Xcel Energy Smaller
Scale Transmission
Projects
Northern MAPP Subregional
Planning Group
April 3, 2007
Srinivas Vemuri, Jason Standing,
and Daniel Kline
Small Project Information
T-Corners Transformer Replacement
Hyland Lake – Dean Lake 115 kV Upgrade
Woodbury – Tanners Lake Upgrade
Northeast Mankato 69 kV Plan
South Shakopee Substation
Ironwood Second Transformer
Ironwood Bus Upgrade
Lawrence Second Transformer
Tracy Switching Station Capacitors
Keegan Lake – Lebanon Hills
Prescott 10 MVAR Cap Bank
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T-Corners 115/69 kV
Transformer Replacement
Substation currently has two 115/69 kV
transformers (#1 & #2)
Tx #1 – 62.5 MVA
 Tx #2 – 112 MVA

Summer 2011 – Loss of Transformer #2 will
load #1 to 80 MVA (128%)
Plan to replace existing 62.5 MVA bank
with matching 112 MVA bank
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T-Corners 115/69 kV
Transformer Replacement
T-Corners
52 Miles
Eau Claire
Metro Area
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Ironwood Second
Transformer
Ironwood 88/34.5 kV Transformer currently rated
at 25 MVA
78 MW generation at Bayfront Substation
Loss of Bayfront 115/92 kV transformer sends
Bayfront generation through 88 & 34.5 kV systems


Severely overloads Ironwood – Bayfront 88 kV line
Severely low voltages along Ironwood 34.5 kV system
Add second Ironwood 88/34.5 kV transformer
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Ironwood Second
Transformer
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Ironwood Terminal
Equipment Upgrade
Ironwood – Bayfront 115 kV conductor rated at 189
MVA (850 Amps)
Ironwood 115 kV substation equipment with
various ratintgs




200 Amp CT
300 Amp Wave Trap
380 Amp Bus
400 & 800 Amp Breakers, 600 Amp Switches
Outage of Bayfront – Saxon Pump 88 kV line loads
Ironwood 115 kV to 72 MVA (361 Amps)
Outage of Bayfront 115/92 kV transformer loads
Ironwood 115 kV to 87 MVA (437 Amps)
Replace capacity-limiting terminal equipment
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Lawrence Second 112 MVA
Transformer
This project is to add an additional 115/69
kV, 112 MVA transformer at the Lawrence
Substation in Sioux Falls. This is needed
due to the double-circuit outage of the 115
kV line out of Split Rock to Cheery Creek.
In Summer 2011, loss of Split Rock-Cherry
Creek and Split Rock-West Sioux Falls
double-circuit outage results in a loading
of 145.9 MVA (130.2%) of the 112 MVA
transformer at Lawrence.
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Lawrence Second 112 MVA
Transformer
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Tracy SW 12 MVAR CAP
 This project is to replace the existing 5.4 MVAR, 69 kV cap
bank at the Tracy Switching Station with a new 12 MVAR cap
bank.
 In Summer 2006, for loss of the Lyon County 69 kV source,
the following buses have low voltage:
Walnut Grove = 0.855 pu
Tracy SS = 0.856 pu
Lake Sarah = 0.860 pu
Currie = 0.872 pu
Slayton = 0.886 pu
Hadley = 0.898 pu
Lake Wilson = 0.905 pu
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Tracy SW 12 MVAR CAP
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Kegan Lake – Lebanon Hills
69 kV Line Upgrade
Reconductor the 3 #8 CU section of the
Kegan Lake – Lebanon Hills 69 kV line to at
least 48 MVA.
During 2011 summer peak conditions, the
line overloads to 110.5% in the base case.
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Kegan Lake – Lebanon Hills
69 kV Line Upgrade
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