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Power Delivery, IEEE Transactions on

Issue 1 • Date Jan. 1990

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Displaying Results 1 - 25 of 77
  • Bibliography of switchgear literature: IEEE committee report

    Page(s): 177 - 188
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (912 KB)  

    This bibliography of 255 references was prepared by the Recognition and Planning Subcommittee of the IEEE Power Engineering Society Switchgear Committee to be used as a reference for switchgear education. The references generally cover the period of mid-1983 through mid-1988. The last complete switchgear bibliography was published in 1984 covering the period through September of 1983. This reference is updated at five-year intervals.<> View full abstract»

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  • Field evaluation of industry's first self-protected, light-triggered thyristor

    Page(s): 110 - 116
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    A description is given of the industry's first self-protected, light-triggered thyristor to be developed, fabricated, and field-demonstrated. This device is installed on a 13.8 kV, 40 MVAr AC switch using 16 series-connected devices operating in one phase of a static VAr compensator at the Minnesota Power Co.'s Shannon substation. The light-triggered thyristor was designed with internal overvoltage protection (safe turn-on at a preset overvoltage level) and with significantly improved dv/dt withstand characteristics. In the process, the AC switch in the static VAr compensator was redesigned to incorporate 16 instead of the originally installed 24 series-connected thyristors View full abstract»

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  • Measurements and computer simulation of fast transients through indoor and outdoor substations

    Page(s): 117 - 123
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    The high-frequency modeling of substations is discussed. The response of three different substations (both indoor compartmented substations and outdoor substations) to fast front overvoltages (lightning overvoltages) has been measured by a low-voltage injection technique. Detailed modeling of substations, including busbars, circuit breakers, and disconnectors, has been derived from the test results. EMTP (electromagnetic transient program) simulations were run using these models, and in most cases very good agreement has been obtained with another independent series of tests View full abstract»

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  • Separable connector switching performance

    Page(s): 435 - 441
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    Laboratory loadbreak testing of 25 kV class separable insulated connectors suggests that switching reliability achieved in the field will vary between 93.5% and 99.9% depending on the type of tool used, the condition of the connector system, the circuit voltage and loading, and ground plane proximity. A survey of user reliability requirements concluded that a reliability of at least 99.7% is needed to retain separable connector switching as a viable means of providing URD flexibility. It is concluded that in order to maintain the required reliability for live switching, the best operating tools and the best separable connector system components must be used View full abstract»

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  • Lightning overvoltage protection of the Paddock 362-145 kV gas-insulated substation

    Page(s): 144 - 150
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    Backflashovers close to the Paddock 362-145 kV gas-insulated substation (GIS) have been analyzed with the electromagnetic transient program (EMPT) using a frequency-dependent multiconductor system. The severities of the lightning stroke currents were based on recent recordings in the eastern United States. The effects of corona attenuation and distortion were accounted for using a shunt linear model approach. Turn-up effects of both line insulator flashover voltages and surge arrester protective characteristics were based on manufacturer's volt-time curves. Wave-shaping effects of substation capacitances were modeling details in determining the overvoltages inside the GIS due to close backflashovers, which are caused by lightning strokes with varying intensity. These results are aimed at better evaluation of lighting protection requirements for GIS protected by metal-oxide surge arresters View full abstract»

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  • Advantages and disadvantages of embedment to prevent external mechanical damages to submarine cables

    Page(s): 54 - 57
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    The CIGRE paper `Methods to Prevent Mechanical Damage to Submarine Cables' (1986) deals with failures in submarine cable links. However, it does not deal with power transmission availability. Furthermore, it may give the impression that total embedment is recommended. The authors argue that this is much too expensive and might endanger the economic viability of a cable solution. A definition of power availability is given. The importance of spare cables is stressed. After a review of the cable protection methods, some examples of power availability in existing submarine cable links are given. The authors also state that, in order to optimize the cost of protection, new guidelines need to be developed. A CIGRE working group has been set up to accomplish this task View full abstract»

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  • Transfer switch ratings `without fuses or circuit breakers'

