Fault Response and Protection System Impacts of Large Electronic Loads Considering Emerging Ride-Through Requirements

The prevalence of gigawatt-scale large electronic loads such as data centers on the grid is rapidly increasing. The fault ride-through behavior of these loads can significantly impact system stability, prompting transmission service providers (TSPs) to begin developing ride-through requirements that specify how the loads should respond to faults. As with power electronics-based resources, the fault ride-through requirements set by system planners for large loads can affect the performance of transmission system protection. Depending on how large loads implement undervoltage ride-through controls, fault current contributions from large electronic loads can be comparable to those from generation, especially if nearby generation is primarily inverter-based.

In this work, we consider different possibilities for fault ride-through performance that TSPs may require, how load electronics might implement them, and how the resulting fault response might impact nearby transmission system protection. Studies are performed using electromagnetic transient (EMT) analysis with detailed protective relay and load electronics models. Effects on step distance protection, line current differential, directional elements, and reclosing are considered. From these studies, we identify critical protection system impacts and design tradeoffs that TSPs and protection engineers should consider when developing ride-through requirements for large electronic loads. We also discuss approaches for studying datacenter protection impacts with short-circuit models (rather than a detailed EMT model). Field data and experiences from transmission system operators and protection engineers who are actively involved in the integration of large electronic loads are included.