DESIGN PROJECT: A NEW WIND FARM
You’ve just been hired as new power engineers with Kyle and Weber Wind (KWW), one of the
country’s leading wind energy developers. KWW has identified the rolling hills to the northwest of the
Metropolis urban area as an ideal location for a new 200 MW wind farm. The local utility, Metropolis
Light and Power (MLP), seems amenable to this new generation development taking place within their
service territory. However, they are also quite adamant that any of the costs associated with
transmission system upgrades necessary to site this new generation be funded by KWW. Therefore, your
supervisor at KWW has requested that you do a preliminary transmission planning assessment to
determine the least cost design.
Hence, your job is to make recommendations on the least cost design for the construction of new
lines and transformers to ensure that the transmission system in the MLP system is adequate for any
base case or first contingency loading situation when the KWW wind farm is installed and operating at
its maximum output of 200 MW. Since the wind farm will be built with Type 3 DFAG wind turbines, you
can model the wind farm in the power flow as a single, equivalent traditional PV bus generator with an
output of 200 MW, a voltage setpoint of 1.05 per unit, and with reactive power limits of ±100 Mvar. In
keeping with KWW tradition, the wind interconnection point will be at 69 kV, and for reliability purposes
your supervisor requests that there be at least two separate feeds into the interconnection
The following shows the available right-of-way distances for the construction of new 69 kV and/or
new 138 kV lines. All existing 69 kV only substations are large enough to accommodate 138 kV as well.
1. Load DesignCase1 into PowerWorld Simulator. This case contains the initial system power flow case,
and the disconnected KWW generator and its interconnection bus. Perform an initial power-flow
solution to determine the initial system operating point. From this solution you should find that all
the line flows and bus voltage magnitudes are within their limits. Assume all line MVA flows must be
at or below 100% of their limit values, and all voltages must be between 0.95 and 1.10 per unit.
2. Repeat the above analysis considering the impact of any single transmission line or transformer
outage. This is known as n-1 contingency analysis. To simplify this analysis, PowerWorld Simulator
has the ability to automatically perform a contingency analysis study. Select Tools, Contingency
Analysis to show the Contingency Analysis display. Note that the 57 single line/transformer
contingencies are already defined. Select Start Run (toward the bottom right corner of the display)
to automatically see the impact of removing any single element. Without the KWW generation the
system has no contingency (n-1) violations.
3. Using the available rights-of-ways and the transmission line parameters/costs given in the table,
iteratively determine the least expensive system additions so that the base case and all the
contingences result in reliable operation points with the KWW generation connected with an output
of 200 MW. The parameters of the new transmission lines(s) need to be derived using the tower
configurations and conductor types determined by your team. In addition, the transmission changes
you propose will modify the total system losses, indicated by the yellow field on the one-line. While
the system losses are not KWW’s responsibility, your supervisor has asked you to consider the
impact your design changes will have on the total system losses assuming the system operates in
the studied condition for the next five years. Hence, you should minimize the total construction
costs minus the savings associated with any decrease in system losses over the next five years.