Showing papers by "K. Shanti Swarup published in 2012"

Design of pattern recognition system for static security assessment and classification

Abstract: Static security analysis is an important study carried out in the control centers of electric utilities. Static security assessment (SSA) is the process of determining whether the current operational state is in a secure or emergency (insecure) state. Conventional method of security evaluation involves performing continuous load flow analysis, which is highly time consuming and infeasible for real-time applications. This led to the application of pattern recognition (PR) approach for static security analysis. This paper presents a more efficient design of a PR system suitable for on-line SSA. The feature selection stage in the PR system uses many algorithms to select the optimal feature set. This paper proposes the use of Support Vector Machine (SVM), a recently introduced machine learning tool, in the classifier design stage of PR system. The developed PR system is implemented in IEEE standard test systems for SSA and classification. The performance of SVM classifier is compared with the conventional K-nearest neighbor, method of least squares and neural network classifiers. Simulation results prove that the SVM-PR classifier outperforms other equivalent classifier algorithms, giving high classification accuracy and less misclassification rate. The feasibility of SVM-PR classifier for on-line security assessment process is also presented.

Insights into testing and validation of DC offset removal filters in numerical distance protection

Abstract: Distance relay maloperates due to various reasons, like dc offset in current waveforms, capacitive voltage transformer transients, remote-end in-feed in the presence of fault resistance, power swings and loading. dc offset in current waveforms results in overreach, causing distance relay to operate for faults outside its protected zone. There are many offset removal filters proposed by researchers in literature, but it is found, that the same ideas fail to penetrate as a filter into today's Intelligent Electronic Devices (IED). The objective of this paper is not to propose a new filter, but to provide insights into testing and validating those DC offset removal filters, which are not focused till now. This paper provides the additional factor to be considered for validating filters, which are proposed for dc offset removal and this is done by comparing the performance of three dc offset removal filters, digital mimic filter (dmf), patented filter (pf) to remove dc offset and double differentiator filter (ddf) which are currently used by relay manufacturers.

Investigating performance of numerical distance relay with higher sampling rate

Abstract: This paper investigates the impact on operating time delay and relay maloperation i.e. selectivity, when high sampling rate is used in numerical distance protection (NDP). Simulation is carried out in an on-line way, for different source to line reach impedance ratio (SIR), fault type, fault locations and for different loading conditions. The voltage and current signals from capacitive voltage transformers and current transformers respectively are fed to the numerical distance relay (NDR). Sampling rate of 12, 16, 24, 32 and 64 times the fundamental frequency (50 Hz) are chosen for this investigation, since these are typically used in conventional distance relays.