Ravi Seethapathy

Bio: Ravi Seethapathy is an academic researcher from University of Western Ontario. The author has contributed to research in topics: Wind power & Distributed generation. The author has an hindex of 18, co-authored 32 publications receiving 2530 citations. Previous affiliations of Ravi Seethapathy include University of Waterloo.

Optimal Renewable Resources Mix for Distribution System Energy Loss Minimization

Abstract: It is widely accepted that renewable energy sources are the key to a sustainable energy supply infrastructure since they are both inexhaustible and nonpolluting. A number of renewable energy technologies are now commercially available, the most notable being wind power, photovoltaic, solar thermal systems, biomass, and various forms of hydraulic power. In this paper, a methodology has been proposed for optimally allocating different types of renewable distributed generation (DG) units in the distribution system so as to minimize annual energy loss. The methodology is based on generating a probabilistic generation-load model that combines all possible operating conditions of the renewable DG units with their probabilities, hence accommodating this model in a deterministic planning problem. The planning problem is formulated as mixed integer nonlinear programming (MINLP), with an objective function for minimizing the system's annual energy losses. The constraints include the voltage limits, the feeders' capacity, the maximum penetration limit, and the discrete size of the available DG units. This proposed technique has been applied to a typical rural distribution system with different scenarios, including all possible combinations of the renewable DG units. The results show that a significant reduction in annual energy losses is achieved for all the proposed scenarios.

Adequacy Evaluation of Distribution System Including Wind/Solar DG During Different Modes of Operation

Abstract: Keen interest in the development and utilization of renewable distributed generation (DG) has been currently observed worldwide. The reliability impact of this highly variable energy source is an important aspect that needs to be assessed as renewable power penetration becomes increasingly significant. Distribution system adequacy assessment including wind-based and solar DG units during different modes of operation is described in this paper. Monte Carlo simulation (MCS) and analytical technique are used in this work with a novel utilization of the clearness index probability density function (pdf) to model the solar irradiance using MCS. The results show that there is no significant difference between the outcomes of the two proposed techniques; however, MCS requires much longer computational time. The effect of islanding appears in the improvement of the loss of load expectation (LOLE) and loss of energy expectation (LOEE).

Power Engineering Letters Nighttime Application of PV Solar Farm as STATCOM to Regulate Grid Voltage

Abstract: This letter presents a novel concept of utilizing pho- tovoltaic (PV) solar farm (SF) as a flexible ac transmission systems controller—static synchronous compensator, to regulate the point of common coupling voltage during nighttime when the SF is not producing any active power. This concept, although general, is pre- sented for the scenario of a distribution feeder, which has both PV solar and wind farms connected to it. The proposed control will en- able increased connections of renewable energy sources in the grid. A MATLAB/Simulink-based simulation study is presented under variable wind power generation and fault condition to validate the proposed concept. Index Terms—Distributed generation, flexible ac transmission systems (FACTS), solar energy, static synchronous compensator (STATCOM), voltage regulation, wind energy.

Nighttime Application of PV Solar Farm as STATCOM to Regulate Grid Voltage

Abstract: This letter presents a novel concept of utilizing photovoltaic (PV) solar farm (SF) as a flexible ac transmission systems controller-static synchronous compensator, to regulate the point of common coupling voltage during nighttime when the SF is not producing any active power. This concept, although general, is presented for the scenario of a distribution feeder, which has both PV solar and wind farms connected to it. The proposed control will enable increased connections of renewable energy sources in the grid. A MATLAB/Simulink-based simulation study is presented under variable wind power generation and fault condition to validate the proposed concept.

