A Powerful Highway of Lines

Two linemen repairing a junction box in the dirt on the side of a road.
NLI linemen Bill Murray, left, and Marc Hull repair a junction box. Power was rerouted to prevent an extended outage.

The electricity grid is an incredibly complex and important system, and an impressive engineering feat.

The grid is a large, interconnected system of generators, substations, and distribution and transmission lines that require a coordinated and balanced effort among utilities to make it all work.

Think of the transmission system—the big poles and towers—as being like an interstate or freeway. There are limited on and off ramps (substations) and they are generally meant for long-distance and heavy traffic (more kilowatts).

The distribution system is like county roads, neighborhood streets, and side roads. If NLI needs to perform maintenance, or has an unplanned outage that may cause an extended power outage, sometimes we can provide a “detour” for your power.

For example, we may need to de-energize one of our substations to perform scheduled work. If there are other substations in the area that serve power lines with the same voltage we may be able to switch service to that substation.

Many times, we may need to switch lines to more than one substation to have enough capacity to serve all our members’ power needs.

When NLI needs to do such switching, an order is written and reviewed using our system maps. It is possible to have switching orders with 30 to 40 steps. It can take 2 to 3 hours for NLI linemen to complete switching in the field.

Switching can be complex and time-consuming, so this is not something we immediately use for unplanned outages. Extending one section of line to isolate a problem may be a simple fix. However, repairing the problem that caused an outage may be quicker than switching to a different substation.

When we have extended planned or unplanned work, or we are waiting for materials to arrive, we will look to provide a detour to keep as many members’ power on as possible.

Detours are not always an option since we have many members on long radial distribution lines with no options for switching.

When possible, and safe to do so, NLI crews perform “hot” or energized work on NLI’s lines, which does not require switching. However, when we do need to switch, it typically happens behind the scenes. You will not notice your electric service has been switched from one substation to another.

Thinking of our electrical system in terms of a road system, you could follow an electrical path from a home in north Idaho all the way to a home in southern Arizona! There might be a detour or stop along the way, but there will always be a path there.

Kristin MettkeNorthern Lights Engineering & Operations Manager Kristin Mettke is an electrical engineer and has worked in the electric utility industry most of her career.