WS3: Interconnection Practices

This report compares mitigation technologies with emphasis on how fluctuation magnitude, fluctuation frequency, response latency, control topology, and energy storage capacity determine appropriate device selection and sizing. Enhanced STATCOMs, battery energy storage systems, and localized active filtering approaches are evaluated across rack, medium-voltage facility bus, and point-of-common-coupling deployment locations. The report also examines the role of grid-following and grid-forming controls, the tradeoff between ultra-fast dynamic response and sustained energy capability, and opportunities to stack secondary benefits such as voltage support, fault ride-through, and ramp-rate smoothing. The resulting framework supports a tiered mitigation strategy that matches the disturbance spectrum and site constraints to the most effective combination of local and centralized power-electronic resources.

This report compares mitigation technologies with emphasis on how fluctuation magnitude, fluctuation frequency, response latency, control topology, and energy storage capacity determine appropriate device selection and sizing. Enhanced STATCOMs, battery energy storage systems, and localized active filtering approaches are evaluated across rack, medium-voltage facility bus, and point-of-common-coupling deployment locations. The report also examines the role of grid-following and grid-forming controls, the tradeoff between ultra-fast dynamic response and sustained energy capability, and opportunities to stack secondary benefits such as voltage support, fault ride-through, and ramp-rate smoothing. The resulting framework supports a tiered mitigation strategy that matches the disturbance spectrum and site constraints to the most effective combination of local and centralized power-electronic resources.

This report examines how data center load behavior may affect synchronous generator reliability. Large data centers, especially those supporting AI, can create cyclical and oscillatory demand patterns that differ from traditional loads and introduce new operational challenges. The report describes how these load oscillations can interact torsionally with synchronous turbine-generator shafts, amplifying mechanical stress, accelerating fatigue, and reducing reliability. It also presents a practical screening method and planning framework for assessing generator exposure with standard planning tools, along with guidance on mitigation, protection, and stakeholder coordination.

This paper summarizes the NERC Level 3 Essential Action Alert issued in response to emerging reliability risks from large computational loads such as data centers. It outlines the seven Essential Actions addressing modeling, system studies, commissioning, protection coordination, disturbance analysis, and operational coordination.

This paper examines disturbance ride-through expectations for large data centers and identifies critical gaps in how current requirements are defined, interpreted, and implemented. While grid operators increasingly specify voltage and frequency ride through criteria at the point of interconnection, the paper shows that compliance is ultimately governed by facility-level architectures and equipment-level behavior. It highlights possible misalignment between system-level intent and internal facility responses arising from transformer connections, voltage measurement definitions, and unbalanced fault behavior. The paper clarifies how differences such as positive sequence versus worst phase voltage interpretation can materially alter compliance outcomes. It distinguishes grid-oriented ride through requirements from equipment immunity standards and demonstrates the absence of a consistent mapping between the two. Key challenges related to testing, certification, and verification of equipment and facility compliance are identified. The paper also highlights emerging reliability risks for data centers with tightly coupled onsite generation where load and generator ride through requirements are not coordinated. Practical design and coordination considerations are discussed for UPS systems, protection schemes, and cooling infrastructure. Drawing on lessons from IEEE 1547 and IEEE 2800, the paper outlines attributes of effective ride through requirements. It concludes by describing EPRI’s DCFlex initiative as a pathway to harmonize requirements, improve traceability, and establish practical compliance and certification approaches to support grid reliability at scale.

This report examines the emerging risks associated with subsynchronous torsional interactions (SSTI) between turbine-generator shafts and the variable, high-power loads produced by AI data centers, especially during intensive training activities. The document outlines the physical mechanisms through which fluctuating electrical demands can stimulate generator torsional modes and introduces a screening approach based on interharmonic current gains to determine when comprehensive data collection and assessment are warranted.