P37.104: Substation Corrosion Management

Inspection and Maintenance of Pad‑Mounted Transformers The geometry and construction of pad‑mounted transformers can accelerate corrosion damage and, in advanced cases, create public safety risks due to cabinet perforations and fluid leaks. This task focuses on identifying best‑in‑class practices for both internal and external inspections, while documenting known challenges and limitations associated with maintenance activities. In 2027, a peer‑reviewed report will be completed that provides guidelines for inspection, assessment, and maintenance of pad‑mounted transformers.

Field Guides Field guides are pocket‑sized reference documents that enable field personnel to identify corrosion mechanisms, assess severity, and prescribe appropriate corrective actions using visual indicators. In 2027, the second field guide—focused on ground grid inspection and assessment—will be published. This guide supports Tier II inspections performed by substation operators and grounding technicians with advanced skill sets.

Atmospheric Corrosion Modeling in Substations Atmospheric environments within a substation can vary significantly due to energized equipment, proximity to generation facilities, site topography, and localized microclimates, complicating the prediction of corrosion-related maintenance needs. By developing corrosion rate data for steel, zinc, and aluminum in substation environments, asset managers can more accurately forecast maintenance requirements and replacement intervals. The 2027 report will provide guidance on modeling conductor degradation under atmospheric exposure in substation environments.

Corrosion and Corrosion Control Workshop This workshop combines corrosion theory with practical, hands‑on experience to support the assessment and application of corrosion control technologies. The 2027 workshop is designed for asset managers, engineers, maintenance supervisors, and field crews, and emphasizes practical methods for extending asset service life through informed inspection, assessment, and mitigation strategies.

Cathodic Protection Guidelines This document provides guidance for the design, installation, and maintenance of impressed current cathodic protection systems. The intent of this document is to detail the requirements for a utility to develop a cathodic protection program, starting with purchasing groups, the engineering groups, and the maintenance groups.

Mapping Equipotential Gradients within a Substation Monitoring and trending changes in ground grid condition offers a promising approach for understanding degradation rates; however, traditional data collection methods are labor intensive, time consuming, and present safety challenges. This research evaluates the use of autonomous robotic systems to map equipotential gradients within substations. By identifying changes in ground potential rise, these systems may enable detection and localization of degraded ground grid elements while reducing exposure of personnel to hazardous conditions.

Corrosion Management Reference Book (“The Rust Book”) Comprehensive corrosion management guidance is needed across all areas of power delivery. This reference book will provide utilities with a unified framework for inspection, assessment, mitigation, and remediation applicable across departments. Content includes corrosion fundamentals, inspection and assessment methodologies, and guidance on selecting mitigation strategies that align with environmental conditions and asset types. Long‑Term Research

Sensor Development to Discriminate Between Corrosion Mechanisms Corrosion behavior is influenced by environmental factors such as moisture, temperature, pH, and stray or circulating currents. To distinguish between localized, general, and stray current corrosion mechanisms, EPRI has developed a sensor array capable of identifying and quantifying the severity of each corrosion type. In 2020, the array was expanded to incorporate atmospheric monitoring to correlate weather patterns with subgrade corrosion activity. Ongoing research focuses on analyzing large sensor datasets to improve understanding of diurnal and seasonal corrosion behavior for substation assets exposed to soil environments.

Substation Ground Inspection Workshop This workshop provides guidance to early career grounding engineers and substation operators on best practice methods for ground grid inspection and assessment. The workshop covers corrosion fundamentals, defines tier based inspection skill sets, and outlines inspection workflows associated with each tier to support consistent and effective ground grid condition assessment.