V. Jayashankar

Bio: V. Jayashankar is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Turbine & Oscillating Water Column. The author has an hindex of 13, co-authored 48 publications receiving 481 citations.

On Minimizing the Fluctuations in the Power Generated from a Wave Energy Plant

Abstract: This paper investigates on the reduction of fluctuations in power generated from a prototype wave energy plant, installed as a part of the on-going Indian wave energy programme, when operated on grid connected mode. The plant, employing an impulse turbine for conversion of differential pressure due to the oscillating water column (OWC) into mechanical shaft power, typically shows a peak to average power ratio of 4.5 to 5.0, which is unacceptable to be readily exported to power grid. A novel method of decoupling the energy storage, by addition of one more energy conversion stage, is tried out. Steady-state based MATLAB - Simulink model and laboratory prototype implementation are carried out and the results are reported. It is seen that the ratio of peak to average power can be brought down to about 1.25, thereby improving the acceptability of power generation from the ocean waves

Instrument transformer performance under distorted-conditions

Abstract: Current transformers (CT) and voltage transformers (VT) are the primary sensing elements in electric power systems. While their performance at a single frequency is well known, it is necessary to analyze the performance of CTs and VTs for harmonic excitation. A single virtual instrument that can be used for performance measurements of instrument transformers (IT) in addition to analyzing the magnetic characteristics of cores is proposed. Experimental results are shown to validate the proposed method.

Fluidic Components for Oscillating Water Column Based Wave Energy Plants

Abstract: A bidirectional (oscillating) air flow is central to energy conversion from wave to wire in an oscillating water column based wave energy plant. Several classes of bidirectional turbines, which operate with such an oscillating flow, have been designed and tested with limited efficiencies. A topology which uses fluidic diodes in conjunction with unidirectional turbines is shown to significantly improve the efficiency. The design and test results from several fluidic diodes for such an application are discussed. It is shown that a combination of a fluidic diode and the unidirectional turbine can achieve a very high impedance to reverse flow while having a high efficiency in the forward direction, over a wide range of flow coefficients.Copyright © 2011 by JSME

Continual Assessment of Winding Deformation during a Short Circuit Test

Abstract: A new approach for the continual assessment of winding deformation during short circuit test is proposed. The method is validated through FEM analysis of axially unbalanced axisymmetric configurations. Simulation results are shown to validate the proposed method.

Wave energy in Europe: current status and perspectives

Abstract: The progress in wave energy conversion in Europe during the past ten years is reviewed and current activities and initiatives in the wave energy sector at National and Union level are described. Other important activities worldwide are summarized. The technical and econ

Advancement of energy storage devices and applications in electrical power system

Abstract: Overall structure of electrical power system is in the process of changing. For incremental growth, it is moving away from fossil fuel based operations to renewable energy resources that are more environmentally friendly and sustainable. At the same time it has to grow to meet the ever increasing need for more energy. These changes bring very unique opportunities and obstacles. Over the past few decades many new and innovative ideas have been explored in the broad area of energy storage. They range in size, capacity and complexity in design. Some of the systems are designed for applications in large scale power and others are performing short term energy storage ride through capabilities for critical manufacturing and technology systems. Energy storage technology has become an enabling technology for renewable energy applications and enhancing power quality in the transmission and distribution power systems. This paper summarizes all the advancements made and provide a composite picture of costs and trends in storage technologies.

Advanced transformer winding deformation diagnosis: moving from off-line to on-line

Abstract: On-line monitoring and diagnosis of transformers have been investigated and discussed significantly in last decade. This study has concentrated on issues arising while on-line transformer winding deformation diagnosis is going to be applied on transformers with various kinds of techniques. From technical perspective, before replacing off-line methods by on-line methods and eventually by intelligent approaches, practical challenges must be addressed and overcome. Hence, available off-line transformer winding deformation diagnosis methods are discussed precisely. Mathematical calculation in on-line short circuit impedance measurement is investigated. On-line transformer transfer function measurement setup is presented. A profound insight to the problems pertaining on-line transformer winding deformation recognition methods, characterizes existing online methods, explains the concepts behind online measurements and striving to open the discussion doors towards challenges are discussed. In the end a 400 MVA step up transformer has been taken as a case in order to clarify the capability of Frequency Response Analysis (FRA) method in fault detection while short circuit impedance could only demonstrate some rough understanding about transformer condition.