Voltage-Stability Monitoring Using Wide-Area Measurement Systems

2008 IEEE Power and Energy Society General Meeting - Conversion and Delivery of Electrical Energy in the 21st Century

2008

Abstract-This paper deals with long-term voltage instability triggered by the outage of transmission or generation equipments. It is shown how the onset of voltage instability could be detected in real-time from post-disturbance bus voltages provided by Phasor Measurement Units (PMUs), assuming observability of the whole region prone to voltage instability. An extended set of equilibrium equations is fitted to the measurements and the change in sign of sensitivities is monitored. The latter are easily computed even for a large system. The important effects of overexcitation limiters and load tap changers are taken into account. The approach is illustrated on a 52-bus 20-machine system, where PMU outputs are simulated from detailed time simulation.

Section: Methods Assuming Observability Of the Whole Voltage Unstamentioning

confidence: 99%

Detecting with PMUs the onset of voltage instability caused by a large disturbance

2008 IEEE Power and Energy Society General Meeting - Conversion and Delivery of Electrical Energy in the 21st Century

2008

“…[51] the voltage drop across the Thévenin impedance was approximated by the sum of the absolute values of the complex voltage drops over the branches located on the shortest path from the load bus of concern to a generator under voltage control. The impedance matching criterion is then replaced by a voltage drop matching criterion.…”

Section: B Vid From Estimated or Reconstructed System Statesmentioning

confidence: 99%

A short survey of methods for voltage instability detection

2011 IEEE Power and Energy Society General Meeting

2011

117

100

Abstract-This paper shortly surveys existing and proposed methods for voltage instability detection. The emphasis is on methods relying on real-time measurements as well as on longterm voltage instability. Methods are classified according to the required measurement configuration: local vs. wide-area, standard SCADA-type vs. synchronized phasor measurements, etc. In the various categories, some of the features are summarized, and what appears to the authors as advantages or limitations is shortly discussed. An important feature is the ability to anticipate instability. Some tracks for further work on the subject are also outlined.

“…Furthermore, it is of interest to anticipate the effect of an approaching OEL activation [8]. To this purpose, when E q > E lim q + ǫ, the OEL equation (3) is anticipatively substituted to the AVR equation (2) when evaluating the Jacobian ϕ z .…”

Section: A Anticipating Oel Activationmentioning

confidence: 99%

Wide-Area Detection of Voltage Instability From Synchronized Phasor Measurements. Part II: Simulation Results

IEEE Trans. Power Syst.

2009

115

106

Abstract-This two-part paper deals with the early detection of an impending voltage instability from the system states provided by synchronized phasor measurements. Recognizing that voltage instability detection requires assessing a multidimensional system, the method fits a set of algebraic equations to the sampled states, and performs an efficient sensitivity in order to identify when a combination of load powers has passed through a maximum. This second part of the paper presents simulation results obtained from detailed time-domain simulation of the Nordic32 test system, without and with measurement noise, respectively. Several practical improvements are described such as anticipation of overexcitation limiter activation, and use of a moving average filter. Robustness to load behaviour, non updated topology and unobservability is also shown. Finally a comparison with Thévenin impedance matching criterion is provided.