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Distribution System Data Exchanges to Support Line and Cable Parameter Calculations
T. E. McDermott, Senior Member, IEEE

Abstract—Line and cable parameter calculations appropriate for distribution lines are summarized. These lead to a definition of data formats required to support the calculations, implemented as an open-source software project using the Common Information Model withDistribution extensions (DCIM), and the MultiSpeak formats. This government-funded project will continue to define data exchanges for other important distribution system analysis functions. Index Terms—power modeling. distribution lines, power system

I. NOMENCLATURE a = inside radius of cable insulation, excluding semicon b = outside radius of cable insulation, excluding semicon Cabc = expandedthree-phase capacitance matrix CCN = self-capacitance of a CN cable per unit length CN = concentric neutral cable Cphases = reduced capacitance matrix of phases present CTS = self-capacitance of a TS cable per unit length dc = complex skin depth in conductor de = complex skin depth in earth dod = diameter over a tape shield or CN strands GMRCN = geometric mean radius, phase to its own CN GMRs =geometric mean radius of one CN strand GMRTS = geometric mean radius, phase to its own TS Hi or Hj = height of conductor i or j above ground k = number of CN strands L = tape shield lap in percent M = temperature coefficient of resistance Nb = number of subconductors per bundle Pii = self potential coefficient of conductor i Pij = mutual potential coefficient, conductors i and j Pnn = primitiveneutral potential coefficients Pnφ = primitive neutral-phase potential coefficients Pphases = reduced impedance matrix of phases present Pprim = primitive impedance matrix Pφn = primitive phase-neutral potential coefficients Pφφ = primitive phase potential coefficients rb = radius of circle through subconductors rbeq = bundle equivalent radius rCN = radius through centers of the CN strands
This workwas supported in part by the U.S. Department of Energy under Grant DE-FG02-06ER84648. T. E. McDermott is with EnerNex Corporation, Pittsburgh, PA 15236 (email: tom@enernex.com).

RCN = resistance of a CN, including all strands Rdc = conductor dc resistance per unit length ri = radius of conductor’s hollow core (0 if solid) ro = conductor outer radius rs = radius of a CN strand Rs = resistance ofone CN strand Rt1, Rt2 = resistances at temperatures t1 and t2 rTS = inside radius of a tape shield RTS = resistance of a tape shield Sb = separation between adjacent subconductors T = thickness of tape shield t1, t2 = temperatures in °C TS = tape shielded cable Xi or Xj = horizontal position of conductor i or j Zabc = expanded three-phase impedance matrix Ze-ii = external self impedance forconductor i Ze-ij = external mutual impedance, conductors i and j Zhigh = internal conductor impedance at high frequency Zii = self impedance of conductor i Zij = mutual impedance between conductors i and j Zint = total internal conductor impedance Zlow = internal conductor impedance at dc Znn = sub-matrix of primitive neutral self impedances Znφ = sub-matrix of primitive neutral-phase impedancesZphases = reduced impedance matrix of phases present Zprim = primitive impedance matrix Zφn = sub-matrix of primitive phase-neutral impedances Zφφ = sub-matrix of primitive phase self impedances ε = permittivity of cable insulation ε0 = permittivity of free space εr = effective relative permittivity of cable insulation εr-ins = relative permittivity of cable insulation µ0 = permeability of free space ρc= conductor resistivity ρe = earth resistivity ρTS = resistivity of a tape shield σc = conductor conductivity σe = earth conductivity ω = angular electrical frequency

II. INTRODUCTION HE databases and software tools for electric power distribution systems have not been integrated. Users must contend with data formats and software interfaces that are

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