Kenan Hatipoglu

Analysis of large scale photovoltaic power system integration into the existing utility grid using PSAT

When alternative power sources are connected to the utility grid the core characteristics of the system are changed. This fact is especially true for intermittent, volatile power sources such as photovoltaic (PV) systems. In recent years, PV power systems have become increasingly cost competitive leading to greater penetrations of both large and small scale PV systems. The large scale integration of PV power systems into the existing utility grid may have significant - and potentially negative - impacts on the power flow, power quality, and overall stability of the system. This paper analyzes the impacts of connecting a large scale photovoltaic power source to the existing utility grid using the MATLAB based Power System Analysis Toolbox (PSAT). This paper reveals a solid method for analyzing the effects a large scale PV system can have on the stability of the power grid and the results of this analysis reveal the potentially harmful effects of integrating such a system into the existing grid.

An overview of hydrogen electrical energy storage meeting energy demand with intermittent renewable resources

The world is beginning to embrace a transition from fossil fuel-based energy production and distribution methods to renewable energy-based methods. This is becoming more and more evident as governments around the world enact standards and regulations that require energy portfolios to be composed of ever-growing portions of renewable production. However, as this transition develops many questions and issues arise. One of the most significant of these is the inherently intermittent nature of power derived from renewable sources, such as wind and solar. A number of storage methods exist that may be part of the solution to this problem. This paper examines hydrogen electrical energy storage (EES), which is among the technologies that are being seriously considered as a solution to the intermittency problem of wind and solar.

MATLAB-Graphical User Interface to study partial shading of PV array characteristics

The photovoltaic (PV) arrays can be affected by several factors such as temperature, shading, solar insolation, and the array configuration. In some cases, PV arrays can be completely or partially shaded by obstacles such as clouds and trees or manmade structures. The PV characteristics become complex with the shading effect on the system. Therefore to achieve the maximum power possible, it is important to understand and predict such occurrences. This paper presents a MATLAB Graphical User Interface (GUI) for studying the PV array characteristics under partial shading.

MATLAB based GUI to investigate effect of voltage changes on static ZIP load model in a microgrid

A microgrid system under three phase fault is investigated with MATLAB based Graphical User Interface (GUI) for studying the effects of voltage changes on load buses having static polynomial (ZIP) loads. Load modeling is always a critical aspect on approaching power system rationally. Examining the behavior of the ZIP load model under a faulty condition is the main objective of this paper. Static characteristics of common load models can be grouped into three categories based on their dependency on voltage. Quadratic relation between power and voltage exists for constant impedance load model (Z). Linear power-voltage relation is true for constant current load model (I). Power is independent of voltage changes for constant power load model (P). The sum of these three categories is a polynomial model known as ZIP load. Voltage and power variations of ZIP load will be investigated with designed user-friendly MATLAB based GUI and overall changes will be discussed.

The effects of major solar integration on a 21-Bus system: Technology review and PSAT simulations

The worlds energy needs are changing and so are the methods by which it generates power. Photovoltaic Cells are leading this revolution by harnessing the power of the sun and transforming it into DC power. Integrating this “too good to be true” power source into the grid has been in the mind of those who plan for future grid alterations for a while and the need for seamless integration has arrived. Power systems and power-flow through the grid are planned precisely and do not respond well to sudden changes. Large-scale PV grid integration is challenging and requires preparation to deal with the intermittency of power production. This paper analyzes an IEEE 21-Bus power system with regards to power-flow and small to large scale integration of PV generation. The pros and cons of this addition are researched and documented here as well as simulations of PV integration using Matlabs Power System Analysis Toolbox (PSAT) software. There are a few correction methods that attempt to solve some of the known problems with adding solar generation into the grid such as tap-changer transformers, capacitor banks, and synchronous condensers. Besides normal analysis, this paper also presents one of these correction methods into simulation to show how part of the large-scale integration problem can be corrected.

The effect of variable speed wind turbines on a 21 bus power system

The purpose of this paper is to study the effects of variable speed wind turbines (VSWTs) on a power system. The power system model used for this study is the IEEE 21 Bus System. Each system, one powered solely by the diesel powered synchronous generators (DPSGs), and the other powered by both VSWTs and a DPSG, were tested under different conditions including a three phase fault, line outage/break, and load changes. To be able to analyze and simulate these conditions the Power System Analysis Toolbox (PSAT) was used along with Matlab. This paper will begin by giving a brief introduction about variable speed wind turbines. Also, the advantages and disadvantages using wind turbines in the power grid will be discussed. The introduction will conclude by comparing VSWTs to their counterpart, constant speed wind turbines. Many conclusions could be drawn from the tested conditions stated above. When the system with VSWTs was faulted, it resembled the behavior of the diesel generator system. However, when a line outage was applied to the system with VSWTs, it did not behave as expected like the diesel generator system did. Also, when a load is dropped, the generator bus voltage tends to rise.

An overview of photoelectrochemical cells (PEC): Mimicking nature to produce hydrogen for fuel cells

In order to meet the energy demands of the world in the future, clean renewable resources must be explored to the fullest. While many renewable energy avenues exist, to be competitive with fossil fuels an efficient cost effective means of storing converted energy must be found. Photoelectrochemical cells offer an excellent potential solution to this problem. By taking advantage of the most abundant resource available on the Earth, the sun, these cells offer a significant opportunity to make great strides in meeting sustainable energy goals through an efficient and cost effective means of hydrogen production. In recent years, photoelectrochemical cells have gained significant ground through advancements in nanostructured materials and dye sensitized catalysts. They have shown much promise not only in hydrogen production, but also in areas such as waste water treatment and CO2 reduction. The technology is still in its infancy however, and many challenges must be overcome in order to realize its full potential. Chief among these are improving the ability to harvest energy from the visible light spectrum and developing reliable, efficient, and cheaper semiconductor materials. However, the potential benefits of a fully developed photoelectrochemical cell make the technology well worth exploring.

Hardware implementation of a microgrid controller for enhancing dynamic voltage stability

This paper presents the dynamic voltage stability analysis of a 4-bus micro grid set-up with the implementation of the MicroGrid Voltage Stabilizer (MGVS). Dynamic voltage stability analysis of microgrid systems using MGVS was introduced in the literature on simulation level. However, implementation of the controller at hardware level have not been accomplished. This paper provides detailed information on implementing the MGVS to a 4-bus microgrid set-up and improvements on overall dynamic voltage stability. The implementation is performed in a lab environment using LabVolt and Texas Instruments equipment, along with MATLAB/Simulink interface. Several case studies are performed and relevant graphs showing the dynamic voltage stability analysis of the system data are presented in this paper. The 4-bus micro grid system is also simulated using the MATLAB based Power System Analysis Toolbox (PSAT). Furthermore, comparison between hardware and software results are presented and it validates the successful implementation of the MGVS.

Comparison of IGBT modules focus on high power systems

Power demand of modern systems can be very high. A very reliable power electronic component largely present in todays high power system is the IGBT (Insulated Gate Bipolar Transistor). However, for very high power systems, a series or parallel connection is required either to obtain a higher voltage blocking capability or to be able to handle high output current demands. In addition, a series or parallel connection may also be used for a better design (to improve project cost, reduce power loss, etc.). This paper provides the reader background information on IGBTs, its functionality, and the two different types of packaging. Furthermore, this paper provides information on comparison of the losses of series connection of lower rated modules to a higher rated module, and a simulation of parallel connection of lower rated IGBT modules to a single higher rated module. Moreover, a simulation comparing different frequency operations is also provided along with IGBTs costs study for a better scope of overall design projects considerations.