ABB circuit-breakers for DC applications

The advantages in terms of settings, offered by the use of DC motors, and by supply through a single line, make DC supply a good solution for railway and underground systems, trams, lifts and other transport types. In addition, DC is used in conversion plants (installations where different types of energy are converted into electrical direct energy, e.g. photovoltaic plants) and, above all, in those emergency applications where an auxiliary energy source is required to supply essential services, such as protection systems, emergency lighting, wards and factories, alarm systems, computer centres, etc.

Accumulators - for example - constitute the most reliable energy source for these services, both directly in direct current as well as by means of uninterruptible power supply units (UPS), when loads are supplied in alternating current.

This Technical Application Paper explains the main aspects of the most important applications in DC and presents the solutions offered by ABB SACE.

The main purpose is giving precise information by means of tables providing a rapid choice of the protection/disconnection device and paying particular attention to the installation characteristics (fault typologies, installation voltage, earthing arrangement). There are also annexes giving further information about DC, including:

• Information about the distribution systems in compliance with international Standard IEC 60364-1.
• Calculation of the short-circuit current in DC in compliance with international Standard IEC 61660-1.
• Circuit-breakers and disconnectors for applications up to 1000 VDC.
  

To see the full and extensive PDF document, which is highly detailed and very comprehensive, please click on the download button below (886kB file size). Alternatively, go to http://search.abb.com/library/Download.aspx?DocumentID=1SDC007104G0201&LanguageCode=en&DocumentPartId=&Action=Launch&IncludeExternalPublicLimited=True