A Two Ways Communication-Based Distributed Control for Voltage Regulation in Smart Distribution Feeders

Abstract: Smart grid initiative is based on several pillars among which integrating a wide variety of distributed generation (DG) is of particular importance. The connection of a large number of DG units among loads may result in a severe voltage regulation problem and the utility-side voltage regulators might no longer be able to use conventional control techniques. In addition, smart grid should provide new digital technologies such as monitoring, automatic control, and two way communication facilities to improve the overall performance of the network. These technologies have been applied in this paper to construct a distributed control that has the capability to provide proper voltage regulation in smart distribution feeders. The functions of each controller have been defined according to the concept of intelligent agents and the characteristics of the individual DG unit as well as utility regulators. To verify the effectiveness and robustness of the proposed control structure, a real time simulation model has been proposed. The simulation results show that distributed control structure has the capability to mitigate the interference between DG facilities and utility voltage regulators.

Control of Power Converters in AC Microgrids

Abstract: The enabling of ac microgrids in distribution networks allows delivering distributed power and providing grid support services during regular operation of the grid, as well as powering isolated islands in case of faults and contingencies, thus increasing the performance and reliability of the electrical system. The high penetration of distributed generators, linked to the grid through highly controllable power processors based on power electronics, together with the incorporation of electrical energy storage systems, communication technologies, and controllable loads, opens new horizons to the effective expansion of microgrid applications integrated into electrical power systems. This paper carries out an overview about microgrid structures and control techniques at different hierarchical levels. At the power converter level, a detailed analysis of the main operation modes and control structures for power converters belonging to microgrids is carried out, focusing mainly on grid-forming, grid-feeding, and grid-supporting configurations. This analysis is extended as well toward the hierarchical control scheme of microgrids, which, based on the primary, secondary, and tertiary control layer division, is devoted to minimize the operation cost, coordinating support services, meanwhile maximizing the reliability and the controllability of microgrids. Finally, the main grid services that microgrids can offer to the main network, as well as the future trends in the development of their operation and control for the next future, are presented and discussed.

Smart Grid — The New and Improved Power Grid: A Survey

Abstract: The Smart Grid, regarded as the next generation power grid, uses two-way flows of electricity and information to create a widely distributed automated energy delivery network. In this article, we survey the literature till 2011 on the enabling technologies for the Smart Grid. We explore three major systems, namely the smart infrastructure system, the smart management system, and the smart protection system. We also propose possible future directions in each system. colorred{Specifically, for the smart infrastructure system, we explore the smart energy subsystem, the smart information subsystem, and the smart communication subsystem.} For the smart management system, we explore various management objectives, such as improving energy efficiency, profiling demand, maximizing utility, reducing cost, and controlling emission. We also explore various management methods to achieve these objectives. For the smart protection system, we explore various failure protection mechanisms which improve the reliability of the Smart Grid, and explore the security and privacy issues in the Smart Grid.

Optimal Distributed Generation Placement in Power Distribution Networks: Models, Methods, and Future Research

Abstract: The integration of distributed generation (DG) units in power distribution networks has become increasingly important in recent years. The aim of the optimal DG placement (ODGP) is to provide the best locations and sizes of DGs to optimize electrical distribution network operation and planning taking into account DG capacity constraints. Several models and methods have been suggested for the solution of the ODGP problem. This paper presents an overview of the state of the art models and methods applied to the ODGP problem, analyzing and classifying current and future research trends in this field.

Multiple Distributed Generator Placement in Primary Distribution Networks for Loss Reduction

Abstract: This paper investigates the problem of multiple distributed generator (DG units) placement to achieve a high loss reduction in large-scale primary distribution networks. An improved analytical (IA) method is proposed in this paper. This method is based on IA expressions to calculate the optimal size of four different DG types and a methodology to identify the best location for DG allocation. A technique to get the optimal power factor is presented for DG capable of delivering real and reactive power. Moreover, loss sensitivity factor (LSF) and exhaustive load flow (ELF) methods are also introduced. IA method was tested and validated on three distribution test systems with varying sizes and complexity. Results show that IA method is effective as compared with LSF and ELF solutions. Some interesting results are also discussed in this paper.