Conference Papers
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506
Browse
45 results
Search Results
Item Performance of power system stabilizers in a fixed series capacitor compensated system(2011) Shashidhara, M.K.; Shubhanga, K.N.In this paper, the performance of two IEEE-type power system stabilizers (PSS), i.e., a slip-signal PSS and a Delta-P-Omega PSS are studied in a fixed series capacitor compensated system employing the IEEE first benchmark system. An eigenvalue analysis of the well-known slip-signal-torsional interaction showed that the slip-signal-interactions occur only when the degree of line compensation is above a certain level depending on the loading condition. The time-domain verifications of the eigen-predictions are carried out through modal speed plots instead of a confusing participation factor-based method. Further, the swing-mode damping performances of PSS are analyzed for different levels of series compensation. This study not only validated the poor swing-mode damping performances of a slip-signal PSS, but also demonstrated that a Delta-P-Omega PSS does not worsen the damping of swing-mode even at higher levels of series compensation which permits a straight forward PSS design. © 2011 IEEE.Item Some aspects of power system stabilizer performance in subsynchronous resonance study(2011) Shashidhara, M.K.; Shubhanga, K.N.In this paper, behavioural aspects of two types of power system stabilizers (PSS), i.e., a slip-signal PSS and a Delta-P-Omega PSS are studied in a fixed series capacitor compensated system employing the IEEE first benchmark system for SSR study. The well-known slip-signal-torsional interaction is studied to understand its dependency on the magnitude of network compensation. From such a study it is noted that the slip-signal-interaction is prominent only at higher degree of line compensation. It is also shown that Delta-P-Omega PSS is immune to such torsional interactions. Further, using the eigenvalue-based study, the swing-mode damping performance of slip-signal PSS and Delta-P-Omega PSS are studied when a system is series compensated. This study not only demonstrated the superiority of Delta-P-Omega PSS, but also validated the poor performance of slip-signal PSS. All these observations are verified by carrying out simulations on PSCAD/EMTDC. To enhance the understanding about the SSR phenomenon, some fundamental observations made in the study are also listed. © 2011 IEEE.Item Development of a power system laboratory supported by real-time systems(2011) Surendra, D.; Shubhanga, K.N.In this paper, features of a power system laboratory supported by real-time systems are outlined. These real-time systems are built using an open-source RTAI-Linux which not only offers a general purpose operating system features, but also has the hard real-time capabilities. On such a platform a transient waveform recorder is developed to capture the transient behaviour of a synchronous machine under various operating conditions such as voltage buildup and sudden 3-phase symmetrical short-circuit. Using the recorded transient waveforms, a synchronous machine model development task is carried out as per the IEEE Std. 115-2009 specified procedures. Employing such a model a time-domain simulation programme is run to tune the model parameters of the machine by comparing the simulation results against the recorded waveforms. It is also found that the transient waveform recorder provides a useful tool to visualize the synchronization and loss-of-synchronism transients either with the mains supply or with another machine. As an additional application, an open-loop excitation controller for a synchronous machine is developed which involved the realization of many hardware circuits such as inverse-cosine firing-circuit module, single-phase thyristor bridge-rectifier circuits and a DAC interfacing card. Such a laboratory is found to augment the classroom teaching of a power system dynamics course. © 2011 IEEE.Item Development of a PC based multi-function recorder for the laboratory model power system on RTAI-Linux platform(2012) Deepak, M.; Shubhanga, K.N.This paper presents the development of a PC based multi-function recorder using an open-source real-time application interface (RTAI) in Linux environment. Here, various quantities such as three-phase real and reactive power (including the sign), power factor, RMS value of the voltage and currents and frequency are estimated employing the instantaneous samples of 3-phase voltages and currents. Such a setup not only permits easy handling of plots in an off-line environment, but also helps to visualize the operating conditions of machines which are generally learnt only by mathematical models and time-domain simulations. In the paper, this aspect has been demonstrated by acquiring the operating conditions of a lab synchronous machine when it is subjected to loss-of-synchronism and loss-of-excitation. Further, since the system provides values of quantities in real-time, it is found that such a set up can be upgraded to a protective relaying system, for example, reverse power detection relay, and even for controller implementation. © 2012 IEEE.Item Development of a digital excitation system for synchronous generator on RTAI-Linux platform(2012) Deepak, M.; Shubhanga, K.N.In this paper realization of a digital excitation system for synchronous generator is discussed. Such a real-time task is implemented using Real-Time Application Interface on Linux platform which is an open source effort. In this work a static excitation system is considered which involved the development of additional hardware circuits such as fully-controlled thyristor bridge-rectifier, the associated firing circuit module and data acquisition systems. In addition to normally discussed proportional controller, a proportional-integral controller is also realized to understand its generator voltage regulation performance