I have a single machine connected to an infinite bus with the following parameters:(adsbygoogle = window.adsbygoogle || []).push({});

- Sending end power = 3.75MW

- RL=5.18 ohms

- XL=130 ohms

- VS (Generator bus)=161kV

- VR (Infinite bus)=161kV

- Sending end voltage angle (delta) = 0.01877 (Angle which allows 3.75MW to be transferred)

Using these I want to calculate the amount of reactive power sent by the sending end as well.

I calculated it first without factoring in the line resistance (RL=0) Then got the result for Q as : **35.24kVAR**

Next I calculated it with the line resistance factored in Then got the result for Q as: **-114.77kVAR**

When the line resistance is factored in, the answers for reactive power vary immensely. And when the resistance is factored in, the sign of Q is negative indicating the generator bus is absorbing VARS which doesn't seem to make sense.

Why are they so different? What am I doing wrong?

The equations I used are here

I derived these equations using Matlab to do the algebra, so it hopefully should be correct :)

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Calculating the reactive power of a transmission line

Have something to add?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**