    Page(s): 202 - 203
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    The problem of insufficient data for the specification of transfer switches is identified as a problem with regard to available fault current. Typical examples are given to explain the necessity of obtaining additional data, beyond what is traditionally published, in order to specify automatic transfer switch applications safely. A suggestion for a more realistic nomenclature is made View full abstract»

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  • Specifying bar codes for distribution transformers: a guideline

    Page(s): 233 - 238
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    The electrical industry has demonstrated an interest in applying bar code technology to distribution transformers. A comprehensive scheme relative to distribution transformer bar codes is presented in support of ongoing efforts by both EEI and NEMA (National Electrical Manufacturers' Association) to develop guidelines for bar coding distribution transformers. Specific requirements including bar coded information, longevity, location, format, symbology, and density are addressed. General guidance is provided to transformer manufacturers and users for planning and specifying distribution transformer bar codes View full abstract»

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  • An integrated load management, distribution automation and distribution SCADA system for Old Dominion Electric Cooperative

    Page(s): 384 - 390
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    A computer and communications system is presented for controlling the operations of load management, distribution automation, and distribution SCADA for a G&T cooperative, Old Dominion Electric Cooperative, and its 12 member cooperatives. The system is currently being designed and delivered by a team of vendors, which involves an EMS/SCADA system vendor and a load management/distribution automation equipment vendor. The system coordinates the scheduling of load management for the member cooperatives so as to minimize the power bills to the power suppliers. Each member cooperative can use the system to implement distribution SCADA and distribution automation functions, thus improving its operation efficiency and service quality. A description is given of the functions, special features, and implementation and development experience for the system View full abstract»

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  • Computer aided tools in gas circuit breaker design

    Page(s): 163 - 169
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    A software tool that allows the numerical investigation of the gas flow in circuit breaker chambers has been devised. A zonal grid methodology, with a corresponding finite-volume flow solver for the Euler equations, has been implemented for the treatment of the intricate geometries of the interrupter. Computational examples to illustrate the validity of the method are presented. Experimental tests were done on full-size breakers, and the results are analyzed using the proposed computational approach View full abstract»

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  • Ground grid design of a transition station system-a typical example of fault transfer

    Page(s): 124 - 129
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    E.T.D. Barra Funda I urban station, located in Sao Paulo, Brazil, is surrounded by several buildings, so it is not possible to make reliable earth resistivity and ground electrode resistance measurements. The grounding of this station was designed by using external circuits connected to the ground mat (sheaths and bare copper bondings). The use of these circuits allows a transfer of the fault potentials from E.T.D. Barra Funda I to E.T.R. Barra Funda II due to a strong cable shielding. A discussion is presented of the basic procedures adopted for controlling the potential rise at the E.T.D. Barra Funda I station in order to ensure the safety of people and equipment during the occurrence of a fault to the ground. This study deals with such design aspects as: high short-circuit level, high soil resistivity and backup protection time, and reduced area for diffusion of short-circuit current View full abstract»

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  • Development of outdoor epoxy resin molded apparatus for distribution systems

    Page(s): 204 - 211
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    The trend toward oil-less electric power apparatus makes it desirable to put outdoor epoxy resin modeled apparatus into practical use as early as possible. In order to achieve this, it is necessary to develop an apparatus with high reliability. A description is given of results of research activities to improve the resin compound, the examination of the transformers used outdoors for more than 15 years, and the outdoor demonstration test to confirm long-time reliability of the molded apparatus View full abstract»

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  • Distribution transformer BIL reduction feasibility study

    Page(s): 509 - 513
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    A summary is presented of an investigation into the feasibility of reducing basic insulation levels (BILs) for oil-immersed distribution transformers. A projected market make-up of popular kVA and system voltages was determined for the 5-35 kV insulation classes of pole-type and pad-mount distribution transformers. Reduced BIL design cases were used to determine the impact on the transformer's design and performance. The final results provide both industry cost and total owning cost savings View full abstract»

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  • Implementation of heuristic search strategies for distribution feeder reconfiguration

    Page(s): 239 - 246
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (812 KB)  

