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Signatures of Voltage Dips: TransformerSaturation and Multistage Dips
Styvaktakis, Emmanouil; Bollen, Math H.J.
Author Affiliation: Chalmers University of Technology.Abstract: Obtaining information on voltage dips that occur in a net-
work is one of the most important tasks of a power quality monitoringprogram. This paper focuses on two types of voltage dips that, althoughmentioned in the literature, have characteristics that have not been pre-sented before. These types are: voltage dips due to transformer satura-tion and multistage voltage dips due to faults (dips that present morethan one stages of voltage magnitude before the fault clearing opera-tion). Simulations and real measurements are used to show the featuresof these types of phenomena. The paper offers the means for asystematic processing of the measurements obtained by power qualitymonitors.
Keywords: Power system monitoring, power quality, voltage dips,power system faults, power transformers.
Preprint Order Number: PE-548PRD (06-2002)Discussion Deadline: November 2002
The Temperature Characteristicsand Current Conducting Ability ofHorizontally Curved ConductorsLiu, Yafang; Morita, Kazunari; Iwao, Toru;Endo, Masao; Inaba, Tsuginori
Author Affiliation: Institute of Science And Engineering ofCHUOUniversity.
Abstract: According to experimental results, the temperature on ahorizontally curved conductor was proved to be higher than that on astraight conductor. The temperature deviation increased while the cur-rent ratio I"Cr, increasing or the curved angle oc and curved radius Rodecreasing. Where, ICr is the critical melting current. Therefore, if themaximum surface temperature is settled, for conductors of the same di-ameter and being made of the same material, the current conducted by a
curved conductor was smaller than that conducted by a straight one.When the curved angle a was /45' and current ratio IIICr, was 38.5%,the current decrease deviation was about 10%.
Keywords: Curved conductor, heavy current, surface temperature,current conducting ability.
Preprint Order Number: PE-026PRD (06-2002)Discussion Deadline: November 2002
Predicting Vegetation Related FailureRates for Overhead Distribution Feeders
Radmer, D.T.; Kuntz, Paul A.; Christie, Richard D.;Venkata, S.S.; Fletcher, Robert H.
Author Affiliation: University of Washington; Iowa State Univer-sity; Snohomish County PUD #1.
Abstract: Faults on the electric power distribution system are re-sponsible for a large portion of the interruptions a customer will experi-ence. To maintain a high level of system reliability, vegetationmaintenance is often required. Analytical prediction of the effects ofvegetation maintenance on distribution system reliability requires amodel of the expected failure rate of line sections that includes the ef-fects of vegetation. Vegetation related failures are more likely to occuras the vegetation near the overhead power lines grows, increasing theline section failure rate. Due to difficulties in utilizing existing growthmodels, this paper proposes to use a direct model for failure rate predic-tion based on factors that affect vegetation growth. Four models areconsidered: linear regression, exponential regression, linearmultivariable regression, and an artificial neural network. The modelsare tested with historical vegetation growth parameter data and feederfailure rates. Results are compared and the features of each model arediscussed.
Keywords: Power distribution systems, reliability, failure ratemodeling, failure rate prediction, line clearance, vegetation mainte-nance, tree trimming, regression, neural networks.
Preprint Order Number: PE-084PRD (06-2002)Discussion Deadline: November 2002
IEEE Power Engineering Review, September 2002
2004 IEEE Fellow NominationsDeadline: 15 March 2003
Recognizing the achievements of its members is an important part of the mission of the IEEE. The IEEE grade of Fellow isconferred upon a person of "outstanding and extraordinary qualifications and experience in IEEE designated fields, and whohas made important individual contributions to one or more of these fields." The total number of Fellows selected each yeardoes not exceed 0.1% of the total IEEE membership.
The number of IEEE Fellow nominations for PES members has declined in recent years. As a result, fewer of our colleagueswere considered for the recognition that they deserve through their contributions to power engineering. Many of our PES col-leagues made significant contributions to the profession through their work in engineering, technical leadership, and educa-tion. As a professional community, we need to be more proactive in nominating our colleagues forthis significant award.
Any person, including nonmembers, is eligible to serve as a nominator with the following exceptions: members of the IEEEBoard of Directors, members of the IEEE Fellow Committee, IEEE Technical Society/Council Fellow Evaluating CommitteeChairs, members of IEEE Technical Society/Council Evaluating Committees reviewing the nomination, or IEEE staff. Thedeadline for nominations is 15 March 2003.
The candidate must be an IEEE Senior Member at the time the nomination is submitted, and he/she must have completed 5years of service in any grade of IEEE membership.
All the necessary material to assist you in the nomination process is available on the IEEE Web site:http://www.ieee.org/about/awards/fellows/fellows.htm. If you prefer a hard copy, please send an e-mail to [email protected]. Include your name, street address, city, state/province, postal code, country, and telephone/fax numbers.For more information, contact Chen-Ching Liu, PES Fellows Committee chair, [email protected].
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