Resilience, criticality and operating limits of a MALT 30 kV 4-wire electrical distribution network without conformity of the medium voltage neutral

The present article highlights the atypical power grid resilience of the northernmost point of the African countries against repeated acts of vandalism on its MV distribution lines. To counter this threat, the present article reports a comparison between a 3-wire and 4-wire MV power grid in the event of a single-phase or three-phase short-circuits. The evolution of the voltage of the healthy phases during a single-phase fault and the impact on the power supply signal are mathematically studied. The study shows that an adequate resizing of the protection devices is sufficient to operate the MALT system in complete safety without its neutral wire. Thus, by allowing saving copper wire, this finding is actually a turning point in the implementation of the malt system. To better contextualize this result, which was actually initicated by an unpleasant experience, the article begins with a historical assessment of the 30 kV 4-wire MALT electrical distribution systems and a technical calibration of its specificities in relation to the two conventional practices of standard IEC 60038.

Automated summary

This article discusses the atypical power grid resilience of the northernmost point of the African countries against vandalism, and compares the performance of 3-wire and 4-wire MV power grids in different fault scenarios. The study shows that with proper adjustment of protection devices, the MALT system can operate safely without the neutral wire.