Faculty Publications
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Publications by NITK Faculty
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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 Rotor speed-instability performance of type-1 WECS employing double-cage induction generator(Institute of Electrical and Electronics Engineers Inc., 2017) Rashmi, n.; Shubhanga, K.N.In this paper, the interfacing of the type-1 wind turbine employing double cage induction generator to the grid is presented. Rotor instability performance of this system is studied and a detailed comparison is done with the single-cage. Steady-state torque-speed characteristics are compared and the results are validated through transient and eigenvalue analysis. The effect of wind turbine characteristics on rotor stability has been brought out. © 2017 IEEE.Item Analytical design of static VAR compensator-based subsynchronous damping controller(Institute of Electrical and Electronics Engineers Inc., 2018) Kotian, S.M.; Shubhanga, K.N.In this paper, using a dynamic phasor model of static VAR compensator (SVC) a method to determine the phase response of a system analytically is presented. Then using the phase compensation method a subsynchronous damping controller (SSDC) for SVC is designed to mitigate subsynchronous resonance (SSR) in series capacitor compensated power systems. The designed SSDC is validated using detailed time-domain simulations in PSCAD/EMTDC. The case studies are carried out on the IEEE first benchmark system. © 2018 IEEE.Item Performance of synchronous machine models in a series-capacitor compensated system(Institute of Electrical and Electronics Engineers Inc., 2014) Kotian, S.M.; Shubhanga, K.N.This paper compares the IEEE-specified generator models such as the equivalent circuit (EC) models and the operational inductance (OI) models to understand their damping performances in the IEEE first-benchmark system for subsynchronous resonance study. These models are found to differ from one another only to an extent they accurately represent the standard transfer functions. By carrying out different case studies an effort is made to analyze the influence of these differences among the models on the damping performance of swing-mode and torsional modes. Through a detailed eigenvalue analysis and time-domain simulations, it is demonstrated that these models offer differing results with respect to swing-mode, thereby strongly influencing the power system stabilizer (PSS) performances, especially when the system is series compensated. Even the torsional mode interactions are found to exhibit dependency on the models employed for the generators. Such a study is expected to provide better insight into the behavior of generator models and controller design/tuning in system analysis. © 1969-2012 IEEE.