Equipment in electricity distribution networks – Latest developments review

Development of network equipment

This session deals with all aspects related to the components used in the electricity distribution networks: cables, overhead lines, primary and secondary substations, transformers, switchgear and their control, protection and monitoring systems, new active power electronics devices.

It covers topics related to the life cycle optimisation of assets from design through installation, operation and maintenance to the end of life management, as well as new solutions for diagnosis and monitoring.

The session also covers environmental aspects including eco-design and life cycle analysis, standardisation, ergonomics and the safety of both the operating staff and the public.

This session is an opportunity for DSO and manufacturers to share their objectives.

Diagnosis and maintenance of Cables and lines

The first block is focused on methods and tools for cables and lines assets management. The 34 concerned papers were split within 3 sub-blocks:

1. Mechanism or phenomenon studies and diagnostic measurement methods (14p.) for assets management of cables and lines
2. Proposed methods and tools in asset management on cables and distribution lines assessment methods and solutions (14p.)
3. Some specific solutions or method to be applied in line ratings and some standards (6p.)

Diagnostic measurements methods

For a few years, various diagnostic methods are applied on distribution networks. On MV underground lines, tan delta (TD) and partial discharges (PD) measurements seem to be the way to assess the insulation condition in off-line situation.

A five years off line diagnostic experience on MV cable is presented in Paper 0999. This method was deployed in a quite large scale on the French network impacting maintenance program and pointed out some new criteria – as water penetration in cables – and tools to be studied.

Finally, the use of such diagnostic method requires specific skills.

Similarly, since 2001 in Denmark Paper 0471, the tan delta diagnostic method was applied on 86 sections of MV cables installed between 1982 and 2010. All cables sections were ranked from bad cables with leakage current at normal operating voltage up to good cables with low losses.

It mentions the relationship between the missing water barrier in the cable and its lifetime.