Off-Grid Utility Microgrid Protection: NEUTRON Scope at the Red Sea Project

1. An islanded utility

With no public grid to fall back on, the microgrid must be self-sufficient. Protection and switching equipment must keep the array safe, allow clean isolation, and let the system ride through a fault without a full blackout of the resort load.

2. DC side protection

• PV combiner boxes with individual gPV fuse protection per string.
• DC isolation switches for safe maintenance of the array.
• DC surge protective devices matched to the system voltage.

3. Low-voltage switching and ATS

NEUTRON supplied low-voltage switchgear and automatic transfer switching so the resort load can be fed from the solar-storage bus and, where a backup generator is present, transferred cleanly. The ATS keeps the critical load supplied during a transition.

4. AC side residual-current protection

On the AC distribution boards NEUTRON installed Type B RCBO units. Because the inverter stage can present smooth DC, a Type B device senses AC, pulsating DC and smooth DC, closing the shock-protection gap left by a Type A device.

5. Coordination with EPC-supplied storage

NEUTRON did not supply the batteries or inverters. The protection scope was coordinated to the EPC ratings: combiner and DC fuse limits matched to the array the inverter expects, and the AC board sized to the inverter output and priority loads.

6. Outcome

The protection and switching layer gave the off-grid utility a safe, serviceable foundation. The lesson is that an islanded resort microgrid needs the same DC discipline as a grid plant, plus ATS and Type B RCBO for resilient local supply.