## How does Simulator convert transmission line flow between MVA and Amps?

Variables that are calculated by a power flow are the MVA flow leaving a bus along a transmission line and the bus voltage.

-The MVA flow is the total MVA flow on all three phases of the transmission line (S

_{3-ø}).

-The voltage is the line-to-line voltage (V_{line-line})

Current is only defined for a single phase, so in order to determine the single phase current, solve

S

_{1-ø}= V_{line-nuetral}* I (where I = current)

To convert the values the power flow calculates to the ones in this equation, do the following

S

_{1-ø}= S_{3-ø}/ 3

V_{line-nuetral}= V_{line-}_{line }/ sqrt(3)

Thus we can write

S

_{3-ø}/ 3 = V_{line-line}/ sqrt(3) * I

Which simplifies to the equation used to determine the current on a transmission line

I = S

_{3-ø }/ ( sqrt(3)* V_{line-line})

Note: The same equation is true for a transformer.

July 5, 2012