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:

  • Columbia-North Madison 345‑kV lines,
  • Columbia-Rockdale 345‑kV line,
  • Paddock-Rockdale 345‑kV line,
  • Paddock-Wempletown 345‑kV line,
  • Rockdale-Wempletown 345‑kV line
  • Rockdale-Cardinal 345-kV line, and
  • 138‑kV facilities from the Nelson Dewey Power Plant, 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 2024, and employment is projected to grow about 1.4 percent each year for the same time period. Dane County is projected to realize the largest increase in population and employment

Electricity usage growing

Electric load is expected to grow approximately 1.0 percent annually through 2025.

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
[table “10” not found /]

Zone 3 Proposed Projects

Project DescriptionIn-service yearNeed driver
Cardinal-Hickory Creek 2020Reliability, economics and public policy

Zone 3 Provisional Projects

Project DescriptionIn-service yearNeed driver
Cardinal-Blount 138‑kV line construction2029Overloads and low voltages
[table “13” not found /]
Related Resources