Lecture15

# Lecture15 - Page 1 Fundamentals of Power Systems Lecture 15 1 Ampacity Fundamentals of Power Systems Lecture 15 2 Geometric Mean Radius(GMR 1 1 ln

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Unformatted text preview: Page 1 Fundamentals of Power Systems Lecture 15 1 Ampacity Fundamentals of Power Systems Lecture 15 2 Geometric Mean Radius (GMR) ' 1 1 ln ln ln 2 4 2 4 1 r r D D L r r µ µ µ µ π π ⎛ ⎞ ⎛ ⎞ = + = + + ⎜ ⎟ ⎜ ⎟ ⎝ ⎠ ⎝ ⎠ ' 1 ln 2 D L GMR µ π = Inductance of conductor up to a distance of 1 unit (e.g. 1 foot) ' 1 ln 2 GMR L GMR µ π = Per definition the GMR of a specific conductor or conductor arrangement is the radius of an infinitely thin tube with the same internal inductance as the conductor itself out to a 1-foot radius Inductance of conductor in H per meter length with return path at distance D Page 2 Fundamentals of Power Systems Lecture 15 3 Alternative Formula used in Practice Substituting ln (base e) by log (base 10) Inserting µ = 4 π 10-7 Vs/Am Expanding 1 mile = 1609.344 m ' 2 l n 2 6 l n 2 6 2 D f D X f GMR GMR µ µ π π π π = = 7 ' 4 10 1609.344 2 60 log 60 2 log( ) f D X e G M R π π π − = in Ω /mile (per conductor) ' 0.2794 log 60 f D X GMR = Fundamentals of Power Systems...
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## This note was uploaded on 11/10/2011 for the course EEL 3216 taught by Professor Brooks during the Fall '08 term at FSU.

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Lecture15 - Page 1 Fundamentals of Power Systems Lecture 15 1 Ampacity Fundamentals of Power Systems Lecture 15 2 Geometric Mean Radius(GMR 1 1 ln

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