Learning to Learn-Concepts in a First Power Engineering Course

Three well-known and widely accepted concepts in educational psychology are revisited. These are inventory of learning styles, taxonomy of educational objectives, and metacognition. Relationships among these concepts are highlighted. Often, a student can develop his (or her) own learning style by the process of metacognition. Ideas are borrowed from these concepts for use in a first-level power systems course. It is beyond a doubt that both cognitive and metacognitive skills are necessary for students to succeed in any course. While a semester-long power systems course leaves little time for critical thinking and passive reflection for students, certain activities may very well serve for some of these learning processes

Optimizing the Integration of Photovoltaic Systems with Electric Utilities

The author introduces a comprehensive simulation package whereby the optimal size, operation, performance and economics of a photovoltaic (PV) system can be determined in the utility-integrated mode. The central issue is to present a single definitive optimization model. A stepwise analytical methodology starting at the solar resource and culminating in the value of the PV system in terms of avoided costs is provided. The methodology includes processing of the solar irradiance; identification of the PV system\u27\u27s configuration and operational features; identification of real-time system controls in the presence of PV generation; security assessment in the presence of PV and production costing and capacity expansion analysis with PV. The optimization package is subdivided into five different subgroups based on their respective purposes in the context of the overall scheme. The author describes the functions of each subgroup

Power Education at the Crossroads

To meet the demands of designing and running far more complex and highly integrated electricity systems, a new kind of power engineer is needed. In this paper, the author describes how, though students tend to favor higher-tech and more lucrative fields than power Engineering; reports of the discipline\u27\u27s demise are exaggerate

Effect of Central Station Photovoltaic Plant on Power System Security

The value of photovoltaic (PV) plants to electric utilities is investigated under constraints of power system security. It is suggested that the generally adopted methods of analysis for determining the capacity credit, energy displacement, and production cost savings due to the PV plants have neglected the adverse conditions that may arise out of a random preselection of a substation where PV power is injected into the system. The author presents an extensive approach to determining the realistic value of a PV plant to the utility. The method consists of using a power flow algorithm to determine system conditions under specific load scenarios. Identification of bus voltage violations and branch overloads is an integral part of the method. The location of the substation where PV is included is very important. Determination of system behavior under contingency conditions with and without PV is also investigate

Power Quality

One big reason for the poor power quality incidents experienced today is the proliferation of electronic devices. A voracious appetite for higher efficiency and productivity in the manufacturing sector, comfort and automation in homes, and efficient lighting systems in commercial installations are driving the market for power electronic devices. At the forefront of this explosion is the switched power supply. Compared to its predecessor-the linear power supply-it can convert higher power much more efficiently and with a significantly smaller footprint. The switched power supply is found in most of today\u27\u27s computers, fax machines, laser printers, office copiers, etc

Operational Characteristics of Wind Plants and Windfarms

A wide range of power generation technologies exist today, whose characteristics can vary significantly. Additionally, a diverse range of wind turbines are available in the market. With experienced wind developers taking the charge in installing multi-megawatt-size windfarms at a rapid pace, the role of wind power in electricity generation is bound to grow in significance in the coming years. This panel takes a critical look at the operating characteristics of existing and planned wind power generation systems and their relationship to interconnection requirements and performance standards

Central-Station Photovoltaic Plant with Energy Storage for Utility Peak Load Leveling

The impact of photovoltaic (PV) power generation with energy storage on the electric utility\u27s load shape for load leveling purposes is explored. Results show that utilities employing battery storage for peak load shaving might benefit from use of photovoltaic power, the extent of its usefulness being dependent on the specific load shapes as well as the photovoltaic array orientations. Typical utility load shapes both in the eastern and in the western parts of the US are examined for this purpose. Although photovoltaic power generation seems to have a bigger impact on the load of the western utility, utilities in both areas will experience considerable savings on the size of the battery system required to shave the peak loads and also in the off-peak base capacity required to charge the batter

A Rule-Based Dynamic Economic Dispatch for Power Systems

The author introduces a novel operation tool for economic dispatch. It deals with the development and implementation of a new approach-a dynamic rule-based dispatch algorithm that takes into account the major problems faced by the dispatch operator during a dispatch interval and channels those into a database for use by a rule-based system. The algorithm is very fast and can be used effectively in interconnected systems. It can also handle renewable technologies and is therefore considered useful for major electric power utilities contemplating adding a significant amount of these new generation sources to their existing mi

AC/DC Power Systems with Applications for future Lunar/Mars base and Crew Exploration Vehicle

ABSTRACT The Power Systems branch at JSC faces a number of complex issues as it readies itself for the President's initiative on future space exploration beyond low earth orbit. Some of these preliminary issues - those dealing with electric power generation and distribution on board Mars-bound vehicle and that on Lunar and Martian surface may be summarized as follows: Type of prime mover - Because solar power may not be readily available on parts of the Lunar/Mars surface and also during the long duration flight to Mars, the primary source of power will most likely be nuclear power (Uranium fuel rods) with a secondary source of fuel cell (Hydrogen supply). The electric power generation source - With nuclear power being the main prime mover, the electric power generation source will most likely be an ac generator at a yet to be determined frequency. Thus, a critical issue is whether the generator should generate at constant or variable frequency. This will decide what type of generator to use - whether it is a synchronous machine, an asynchronous induction machine or a switched reluctance machine. The type of power distribution system - the distribution frequency, number of wires (3- wire, 4-wire or higher), and ac/dc hybridization. Building redundancy and fault tolerance in the generation and distribution sub-systems so that the system is safe; provides 100% availability to critical loads; continues to operate even with faulted sub-systems; and requires minimal maintenance. This report descril_es results of a summer faculty fellowship spent in the Power Systems Branch with the specific aim of investigating some of the lessons learned in electric power generation and usage from the terrestrial power systems industry, the aerospace industry as well as NASA's on-going missions so as to recommend novel surface and vehicle-based power systems architectures in support of future space exploration initiatives. A hybrid ac/dc architecture with source side and load side redundancies and including emergency generators on both ac and dc sides is proposed. The generation frequency is 400 Hz mostly because of the technology maturity at this frequency in the aerospace industry. Power will be distributed to several ac load distribution buses through solid state variable speed, constant frequency converters on the ac side. A segmented dc ring bus supplied from ac/dc converters and with the capability of connecting/disconnecting the segments will supply power to multiple de load distribution buses. The system will have the capability of reverse flow from dc to ac side in the case of an extreme emergency on the main ac generation side