Legalectric

Citizens Utility Board has filed with WI’s Public Service Commission, saying the design of the Arrowhead-Weston Transmission Line is flawed. Yeah… your point???

From today’s St.PPP:

Group alleges flaws in powerline
But transmission company says complaint is old, has no merit

Associated Press

MADISON â?? A utility watchdog group asked state regulators Tuesday to investigate what it says are serious flaws in the design of a high-voltage transmission line under construction between Wausau and Duluth, Minn.

In a worst-case scenario, a failure with the line could lead to a cascade of outages and possible damage to power plants, said Charlie Higley, executive director of the Citizens Utility Board.

But Mark Williamson, vice president of Pewaukee-based American Transmission Co., said the group’s concerns are unfounded and based on a “flawed” analysis that already has been investigated.

American Transmission will own and operate the $420 million line, being built by Wisconsin Public Service Corp., when it is brought into service in 2008.

In a letter delivered to each company, the citizens’ group said engineering mistakes mean the 345-kilovolt Arrowhead-Weston power line is undersized in capacity.

“The Arrowhead line will likely not work when it’s most needed,” Higley said. “And that’s when it’s helping support other transmission lines in the region while power is flowing heavily. That’s when the line is most vulnerable.”

Linda Barth, a spokeswoman for the state Public Service Commission, said the regulatory agency is looking at the issues raised in the group’s letter.

“But that said, this line has been approved twice and we’re confident in the exhaustive process we used in approving the Arrowhead-Weston line,” she said. “It was a sound and thorough decision.”

The Citizens Utility Board raised its concerns following an in-depth analysis by Larry Thiele, an independent consulting electrical engineer. The board hired Thiele in 2003 to provide expert testimony regarding the line’s design.

Thiele’s analysis concluded the line would fail if an outage occurred on the King-Eau Claire-Arpin transmission line, the only high-capacity line connecting Wisconsin directly to Minnesota. The failure would cause transmission lines to carry too much power and could damage power plants and lead to blackouts, Thiele concluded.

Williamson said those concerns had already been investigated and dismissed.

“This is the third time that the same complaint has been raised and there’s just no merit to it,” he said.

He said the purpose of the Arrowhead line was to strengthen the system by providing redundancy and protection for the power grid â?? solving the very problems Thiele says would threaten it.

Here’s the CUB Request for Investigation: Download file

Essentially, they’re saying that the Arrowhead line is unstable because the capacity is too low. But it seems to me they’re not taking into account the old news of the EQB’s design requirement of a capacity limitation of 800MVA through the phase shifting transformer. Here’s the MPCA Commissioner’s Memorandum to the EQB that resulted in the limitation: Download file

Mesaba Interconnection

Through all of this though, no one’s paying any attention to the impact of Mesaba on Arrowhead. Originally they were planning on connecting to Blackberry and from there going to the Forbes sub and out over Arrowhead — thankfully that is not now in the plans (it seems). Now it’s going from Blackberry to the Riverton sub. The MISO interconnection study, G519, has just been released:
MISO System Interconnection Study G519

The Conclusion of the study states that:

Under high off peak transfer conditions G519 aggravates voltage problems at 230kV, 161kV and 115kV buses around Arrowhead and Stone Lake. (Ch. 7, p. 7-1)

Going to the horse’s mouth, it says:

Transient voltage violations are attributed to the G51 project. HOwever, Table 5-2 shows that in the G519 study model the Forbes-Chisago 500kV line (F601C) is overloaded and Arrowhead-Weston is loaded above its expected operating limit of 650MW. Sensitivity analysis, presented in Section 6, was performed to verify the potential constraints with flows on F601C and Arrowhead-Weston within limits. (Ch. 5, p. 5-7)

The MISO study found that the connection of Mesaba adds to stability problems, and the modeling assumes the line is operating at above the stated capacity, above the limits, but below the phase shifting transformer limits.

More on what it means for Mesaba, but the bottom line is that Excelsior will have to have “someone” (because heaving forbid they would be responsible for their own infrastructure) make the following associated transmission system upgrades:

1) Add new 230kV line from Boswell to Riverton
2) New 230kV bus position for Boswell-Riverton line at Boswell
3) New 230kV bus position for Boswell-riverton line at Riverton
4) New 230kV subsation at Hill City
5) Replace 4 115kV circuit breakers at Nashwauk

Corresponding costs:
1) $45 million
2) $1.9 million
3) $1.7 million
4) $3.5 million
5) $720,000

TOTAL NECESSARY MESABA UPGRADES: $52.82 million

And remember, this does not include the direct interconnection costs from the plant to the Blackberry sub… and I think those costs are grossly underestimated.

Lots more on this topic later!