Electrical cable that limits partial discharges

An aerospace cable that limits the occurrence of partial discharges comprising:

• an elongate electrically conductive element;
• and
• an insulation system having a plurality of electrically insulating layers surrounding said elongate electrically conductive element,
• wherein each of the plurality of electrically insulating layers of the insulation system has a radial thickness, and wherein an equivalent insulation thickness (teq) of this insulation system is greater than the result of a polynomial function equation of a minimum pressure and of a maximum temperature at which the cable is intended to be used, and wherein the equivalent insulation thickness teq and
• the respective radial thicknesses satisfy the following relationship:
• t
• eq
• =
• ∑
• Numbers
• ⁢
• of
• ⁢
• layers
• ⁢
• of
• ⁢
• the
• ⁢
• insulation
• ⁢
• system
• x
• =
• 1
• e
• x
• ε
• rx
• [
• Math
• .
• 4
• ]
• where ex is the radial thickness of a layer x
• and εrx is the relative dielectric permittivity of the layer x, and
• wherein the equivalent insulation thickness teq, in mm, is such that:
• t
• eq
• ≥
• ∑
• n
• =
• 1
• 4
• a
• n
• ·
• PDIV
• n
• -
• 1
• [
• Math
• .
• 1
• ]
• with
• a
• n
• =
• ∑
• m
• =
• 1
• 4
• b
• n
• ,
• m
• ·
• p
• T
• n
• -
• 1
• [
• Math
• .
• 2
• ]
• and
• p
• T
• =
• 273
• ,
• TagBox[",", "NumberComma", Rule[SyntaxForm, "0"]]
• 15
• 273
• ,
• TagBox[",", "NumberComma", Rule[SyntaxForm, "0"]]
• 15
• +
• T
• [
• Math
• .
• 3
• ]
• where pT is the minimum pressure in mbar or hPa
• T is the maximum temperature in degrees Celsius and PDIV represents an amplitude of the partial discharge inception voltage, in kV (kVpeak),
• under the minimum pressure and maximum temperature conditions, and
• wherein coefficients from the equations math 1, math 2, and math 3 are the following:
• bn, m
• n = 1
• n = 2
• n = 3
• n = 4
• m = 1
• −0.58133
• 0.81629
• 0.02282
• 0.00864
• m = 2
• 2.11632
• −2.91153
• −0.02497
• −0.03217
• m = 3
• −2.88833
• 3.94018
• 0.01584
• 0.04238
• m = 4
• 1.31095
• −1.78528
• −0.01122
• −0.01814