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

In summary: I am sorry if I have not been clear. If something comes in contact with the Earth, there is a chance that it could cause some sort of short. However, the current that would flow would be very small.
  • #1
I_am_learning
682
16
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.
 
Engineering news on Phys.org
  • #2
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?
 
  • #3
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.
 
  • #4
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.
 

1. What is fault current calculation?

Fault current calculation is the process of determining the amount of current that would flow through an electrical system in the event of a fault or short circuit. It is an important aspect of electrical system design and safety.

2. Why is fault current calculation important?

Fault current calculation is important because it helps engineers and electricians design and select the appropriate equipment and protective devices for an electrical system. It also ensures the safety of the system and prevents any potential damage or hazards from excessive current flow.

3. What factors affect the fault current calculation?

The fault current calculation is influenced by several factors, including the system voltage, the impedance of the power source, the impedance of the system components, and the type and location of the fault.

4. How is fault current calculated?

Fault current is calculated using Ohm's Law, which states that current is equal to voltage divided by resistance. The system voltage is divided by the total impedance of the system to determine the fault current.

5. Are there any industry standards for fault current calculation?

Yes, there are industry standards and guidelines, such as the National Electrical Code (NEC) and the Institute of Electrical and Electronics Engineers (IEEE) standards, that provide guidance for calculating fault current and selecting appropriate protective devices for electrical systems.

Similar threads

Replies
6
Views
3K
  • Electrical Engineering
Replies
33
Views
559
Replies
6
Views
1K
Replies
2
Views
635
  • Electrical Engineering
Replies
1
Views
4K
Replies
4
Views
4K
  • Electrical Engineering
Replies
1
Views
2K
Replies
8
Views
6K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
3K
  • Electrical Engineering
Replies
10
Views
6K
Back
Top