Zero Load Current??

[eamonkerrigan]

Hello,
I'm new to the forum and I think I have an easy question to start out with.

I can usually take my questions straight to the horses mouth but in this case I am working on a project in Saudi Arabia and communicating back and forth doesn't seem to work too well.

I'm working on an AC interference study on a proposed pipeline. My induced steady state voltages are dependent on the load current from the nearby transmission line. The data I was given is that the "load current" equals zero and the "line power carrying capacity" equals 200 MVA.

I have ignored the load current thing and calculated the current myself from the MVA rating.
200 MVA = 1,000 Amps (115 kV power line)

I just don't know if I'm out of line here. Where does this zero load current come from? Is it unreasonable to use this 200 MVA to calculate line load?

I was also given X and R values (R = 0.0244 X=0.0352) but I thought this would only concern short circuit scenarios.

I appreciate all your help. Thanks

 

[wareagle]

AS Posted "The data I was given is that the "load current" equals zero and the "line power carrying capacity" equals 200 MVA.I have ignored the load current thing and calculated the current myself from the MVA rating.200 MVA = 1,000 Amps (115 kV power line)"

The fact that the line has a capacity of 200 MVA(1000 amps)
does not mean that the load is 1000 amps. If you have no load connected the line current is zero if the capacitive
effects are ignored.

 

[eamonkerrigan]

wareagle

I realize that if there is no load than no current will be flowing, but I am looking for worst case effects here. Therefore I'm trying to assume maximum load current. I just want to be sure that maximum current capacity is the same as maximum load current. Does this transfer directly or am I missing a calculation in between?

 

[jghrist]

Your calculation of maximum current capacity is correct. You should also consider fault currents in the interference study if short time induced voltages are a concern.

 

[eamonkerrigan]

Thanks for the info guys. At first it just seemed too simple but I needed to be sure.