Journal Articles

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884

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Author: search.filters.author.Vittal, K.P.

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    Integrated adaptive reach setting of distance relaying scheme in series compensated lines
    (School of Electrical Engineering and Informatics, 2010) Srivani Iyengar, S.G.; Vittal, K.P.
    The protection of series compensated lines is considered to be one of the most difficult tasks. The paper reviews the series compensated line protection challenges initially and presents state of art solution to improve the distance relay performance. The work describes the development and evaluation of an integrated adaptive distance protection scheme. Development of the adaptive scheme is in the specific area of incorporating the adaptive feature like adaptive reach setting of the relay as the compensation level changes in the series compensated lines, for optimum dependability and security of the protection system. The relay adapts its characteristics according to the informations received from the communication unit. Upon extensive testing on different data set of fault cases with fault resistance and varying percentage compensation level and fault location, performance of the developed method ensures that the proposed scheme overcomes the overreach/underreach problem of the distance relay in series compensated lines and is found to be quite promising.
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    An integrated adaptive distance relaying scheme in series compensated transmission lines
    (Universitatea Politehnica din Timisoara blucretiu@yahoo.com, 2011) Srivani Iyengar, S.G.; Vittal, K.P.
    The introduction of the capacitance in series with the line reactance adds certain complexities to the effective application of impedance based distance relays. The paper reviews series compensated line protection challenges and present modern solution to improve the distance relay performance. The work presents development and evaluation of an integrated adaptive distance protection scheme. Development of the proposed scheme is in the specific area of incorporating the Adaptive features like adaptive Relay setting as the compensation level changes in the series compensated lines of the transmission system for optimum reliability. Upon extensive testing on different data set of fault cases with fault resistance and varying percentage compensation level, performance of the developed method ensures that the proposed scheme overcomes the overreach/underreach problem of the distance relay in series compensated lines and is found to be quite promising.
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    This paper presents a Microcontroller based three phase induction motor protection relay. The scheme employs the Hall effect current transducers for sensing motor line currents, and an ‘Auto ranging ’ feature, in order to acquire motor line currents accurately from no load to blocked rotor current. The flexibility of ‘Operator selectable thermal current versus time (I-T) curves feature’ is incorporated in the relay software, in which using the operator fed cold curve points and the thermal time constant of the motor, the corresponding I-T cold and hot curves can be fitted by the relay Software. The relay performance, with the selected I-T curves has been studied in the laboratory by testing on a three phase, 5 h.p. induction motor and it has been observed that the relay to follow the selected I-T characteristics. © 1998 Taylor & Francis.
    (Microcontroller based three-phase induction motor protection relay with operator selectable thermal it curve feature) Vittal, K.P.; Fakruddin, D.B.; Raghavendra Rao, I.; Parthasarathy, K.
    1998
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    A heuristic approach to distributed generation source allocation for electrical power distribution systems
    (Iran University of Science and Technology, 2010) Manjunatha Sharma, K.; Vittal, K.P.
    The recent trends in electrical power distribution system operation and management are aimed at improving system conditions in order to render good service to the customer. The reforms in distribution sector have given major scope for employment of distributed generation (DG) resources which will boost the system performance. This paper proposes a heuristic technique for allocation of distribution generation source in a distribution system. The allocation is determined based on overall improvement in network performance parameters like reduction in system losses, improvement in voltage stability, improvement in voltage profile. The proposed Network Performance Enhancement Index (NPEI) along with the heuristic rules facilitate determination of feasible location and corresponding capacity of DG source. The developed approach is tested with different test systems to ascertain its effectiveness.
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    Assessment of distributed generation source impact on electrical distribution system performance
    (2010) Sharma, M.; Vittal, K.P.
    The recent trends in electrical power distribution system operation and management are aimed at improving system conditions in order to render good service to the customer. The reforms in distribution sector have given major scope for employment of distributed generation (DG) resources which will boost the system performance. This paper proposes a heuristic technique for allocation of distribution generation source in a distribution system. The allocation is determined based on overall improvement in network performance parameters like reduction in system losses, improvement in voltage stability, improvement in voltage profile. The proposed Network Performance Enhancement Index (NPEI) along with the heuristic rules facilitate determination of feasible location and corresponding capacity of DG source. A Priority list is prepared with decreasing values of NPEI so that the designer can select most feasible location. The developed approach is tested with different test systems to ascertain its effectiveness. © 2010 AECE.
