Southeast Wisconsin
Zone 5
Transmission system characteristics in Zone 5
ATC delivers power in Zone 5 with various transmission facilities including:
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The southern portion of 345‑kV lines from Point Beach and Edgewater,
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The Saukville, Arcadian, Granville, Oak Creek and Racine 345/138‑kV substations,
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The transmission lines emanating from the Pleasant Prairie and Oak Creek power plants,
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230‑kV facilities near Milwaukee, and
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A significant 138‑kV network in the Milwaukee area, a portion of which is underground.
Transmission system limitations in Zone 5
Transmission system performance issues in Zone 5 are generally related to heavy market flows from and to the south, resulting in high 345-kV and 138-kV line loadings and the need to monitor potential multiple contingency conditions.
While not specifically identified in the project list for this assessment, ATC’s capital forecast includes the cost of a preliminary alternative needed to address additional constraints identified in the southeast portion of ATC’s system. Potentially, the scope of this project might include additional connections between existing transmission lines in this part of the system.
Electric system overview
Increases expected in population, employment – Population in Zone 5 is projected to grow 0.6 percent annually between now and 2023, and employment is projected to grow 1.1 percent in the same time period. Waukesha County is projected to realize the largest increase in both population and employment.
Electricity usage growing
Peak electric demand typically occurs during the summer months. Large industrial loads in the Milwaukee metropolitan area, including Charter Steel and Miller Brewing, are among the largest electricity users in the zone.
Electric load is projected to grow approximately 0.8percent annually through 2024.
Transmission projects in Zone 5
The most notable planned, proposed and provisional network projects and asset renewal projects in Zone 5, along with their projected year of completion and the factors driving the need for the projects, are listed below.
Zone 5 includes the counties of:
- Kenosha , WI
- Milwaukee , WI
- Ozaukee , WI
- Racine , WI
- Washington , WI
- Waukesha , WI
Zone 5 Planned Projects
| Project Description | In-service year | Need driver |
|---|---|---|
| Milwaukee County T-D 138u2011kV lines | 2015 | T-D interconnection |
Zone 5 Proposed Projects
| Project Description | In-service year | Need driver |
|---|---|---|
| Spring Valley-North Lake Geneva 138u2011kV line construction | 2019 | Overloads and low voltages,nprovide network service |
Zone 5 Provisional Projects
| Project Description | In-service year | Need driver |
|---|---|---|
| None |
Zone 5 Asset Renewal Projects
| Project Description | In-service year | Need driver |
|---|---|---|
| Concord-Cooney 138u2011kV line rebuild (portion of Quad Counties project) | 2015 | Condition and performance |
| Merrill Hills-Summit 138u2011kV line partial rebuild (portion of Quad Counties project) | 2015 | Condition and performance |
| Paris-Albers 138u2011kV line rebuild | 2015 | Condition and performance |
| Waukesha u2013 Merrill Hills 138-kV line partial rebuild (portion of Quad Counties project) | 2016 | Condition and performance |
| St. Lawrence-Hartford 138u2011kV line rebuild (portion of Quad Counties project) | 2016 | Condition and performance |
| Mukwonago-Edgewood-St. Martins 138u2011kV line rebuild | 2017 | Condition and performance |