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HV Cables - Single core HV cables (induced EMF / Circulating currents) 1

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cflatters

Electrical
Joined
Jan 15, 2005
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40
Location
GB
I am currently looking at a design using single layer spaced cables installed on cable ladder, spaced De apart based on IEC 60502, the standard refers to cables earthed at each end (solidly earthed).

The induced voltage when using 300mm Cu/XLPE/AWA/PFC cables to BS6622/7835 equates to 15.3V (Phases A & C) and 11.92V (Phase B)

What is the relationship between the load current of 656A, the sheath resistance and the armour resistance

My mistake has been to assume I = Induced EMF / Sheath resistance ??
 
IEC 60502-2 Standard presents the ampacity[continuous current ratings] for cable construction as per this standard for EPR and XLPE insulated shield bonded both ends and certain installation conditions. For other construction and materials and other conditions it is indicated to follow IEC 60287-1-1 in order to calculate the cable rating. In this latter standard ch.2.3 Loss factor for sheath and screen 2.3.6 Single-core cables, with sheaths bonded at a single point or cross-bonded .More information in IEC 60287-1-2. Of course, no indication how to calculate the induced voltage built-up.
IEEE Std 575-2014 IEEE Guide for Bonding Shields and Sheaths of Single-Conductor Power Cables Rated 5 kV through 500 kV Annex D [informative] Calculation of induced voltages.
D.2 Voltage gradients induced in the cable shield/sheath.
In D.2.1 General case of any cable formation. The Ea, Eb, Ec induced voltage is direct proportional with the current Ia, Ib, Ic flowing in the main circuit.
 
Many thanks

I am currently trying to obtain either IEC 60287 or the IEEE 575-2014 to progress

 
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