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Author: | Omidiora, Michael Adebayo |
Title: | Lightning overvoltage studies in medium voltage distribution lines |
Publication type: | Master's thesis |
Publication year: | 2008 |
Pages: | 78 + (13) Language: eng |
Department/School: | Elektroniikan laitos |
Main subject: | Sähköverkot ja suurjännitetekniikka (S-18) |
Supervisor: | Lehtonen, Matti |
Instructor: | Lehtonen, Matti |
OEVS: | Electronic archive copy is available via Aalto Thesis Database.
Instructions Reading digital theses in the closed network of the Aalto University Harald Herlin Learning CentreIn the closed network of Learning Centre you can read digital and digitized theses not available in the open network. The Learning Centre contact details and opening hours: https://learningcentre.aalto.fi/en/harald-herlin-learning-centre/ You can read theses on the Learning Centre customer computers, which are available on all floors.
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Location: | P1 Ark TKK 2542 | Archive |
Keywords: | lightning strokes lightning overvoltages MOV arresters ATP/EMTP test feeder distribution line exposure-arc (EA) electro-geometric model tree |
Abstract (eng): | This research work involves simulations, laboratory experiments and statistical analyses of lightning overvoltages in MV distribution lines. The present understanding of lightning models and the nature of lightning overvoltages are also critically investigated and evaluated. All simulations are carried out with reference to fast transient simulation guidelines as specified in the lightning literature. In the experimental work, the electrical breakdown characteristics of lightning impulse voltages are observed on both the tree and the grounded conductor with variations in the striking distances from the lightning electrode to the two objects. This is used to determine the attractiveness of the tree on direct strokes to the grounded conductor. A calibration constant is extracted, which corresponds to the probability of occurrence of direct strokes to both the tree and the grounded conductor being equal. This constant is then incorporated in the electro geometric model to determine the influence of tree height on the exposure arc of a grounded conductor. The experimental result is compared with similar work available in the literature. Finally, the statistical analyses are performed in order to estimate the lightning performance level of the two existing distribution line designs in Finland, which are overhead lines and covered conductors, and also investigate improvements. |
ED: | 2008-03-13 |
INSSI record number: 35424
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