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Papers by Kailash Srivastava

— This paper presents application of online monitoring concept, based on fundamental frequency si... more — This paper presents application of online monitoring concept, based on fundamental frequency signals, developed at ABB Corporate Research, Sweden. Using ordinary voltage and current signals available in station control room, one can estimate the turn ratio, magnetizing current, short-circuit impedance and power loss. For the case studies presented in this paper, digitized voltage and current signals of two transformers were recorded by Digital Fault Recorders (DFR) under steady state conditions. The two transformers investigated in this study are installed in Indonesia: 500/150 kV 250 MVA at Suralaya station and 500/168/71.5 kV 500 MVA at Cilegon station. As per the results from these two cases, the proposed online monitoring method has demonstrated comparable change detection accuracy (sensitivity) to the corresponding off-line tolerance limits stipulated by IEC and IEEE Standard.

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—This paper presents results of a simulation study to quantify the effect of zero sequence remova... more —This paper presents results of a simulation study to quantify the effect of zero sequence removal on the accuracy of transformer fundamental quantities estimated from ordinary voltage and current signals by linear fitting selected quantities as a function of loads. Unbalanced system conditions and asymmetrical loads are some of the common causes of zero sequence. Flow of zero sequence across a transformer is dependent on the winding configuration of the transformer and the system grounding conditions. As all possible combinations of winding and grounding configurations, and appearance of zero sequence cannot in practice be tested, in this study, a series of PSCAD model simulations was performed based on a typical power system with two transformers, transmission lines, industrial and domestic loads. The transformers were configured in different vector groups (Y-Y, Y-∆) and grounding states to replicate commonly encountered scenarios. System and load imbalances were created by asymmetrical loads on the transmission side and asymmetrical reactive power compensation on the consumer side respectively. The results indicates that the zero sequence removal result in good accuracy compare to estimation with zero sequence irrespective of the winding and grounding configurations.

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ABSTRACT In HVDC-connected wind farms with full converter generator (FCG) the short-circuit curre... more ABSTRACT In HVDC-connected wind farms with full converter generator (FCG) the short-circuit currents are mainly governed by the control systems of HVDC and wind generators’ converters. This peculiarity requires accurate studies for the design and evaluation of reliable fault detection methods. In line with this need three-phase faults analyses have been performed on a test-case system, using PSCAD/EMTDC, and protection strategies have been proposed and analyzed.

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Page 1. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS Editor-in-Chief BALDWIN BRIDGER, JR. 15526 Tor... more Page 1. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS Editor-in-Chief BALDWIN BRIDGER, JR. 15526 Torry Pines Road Houston, TX 77062-3420 USA +1 281 461 8150 b.bridger@ieee.org Industrial and Commercial Power Systems Department ...

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IEEE PES Innovative Smart Grid Technologies, Europe, 2014

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The study presented in this paper determines the optimal location for the Belgian substation of a... more The study presented in this paper determines the optimal location for the Belgian substation of a potential Belgium-UK VSC HVDC connection from stability considerations. Two locations are taken into consideration: Zeebrugge and Eeklo-Noord. This study analyzes the impact of the VSC HVDC connection on the transient stability of the Belgian grid. The main focus lies on large-disturbance rotor angle stability of the production units in Herdersbrug. The generators of Herdersbrug are located close to the VSC substation in both scenarios. The evolution of the grid voltage in time following a large disturbance is analyzed briefly. The UK side of the connection is not analyzed in this study. Load flow analyses and dynamic simulations are performed. Active modulation of the VSC HVDC connection is not applied in this study. The load flow results show that static stability is maintained with the installation of a VSC HVDC connection. Power system stability is maintained in the simulated scenar...

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IEEE PES Innovative Smart Grid Technologies, Europe, 2014

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