REE-Seminar - 1 POWER SYSTEM VOLTAGE STABILITY: A SHORT...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 POWER SYSTEM VOLTAGE STABILITY: A SHORT TUTORIAL Dr. Mevludin Glavic University of Liège Electrical Engineering and Computer Science Department (The demos included and the material in part are provided by Dr. Thierry Van Cutsem) Power system stability and voltage stability. o Is power system stability a single problem? YES! “is the property of a power system which enables it to remain in a state of equilibrium under normal operating conditions and to regain an acceptable state of equilibrium after a disturbance” o What is voltage stability? “voltage instability stems from the attempt of load dynamics to restore power consumption beyond the capability of the combined transmission and generation system” o What is voltage collapse? “the process by which the sequence of events accompanying voltage instability leads to a low unacceptable voltage profile in a significant part of the power system” (may or may not be the final outcome of voltage instability) 2 Voltage stability and angle stability. o Is there clear distinction between angle and voltage instability? NOT ALWAYS! “often both types of instabilities come together and one may lead to other” o Distinction between the two types is important for understanding of the underlying causes of the problems in order to develop appropriate design and operating procedures. o Distinction is effective but the overall stability of the system should be kept in mind. o Solutions for one problem should not be at expense of another. o It is essential to look at all aspects of the stability phenomena and at each aspect from more than one viewpoint. Why Voltage Stability is more and more important? o Generation centralized in fewer, larger power plants:- fewer voltage controlled buses- longer electrical distances between generation and load o Extensive use of shunt capacitor compensation o Voltage instability caused by line and generator outages o Many incidents throughout the world (France, Belgium, Sweden, Japan, USA, etc.) o Operation of system closer to its limits 3 Main results of the post-mortem analysis of 20 incidents o The initial event may be due to a variety of causes:- Small gradual changes such as natural increase in system load,- Large sudden disturbances such as loss of a generating unit or a heavily loaded line,- cascading events o The inability of the system to meet its reactive demands. o Voltage collapse generally manifests itself as a slow decay in voltage. o Voltage collapse is strongly influenced by system conditions and characteristics:- large distances between generation and load,- ULTC actions,- Unfavorable load characteristics,- Poor coordination between various control and protective systems o The voltage collapse may be aggravated by excessive use of shunt capacitor compensation....
View Full Document

This note was uploaded on 10/02/2009 for the course G 001 taught by Professor Shmmygr during the Spring '07 term at National Technical University of Athens, Athens.

Page1 / 23

REE-Seminar - 1 POWER SYSTEM VOLTAGE STABILITY: A SHORT...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online