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Description:
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The electric power systems in U .S . Navy ships supply energy to sophisticated systems for weapons , communications , navigation and operation . The reliability and survivability of a Shipboard Power System (SPS ) are critical to the mission of a Navy ship , especially under battle conditions . When a weapon hits the ship in the event of battle , it can cause severe damage to the electrical systems on the ship . Researchers in the Power System Automation Laboratory (PSAL ) at Texas A &M University have developed methods for performing reconfiguration of SPS before or after a weapon hit to reduce the damage to SPS . Reconfiguration operations change the topology of an SPS . When a system is stressed , these topology changes and induced dynamics of equipment due to reconfiguration might cause voltage instability , such as progressive voltage decreases or voltage oscillations . SPS stability thus should be assessed to ensure the stable operation of a system during reconfiguration .
In this dissertation , time frames of SPS dynamics are presented . Stability problems during SPS reconfiguration are classified as long -term stability problems . Since angle stability is strongly maintained in SPS , voltage stability is studied in this dissertation for SPS stability during reconfiguration . A test SPS computer model , whose simulation results were used for stability studies , is presented in this dissertation . The model used a new generalized methodology for modeling and simulating ungrounded stiffly grounded power systems .
This dissertation presents two new indices , a static voltage stability index (SVSILji ) and a dynamic voltage stability index (DVSI ) , for assessing the voltage stability in static and dynamic analysis . SVSILji assesses system stability by all lines in SPS . DVSI detects local bifurcations in SPS . SVSILji was found to be a better index in comparison with some indices in the literature for a study on a two -bus power system . Also , results of DVSI were similar to the results of conventional bifurcation analysis software when applied to a small power system . Using SVSILji and DVSI on the test SPS computer model , three of four factors affection voltage stability during SPS reconfiguration were verified . During reconfiguration , SVSILji and DVSI are used together to assess SPS stability . |