Short and Medium Transmission Lines

The purpose of this lab was to examine the characteristics of a short transmission line by looking at a simple circuit model of a short line, and to examine the characteristics of a medium transmission line by looking at a simple circuit model of a medium line. In the first step, we placed a 300 Q resistor in parallel with a 300 Ј1 inductor for the load, set the transmission line impedance to 60 Q, and set Vs = 200 V. Next we removed the load and found the no load measurements. For the next step, we reconnected the load and inserted the phase angle meter to measure the angle of the sending end voltage with respect to the receiving end voltage. For step five, we used the same load, but this time we set the impedance of the transmission line to 120 Q and added a shunt capacitance of 300 Q. Next, we removed the load to find the no load measurements. Then, we reconnected the load and inserted the phase angle meter to find the same values as before. We then removed the phase angle meter and inserted the watt/VARmeter to find the complex power.

Quantity Value Units

P3Φ 40 Watts

Q3Φ 250 VAR

The real power creates torque while the reactive power induces a magnetic field. The power factor is cos (80.91˚) =0.158.

CONCLUSIONS

The 3Φ power system is a complicated network of devices which requires understanding