Abstract

Herein, a three‐dimensional (3D) finite element model of a strain clamp‐conductor system is established, with an NY‐300/40 compression‐type strain clamp taken as an example. The tensile load‐carrying capacity of the strain clamp under standard crimping conditions is analyzed with LS‐DYNA software, and the simulation results are compared with the experimental results to verify the accuracy of the model. On this basis, the tensile load‐bearing capacity and failure mode of the strain clamp‐conductor system are analyzed when the crimping length between the steel anchor and steel core is insufficient. Studies have shown that the grip strength of a strain clamp is provided mainly by the crimping between the steel anchor and the steel core. Under standard crimping conditions, the tensile load‐bearing capacity of the strain clamp can meet the design requirements. Moreover, because the crimping length between the steel anchor and steel core is sufficient, the strain clamp fails due to aluminum strand breakage rather than the steel core being pulled out of the steel anchor. When the crimping length is insufficient, the grip strength of the strain clamp decreases with decreasing crimping length. Although the absolute value of the grip strength does not decrease significantly, the failure mode gradually changes from the breakage of the aluminum strands to the steel core being pulled out of the steel anchor. For the NY‐300/40 compression‐type strain clamp, the corresponding critical crimping length (i.e., when the change in failure modes occurs) between the steel core and the steel anchor is 50∼60 mm.

Highlights

  • Power and energy systems are important lifeline engineering infrastructures that are vital to the stability and sustainable development of society

  • To our knowledge, there has been relatively little research on the overall tensile performance of a strain clamp-conductor system after crimping due to the difficulty of obtaining the internal stress-strain information of a closed strain clamp-conductor system through tests. erefore, in this paper, an NY-300/40 compression-type strain clamp is used as an example to simulate the tensile behavior of the strain clamp-conductor system after crimping. e variation characteristics of the tensile load-bearing capacity of this system and the corresponding failure modes of the system under different crimping lengths are analyzed. e results may provide an approximate prediction of the load-carrying capacity and safety of a strain clamp-conductor system

  • When the tensile load increases to 95% rated tensile strength (RTS), the maximum stress in the inner steel core inside the crimped area of the aluminum pipe increases to 1257 MPa, which is slightly greater than its yield strength of 1210 MPa

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Summary

Introduction

Power and energy systems are important lifeline engineering infrastructures that are vital to the stability and sustainable development of society. E studies of Liu et al [21] showed that incomplete surface cleaning or poor high-current drainboard installation in the crimping process could generate a large amount of heat, leading to a reduction in the strength of the steel core and causing a disconnection accident He et al [22] analyzed the mechanisms governing the breakage of a 750 kV line with improperly crimped strain clamps. Wang et al [30] theoretically analyzed the feasibility of using this technology in transmission lines, determined the different defect conditions via field X-ray detection and tensile tests, and provided a reliable basis for the use of X-rays to measure the quality of crimping of fittings. To our knowledge, there has been relatively little research on the overall tensile performance of a strain clamp-conductor system after crimping due to the difficulty of obtaining the internal stress-strain information of a closed strain clamp-conductor system through tests. erefore, in this paper, an NY-300/40 compression-type strain clamp is used as an example to simulate the tensile behavior of the strain clamp-conductor system after crimping. e variation characteristics of the tensile load-bearing capacity of this system and the corresponding failure modes of the system under different crimping lengths are analyzed. e results may provide an approximate prediction of the load-carrying capacity and safety of a strain clamp-conductor system

Finite Element Model for a Typical Strain Clamp-Conductor System
E Steel core at the opening of steel pipe
Findings
Conclusions
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