Zero sequence Resistance and Reactance.

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Anwar Pasha

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For a load flow study the values of positive and zero sequence reistance and reactance are required.I checked technical data sheet of cable manufacturers all of them talk about ac and DC ŕesistance but nothing about zero sequence resistance or reactance. Any clue how can this zero sequence resistance and reactanc can be calculated for MV cables.
 
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junkhound

junkhound

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EE, power electronics specialty
Anwar Pasha said:
For a load flow study the values of positive and zero sequence reistance and reactance are required.I checked technical data sheet of cable manufacturers all of them talk about ac and DC ŕesistance but nothing about zero sequence resistance or reactance. Any clue how can this zero sequence resistance and reactanc can be calculated for MV cables.
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Unless definitions have changed in the last few years, there is no zero sequence for a cable by itself.
Positive, negative, and zero sequence are simply components of a 3 phase analysis tool, there is no physical properties of 'zero sequence' to assign to a cable by itself.
 
beanland

beanland

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Southwire Power Cable manual

Southwire Power Cable manual

The zero-sequence impedance of three underground cables is not the same as the positive sequence impedance. The zero-sequence impedance is used when calculating the line-ground fault magnitude. The equations are well documented in IEEE standards but the Southwire Power Cable manual has a good summary, too.
 
I

Ingenieur

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Zm = mutual impedance of ckt (assumed equal between conductors)
transposed lines or a cable
Zs = self impedance

Z1 = Z2 = Zs - Zm
Z0 = Zs + 2Zm

calcs are typically done for a single phase
the 3 networks are each drawn then interconnected based on the fault scenario to be studied
results in a very simple hand calc
 
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