Refer to Table ZS-4 and Figure ZS-16

Summary of key findings

• Load growth in the Sheboygan and northern Ozaukee Counties may drive the need for system reinforcements.
• Additional reinforcements may be needed due to the load growth in the Appleton area.
• Additional reinforcements may be needed due to load growth in central Kewaunee County.

Transmission reinforcements appear to be needed in the Sheboygan, Kewaunee, and Green Bay areas. The reinforcements listed below are based upon our preliminary analysis to address system problems under single-contingency conditions. Further adjustments will be made to reflect needs as well as in-service dates in the upcoming 2009 10-year Assessment.

• Between 2019 and 2023, additional transmission reinforcements such as installing capacitor banks may be needed to boost the voltages at the Holland, Plymouth #4 and Howards Grove 138-kV substations under single contingency conditions.
• Heavy flows on the 138-kV lines around the City Limits 138-kV Substation may occur under single-contingency conditions. The City Limits-Maes 138-kV line ratings are currently under review. A detailed study will be performed with the updated/validated line ratings during the 2009 10-Year Assessment to identify the need year of this project. Constructing a second North Appleton-Apple Hills 138-kV line could be one of alternatives studied to address the heavy flow issues.
• Uprating the Edgewater-Washington 69-kV line may be needed in the 2022 timeframe to address line overloads under single-contingency conditions.
• Additional transmission reinforcements such as adding a second 138/69-kV transformer at the East Krok Substation may be needed in the 2024 timeframe to boost voltages at the 69-kV substations along line J-10 under single-contingency conditions.
• Additional transmission reinforcements such as rebuilding the existing Oak Street-Ashland 69-kV line may be needed in the 2023 timeframe to address line overloads under single-contingency conditions.

With the Kewaunee bus reconfiguration and the addition of a second 345/138-kV transformer project expected to be in-service by 2011, the next equipment limiting the generation at the Kewaunee Nuclear Power Plant under certain transmission outage conditions is the Kewaunee-East Krok 138-kV line. If additional generation from Kewaunee is desired, transmission reinforcements such as uprating the Kewaunee-East Krok 138-kV line will be required.

Summary of Compliance with NERC Standards

The mitigation plans, planned, proposed and provisional projects identified for Zone 4 in this Assessment will allow the ATC system in Zone 4 to meet NERC standards TPL-001, TPL-002, TPL-003 and TPL-004 in each of the four years 2009-2013, and for the 2014-2018 planning horizon.