Siddharth Suryanarayanan

Fault Current Contribution From Synchronous Machine and Inverter Based Distributed Generators

There are advantages of installing distributed generation (DG) in distribution systems: for example, improving reliability, mitigating voltage sags, unloading subtransmission and transmission system, and sometimes utilizing renewables. All of these factors have resulted in an increase in the use of DGs. However, the increase of fault currents in power systems is a consequence of the appearance of new generation sources. Some operating and planning limitations may be imposed by the resulting fault currents. This paper discusses a model of inverter based DGs which can be used to analyze the dynamic performance of power systems in the presence of DGs. In a style similar to protective relaying analysis, three-dimensional plots are used to depict the behavior of system reactance (X) and resistance (R) versus time. These plots depict operating parameters in relation to zones of protection, and this information is useful for the coordination of protection systems in the presence of DG

An Energy Management System for Building Structures Using a Multi-Agent Decision-Making Control Methodology

Aligned towards net zero energy building goals, building energy management systems will consider energy utilization efficiency improvement, energy cost reduction and renewable energy technology utilization to serve the local energy loads in building structures with dispersed resources. The distributed management of building energy system in this paper describes a semi-centralized decision making methodology using multi-agent systems for building energy management system in electrical, heating and cooling energy zones with combined heat and power system optimization aimed at improving energy efficiency and reducing energy cost. The semi-centralized decision making process will be implemented in a case study to pursue minimum energy cost.

Investigating the Impact of Pulsed Power Charging Demands on Shipboard Power Quality

The impact of pulsed power loads on shipboard power systems need to be properly determined to prevent pulsed loads from causing unacceptable power quality deviations, interference with other loads and degradation of overall system performance. This paper uses a high fidelity modeling and simulation approach to investigate the impact of real and reactive power, pulse ramp rate, pulse duration and frequency of occurrence of the pulsed power load. For this purpose, a notional shipboard power system, modeled in a real-time digital simulator, is used. Most pulsed loads on shipboard systems are not fed directly from the prime power system but via an energy storage system. This energy storage system in turn is interfaced with the shipboard prime power system typically through an electronic front-end charging circuit. In order to evaluate the impact of pulsed loads, existing power quality standards (related to voltage transients, harmonic distortions, and frequency variations) are applied.

Electric Energy Management in the Smart Home: Perspectives on Enabling Technologies and Consumer Behavior

Smart homes hold the potential for increasing energy efficiency, decreasing costs of energy use, decreasing the carbon footprint by including renewable resources, and transforming the role of the occupant. At the crux of the smart home is an efficient electric energy management system that is enabled by emerging technologies in the electricity grid and consumer electronics. This paper presents a discussion of the state of the art in electricity management in smart homes, the various enabling technologies that will accelerate this concept, and topics around consumer behavior with respect to energy usage.

Smart Grid Initiative

The Primary Goal of this article is to discuss the development of intelligent controls for a power electronic inverter capable of interfacing a photovoltaic (PV)-based unit to the utility grid. The inverter is designed as a single-phase, full-bridge converter operating at 120 V, 60 Hz ac. The control functionalities of the inverter are defined under the perspective of the Smart Grid Initiative (SGI) of the U.S. Department of Energy and substantiated via case studies in this article as the ability to supply real and reactive power to local loads, supply real and reactive power to other utility loads up to the rated capacity of the inverter, provide voltage support at the point of common coupling (PCC), store energy in a lead-acid battery bank, and enable the provision of control options to the consumer based on near real-time electricity information obtained from the utility through advanced metering devices.

Achieving the Smart Grid through customer-driven microgrids supported by energy storage

This paper describes some of the aspects of the Smart Grid Initiative in the US and purports its realization through an emerging paradigm in microgrids, i.e., the customer-driven microgrids. Special attention is paid to the increasing role played by energy storage elements. Some existing technologies of energy storage are revisited in the perspective of their utilization in customer-driven microgrids.

Improving Reliability of Islanded Distribution Systems With Distributed Renewable Energy Resources

An optimization problem called “the feeder addition problem” is defined to determine potential locations for adding interties between feeders in a legacy radial distribution system to improve the reliability in the islanded mode of operation - a desired feature under the Smart Grid Initiative. Numerical bounds are established on the growth of the feeder addition problem. The feeder addition problem in a popular test system is handled using two different optimization methods to balance cost and reliability for utility applications. To approximate the power output of the distributed generation sources considered, an empirical equation incorporating the capacity factors of renewable energy-based distributed generation sources and results of an industry survey is used. Both optimization methods are shown to improve the system reliability for cases where the distributed generation output exceeded feeder demand.

Two Techniques to Enhance Empirical Mode Decomposition for Power Quality Applications

Joint time-frequency characterization techniques are gaining importance in power quality studies of time-varying waveform distortions. In this context, the performance of the recently introduced empirical mode decomposition (EMD) as a second order filter is examined in this paper. The original EMD technique is incapable of separating components whose frequencies lie within the same octave. Using appropriate masking signals, the EMD can be made more discriminating for closely spaced frequency components. However, limitations still remain, and this paper discusses some aspects thereof. A frequency shifting technique is suggested to further enhance the discriminating property of EMD. Synthetic data similar to signals found in power quality studies are employed for demonstration purposes.

Smart-grid technologies and progress in Europe and the USA

The work discusses historical and technical events in USA and Europe over the last few years that are aimed at modernizing the electric power grid. The US federal government has ratified the “smart grid” as official policy for modernizing the electricity grid with provisions for timely information and control options to consumers and deployment of “smart” technologies. European countries are unified in researching and developing related technologies through various structures supported by the European Union. This paper presents the development of smart grids and in-depth analysis of the methodologies, milestones and expected evolutions of grid technologies that will transform our society in the very near future.

A survey seeking a definition of a smart distribution system

Recently, the U.S. Government has mandated the transformation of the existing electric grid into a “smart” grid through the Energy Independence and Security Act of 2007 (EISA07) and the American Recovery and Reinvestment Act of 2009. To create a “smart” grid, intelligence must be incorporated at all levels of the electric power grid, especially at the distribution level. Using Title XIII of the EISA07 as a guide, a survey to define a “smart distribution system” was designed to study the implications of the smart grid initiative on distribution engineering. The objectives of this survey are threefold: 1) to provide a definition of a smart distribution system from the perspective of the industry, 2) to identify existing tools from transmission engineering that can be applied at the distribution level, and 3) to guide investigation into the technical requirements and implications of a smart distribution system. The motivation and methods used in the design of this survey, which has been circulated among potential respondents in academia and the U.S. industry, are presented in this paper. This paper also includes a contemporary list of references on the topic of a smart grid.