### Abstract

In this paper, an overview is provided of a new
method that in real-time provides an early warning for an
emerging blackout that are characterized by a slowly increasing
angular separation between sub-groups of system generators.
Such angular separation between subgroups of generators can
eventually cause in very sharp decline in system voltages at
intermediate locations between the two groups as the angular
separation approaches 180◦. In order to receive an early warning
for the occurrence of such type of blackouts, the boundaries of the
system generators aperiodic small-signal stability are suggested to
be monitored. For that purpose, method for real-time assessment
of aperiodic small-signal rotor angle stability is presented. The
approach is based on an element-wise assessment of individual
synchronous machines where the aim is to determine the maximum
steady state power that each synchronous generator can
inject into the system. The limits for maximum injectable power
represent the boundary for aperiodic small signal stability.
The concept of the proposed method is tested on two different
systems. The results show that the method is capable of accurately
detecting when a given machine crosses the stability boundary.
The method can as well provide in real-time a margin to the
machines stability boundary, which can be used as an early
warning for an impending system stability problem.

Original language | English |
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Title of host publication | IEEE PES Trondheim PowerTech |

Publisher | IEEE |

Publication date | 2011 |

Publication status | Published - 2011 |

Event | IEEE PES Trondheim PowerTech 2011 - Trondheim, Norway Duration: 19 Jun 2011 → 23 Jun 2011 |

### Conference

Conference | IEEE PES Trondheim PowerTech 2011 |
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Country | Norway |

City | Trondheim |

Period | 19/06/2011 → 23/06/2011 |

## Cite this

Jóhannsson, H., Garcia-Valle, R., Weckesser, J. T. G., Nielsen, A. H., & Østergaard, J. (2011). Real-Time Stability Assessment based on Synchrophasors. In

*IEEE PES Trondheim PowerTech*IEEE. http://ewh.ieee.org/conf/powertech/2011/