Thesis (M.S.)--Drexel University, 2007. / Includes abstract. Includes bibliographical references (leaves 81-83).

Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains xv, 165 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 133-142).

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 16, 2007) Includes bibliographical references (p. 71-74).

Thesis (Ph. D.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xiii, 126 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 120-126).

Thesis (Ph. D.)--Drexel University, 2005. / Includes abstract and vita. Includes bibliographical references (leaves 130-133).

Indiana University-Purdue University Indianapolis (IUPUI) / The interconnection of distributed resources requires specific voltage regulation, monitoring, protective relaying, power quality, and islanding detection. For this reason IEEE established standard IEEE 1547 that ensures the compliance with such requirements and it will help formulate technical specifications for grid interconnection with Distributed Generator (DG) resources. In search of meeting the IEEE 1547 standard requirement of detecting unintentional islanded operation, there has been ongoing research to develop anti-islanding methods that can detect the different changes that can occur when the grid is disconnected. A team of Electrical Engineering faculty at Indiana University Purdue University Indianapolis has worked previously on testing a DG unintentional Islanding Detection Scheme. This scheme uses an active anti-islanding method in which a small 1 Hz perturbation signal is added into the DG system and it helps detect when the grid is disconnected. The scheme uses the premise that a frequency deviation caused by perturbation to the system is smaller when the grid is connected than when it is in an island. In an initial dynamic simulation model for the islanding detection scheme, a two-machine microgrid system is used to explore frequency and voltage responses when the grid is disconnected. In this thesis, the two-machine microgrid is expanded to a ten-machine system so it can be shown that the frequency deviation caused by a perturbation signal is much smaller when the grid is connected even for a larger DG network. The 1 Hz component of the DG electrical frequency in a multiple machine microgrid system is also calculated in this thesis. This project was conducted in different stages. First, it was necessary to calculate the steady state power flow and electric power of a three-machine system and update the two-machine MATLAB program with the necessary changes. After making the changes, it was necessary to simulate the system and adjust the inertia of the machine that represents the grid to ensure that the simulation output was close in magnitude to previous testing results. When the three-machine system was successfully generated, a brand new program was created so a multiple machine system could be simulated. Then the multiple machine program was used to simulate and experiment with up to a ten-machine system. Finally a program to calculate the 1 Hz component of the DG electrical frequency was generated and used to show that the magnitude squared of the 1 Hz component is inversely proportional to the number of machines connected to the system. These last findings will later help set the threshold for islanding detection appropriately for different numbers of DG.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in ful lment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 2016 / This research investigates the power sharing between distributed energy resources with voltage and frequency droop control. A case study based on voltage sources in an islanded microgrid is set up in the laboratory, referred to as: The Example Microgrid. The Example Microgrid consists of two synchronous generators, active and reactive power loads. A simulation model is constructed based on the laboratory set-up, where componentwise and system-wise testing are completed. The simulation results are validated with the experimental set-up, and it is concluded that the model accurately represents the physical system under steady-state conditions. Further simulation studies on conventional droop controllers are conducted based on the Example Microgrid model. The results indicate that the use of conventional droop control is inappropriate for small, low-voltage islanded microgrids. As a possible application of this work, three variations of adapted droop controllers are simulated and their performance evaluated. It is found that with the adapted droop controllers, the power sharing error can be minimised / M T 2016

This study is performed as a partial aid to a larger study that aims to determine if electromagnetic fields produced by underwater power cables have any effect on marine species. In this study, a new numerical method for calculating magnetic fields around subsea power cables is presented and tested. The numerical method is derived from electromagnetic theory, and the program, Matlab, is implemented in order to run the simulations. The Matlab code is validated by performing a series of tests in which the theoretical code is compared with other previously validated magnetic field solvers. Three main tests are carried out; two of these tests are physical and involve the use of a magnetometer, and the third is numerical and compares the code with another numerical model known as Ansys. The data produced by the Matlab code remains consistent with the measured values from both the magnetometer and the Ansys program; thus, the code is considered valid. The validated Matlab code can then be implemented into other parts of the study in order to plot the magnetic field around a specific power cable. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

