IEC 60794-1-401:2021

Overview

IEC 60794-1-401:2021 - "Optical fibre cables - Part 1-401: Generic specification - Basic optical cable test procedures - Electrical test methods - Short-circuit test (for OPGW, OPPC and OPAC), Method H1" specifies a reproducible short-circuit test to assess the electrical and optical performance of overhead optical cables during fault conditions. The standard covers testing of OPGW (optical ground wire), OPPC (optical phase conductor) and the behaviour of OPAC (optical attached cable) when short-circuit currents flow in the messenger. This first edition (2021) supersedes IEC 60794-1-24:2014, adding OPPC and updating test methods.

Key topics and requirements

• Scope and objective: Evaluate impact of short-circuit current on optical attenuation and mechanical/thermal behaviour of OPGW, OPPC and OPAC.
• Test arrangements: Two sample and one sample methods for OPGW/OPPC; OPAC test arrangement attaches cable to a messenger wire as in service.
• Sample and fibre loop:
  • Sample length: minimum 10 m.
  • Fibre test length: >100 m; looped test preferably includes at least 24 fibres (fibre concatenation allowed) or all fibres when fewer.
  • For multi-unit cables measure fibres from all units equally.
• Instrumentation and apparatus:
  • Thermocouples (on armour, optical core surface, or messenger), thermocouple recorder, AC current source, mechanical load system, light source and power meter for optical attenuation.
• Measurement method: Optical attenuation measured according to IEC 60793-1-46 (monitoring changes in optical transmittance).
• General test conditions (examples provided):
  • Tensile load for OPGW/OPPC: 15%–20% of RTS.
  • Number of fault pulses: minimum 3; waveform to be symmetrical after the 3rd cycle.
  • Fault current intensity and duration: agreed between customer and supplier.
  • Initial temperatures: OPGW default 40 °C ± 5 °C; OPPC at steady-state operating temperature (±5 °C) or emergency worst-case temperature as agreed.
• Data recorded: Temperature histories, optical attenuation before/after and during test, mechanical load conditions.

Practical applications

• Product qualification and type testing for overhead optical cables exposed to electrical faults.
• Supplier/customer acceptance testing and contract verification for transmission-line optical components.
• Design validation, reliability assessment and safety analysis for utilities and OEMs deploying OPGW, OPPC, or OPAC.
• Laboratory test procedures for independent test houses and R&D for cable manufacturers.

Who should use this standard

• Power utilities, transmission line engineers, cable manufacturers, test laboratories, procurement/specification authors and consultants involved in overhead optical fibre systems.

Related standards

• IEC 60794-1-1 (generic optical cable specs)
• IEC 60793-1-46 (optical attenuation measurement)
• Other parts of the IEC 60794 series covering optical fibre cable tests

Keywords: IEC 60794-1-401:2021, short-circuit test, Method H1, OPGW, OPPC, OPAC, optical fibre cables, electrical test methods, optical attenuation.