What is the fault current calculation for a broken line touching a pole?

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Discussion Overview

The discussion revolves around the calculation of fault current in a scenario where a broken distribution line contacts a grounded pole. Participants explore the implications of capacitance in the system, the role of grounding, and the potential current flow resulting from such a fault condition.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes a model involving capacitance between lines and between lines and ground, questioning if this model is sufficient to calculate fault current.
  • Another participant suggests that fault current would depend on the capacitance of healthy phases with ground and the capacitance of the transformer winding with the grounded tank, indicating that current would be proportional to system voltage.
  • A different scenario is proposed where a monkey on the pole touches a phase, with the participant asserting that the resulting current would again be dependent on various capacitances and likely insignificant.
  • Concerns are raised about the nature of the Earth as a conductor, with one participant recalling a previous assertion that the Earth can handle large currents, which leads to uncertainty about the validity of treating it as a simple conductor.

Areas of Agreement / Disagreement

Participants express uncertainty about the adequacy of the proposed models for calculating fault current. There is no consensus on the significance of the fault current or the implications of grounding and capacitance in the system.

Contextual Notes

Limitations include the assumptions made about the system's grounding and the treatment of the Earth as a conductor. The discussion does not resolve the mathematical implications of the proposed models.

I_am_learning
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Last time I was talking about Isolated Voltage, and some of you people were really helping me about, but I posted (did) something stupid and got the thread deleted.
I am sorry for that.

Now, I want to talk about my confusion in a different (safe) way.
fault.jpg


The above figure shows a distribution line along with a Pole. I understand there exist capacitance between lines (shown in pink) and between lines and ground(shown in green) if we treat the Earth as an infinite equipotential surface (conductor). Also the pole is grounded. But please note that the neutral of Distribution Transformer isn't grounded. Also assume that no grounding is done in any other part of the system.

Now, the question is what happens if one of the lines break and comes in contact with the body of the pole? How much fault current will flow?

Thanks.
 
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The point I am unsure off is, can I calculate the fault current based on above model (capacitances between lines and Between line and earth) only OR I have somthing missing in that model?
If I follow only that model, the fault current will not be significantly large, only the capacitor between the faulted Line and Earth shorts out. The faulted line is still capacitively Isolated from other lines.
Do the circuit breaker trip?
 
in this circuit , fault current would depend on capacitance of healthy phases with ground. capacitance of transformer winding with tank(which would be grounded) will play significant role.

current would be proportional to system voltage. and for low voltage <1kV current would be insignificant.
 
Ok, instead of one of the phase shorting to the pole, If a monkey sitting on the pole touches one of the phase how much (tentative) current will flow?
Its again dependent upon the various capacitances and, I think its magnitude will be insignificant.

The reason I am being not totally sure is because someone here had previously told me that the Earth isn't something to be taken just as a plain conductor. It can sink in huge currents, weather you close the circuit or not! Its actually at 0 potential he said, and that anything that comes between Earth and high potential will be burned down.

I don't have enough reason to agree to that.
 

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