ECE-476: Fall 2008
HOMEWORK #7
Due Date: Thursday October 30, 2008
Problems 6.46, 6.49, 6.52, 11.19, 11.21 and 11.27 of Power System Analysis and Design
textbook
6.46) Use PowerWorld Simulator to modify the Example 6.9 case by inserting a second line
between bus 2 and bus 5. Give the new line a circuit identifier of “2” to distinguish it
from the existing line. The line parameters of the added line should be identical to those
of the existing line 2-5. Determine the new line’s effect on V2, the line loadings, and on
the total real power losses.
6.49) Open PowerWorld Simulator case Example 6_13. As in Example 6.13, remove the
TIM69 to HANNAH69 line. Determine the Mvar rating of the shunt capacitor bank at
Bus HANNAH69 necessary to correct the HANNAH69 voltage back to 0.96 per unit.
Use <ctrl> up arrow to zoom the one-line to better see the one-line values.
6.52) Open PowerWorld Simulator case Example 6_13. Sequentially open (remove from
service) each of the case’s twelve 138 kV transmission lines (always closing the previous
device). Record the impact each outage has on system losses. Which device has the
largest impact on system losses?
11.19) An area of an interconnected power system has two fossil-fuel units operating on
economic dispatch. The variable operating costs of these units are given by:
hr
PC
MWPfor
hr
P
MWPforPP
C
$
03.0
1001
$
8
1001002.04
2
22
1
2
11
1
=
⎪
⎩
⎪
⎨
⎧
>
≤<+
=
where P1 and P2 are in megawatts. Determine the power output of each unit, the
incremental operating cost, and the total cost CT that minimizes CT as the load demand PT
varies from 200 to 700 MW. Generating-unit inequalities and transmission losses are
neglected.
11.21) Rework Problem 11.19 if total transmission losses for the power system are given by:
MWPPPL2
2
42
1
4101102 −− ×+×=
