N.L. Hydro optimistic link to island will work

To say last Thursday’s failed tests of the Labrador-island Link (LIL) at a high power flow — which temporarily knocked out power to 58,000 customers — was disappointing may be an understatement at Newfoundland and Labrador Hydro.

Success of that testing would have moved the LIL closer to final commissioning.

It’s taken a long time even to get to this point.

The Muskrat Falls hydroelectric generating station was announced as complete and ready for service in November 2021. The Labrador-island Link hasn’t been able to transfer sustained high levels of power from the generating station to the island, mostly due to nagging and ongoing issues with its custom operating software.

But even with last week’s setback there is optimism at Hydro that the finish line is finally in sight, says Rob Collett, Hydro’s vice-president of engineering and NL system operator.

“This is a tremendously important issue for all Newfoundland and Labrador. For a long time a lot has gone wrong with the LIL, but I think we should have a sense of optimism about it. I think the fact we have proven this link can operate up to 500 megawatts so far is a huge benefit. It allows us to displace a significant amount of fuel at Holyrood (Thermal Generating Station),” Collett said, addressing questions from media.

“We are steadily progressing. It has not all been straightforward. We experienced (Thursday’s) issue and it was significant and as a result we had an appreciable disturbance to a large number of customers, and we absolutely regret that.

“But these tests are necessary, and these tests allow us to find these types of bugs, or issues or protection settings, that need to be adjusted. These tests are how it happens, with everyone at the ready, all battle stations manned. And it’s only through the successful completion of these tests that we can ensure reliable operation.

“I know there’s been a lot of pessimism for a long time about this link, but I think we have reason to be optimistic. We are crawling our way out of the trench on this, and we are going to slip backwards from time to time, but we are closer to the finish line than we’ve ever been and with the successful completion of these final tests we can call this thing commissioned, so we absolutely have reason to be optimistic. There are people who have been working on this a long time who are expressing a hope that we are absolutely going to get there.”

The Labrador-island Link is 1,100-kilometres long. It is a bipole transmission line in which electricity can be delivered over one of two lines, or both at once. It has the capability to carry up to 900 megawatts.

Tests in October saw the system working well at loads up to 500 megawatts.

Last Thursday, Nov. 24, during testing, Hydro loaded the Labrador-island Link up to 700 megawatts of power from Muskrat Falls.

One of the two wires was intentionally tripped. The system worked fine for about 45 seconds with one wire carrying the load — as it was designed to do — but then the protection systems kicked in and shut the line down.

Collett said what went wrong during the tests is being investigated.

“This could have been a sensor issue, an equipment issue, this could have been a software issue,” he said. “Our experts are going through the exact sequence of events looking at exactly what tripped and why, and what were the events that caused it.

“And going forward we will review this issue, to understand it and to solve it, and to be able to perform these tests again. And with these tests complete we can finally commission the LIL.”