B Ravikumar

An Approach Using Support Vector Machines for Distance Relay Coordination in Transmission System

This paper presents transmission system distance relaying co-ordination using detailed simulation studies of the apparent impedance loci as seen from the relaying location considering various operating conditions including fault resistance. Support vector machines (SVMs) are used as a pattern classifier for obtaining distance relay co-ordination. The scheme utilizes the apparent impedance values observed during fault as inputs. An improved performance with the use of SVMs, keeping the reach when faced with different fault conditions as well as system power flow changes are illustrated with an equivalent 246 bus system of practical Indian Southern grid.

Comparison of Multiclass SVM Classification Methods to Use in a Supportive System for Distance Relay Coordination

This paper aims at evaluating the methods of multiclass support vector machines(SVMs) for effective use in distance relay coordination. Also, it describes a strategy of supportive systems to aid the conventional protection philosophy in combating situations where protection systems have maloperated and/or information is missing and provide selective and secure coordinations. SVMs have considerable potential as zone classifiers of distance relay coordination. This typically requires a multiclass SVM classifier to effectively analyze/build the underlying concept between reach of different zones and the apparent impedance trajectory during fault. Several methods have been proposed for multiclass classification where typically several binary SVM classifiers are combined together. Some authors have extended binary SVM classification to one-step single optimization operation considering all classes at once. In this paper, one-step multiclass classification, one-against-all, and one-against-one multiclass methods are compared for their performance with respect to accuracy, number of iterations, number of support vectors, training, and testing time. The performance analysis of these three methods is presented on three data sets belonging to training and testing patterns of three supportive systems for a region and part of a network, which is an equivalent 526-bus system of the practical Indian Western grid.

Harmonic minimization in the operation of static VAR compensators for unbalanced reactive power compensation

Phase-wise unbalanced reactive power compensations are required in distribution systems for dynamic power factor correction and terminal voltage stabilization. Shunt compensators are generally used to reduce or cancel the phase-wise unbalanced reactive power (VAR) demand and to minimize the reactive power drawn from the AC supply lines. Static VAR compensators are preferred over traditional VAR compensators for this purpose. The operation of thyristor-controlled compensators at various conduction angles can be used advantageously to meet the unbalanced reactive power demands in a system. However such an operation introduces harmonic currents in to the AC system. In such cases it becomes necessary either to minimize harmonic generation internally or provide external harmonic filters. In this paper, an approach is presented for operation of VAR compensators for minimization of the effect of the harmonics using the telephone influence factor (TIF) and the total harmonic distortion factor (THD) for a typical distribution system.

An Intelligent Approach Using Support Vector Machines for Monitoring and Identification of Faults on Transmission Systems

Power system disturbances are often caused by faults on transmission lines. When faults occur in a power system, the protective relays detect the fault and initiate tripping of appropriate circuit breakers, which isolate the affected part from the rest of the power system. Generally extra high voltage (EHV) transmission substations in power systems are connected with multiple transmission lines to neighboring substations. In some cases mal-operation of relays can happen under varying operating conditions, because of inappropriate coordination of relay settings. Due to these actions the power system margins for contingencies are decreasing. Hence, power system protective relaying reliability becomes increasingly important. In this paper an approach is presented using support vector machine (SVM) as an intelligent tool for identifying the faulted line that is emanating from a substation and finding the distance from the substation. Results on 24-bus equivalent EHV system, part of Indian southern grid, are presented for illustration purpose. This approach is particularly important to avoid mal-operation of relays following a disturbance in the neighboring line connected to the same substation and assuring secure operation of the power systems

Generators contribution towards loads and line flows-a case study

In many parts of the world, the goal of electricity supply industries is always the introduction of competition and a lowering of the average consumer price. Because of this it has become much more important to be able to determine which generators are supplying a particular load, how much use each generator is making of a transmission line and what is generators contribution to the system losses. In this paper a case study on generator contributions towards loads and transmission flows are illustrated with an equivalent 11-bus system, a part of Indian Southern Grid, based on the concepts of circuit flow directions, for normal and network contingency conditions

A New Approach for Fault Location Identification in Transmission system using Stability Analysis and SVMs

This paper presents a new approach to the location of fault in the high voltage power transmission system using support vector machines (SVMs). A knowledge base is developed using transient stability studies for apparent impedance swing trajectory in the R-X plane. SVM technique is applied to identify the fault location in the system. Results are presented on sample 3-power station, a 9-bus system illustrate the implementation of the proposed method.

An approach for distance relay co-ordination using support vector machines

In this paper, an approach to enhance the extra high voltage (EHV) transmission system distance protection is presented. The scheme depends on the apparent impedance seen by the distance relay during the disturbance. In a distance relay, the impedance seen at the relay location is calculated from the fundamental frequency component of the voltage and current signals. Support Vector Machines (SVMs) are a new learning-by-example are employed in discriminating zone settings (Zone-1, Zone-2 and Zone-3) using the signals to be used by the relay. Studies on 265-bus system, an equivalent of practical Indian Western grid are presented for illustrating the proposed scheme.

Distance Relay Co-ordination Using Support Vector Machines in Power Transmission System

In this paper, a new approach to enhance the transmission system distance relay co-ordination is presented. The approach depends on the apparent impedance loci seen by the distance relay during all possible disturbances. In a distance relay, the impedance loci seen at the relay location is obtained by extensive transient stability studies. Support vector machines (SVMs), a class of patterns classifiers are used in discriminating zone settings (zone-1, zone-2 and zone-3) using the signals to be used by the relay. Studies on a sample 9-bus are presented for illustrating the proposed scheme.