Two bus system analysis

Sim Lab1: Transmission Line 1. Build the power system shown in Figure 1 using the data in the Bus and branch tables

which are given below.

2. Show on the one-line diagram all parameters: bus voltages (both magnitude in per unit

and angels), line flows (both numerical values on both ends of the line and symbolical

by means of arrows) for real and reactive power.

3. Simulate the circuit and observe the values on the one-line diagram and:

a. Explain whether the line flows are as you would expect them (direction and

magnitude of P & Q). Give reasons for your answer.

b. Describe the size of the arrows as they propagate from the Bus 1 to Bus 2 or vice

versa.

4. Graph (record the change in voltage as you vary the load from 0 to 1000 MW) the load

bus voltage magnitude and angle as a function of load real power (assuming unity power

factor at the load). Change the load in steps of 50 MW.

a. Describe the changes you observe.

b. Why does the reactive power flow in the line change despite the load being unity

power factor?

c. Why do you think the arrows that represent reactive power flow diminish as they

get closer to the load end?

5. Increase the load reactive power from 0 to 500 MVArs in steps of 25 MVArs (assume

the load real power remains fixed at the rated value of 500 MW) and plot graph of load

voltage and angle versus load reactive power.

a. Describe the changes you observe.

b. How does your observation differ from that in (4(a)) above?

Figure 1: Two bus power system

Table 1: Bus data

Bus

Number Name Nom kV PU Volt Volt (kV)

Angle (Deg)

Load MW

Load Mvar

Gen MW

Gen Mvar

1 1 138 1 138 0 1000

2 2 138 500

Table 2: Branch Data with MVA Base of 500.

Branch Branch Device Type

From Bus To Bus Line Xfrmr R X B

Lim MVA

1 2 Yes NO 0.02 0.08 0.8 1000