This dissertation describes methodologies for evaluating a set of anticipated and recommended energy infrastructure changes essential to achieving deep greenhouse gas emissions reductions in a dense urban area: Deep penetration of grid-connected wind power, widespread adoption of electric heat pumps, multiple potential services from extensive deployment of distributed generation, and increasing focus on auxiliary energy in heating and cooling systems as cities continue to grow in population and height. The focus of the research presented here was New York City and the surrounding New York State electricity supply infrastructure. After developing a wind power model based on an NREL model wind data set, a linear program model showed that after passing a low-curtailment threshold of 10 GW, energy-related wind power curtailment is driven largely by continuous operation of baseload generation and misalignment of winter wind power peaks and existing summer electricity demand peaks. Separate analyses showed the potential for increase wind-generated electricity utilization through increased use of heat pumps in New York City. A suite of models was developed to assess the zonal effects in New York City of deep statewide penetration of wind power and widespread adoption of electric heat pumps in New York City. New York City was found to have highly fluctuating net loads in deep wind penetration scenarios. Further, with large amounts of existing space heating demand replaced by heat pumps, the increased winter electricity demand peaks occurred infrequently enough that the additional generation capacity required to meet those loads would have a capacity factor well less than 1%. Small-scale, natural gas-fueled internal combustion engines deployed as distributed generation were shown to improve the ability of the system to respond to load fluctuations, to be a more economical option than new large centralized generators at the low capacity factor, and to reduce overall system gas usage due to mitigating part-load effects and startup fuel requirements. This distributed generation, which could in reality also include combined heat and power systems as well as battery storage standing alone, connected to rooftop solar or in electric vehicles, also has potential system resilience benefits. The last research effort described here included long-term monitoring of a high-rise mixed use building’s hydronic system before and after a retrofit of hydraulic equipment. Significant annual reductions of 40% energy usage for pumping were computed, primarily due to part-load flow control effects. Analysis of the monitoring data, as well as computations related to theoretical performance of hydraulic networks, showed that this approach also has potential to reduce peak loads, particularly in high-rise buildings.

Oregon utilities are replacing their portfolios of traditional fossil fuel generation with renewable generating sources. Stepping away from carbon-producing energy will leave a deficit of on-demand power, resulting in decreased reliability. To overcome these technical challenges, utilities must maximize the use of their present dispatchable resources. One such resource is the Portland General Electric (PGE) Dispatchable Standby Generation Program (DSG), which is an aggregated 105 MWs of distributed generation (DG). These resources are brought on-line when there is a critical need for power. Resources are added to the program if a transfer trip scheme is in place or a modeling study reveals that the feeder load is at least three times the generator capacity. If the load-to-capacity ratio were lower, more assets could be added to the DSG program. To investigate the impacts of lowering the DG load-to-capacity ratio on existing distribution feeders, we use Open-Source Distribution System Simulator (OpenDSS). We modeled the Oxford Rural feeder by converting a utility CYME database to instantiation files using several MATLAB programs. A MATLAB control program varies the load-to-capacity ratio of the OpenDSS feeder model and monitors the generator behavior immediately following a fault. We analyzed the results to determine the ideal load-to-capacity ratio that prevents unintentional islanding. The results show that the instantaneous (50) relay element settings dictate both the minimum load-to-capacity ratio and the maximum DG capacity. The present three-to-one ratio is very conservative and can be reduced. Additional dispatchable resources include a five MW battery-inverter system currently used as grid-back up. The battery is grid-tied to a 12.4 kV feeder making it an ideal candidate for conservation voltage reduction (CVR). Using the same feeder model, we investigated the effects of lowering the system voltage to the allowable minimum using injections of reactive power. A lower system voltage reduces the load at peak times. Conversely, increasing the voltage prevents generation conflicts. To determine the benefit of CVR by VAr-injection on the Oxford Rural feeder, we created a MATLAB optimization program to output the optimal feeder voltage for reduced system power. We use a Simulink feedback model to determine the appropriate reactive power needed to achieve the voltage change. We analyze the system model to reveal that the feeder is ideal for CVR but the system capacity must be increased to achieve the maximum power reduction.