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Computer Applications in Power, IEEE

Issue 3 • Date July 1996

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Displaying Results 1 - 9 of 9
  • Guest Editorial

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    Freely Available from IEEE
  • Simulating transformer taps for remote cranking operations

    Page(s): 24 - 29
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    This article describes an attempt at simulating a remote cranking operation for the black start of two coal-fired drum-type power generation units at Northern States Power Company, USA. The simulation system uses power flow and generator reactive capability programs in an iterative process to determine the appropriate tap positions for the combustion turbine (CT) unit and auxiliary transformers, the various transformers installed in the steam power plant path, and for controlling a proper voltage level for the generator system bus at the CT plant View full abstract»

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  • Demystifying power system oscillations

    Page(s): 30 - 35
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    Power systems are among the most complex dynamic systems created by man, and the insidious nature of oscillatory instability has mystified many practicing engineers. The author describes how, with modern computer programs, a thorough study of power system oscillatory stability is possible. The necessary complex mathematics are made transparent to the program user, and the emphasis of studies may be placed on the physical nature of the oscillatory phenomena and the accuracy of the model data. Careful control design and consistent control commissioning and tuning are required to damp power system oscillations sufficiently so that system operating limits are caused by other phenomena View full abstract»

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  • Location-centered mitigation of lightning-caused disturbances

    Page(s): 36 - 40
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    The authors describe a technique by which asset exposure locations and lightning-caused disturbances can be pinpointed by combining accurate power transmission line asset location with lightning timing and location View full abstract»

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  • Expose hidden failures to prevent cascading outages [in power systems]

    Page(s): 20 - 23
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    Major blackouts are rare events, but their impact can be catastrophic. A study of significant disturbances reported by NERC in the period from 1984 through 1988 indicates that protective relays are involved in one way or another in 75 percent of major disturbances. A common scenario is that the relay has an undetected (hidden) defect that was exposed due to the conditions created by other disturbances. For example, nearby faults, overloads, or reverse power flows expose the defective relay and cause a false trip, which exacerbates the situation. Given the importance of hidden failure modes in traditional relaying systems, intervention by computer-based rational control schemes is proposed in this article. Relays with high-vulnerability indices can be identified, and their vulnerable functions and failure modes identified. Countermeasures to reduce or eliminate the likelihood of the hidden failure of key relays can be provided View full abstract»

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  • Coordinating overcurrent protection devices

    Page(s): 41 - 44
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    Distribution, substation, and plant engineers can benefit from using an overcurrent protection program in commercial, industrial, and utility applications to aid in clearing temporary faults and isolating permanent faults. In the time it normally takes to check one coordination scheme manually, dozens of alternatives can be evaluated using a graphics-oriented program, because the engineer receives immediate feedback for quick decision-making. It is well known that accurately coordinating overcurrent protection devices can minimize or prevent equipment damage, and electrical power service to customers can be greatly improved. In addition to assisting experienced engineers, an overcurrent protection program is an excellent training tool for new engineers. One such tool, V-PRO II, is a second generation program that is Windows-based. An extensive protective device library and an interactive on-line diagram for direct data entry are key new features. Easily identifiable icons are used along with pop-up menus and dialog boxes to simplify command selection. HELP can be accessed any time, and information on a specific topic can be retrieved quickly using hypertext. The program contains two separate windows: a one-line diagram with symbols for buses, lines, components, and protection equipment; and a time-current worksheet with time-current characteristic curves for both phase and ground coordination View full abstract»

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  • Information network supports open access [power transmission communication]

    Page(s): 12 - 19
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    On March 29, 1995, the US Federal Energy Regulatory Commission (FERC) issued a notice of proposed rulemaking (NOPR) aimed at promoting wholesale competition through nondiscriminatory open transmission access. Industry working groups were formed to define the content of the transmission services information to be communicated over an electronic network and to define the requirements of the network itself. FERC issued final rules on April 24, 1996. At this writing, the transmission services information network (TSIN) is just completing design, and initial implementation should be in place by November 1, 1996. There will be about 2035 nodes representing all public transmission systems in the United States. The network will use the Internet as a base, allowing access by all authorized users anywhere in the world. The tools used will be based on the standard Internet tools such as World-Wide Web browsers. This provides a low-cost, high-function, consistent interconnected network to provide information to all transmission customers. The network will have good performance and be secure. It will allow transmission customers to have information on available transmission capacity, costs and tariffs for transmission capacity and costs of ancillary services. This article outlines the content of the industry reports and the FERC rulings View full abstract»

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  • System planning tools for the competitive market

    Page(s): 50 - 55
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    A restructuring of the electric power business in the United States is under way. The form of the restructuring will shift the industry focus from local, vertically integrated monopolies to regional, competitive, and unbundled corporate structures. The premise for change is that market imperfections occur under the regulated monopolistic structure, leading to inefficient use of the interconnected transmission and generation systems. The new order, generically called POOLCO, will not require any fundamentally new analytical system planning methods. It will, however, require the merging of existing generation and transmission (G&T) software into a new G&T system planning function. POOLCO will also require development of new accounting software and communications media View full abstract»

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  • Client-server technology meets operational-planning challenges

    Page(s): 45 - 49
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    Utilities must be able to develop IT tools fast enough to address today's emerging business needs, such as open transmission access, real-time pricing, etc. This article describes a client-server implementation launched at Tennessee Valley Authority (TVA) in 1994 to meet the utility's operational-planning needs. The article summarises some of the lessons learned and outlines future development plans View full abstract»

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