Protecting DC Power Networks

by | Sep 22, 2016 | News

Parallel DC power distribution

(With magazine extras) Distribution of electric power using direct current (DC) is proposed to increase on efficiency. DC offers advantages over alternating current (AC) for future naval platforms.

Enduring difficulty in interrupting DC fault currents is a problem that must be overcome before changing the network architecture. Different protective strategies and devices may overcome this challenge, including mechanical, solid-state and hybrid solutions as well as fuses.

The is how the first of two articles on DC power networks starts in SWZ Maritime's summer issue. In this first part, the authors outline the problems with existing solutions to avoid peak loads on DC networks. An inventory of existing technology is given, along with detailed description of the parameters of electro-mechanical devices.

In the second part, to be published next month, a detailed description will follow of the characteristics of fuses, solid state devices and hybrid devices.

An appendix that shows how the 23 per cent higher capacity of DC networks over AC networks is calculated, can be downloaded here (PDF). In addition, below you find the references accompanying the article.

References

  1. Maber, John M., “Electrical Supply in Warships – A Brief History (Part 1)”, Journal of Naval Engineering Volume 25, No. 3, June 1980.
  2. IEC 61660-1:1997 – Short-circuit currents in d.c. auxiliary installations in power plants and substations – Part 1: Calculation of short-circuit currents.
  3. Flurscheim, C. H. (Ed), "Power Circuit Breaker Theory and Design", (IEE Monograph Series 17), Peter Peregrinus Ltd., Southgate House, Stevenage, Herts., SG1 1HQ, UK. 1975. ISBN 090122362X.
  4. Gregory, G.: “Applying Low-voltage Circuit Breakers in Direct Current Systems”, IEEE Transactions on Industry Applications, Vol. 31, No. 4, July/August 1995.
  5. Masterpact NT and NW catalogue 2011, Schneider Electric (hard copy).
  6. Masterpact NW DC Circuit Breakers catalogue 2014, downloaded from https://static.schneiderelectric.us/docs/Circuit%20Protection/DC%20Rated%20Circuit%20Breakers/0613CT0501.pdf March 2015.
  7. Secheron Type HPB45 & HPB60 data sheet. Downloaded from www.secheron.com March 2015.
  8. Kempkes, M., Roth, I. and Gaudreau, M.: "Solid-State Circuit Breakers for Medium Voltage DC Power", IEEE Electric Ship Technologies Symposium, Alexandria, VA., USA, April 2011.
  9. Meyer, C.; Kowal, M.; De Doncker, R.W., "Circuit breaker concepts for future high-power DCapplications," in Industry Applications Conference, 2005. Fourtieth IAS Annual Meeting. Conference Record of the 2005 , vol.2, no., pp.860-866 Vol. 2, 2-6 Oct. 2005.
  10. Qiu Deng; Xing Liu; Soman, R.; Steurer, M.; Dougal, R.A., "Primary and backup protection for fault current limited MVDC shipboard power systems," in Electric Ship Technologies Symposium (ESTS), 2015 IEEE , vol., no., pp.40-47, 21-24 June 2015.
  11. Rampen, P., Meijer, C.G. and Stokman, H.D.: “Next generation hybrid power system: Enhanced safety and performance by full controlled smart DC”, Engine As A Weapon VI, 23 – 24 June 2015, Bath, UK.