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A regime shift occurs when a dynamical system's state shifts from a nominal equilibrium to an alternative equilibrium. This concept is often used to describe the collapse of ecological systems, but it also appears in many engineering systems; most notably in the voltage collapse of power systems. This paper uses an information theoretic index known as the Fisher Information (FI) as a real-time statistical...
Results from two practical and fast methods to estimate systems' Maximum Loading Point (MLP) using Phasor Measurement Units (PMUs) are used in this paper as initial values for a robust and very efficient method that takes advantage of the geometric characteristics of the maximum loading hyperplane and uses the load flow with step size optimization (LFSSO) technique to estimate the system's proximity...
A hybrid simulation/measurement-based framework for online dynamic security assessment (DSA) is proposed in this work. It combines the strengths and features of simulation-based and measurement-based approaches to develop a tool that integrates the results and provides real-time situational awareness on available operating margins against major stability problems. High performance computing capability...
Monitoring the long term voltage stability of the power grid is necessary to ensure its secure operation. In this paper, a voltage stability index that is linear with the power demand, called the M-index, based only on angles is proposed. The linearity of the M-index can be utilized to estimate the load margin directly. The linearity of the M-index is proved for the two-bus system and a method to...
Voltage instability may be predicted by the Thevenin equivalent based approach using only local measurements taken at the monitored buses. This paper focuses on reliable estimation of Thevenin parameters from measurements, which are crucial in judging voltage stability. Two parameter estimation methods (least squares and Kalman filter) and a proposed new hybrid method are tested on the NPCC 140-bus...
In this paper a hybrid method is proposed to reduce the impact of islanding in the presence of Distributed Generation (DG). The issue of islanding is critical in the distribution system as the non- detection of islanding may lead to the collapse of the system. The islanding is prominent due to the increased penetration levels of DG in the network. In the proposed method, first the placement of DG...
This paper proposes a robust control scheme to improve the integration of variable energy sources such as renewables into a DC bus distribution microgrid. The model of the controller is developed and analyzed with simplification of parameters and keeping the effect of the multiple loads and sources connected in parallel as an uncertainty. Various simulated scenarios are used to show the performance...
To assess static voltage stability in power networks, critical load values were examined at each load bus as a voltage instability predictor. However, the information that is required to evaluate loadability conditions is usually not available at load buses. To predict impending voltage collapse in a droop-controlled power distribution network, this paper introduces a static voltage stability detector...
We use synchrophasor measurements of the complex voltage and current at both ends of multiple transmission lines that connect areas of a power system to monitor the online voltage collapse margin. A new reduction is used to reduce the multiple transmission lines to a single line equivalent and determine how to combine the synchrophasor measurements. Generator reactive power limits can be accommodated...
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