Industry

Electrifying a process often multiplies the power demand. RTE plans to add nearly 9 GW of ready-to-connect capacity around Dunkirk, Le Havre and Fos by 2029 (RTE, July 2026).

On the site, two questions arise. The first concerns the connection to the public grid, the second the capacity of the internal network (substations, protection, cables, earthing) to take the load without any loss of safety.

Common situations

Many industrial networks have been built in layers, with thirty years of extensions, drawings that no longer match and settings copied from one feeder to the next. Before calculating, we rebuild the network as it actually is.

New loads (arc or induction furnaces, electrolysers, high-power compressors, large drives) cause voltage dips on starting, harmonics and flicker. They also raise the question of the short-circuit withstand of existing equipment.

For personnel safety, live working, or work near live parts, requires knowing the incident energy at each switchboard. This energy depends directly on the protection settings.

MV connection to the Enedis network

Most industrial sites are connected at MV to the public distribution network. The point-of-connection substation falls under NF C 13-100, the internal installation under NF C 13-200. The main protection must be selective with the Enedis feeder. Its settings are framed by the network operator, and a setting error trips the public feeder instead of the site circuit-breaker.