PROTECTION OF GENERATORS

Changes in generator design during recent years have led to machines with inherently higher impedance; consequently, when the generator is subjected to fault conditions such as earth faults or phase-to-phase short circuits in the distribution network, the level of fault current is reduced in relation to the rated current of the generator. These lower levels of fault current make the selection of protection equipment more critical, particularly when the device is required to operate with very little delay after the application of a fault. (When faults are remote from the generator, there will in general be sufficient fault current to operate the protection equipment). The Author, of Newage Engineers Ltd/Stamford Generators, discusses these problems in the selection of protection equipment, and explains the relevant principles with the aid of a graph in which typical characteristics of a circuit breaker and fuse, and of the generator for which these devices have been selected, are plotted. It is shown inter alia that, for early rupturing, the fuse requires fault current well inexcess of that provided by the generator, and may be useless as a protection for it. The circuit breaker (which has magnetic and thermal trips) is shown to have its limitations; these are discussed, together with the need for back-up protection for the generator. The Stamford "C" range Series 3 control system incorporates a circuit which de-excites the generator and thereby provides back-up protection; the advantages of this system are explained. Order from BSRA as No. 49,057.

  • Corporate Authors:

    Seehafen-Verlag Erik Blumenfeld

    Celsiusweg 15, Postfach 1347
    2000 Hamburg 50,   Germany 
  • Authors:
    • Rounce, W
  • Publication Date: 1978-3

Media Info

  • Pagination: p. 73
  • Serial:
    • New Ships
    • Publisher: Seehafen-Verlag Erik Blumenfeld

Subject/Index Terms

Filing Info

  • Accession Number: 00182990
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Oct 31 1978 12:00AM