Please find below an updated version of our comprehensive description of low voltage DC microgrids here. We have carefully reviewed the document, corrected some editorial mistakes, and clarified the description of these topics:

• For AC-side grounded DC-systems
  • Reflecting an upcoming change in the IEC installation rules (60364-1) we updated the rationale for AC side grounded DC systems in chapter 7.2.2.
  • We closed a gap in the case of a fault on the DC bus with multiple sources with respect to monitoring if the connection to the AC side grounding is still available (chapter 7.2).
  • Added a comprehensive calculation method for earth fault currents (chapter 11.1.2.2).
• For IT systems without continued operation after first fault
  • The wording for fault current protection and isolation requirements was misleading in chapter 7.3. Accordingly in the protection chapters 11.1.2.4 and 11.3.3.
• Other topics
  • EMC emissions: In Figure D.19 the limit according to EN 55011 was partly wrong.
  • Disconnection times for indirect contact with voltage carrying parts: In table 11.6 we removed the entry for TT systems, since those systems are not recommended for DC installations.
  • The required clearance distance between L+ and L- is clarified in figures 11.13 through 11.15.

This document is the most comprehensive description of LVDC microgrids available. It has been used for the approval of several industrial investments.

A full list of changes can be found in Annex G of the document.