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ADSS to Hardex Cost Study—United Kingdom
INTRODUCTION
Great Britain based DNO have been considering the use of All-Dielectric Self-Supporting (ADSS) for some time as a replacement for Hardex. This
is an efficient, cost effective solution/approach and, moving forward, this DNO decided to change two power circuits from Hardex to ADSS as a
technology trial projects.
TECHNOLOGY OVERVIEW
ADSS—All-Dielectric Self-Supporting
Technology very well‐known and very popular for adding the fibre in to the existing overhead
infrastructure.
ADSS is designed to International Specification IEEE 1222 and is manufactured and tested in
accordance with ISO 9001. ADSS is a fully insulated self‐supporting fibre catenary, which can
be erected underneath lines up to 500 kV. It is a system that is totally independent and can
be installed under live conditions given the correct clearances and procedures.
Product (ADSS) considered for replacement of Hardex weighs in the order of 17 kg/100 m
and is 15 mm in diameter.
Figure 1—ADSS Cable
ADSS cable weight = 150‐170 kg/km (approx.)
Typical installation tension = 1.7-1.9 kN
for span length and sagging allowance given in
this specific project
Hardex
Hardex is a galvanic pilot commonly deployed on 33 kV overhead line OHL or mixed underground (UG) and OHL circuits. It contains metallic
elements, therefore applies a significant weight on the pole structures.
When Hardex faults occur, protection on the system is depleted and risk can only be mitigated in short time scales by temporary pilot
deployment/temporary way‐leaves or repairs using spare cable.
Hardex cable is no longer manufactured, therefore replacement or repairs are not possible.
