General Notice to PSCO OASIS Users

General Notice to MISO OASIS Users NSP/NSPW 345 kV Insulator Replacement Project February 20, 2004

Xcel Energy is planning to replace polymer insulators on approximately 120 transmission structures along three 345 kV lines on the NSP and NSP-Wisconsin transmission systems starting on March 15, 2004 and ending April 10, 2004. The insulator replacement project will require scheduled outages of the King/Eau Claire/Rocky Run 345 kV line and the Prairie Island/Pleasant Valley 345 kV line. The tentative outage schedule is shown below.

Background

In the past four years we have experienced insulator failures that caused four trips of the 345 kV line between the A.S. King generating plant and Rocky Run, including two failures within the past month. To minimize the potential for a future insulator failure to affect the availability or reliability of the 345 kV lines during the upcoming 2004 Summer Season, we’re replacing insulators on the King/Eau Claire/Rocky Run and Prairie Island to Pleasant Valley 345 kV transmission lines.

The affected lines are: . An 84-mile section from the Allen S. King plant in Oak Park Heights, Minnesota to Eau Claire, Wisconsin. . A 100-mile section from Eau Claire to Rocky Run substation located south and east of Stevens Point, Wisconsin . A 76-mile section from the Prairie Island plant near Red Wing, Minnesota, south to the Iowa border

Outage Schedule

The insulator replacement project is being coordinated through the Midwest ISO outage scheduler so the transmission line outages required to perform the insulator replacement are scheduled consistent with regional reliability requirements.

The specific transmission line section outages for the insulator replacement project are tentative and are being confirmed with MISO and neighboring utilities to avoid conflicts with planned or ongoing outages of lower voltage (below 100 kV) systems, particularly on the ATCo system. The following are the line sections with their tentative outage dates.

Line number 3102 Arpin – Rocky Run 3/15/04 to 3/19/04 Line number 3102 Eau Claire – Arpin 3/19/04 to 3/29/04 Line number 3101 A.S. King – Eau Claire 3/28/04 to 4/1/04 Line number 0979 Prairie Island – Byron 4/2/04 to 4/6/04 Line number 0979 Byron – Pleasant Valley 4/6/04 to 4/10/04

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When finalized, the specific outages and dates will be reflected in the MISO outage scheduler. OASIS users that may be affected by the outage of a specific line should periodically consult the MISO outage scheduler system for the most up to date information.

Notice of Facilities Returning to Service

Once the replacement insulator field work is complete, the field crews will contact Xcel Energy’s Transmission dispatch center and convey their release of the line. When Xcel Energy - Transmission determines the facility can safely be returned to full service, Xcel Energy - Transmission or MISO will post a notice of the system change on OASIS.

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