authority (TVA) Power Quality Studies of 57 Prospective Large (200-MW Typical) Solar Generation Interconnections

Tennessee Valley Authority (TVA) Transmission Power Quality staff evaluated 57 solar interconnection inquiries, representing a total of 8900-MW (or 158-MW per site on average) from August 2019 - January 2021. These studies focused on rapid voltage change during transformer energization and harmonic voltage distortion associated with solar generation operations. This paper presents the use of an electromagnetic transient computer program to simulate operational issues that could be anticipated based on the interconnection of a prospective solar facility. The simulation modeling methodology is discussed in detail, including assumptions that TVA routinely uses in these studies. A discussion of simulating multiple sites operating in close proximity is also presented with emphasis on the potential for harmonics to adversely affect neighboring sites. Finally, mitigation strategies commonly used to limit the impact of model results are provided.