M.S.

A peninsular power company's extra high voltage (EHV) transmission grid and the rest of the country behave as a two machine system for the following two types of disturbances loss of a large generator in the southern region of the peninsular power company faults on the 500 kV interconnections between the two systems Whether the two systems will remain stable relative to each other or go unstable depends on the following three factors • severity of the disturbance • loading on the peninsular power company's EHV transmission grid • amount of power imported from the rest of the country For stable oscillations the two systems must remain coupled at them 500 kV interconnections. For separations the two systems should be immediately isolated from one another at their 500 kV interconnections. Since these two systems behave as a two machine system for these two types of disturbances the extended equal area criterion(EEAC) is used to make an extremely quick and accurate prediction of the relative stability between them. For stable oscillations following a disturbance, circuit breakers at the 500 kV interconnections are blocked from tripping. For separations these circuit breakers are tripped. EEAC requires synchronized voltage phasor measurements at two specific locations within the overall electrical power system. The two sites are substations located on opposite sides of the electrical center of the two systems. The voltage angle at each location's electric bus will swing with respect to its equivalent machine. This information is constantly recorded to monitor the relative stability of the overall system. When a disturbance does occur, a prediction is made and the appropriate control actions are issued. / Master of Science

The Westinghouse Induction Time Klement Overload Relay, Type CO, a relay operating on the same principle as an alternating current watt-hour meter, is considerably affected in its time of operation when non-sinusoidal waves of potential are applied. If the potential wave applied has a flat top or depressed peak or if the wave has a lagging peak, that is, its maximum instantaneous value occurs more than 90 degrees after the beginning of the cycle, the operation of the relay is accelerated. If the wave of potential applied to the relay reaches its peak more than 90 degrees and less than 180 degrees after the beginning of the cycle, the operation of the relay is retarded from what it would be with a sinusoidal potential applied. The operation of a General Electric Time Current Overload Relay, Type PAC, a plunger type relay with an air bellows time delay, is, in general, retarded in operation by the application of non-sinusoidal potential waves. The operation may be slightly accelerated, however, if the wave distortion is slight, the current setting is low, and the distortion is such that the peak of the wave is flat or lagging. The effect of the wave distortion on other relays requires more study. / Master of Science

Philip M. Lewis II. / "June 7, 1956." "This report is based on a thesis submitted to the Department of Electrical Engineering, M.I.T., May 14, 1956, in partial fulfillment of the requirements for the degree of Doctor of Science." / Bibliography: p. 105. / Army Signal Corps Contract DA36-039-sc-64637 Dept. of the Army Task No. 3-99-06-108 Project No. 3-99-00-100

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains x, 105 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 99-105).

An isolated hybrid system comprised of a dispatchable and a non-dispatchable power generation sources, is proposed to supply the load of a remote village in the west coast region of The Gambia. The thesis presents an artificial neural network (ANN) based approach to tune the parameters of the frequency regulator in hybrid wind/diesel power system for isolated area power supply. The multi-layer feed-forward ANN with the error back-propagation training is employed to tune the frequency regulator in the simulation of hybrid system under different load and wind conditions. Using MATLAB/Simulink, dynamic simulations are performed to investigate the interaction between these two power sources for the load management, and the voltage and frequency behaviors during wind speed and load variations. Simulation results show that the wind turbine and the diesel generator can be operated suitably in parallel. During simulation, the frequency and voltage regulators used in the proposed hybrid system performed fairly well under wind speed variations and load changing conditions. A good frequency regulator interface, which is around 50Hz is observed for nearly the entire period of operation.

M. Tech. Electrical Engineering. / Voltage control is an essential part of the electricity transmission and distribution network system for maintaining voltage within statutory limits at the substation bus and at the consumer's point of supply. The most popular voltage control method on the transmission and distribution network system uses the on-load tap changer (OLTC) transformer. This study proposes the use of Fuzzy Logic Control (FLC) systems on the on-load tap changers when two or more mismatched transformers are connected in parallel in order to control the voltage supply to local customers. The actual voltage recordings and on-load tap change operations for each of the paralleled transformers have been analyzed and modelled on MATLAB/Simulink in order to develop an improved control algorithm using Fuzzy Logic Control. With the two-input, one-output FLC system with seven linguistic values giving 49 control rules, the number of tap change operations are minimized and the bus voltage is maintained within the statutory limits.

No description available.

Thesis (M.Eng.)--University of Wollongong, 2005. / Typescript. Includes bibliographical references: leaf 115-120.

Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Swaminatham, Madhavan.