Thesis (Ph. D.)--Ohio University, August, 1981. / Title from PDF t.p.

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains x, 80 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 76-80).

No description available.

Thesis (M.S.)--Ohio University, August, 1986. / Title from PDF t.p.

Eskom is experiencing problems in the field of protection maintenance and in-service breakdowns which negatively influence the quality of electrical supply to the consumer, an integral component of the utility business. These facts initiated the research into the further development of a generic relay to be implemented as a strategic spare for the replacement of several schemes operating within Eskom’s southern region. These include the electromechanical, solid state and numerical distance protection relay and scheme failures on the 132 / 66 kV feeder network. Hence, the primary objective of the research is to develop, test and configure the strategic spare in terms of software and peripheral hardware for the input and output terminal connections, generic equations and settings for the purpose of the scheme replacements. The various schemes are assessed for stepped distance and permissive intertripping for three or single pole operation. This is done in conjunction with the internal and external circuit diagrams in order to understand the detailed operation of the scheme and to ensure the effective implementation of the strategic spare. The generic relay is configured for the emergency replacement of the various schemes during in-service breakdowns. This constitutes a temporary installation and therefore the downtime in essence, of all the distance protection schemes that require replacement, is limited to a minimum. This dissertation therefore explores the implementation of the strategic spare.

No description available.

Thesis (M.S. in electrical engineering)--Washington State University, December 2009. / Title from PDF title page (viewed on Jan. 28, 2010). "School of Electrical Engineering and Computer Science." Includes bibliographical references (p. 99-101).

Generation loss contingencies in electric power systems result in a deviation of system frequency from nominal, a condition which must be corrected promptly in order to prevent further degradation of the power system. Automatic load-shedding using underfrequency relays is one of the techniques used to correct abnormal frequency deviations and prevent the risk of uncontrolled outages. If sufficient load is shed following a contingency to preserve interconnections and keep generators on-line, the system can be restored with relative speed and ease. On the other hand, if a declining frequency condition is not dealt with adequately, a cascading disconnection of generating units may develop, leading to a possible total system blackout. / This thesis develops and tests a new systematic method for setting underfrequency relays offering a number of advantages over conventional methods. A discretized swing equation model is used to evaluate the system frequency following a contingency, and the operational logic of an underfrequency relay is modeled using mixed integer linear programming (MILP) techniques. The proposed approach computes relay settings with respect to a subset of all plausible contingencies for a given system. A method for selecting the subset of contingencies for inclusion in the MILP is presented. The goal of this thesis is to demonstrate that given certain types of degrees of freedom in the relay setting problem, it is possible to obtain a set of relay settings that limits damage or disconnection of generating units for each and every possible generation loss outage in a given system, while attempting to shed the least amount of load for each contingency.

This dissertation report began as an investigation into an overcurrent relay protection operation on a shunt capacitor bank (SCB) at ESKOM’s Westgate substation. Westgate substation has two SCBs, both of which were in service at the time of the 2007 incident. However, only the overcurrent protection scheme applied on SCB No.2 operated due to an external feeder fault on the Eltro feeder at Westgate substation. In 2004, SCB No.2 had tripped also on an overcurrent relay protection operation for an external fault. The difference identified in the otherwise identical SCBs was the relay technology employed by the overcurrent protection schemes i.e. electromechanical and electronic overcurrent relays were utilised. Therefore an investigation was initiated to determine any difference in the performance and reliability of overcurrent relay technologies in the SCB environment. The purpose of this work is to present the performance of the different technologies of overcurrent relays (electromechanical, electronic and digital) as applied to an ESKOM SCB during system disturbances and to compare their operation and behaviour. MatLAB and DigSILENT simulation packages were used to conduct preliminary fault studies to determine overcurrent relay performance, for a definite time overcurrent setting. These simulation results indicated that the simple electromechanical and electronic overcurrent relay could operate incorrectly in the SCB environment, during system disturbances. Practical laboratory tests were also conducted. This comprised of injecting DigSILENT simulations, comprising of system switching events and external faults, into three technologies of overcurrent relays. These Omicron injection tests found that the Westgate electronic relay would operate incorrectly for certain fault events in the SCB environment. Due to the results observed, further frequency response tests were conducted. These results suggested that the electronic and electromechanical overcurrent relays were susceptible to harmonics i.e. harmonics impact both the pick-up current setting and operating time of electronic and electromechanical overcurrent relays. The digital relay did not exhibit this vulnerability. Finally, recommendations were made to address the incorrect operation of the Westgate electronic relay in its SCB application. These recommendations could be applied in other ESKOM SCB overcurrent protection schemes, to prevent incorrect operation for system disturbances. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2009.

Thesis (M.Eng.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 127-132. Also available online.