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Studies and Reports > 2009 MN Biennial Report > TC Planning Zone > Needs: 6.5.9 Twin Cities Fault Current Issue

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Transmission Projects Report 2009
Section 6.5: Twin Cities Zone
p. 197

6.5.9 Twin Cities Fault Current Issue

Tracking Number. 2005-TC-N7

Utility. Xcel Energy and Great River Energy

Inadequacy. General fault current levels on the system in the Twin Cities are increasing as transmission lines and generation are added to the transmission system. The grounding capability in the inner Twin Cities substations may be exceeded as loads continue to increase. At present there is no immediate need to address this concern. As transmission and generation facilities are added to the transmission grid, planning engineers will continue to monitor the fault currents that will result. When a potential problem is detected, a specific study will be launched to address the need.

A map of the area is shown on the following page.

Alternatives. Sectionalizing the system may be needed to decrease the fault current levels, but no alternatives have been identified or evaluated.

Analysis. These issues have not yet been evaluated at this early stage of the planning process. Until possible solutions are identified, it is not possible to determine the possible environmental impacts.

Schedule. Since the 2007 Biennial Transmission Projects Report was submitted two years ago, no specific needs for fault current mitigation have been identified, though fault current levels at some substations continue to creep closer to their limits. This issue continues to be monitored and will be addressed as needs are identified.


Transmission Projects Report 2009
Section 6.5: Twin Cities Zone
p. 198

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