2. Origin

2.1 Distributor network

Insulation faults affecting transmission, distribution or distribution networks are caused by external or internal causes within the distributor's network.

External causes include atmospheric conditions (in more than 70% of cases for an overhead network), and contact with foreign objects (vegetation, animals, vehicle impacts, earthworks, etc.).

Internal causes are mainly equipment failures (lines, cables, transformers, etc.).

There are different types of defects:

• depending...