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Monday, March 11

Reliability Investigation of ACSR Splice Connector Systems Used in Overhead Power Transmission Lines

Hao Jiang, Ph.D., ORNL Postdoctoral Associate, Oak Ridge
Materials Science & Technology Division Seminar
1:00 PM — 2:00 PM, High Temperature Materials Laboratory (HTML), Building 4515, Conference Room 265
Contact: Christine Goudy (goudyc@ornl.gov), 865.574.8295

Abstract

Due to increased power demand and limited investment in new infrastructure, existing overhead power transmission lines often need to operate at temperatures higher than those specified in the original design criteria. The Electric Power Research Institute (EPRI) and DOE are jointly sponsoring research to develop an inelastic design methodology for evaluating splice connector system performance and estimating the associated effective lifetime under high temperature operation. As a result of material discontinuity and inherited forming mechanism, the conductor-connector system of a crimped-type splice connector is highly sensitive to aging of the system components, especially during high-temperature operations. Therefore, splice connectors are the weakest links in the electric power transmission infrastructure. This presentation will discuss a protocol for integrating analytical and experimental approaches to evaluate the integrity of the aluminum conductor steel-reinforced (ACSR) splice connector system at higher operating temperatures. Topics will include development of time-dependent failure criteria and thermo-mechanical material behavior models, as well as incorporation of models into computational tools for predicting ACSR splice connector system performance and lifetime. A finite-element program has been established to model the structural mechanics under combined mechanical and thermal loading and to simulate the forming process and thermal cycling operation, as well as to investigate the associated geometry deformation in the vicinity of the splice-conductor interface region, coupled with the constitutive models. The protocol developed at ORNL allows the electrical utility industry to predict the service lifetime of ACSR splice connector systems, as related to the number of thermal cycles associated with the operation during peak periods. Lifetime assessment methodology provides the tools to improve the reliability of the electrical grid.

The presenter will also illustrate several challenges in finite element modeling, such as modeling hyperelastic material behavior of polyurethane in ABAQUS, structural dynamics simulation based on Modal Analysis for the U-frame bending fatigue testing system, and fracture toughness evaluation using the advanced spiral notch torsion test finite element model.