Advertisement

Overcurrent Protection

Time-Current Characteristics—Application—Limits of Error—Ratings—Directional Overcurrent Protection—a.c. Tripping—Schemes for Radial Feeders—Construction—Application—Problem
  • A. R. van C. Warrington

Abstract

Fault current can be used as a basis for selectivity only where there is an abrupt difference between its magnitude for a fault within the protected section and a fault outside it, and these magnitudes are almost constant. Where this is so, a current magnitude device can be used, such as a fuse or an instantaneous relay or trip device and selectivity can be obtained by grading current. A typical case where current grading can be used is shown in fig. 4.1, where there is a high impedance unit such as a transformer which makes the fault much less for faults beyond the transformer.

Keywords

Fault Current Protective Relay Ground Fault Zero Sequence Directional Unit 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 17.
    Sonnemann, W. K. and Glassburn, W. E. ‘Principles of Induction-type Relay Design’, Transactions A.I.E.E., 72, Part III, 1953, pp. 23–27.Google Scholar
  2. 18.
    Sonnemann, W. K. ‘A New Inverse Time Overcurrent Relay with Adjustable Characteristics’, Transactions A.I.E.E., 72, Part III, 1953, p. 360.Google Scholar
  3. 21.
    Gross, E. T. B. ‘Sensitive Ground Relaying of a.c. Generators’, Transactions A.I.E.E., 71, 1952, paper No. 51–371.Google Scholar
  4. 32.
    McConnell, A. J. ‘A Single Element Polyphase Directional Relay’, Transactions A.I.E.E., 56, No. 1, 1937, pp. 77–80CrossRefGoogle Scholar
  5. 32a.
    McConnell, A. J. ‘A Single Element Polyphase Directional Relay’, Transactions A.I.E.E., 113; No. 8, 1937 pp. 1025–1028.Google Scholar
  6. 33.
    Sonneman, W. K. ‘A Study of Directional Element Connections for Phase Relays’, Transactions A.I.E.E., 69, Part II, 1950. Also Disc, ibid., pp. 1450–1451.Google Scholar
  7. 34.
    Barnes, H. C. and McConnell, A. J. ‘Some Utility Ground Relay Problems’, Transactions A.I.E.E., June, 1955.Google Scholar
  8. 35.
    Wilson, R. M. and Cannon, C. E. ‘Fundamentals of Co-ordinating Fuses and Relays’, Electrical West., 87, July, 1941, pp. 30–31.Google Scholar
  9. 36.
    Steeb, G. ‘Relay Inverse Time Characteristic Doubled’, Electrical World, 118, October, 1942, p. 1484.Google Scholar
  10. 37.
    Hunt, L. F. ‘Sensitive Ground Relay Protection for Complex Distribution Circuits’, Transactions A.I.E.E., 65, November, 1956, pp. 765–768; disc, Supplement, 1946, pp. 1180–1181.CrossRefGoogle Scholar
  11. 38.
    Graybeal, T. D. ‘Factors which Influence the Behaviour of Directional Relays’, Transactions A.I.E.E., 61, 1942, pp. 942–952.CrossRefGoogle Scholar
  12. 39.
    Morris, W. C. ‘Dual-polarised Directional Ground Relays’, Distribution, April, 1952, pp. 8–9.Google Scholar
  13. 40.
    Pratt, M. G., Audlin, L. J. and McConnell, A. J. ‘New Relay Assures Feeder Resumption After Outage’, Electrical World, Part I, September 10th, 1949, pp. 99–103; Part II, September 24th, 1949, pp. 95–98.Google Scholar
  14. 49.
    Ramsaur, O. ‘A New Approach to Cold Load Restoration’, Electrical World, October, 1952, pp. 101–103.Google Scholar
  15. 71.
    Salzmann, A. ‘Co-ordination of Phase Fault Protection’, Electrical Energy, December, 1958, pp. 480–487.Google Scholar
  16. 118.
    Kreekon, N. and Powchroski, D. W. ‘A New Static Overcurrent Relay’ Allis-Chalmers Review, April, 1960.Google Scholar

Copyright information

© Albert Russell van Cortlandt Warrington 1968

Authors and Affiliations

  • A. R. van C. Warrington
    • 1
  1. 1.The English Electric Company LimitedStaffordUK

Personalised recommendations