    A method for feeder reconfiguration with the potential for handling realistic operating constraints is presented. The approach taken is to set up a decision tree to represent the various switching operations available. A best-first tree searching strategy, based on heuristics, is used to evaluate the various alternatives. Switching options which could result in overloads, voltage problems, or other operating constraints, such as those associated with system protection, are quickly eliminated as possibilities. The development of a rule-based system aimed at the reduction of the search space is presented as a means of implementing the above strategy. An example is used to illustrate the concepts described View full abstract»

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  • A comparative study of dissolved gas analysis techniques: the vacuum extraction method versus the direct injection method

    Page(s): 20 - 25
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    The dissolved gas analysis of transformer oils can now be accomplished without high vacuum extraction of the gases from the oil prior to the chromatographic analysis. The new direct injection technique allow the analysis to be conducted by injecting the oil directly into the gas chromatograph. The author presents comparative data for 100 samples that were analyzed by both the traditional vacuum extraction method and by the new direct injection method. The results indicate that the direct injection method. The results indicate that the direct injection method is a viable alternative technique that offers many advantages over the vacuum extraction method and is a valuable tool in the diagnostic process of evaluating the condition of power transformers View full abstract»

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  • Analysis of a harmonic overvoltage due to transformer saturation following load shedding on Hydro-Quebec-NYPA 765 kV interconnection

    Page(s): 397 - 405
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    An analysis is presented of the harmonic overvoltage recorded on the interconnection between Hydro-Quebec and the New York Power Authority (NYPA) in the Chateauguay area. The overvoltage was caused by transformer saturation, following tripping of the 765 kV transmission line linking both systems. EMTP (electromagnetic transient program) simulation yielded good agreement with field measurements and was valuable in reevaluating operating practices at the Chateauguay station View full abstract»

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  • Protecting firemen against fire-induced flashovers

    Page(s): 297 - 302
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    This study was initiated in response to an accident in which a man was injured because of the step potential generated by a fire-related flashover of a 500 kV line. A safety guide for firemen is presented, describing the conditions under which flashovers are not likely to occur and the extent of the hazardous step potential zone, which should be avoided in cases where flashovers are likely to occur. Conditions where flashovers cannot occur are outlined View full abstract»

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  • Neural-net based real-time control of capacitors installed on distribution systems

    Page(s): 266 - 272
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    An expert system using a two-stage artificial neural network is proposed to control in real time multicap capacitors installed on a distribution system for a nonconforming load profile such that the system losses are minimized. The required input data are directly obtained from online measurements which include the active and reactive line power flows, voltage magnitudes, and the current capacitor settings at certain buses. The optimum control does not involve any iteration procedure; therefore, it is computationally very efficient. Studies on a 30-bus distribution test system show the expert system to have quite satisfactory results View full abstract»

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  • Criteria for phase-to-phase clearances of HV substations

    Page(s): 137 - 143
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    To facilitate uprating of HV substations, a reexamination is made of line-to-line insulation design criteria. The basis for existing practices and the principles of line-to-line lightning surge overvoltage stresses are reviewed. Results of a digital study for a realistic substation are presented. The conclusions show that the line-to-line stresses, as limited by surge arresters, are substantially higher than line-to-ground stresses. This represents increased requirements as compared to existing standards. However, due to the low protective levels of modern arresters, substantial reduction of line-to-line clearances is still feasible View full abstract»

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  • Measurement and characterization of harmonic and high frequency distortion for a large industrial load

    Page(s): 427 - 434
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    A software package is described that was developed to perform harmonic analysis on digitized current and voltage waveforms. The authors also report on the measurement and characterization of voltage and current harmonics and high-frequency distortion of a large industrial load. Since waveform distortions often include periodic high-frequency transients, special signal processing techniques were developed in the software to alleviate misleading results of the calculated harmonics. From simultaneous measurements on all three phases, an investigation of harmonic unbalance at the industrial load is discussed. Problems with the installation of a capacitor bank for voltage regulation purposes are also described View full abstract»

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  • The world's first use of 500 kV XLPE insulated aluminium sheathed power cables at the Shimogo and Imaichi power stations