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    Performance enhancement of electrical distribution systems with multiple distributed generation sources
    (2010) Krishnamurthy, M.; Vittal, K.P.
    The recent trends in electrical power distribution system operation and management are aimed at improving system conditions in order to render good service to the customer. Reforms in the distribution sector have given major scope for employment of distributed generation (DG) resources which will boost system performance. This article proposes a heuristic technique for allocation of multiple distribution generation sources in a distribution system. The allocation is determined based on overall improvement in network performance parameters like reduction in system losses, improvement in voltage stability, improvement in voltage profile. The hybrid of Genetic Algorithm with the proposed Network Performance Enhancement Index (NPEI) along with the heuristic rules facilitates determination of feasible location for insertion of DG sources. A priority list is prepared with decreasing values of NPEI so that the designer can select most feasible locations. The developed approach is tested with different test systems to ascertain its effectiveness.
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    Novel algorithm for control of a shunt active power filter based on a three-level voltage source inverter
    (2010) Rajashekhar, S.; Vittal, K.P.
    A three-level voltage source inverter is utilized to implement a shunt active power filter. SVPWM technique is used in the control circuit to generate the required gate pulses for the voltage source inverter. Principle of operation and analysis of the control circuit is presented. The proposed control algorithm ensures balance of dc bus voltages. Hence this active power filter is ideally suited for high power drives and transmission systems. The simulation results are presented and analyzed. The THD of load current is reduced to 6.47 % from 28.795 % in steady operation. © 2010 Institute of Thermomechanics AS CR.
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    Simulation studies on the distance relay performance in the presence of STATCOM
    (Universitatea Politehnica din Timisoara blucretiu@yahoo.com, 2011) Sham, M.V.; Vittal, K.P.
    Flexible AC Transmission System (FACTS) devices are used to enhance the transient stability limit and power transfer capacity of the existing transmission lines. The mid-point compensation using static synchronous compensator (STATCOM) as a shunt FACTS device is common practice among utilities. But, the presence of STATCOM has influence on performance of the distance relay under normal operating conditions, as well as under fault conditions. This paper presents both analytical and simulation studies carried out using PSCAD/EMTDC on a transmission system connected with a STATCOM at the midpoint and its influence on distance relay performance. Simulation results shows that the presence of STATCOM on transmission line greatly affects the measured impedance at the relaying point.
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    Implementation of Turbine Emulator
    (Universitatea Politehnica din Timisoara blucretiu@yahoo.com, 2011) Vinatha Urundady, U.; Vittal, K.P.
    A Wave Turbine Emulator (WTE) is designed and implemented considering the realistic site data based on Oscillating Water Column (OWC) principle. Wave Turbine Emulator (WTE) is the important equipment for developing the Wave Energy Conversion systems. The Emulator reflects the actual behavior of the wave turbine without reliance on natural wave resources and actual wave turbine. It offers a controllable test environment that allows the evaluation and improvement of control schemes for electric generators which is hard to achieve with an actual wave turbine. The WTE can accurately reproduce the characteristics of real wave turbine. The Emulator can be used for research applications to drive an electrical generator in a similar way as a practical wave turbine. A prototype of turbine emulator is built in the laboratory using a three phase synchronous motor controlled by Rexroth Indra Drive. The system comprises of Simulink model of the Turbine, model of the oscillating water column, Data Acquisition card Instruments, Digital to Analog Converter, 3-phase Permanent magnet Synchronous motor driven by Rexroth Indra Drive Controller.
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    Power control strategy for grid connected permanent magnet synchronous generator for wave energy harnessing
    (Universitatea Politehnica din Timisoara blucretiu@yahoo.com, 2011) Vinatha Urundady, U.; Vittal, K.P.
    This paper describes the operation and control of a variable speed Well's turbine driven permanent magnet synchronous generator connected to the grid by means of fully controlled frequency converter which consist of a PWM rectifier, an intermediate dc circuit and a PWM inverter through a LCL filter. In such systems primary aim is to achieve a low distortion, high power quality power export from the converter with the objective to regulate the power flow or power factor optimization. Control schemes are implemented for regulating the dc link voltage for varying input conditions and for regulating the grid current entering the distribution network and hence the power flow into the grid. Response of the system under steady state at balanced/unbalanced, sinusoidal/distorted grid voltage, constant/varying grid frequency and transients such as voltage sag balanced /unbalanced, step variation in input power and under different fault conditions are investigated. In each case the grid current distortion and the dynamic performance of the converter control schemes are evaluated.