Blackout Prevention by Power Swing Detection and Out-of-Step Protection

J. Blumschein^*, Y. Yelgin, M. Kereit

Infrastructure & Cities Sector, Siemens AG, Munich, Germany.

DOI: 10.4236/jpee.2014.24093                

Abstract

Power swing evoked by sudden changes like faults or switching operations will become more and more important for protective relaying, due to the growing load flow in electrical power networks. Unwanted trips of the distance protection function must be avoided to prevent cascading effects and blackouts in the network. Selective out-of-step-tripping is required to stop unstable power swing and to prevent damage to affected generators. Therefore a reliable method for detection of power swing is presented, which requires no settings for operation. Power swing can be detected from 0.1 Hz up to 10 Hz swing frequency, also during open pole condition and during asymmetrical operation. A blocking logic prevents unselective trips by the distance protection. However, faults that occur during a power swing must be detected and cleared with a high degree of selectivity and dependability. For unstable power swing a flexible out of step tripping function will be proposed. The coordination of power swing detection, distance protection and out of step protection provides a reliable system protection.

Keywords

Power Swing Detection; Distance Protection; Out of Step Protection

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Siemens, A.G., Infrastructure & Cities Sector (2006) User Manual Distance Protection 7SA522 V4.61. Ordering Nr. C53000-G1176-C155-5. http://www.siprotec.com
[2]	Schmaranz, R., Renner, H. and Hübl, I. (2007) Rotor Angle Stability and the Effects on Protection Devices in Distribution Networks. KELAG, Klagenfurt, Austria and University of Technology, Graz, Austria. 19th International Conference on Electricity Distribution, Vienna, 21 May 2007. http://www.ove.at/akademie/cired07.htmT
[3]	Jurisch, A. and Schwenke, M. (2000) Method of Deriving a Signal Indicating an Oscillation in an Electric Power Supply System. US-Patent 6104182.
[4]	Jurisch, A. and Kereit, M. (2000) Process for Producing Signals Identifying Faulty Loops in a Polyphase Electrical Power Supply Network. US-Patent 6034592.