    Page(s): 26 - 32
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    The world's first practical applications of 500 kV XLPE (cross-linked polyethylene) cables took place in 1988 at the Shimogo power station of the Electric Power Development Co. Ltd., and the Imaichi power station of the Tokyo Electric Power Co. Inc.. Research and development work on the cables had been conducted since 1982. Efforts were concentrated on quality control to remove contaminants from the insulation and to extrude the very thick-walled insulation without any defects. Insulation performance tests, including long-term aging, confirmed that the 500 kV XLPE cables and the terminations were highly reliable with superior initial and long-term performance. The installation was completed successfully, and the cables are now in satisfactory operation at both power stations. The cable routes, design of the cable and termination, cable manufacture, results of the insulation performance tests, installation work, and site test are discussed View full abstract»

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  • Investigation of ramped air arcs near current zero in dual-flow nozzle system

    Page(s): 170 - 176
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    Ramped air arcs with a dI/dt= 6 A/μs were investigated in dual-flow nozzle system. The nozzle pressure ratio was varied to study the arc under different flow Mach number gradients. The dI/dt, dV/dt, and postzero resistance and current measurements were taken for an electrode separation of 5.5 cm and a nozzle gap spacing of 1.23 cm. The adverse shock wave effects were quantitatively observed for nozzle pressure ratios with separated flow in the nozzle. The arc power, which is equal to the total radiation losses and heat transferred from the plasma, was determined near current zero for subsonic and supersonic flow fields. It was shown that the nozzle pressure ratio is a very important parameter in the circuit breaker performance. A comparison of this work with Brown Boveri data was made. It was concluded that the convection stabilized ramped arcs near current zero are laminar and become unstable in the dielectric regime View full abstract»

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  • Pilot relaying performance analysis: IEEE committee report

    Page(s): 85 - 102
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    An analysis is conducted of the performance of pilot relay schemes under fault conditions. While it is recognized that this type of investigation can take many directions, the use of relay targets being one such avenue of inquiry, this study concentrates on performance evaluations through the application of fault recorders and sequence-of-event recorders. The specific analog and digital quantities to be monitored to provide for a correct analysis are shown. The many system and equipment phenomena and limitations, external to the pilot relaying terminal, that could affect pilot relaying performance are described. Seven basic pilot relay schemes are discussed, and, for each pilot relay scheme discussed, typical oscillograms are shown for internal and external faults to assist in the proper fault analysis of such pilot systems. Minor variations to the basic scheme are not specifically discussed, but the monitoring and performance analysis of other schemes can be handled using the principles covered View full abstract»

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  • A knowledge-based approach to optimize switching in substations

    Page(s): 103 - 109
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    Automatic sequence switching has been an important pursuit in the field of substation automation. An intelligent approach to the optimization of switching sequences in electric substations is presented. The optimal sequence switching problem is stated. A knowledge-based model of a substation switch network organized in a trilevel hierarchical structure is suggested, and a set of basic techniques suitable for the general task of network reorganization is given. An intelligent optimal sequence switching strategy for substations based on modeling techniques is presented. An expert system in Prolog used to formalize the sequence of switching operation and application in substations is described View full abstract»

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  • Maximum likelihood estimation of high frequency machine and transformer winding parameters

    Page(s): 212 - 219
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    A method is presented to establish a multisection network model for study of high-frequency transient behavior of transformer and machine windings. The parameters of the network model are estimated using the maximum-likelihood estimation technique. In order to verify the proposed estimation method, the parameters of a six-section network model are estimated View full abstract»

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Aims & Scope

Installation and operation of apparatus, equipment, structures, materials and systems for the safe, reliable and economic generation, transmission, distribution, conversion, measurement and control of electric energy.

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Meet Our Editors

Editor-in-Chief
Wilsun Xu
Ph.D., P.Eng.
Dept. Electrical and Computer Eng.
University of Alberta
(9107 - 116 Street)
Edmonton, Alberta T6G 2V4 Canada
wxu@ualberta.ca
Phone:780-492-5965
Fax:780-492-1811