Improved method for considering PMU's uncertainty and its effect on real-time stability assessment methods based on Th&amp;#x00E9;venin equivalent

2017 IEEE Manchester PowerTech

et al. 2017

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In this paper, wind speed models are used to consider its variability in real-time voltage stability assessment using Thévenin equivalent methods. A stochastic differential equation was used to produce a set of wind speeds required for the simulation scenarios together with a very short-term forecast based on a probabilistic method, which provides the means for including anticipation in the stability assessment. This is achieved by representing the variation in the wind as an uncertainty in the Thévenin equivalent parameters, which are used for wide-area assessment, and studying corresponding changes in the stability boundary for a specific time horizon. The methodology was tested with time domain simulation a cigré benchmark system for network integrations of renewables, where the approach successfully represented the final Thévenin Equivalent parameters with a maximum error of 2.5% of the estimated variables, for a time horizon of 1 minute in the used forecast.

Section: A Proposed Methods Overview and Contributionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Considering wind speed variability in real-time voltage stability assessment using Thévenin equivalent methods

Perez

Karatas

2017 IEEE Manchester PowerTech

et al. 2017

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“…The first descriptions of TEM used a least-square procedure to determined the parameters from local measurements [19]. The approach followed in this paper is to compute the parameters from wide-area measurements together with the network model [13,14,20].…”

Section: A Description Of Modified Thévenin Equivalent Methodsmentioning

confidence: 99%

“…The uncertainty in the measurements has been considered using the methodology in [20]; • since the evaluation of long-term voltage stability is of interest, the assessment has been started a few (3 to 15) seconds after the disturbance has been applied to the model.…”

Section: B Processing Of Synchrophasor Measurementsmentioning

confidence: 99%

Improved Thévenin equivalent methods for real-time voltage stability assessment

Perez

2016 IEEE International Energy Conference (ENERGYCON)

Østergaard

et al. 2016

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Abstract-An improved Thévenin equivalent method for realtime voltage stability assessment that uses wide-area information from synchrophasors is proposed. The improvements are a better modeling of the limited synchronous generators, and a processing that anticipates the effect of field current limiters, before the latter are activated. Several study cases using detailed dynamic simulations of the Nordic test system have been used to assess the performance of the proposed improvements. Their effectiveness is analyzed and, based on the results, their possible application in combination with the sensitivity-based voltage stability assessment method is explored.

Reduce–factor–solve for fast Thevenin impedance computation and network reduction

Sommer

Aabrandt

IET Generation, Transmission & Distribution

2018

The complexity and volatility of power system operation increases when larger parts of the power production is based on distributed and non-controllable renewable energy sources. Ensuring stable and secure operation becomes more difficult in these modern power systems. For security assessment, the results of traditional offline simulations may become obsolete prior to the completion of the assessment. In contrast, real-time stability and security assessment aims at online computation, and it is therefore dependent on very fast computation of properties of the grid operating state. The paper develops the reduce-factor-solve approach to real-time computation of two key components in real-time assessment methods, network reduction and calculation of Thevenin impedances. The aim is to allow online stability assessment for very complex networks. The theoretical foundation behind the reduce-factor-solve approach is described together with the ability to handle both algorithms in a common framework. By exploiting parallelization of the reduce and solve steps in combination with fast matrix factorization, Thevenin impedances and reduced networks are computed much faster than previous approaches. The reduce-factor-solve algorithm is evaluated on power grids of varying complexity to show that Thevenin impedance computation and network reduction for complex power systems can be performed on a milliseconds time scale.