South Central/Southwest Wisconsin and North Central Illinois
Zone 3
Transmission system characteristics in Zone 3
ATC delivers power in Zone 3 with various transmission facilities including:
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Columbia-North Madison 345‑kV lines,
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Columbia-Rockdale 345‑kV line,
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Paddock-Rockdale 345‑kV line,
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Paddock-Wempletown 345‑kV line,
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Rockdale-Wempletown 345‑kV line
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Rockdale-Cardinal 345-kV line, and
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138‑kV facilities from Nelson Dewey, around the Madison area, and in the northwest and southeast portions of Zone 3.
Transmission system limitations in Zone 3
In our analysis of Zone 3, we identified low voltages, high voltages and transmission-facility overloads. Low voltages are located in the Verona, Lake Geneva and Hustisford areas. Several overloads on 138-kV and 69-kV facilities in Zone 3 are emerging concerns. The causes of these emerging issues include steady growth in certain areas, power plant retirement and different generation dispatch scenarios.
Electric system overview
Increases expected in population, employment Population in Zone 3 is projected to grow about 0.9 percent annually between now and 2025, and employment is projected to grow about 1.3 percent each year for the same time period. Dane County is projected to realize the largest increase in population and employment. Dane County also is projected to have the highest growth rate in population while Dodge County is projected to have the highest growth rate in employment.
Electricity usage growing
Electric load is expected to grow approximately 1.1 percent annually through 2026.
Transmission projects in Zone 3
The most notable planned, proposed and provisional network projects and asset-renewal projects in Zone 3, along with their projected year of completion and the factors driving the need for the projects, are listed below.
Zone 3 includes the counties of:
- Columbia , WI
- Crawford (S) , WI
- Dane , WI
- Dodge , WI
- Grant , WI
- Green , WI
- Iowa , WI
- Jefferson , WI
- Lafayette , WI
- Richland , WI
- Rock , WI
- Sauk , WI
- Walworth , WI
- Winnebago (N) , IL
Zone 3 Planned Projects
| Project Description | In-service year | Need driver |
|---|---|---|
| Dam Heights - Portage 69-kV line rebuild | 2017 | Condition and performance |
| Kegonsa - Sun Prairie 69-kV line partial rebuild | 2017 | Condition and performance |
| Colley Road - Brick Church 69-kV line | 2018 | Overloads, low voltages and condition |
| Badger Coulee: Briggs Rd - North Madison - Cardinal 345‑kV line construction | 2018 | Reliability, economics and public policy |
| Spring Valley - North Lake Geneva 138‑kV line | 2019 | Overloads and low voltages, provide network service |
| Boscobel - Lone Rock 69-kV line rebuild | 2019 | Condition and performance |
| Portage - Staff - North Randolph 138-kV line rebuild | 2019 | Condition and performance |
| Dane - Waunakee 69-kV line rebuild | 2020 | Condition and performance |
Zone 3 Proposed Projects
| Project Description | In-service year | Need driver |
|---|---|---|
| Cardinal - Hickory Creek | 2023 | Reliability, economics and public policy |
Zone 3 Provisional Projects
| Project Description | In-service year | Need driver |
|---|---|---|
| Cardinal - Blount 138‑kV line construction | 2029 | Overloads and low voltages |