Section: B Case 2: Comparison With Community Detection Methodsmentioning
confidence: 99%
“…To form self-sustained islands, generator coherency and generation/load imbalance need to be considered. In this paper, we treat generator coherency as the constraint and power flow disruption as the minimization objective as shown in (9).…”
“…However, it needs a threshold to identify the correct number of coherent groups, which requires expert knowledge and may vary for different operating conditions and fault locations. Bioinformatics clustering technique is suggested in [9] to determine the coherent groups of generators; however, the number of clusters should be specified which may result in unrealistic grouping if recommended number of clusters is improper. Ariff et al presented an approach based on independent component analysis and considered 20 sec time window data of generator speeds and bus voltage angles to have reasonable and practical grouping [10].…”
Controlled islanding is considered to be the last countermeasure to prevent system-wide blackouts in case of cascading failures. It splits the system into self-sustained islands to maintain transient stability at the expense of possible loss of load. Generator coherence identification is critical to controlled islanding scheme as it helps identify the optimal cutset to maintain system transient stability. This paper presents a novel approach for online generator coherency identification using phasor measurement unit (PMU) data and dynamic time warping (DTW). Results from the coherence identification are used to further cluster non-generator buses using spectral clustering with the objective of minimizing power flow disruption. The proposed approach is validated and compared to existing methods on the IEEE 39-bus system, through which its advantages are demonstrated.
Section: B Case 2: Comparison With Community Detection Methodsmentioning
confidence: 99%
“…To form self-sustained islands, generator coherency and generation/load imbalance need to be considered. In this paper, we treat generator coherency as the constraint and power flow disruption as the minimization objective as shown in (9).…”
“…However, it needs a threshold to identify the correct number of coherent groups, which requires expert knowledge and may vary for different operating conditions and fault locations. Bioinformatics clustering technique is suggested in [9] to determine the coherent groups of generators; however, the number of clusters should be specified which may result in unrealistic grouping if recommended number of clusters is improper. Ariff et al presented an approach based on independent component analysis and considered 20 sec time window data of generator speeds and bus voltage angles to have reasonable and practical grouping [10].…”
Controlled islanding is considered to be the last countermeasure to prevent system-wide blackouts in case of cascading failures. It splits the system into self-sustained islands to maintain transient stability at the expense of possible loss of load. Generator coherence identification is critical to controlled islanding scheme as it helps identify the optimal cutset to maintain system transient stability. This paper presents a novel approach for online generator coherency identification using phasor measurement unit (PMU) data and dynamic time warping (DTW). Results from the coherence identification are used to further cluster non-generator buses using spectral clustering with the objective of minimizing power flow disruption. The proposed approach is validated and compared to existing methods on the IEEE 39-bus system, through which its advantages are demonstrated.
“…The methods in [11] and [12] used bioinformatics clustering technique and K-means clustering technique respectively, for the identification of coherent groups. However, both methods require a pre-specification of the number of clusters, which does not make them adaptive.…”
This paper presents an approach for online generator coherency identification based on windowed dynamic time warping (DTW). Generator rotor speed deviations measured by phasor measurement units (PMUs) are used as input data to compute a DTW dissimilarity matrix. Using the dissimilarity matrix together with Agglomerative Hierarchical Clustering (AHC) and Hubert-Levin index (C-index), generators are optimally grouped into coherent clusters. In addition to the clustering of generators, an index for characterizing the transmission delay of a Wide Area Measurement System (WAMS) is presented. A data delay factor that can indicate whether there is an inconsistent PMU data transmission delay is also proposed. The coherency identification technique and indices were tested using simulations carried out on the IEEE 39-bus system. The test results indicate that the proposed scheme accurately clusters generators into coherent groups. The suggested indices were also found to be valid.
“…The ratio of accelerated kinetic energy is proposed in [8] to the identification of coherent generators. In [9], a Bioinformatics clustering technique is introduced for identifying the generator coherent groups based on information supplied by PMUs, within a certain window of time, after system contingencies. The Bioinformatics toolbox should be fed with the suggested number of clusters, hence results could be inexact if the suggested number of cluster is improper.…”
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