1. Other pre-location methods
1.1 Bridge methods
The Murray loop method is still of some interest, especially for unshielded cables with direct ground faults. This is also the case for sheath faults.
Capacitive bridge methods (Sauty, Wien or Nernst) have now been abandoned in favor of the classical method (continuity faults, cf. ).
Generally speaking, these methods are based on the Wheatstone bridge principle (figure 1 ).
At equilibrium, i.e. when the galvanometer indication is zero, we obtain the relationship :
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Other pre-location methods
Precise localization methods
History of fault finding
(from Henri HUBIN's book – "Un siècle d'histoire – Searching for cable faults" ISBN 2-9511856-1-8 Ó 2001)
EDF network faults
HV grids: 100,000 km, of which a very small proportion is underground. 400 kV, 225 kV, 90 kV and 63 kV
MV networks: 586,000 km, of which 250,000 km underground 95% at 20 kV. The remainder is divided between 10, 15 and very few 30 kV. Purchase and installation of 8,000 km of HVA underground cables per year
LV networks: 654,000 km, of which 216,000 km underground, with...
Job training
As the only network operator, EDF soon needed to develop the skills of groups of agents to carry out this specialist activity. In 1974, Mr. Henri HUBIN, at the Paris Training Center of EDF's Vocational Training Department, in Nanterre, was given the task of building a suitable training program, which would also enable him to invent new methods and materials. In close contact with all the manufacturers of laboratory vehicles,...
References
Standardization
Cable specifications
- Câbles sous plomb, isolés au papier imprégné - NFC 33-100 - 6-67
- Insulated or protected cables for power networks Rigid cables insulated with cross-linked polyethylene and sheathed with polyvinyl chloride. – H1 XDV-A series replaces HN 33-S-33 - NF C 33-210 - 08-95
- Câbles à isolation synthétique avec neutre périphérique, pour réseaux de distribution à basse tension annulée et non...
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