IEC 61597

IEC TR 61597 – Overhead Electrical Conductors – Calculation Methods for Stranded Bare Conductors

IEC TR 61597 is a Technical Report that outlines practical and simplified methods for calculating the electrical and mechanical characteristics of stranded bare conductors, particularly those specified in IEC 61089. It focuses on aluminium and aluminium-steel conductors typically used in overhead line applications.

The IEC 61597 document is intended to support engineers and system designers in evaluating conductor performance under a range of environmental and operational conditions. While it does not aim to present all available theoretical approaches, it offers well-established and straightforward calculation methods that deliver acceptable levels of accuracy for general engineering purposes.

Key Areas Covered in the Technical Report:

• Current Carrying Capacity – Includes a practical method for calculating the ampacity of conductors, along with a typical worked example to illustrate application.

• AC Resistance, Inductive and Capacitive Reactance – Describes how to determine key electrical parameters for stranded conductors operating under alternating current conditions.

• Thermal and Mechanical Elongation – Provides stress-strain and thermal elongation data to evaluate conductor extension under load and temperature variations.

• Conductor Creep – Explains how to estimate long-term mechanical deformation (creep) under sustained loading, which is critical for maintaining ground clearance.

• Loss of Strength – Offers guidance on how elevated operating temperatures affect the tensile strength of aluminium wires, assisting in conductor selection for high-temperature environments.

Purpose and Application

IEC TR 61597, which is a Technical Report, provides information with regard to conductors specified in IEC 61089 and other aluminium and aluminium-steel conductors. It presents practical methods for calculating a range of electrical and mechanical properties, including current-carrying capacity, AC resistance, reactance, elongation, creep, and loss of strength at elevated temperatures.

This document serves as a valuable reference for manufacturers, designers, and utilities involved in the planning, specification, and evaluation of overhead conductor systems.