under different operating conditions. Case studies are presented related to both standalone and parallel operation conditions of the generator without taking up complex controller-tuning procedures. Such a setup is found to augment the generally employed simulation-based power system dynamics analysis. © 2012 IEEE.Item Development of a relay test bench and an arbitrary waveform generator in RTAI-Linux platform(2013) Hazarika, P.P.; Shubhanga, K.N.This paper presents the development of a PC-based relay test bench and an arbitrary waveform generator using an open-source Real-Time Application Interface (RTAI) in Linux environment. Such a setup not only permits the generation of any arbitrary waveforms: steady-state signals as well as transients, but also simplifies the testing of various single-phase or three-phase static relays such as over-voltage relay, directional power relay, negative sequence relay as well as numerical impedance relays. The actuating signal is fed to the relay under test using a set-up that consists of a PCI card with a built-in Digital to Analog Converter and a feedback circuit for detecting the status of the relay. Using any off-line simulation package, sampled data points of a desired waveform are obtained in the form of a data-file. The RTAI-Linux program generates this waveform in real-time which is directly fed to the relay under test. The relay test bench presented in this paper is a cost-effective set-up for laboratories to test and understand the behavior and characteristics of relaying systems. © 2013 IEEE.Item Real-time simulation of synchronous generator and its controllers on RTAI-Linux platform(2013) Latha, A.H.; Shubhanga, K.N.This paper presents a real-time simulation of a synchronous generator using real-time application interface (RTAI) on Linux. Different generator controllers such as exciter and power system stabilizer are also included in the real-time simulation. The Forward Euler method with a suitable step-size has been employed for obtaining the solution of differential equations after justifying its applicability through illustrative examples. Various disturbance conditions are demonstrated to bring out most of the rotor-angle stability issues in a SMIB system. Using a peripheral component interconnect (PCI) card, the real-time simulation results are captured on an oscilloscope and are validated using off-line MATLAB simulations. Such a setup offers a very useful laboratory tool for carrying out the hardware-in-the-loop tests. © 2013 IEEE.Item Implementation and characterization of a numerical distance relay using a relay test-bench on RTAI-Linux platform(2013) Padmasali, A.; Amoghimath, K.; Hazarika, P.P.; Shetty, P.K.; Shubhanga, K.N.This paper deals with the implementation, evaluation and characterization of a numerical distance relay using a laboratory relay test-bench implemented on real-time application interface (RTAI)-Linux platform. The numerical distance relay has been realized on RTAI-Linux platform based on the full-cycle recursive discrete Fourier series algorithm. This relay provides a selectable relay characteristic such as Mho or Quadrilateral or Elliptical characteristic. The relay test-bench not only can be used to obtain steady-state relay characteristics, but also facilitates to generate any fault signals to perform dynamic testing of the relays. In this paper, Mho and Quadrilateral type numerical relay characteristics have been chosen for demonstration. It is found that such an experimental setup provides a hardware-in-the-loop facility in the lab environment to enhance the understanding about protective systems and thereby augmenting the classroom learning. © 2013 IEEE.Item Circuit analysis in the time-domain: Operational approach to form the system-matrix exponential and to obtain the circuit natural response therefrom(IEEE Computer Society help@computer.org, 2014) Rao, I.R.; Shubhanga, K.N.A time-domain operational method for the dynamic analysis of force-free Linear Time-Invariant (LTI) lumped-parameter electrical systems is presented. Starting from the state model of the system, a purely time-domain technique for obtaining the matrix exponential (state-transition matrix) has been developed. This approach preserves the time-domain identity of all the network variables (unlike the transformational approaches) and facilitates analytical, closed-form solutions for number-imposed system parameters (unlike numerical techniques). Furthermore, it provides the 'algebrization'-advantage in the time-domain itself, in which the system variables are directly observable. This obviates the need for any artificial and cumbersome transformations (both direct and inverse). This approach has been here employed to formulate the solution process of the natural (force-free) response of a generic LTI lumped-parameter electrical network of any given order, starting from the vectorized set of time-domain differential equations that collectively govern the behaviour of the said network. Some crucial aspects regarding system modeling have been highlighted. The proposed method is illustrated by examples which demonstrate the ease with which the natural response of an LTI system could be obtained, for specified initial conditions. © 2014 IEEE.Item Rotor speed instability analysis of type-1 wind turbine generator(Institute of Electrical and Electronics Engineers Inc., 2014) Priyanka, A.G.; Shubhanga, K.N.In this paper, type-1 wind turbine generator (WTG) connected to the grid system is analyzed. The phenomenon of rotor speed instability is brought out clearly and it is explained with the help of torque-speed characteristic. It is also shown that if the WTG is made to deliver a load power below a certain value, then the system remains always stable. In addition, case studies are presented to demonstrate the rotor speed instability accounting the two-mass shaft model for the drive train system. © 2014 IEEE.