Studies and Reports > 2009 MN Biennial Report > NE Planning Zone > Needs: 6.3.20 Park Rapids Area

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6.3.20 Park Rapids Area

Tracking Number: 2009-NE-N7

Utility: Great River Energy

Inadequacy: The 34.5 kV system that serves the Park Rapids area is rapidly becoming inadequate to serve the projected system loadings as voltage support on contingency is deteriorating. The GRE member co-op substations around the Park Rapids area have experienced some of the largest growth on the GRE system over the past five years and many are on long, radial lines. Itasca-Mantrap Cooperative Electrical Association is also projecting the need for a new Potato Lake Substation in 2011.

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

Alternatives. Options include conversion of the Itasca-Mantrap substations to looped 69 kV or 115 kV service between the Long Lake and Hubbard substations or installation of distributed generation facilities.

Analysis. Due to the radial nature of the Itasca-Mantrap substation feeds, generation may offer a good solution provided the generation is sized to accommodate future load growth. However, given the high growth rates and limited transmission outlet, siting large amounts of generation on these radial lines may have limited benefit.

Transmission solutions are also very attractive as they have the ability to provide redundant transmission to the Itasca-Mantrap substations and can be sized to accommodate future growth. 115 kV transmission would be better-suited for the area as this is the area’s predominant transmission voltage and offers lower system losses than a 69 kV solution. A 69 kV system would require two new 69 kV switchyards with new transformers whereas only simple modifications at existing switchyards would be required for any 115 kV solution. Any transmission solution would require a relocation of the Hubbard 115/34.5 kV transformers as there are space limitations within the substation. Furthermore, any 115 kV solutions would require Certification from the PUC as the project would be over 10 miles in length. The transmission for the Potato Lake Substation will be constructed to 115 kV standards to accommodate any future conversion that may take place.

Schedule. GRE will continue to monitor load growth to see what solution is appropriate. Right-of-way activities are ongoing for interconnecting the Potato Lake Substation to the system. Based on the 2008 GRE Long-Range Plan, a transmission solution would be constructed in stages, with voltage conversions of the Mantrap and Potato Lake substations as soon as 2013. A full transmission loop project would likely not be completed until around 2020. Generation solutions would be sited as required.

Click here or on map below to download high resolution PDF map.