Electric utilities are hardening their systems to prevent outages, protect their infrastructure from costly damage and boost reliability for their customers. However, even with these measures in place, severe storms can still test the integrity and strength of a utility’s infrastructure.
Case in point: A severe wind event in Michigan knocked about 379,000 homes and businesses out of power and affected 30 out of 32 operating centers. Strong winds caused trees to topple onto power lines, breaking wood crossarms and poles throughout Consumer Energy’s service territory.
Calling for Mutual Assistance
A week before the storm hit, the utility was already monitoring multiple weather services and knew a high wind event was headed toward Michigan. Three days before the high winds blew through the state, Consumers Energy lined up extra workers, including line contractors, office employees, and wire-down and damage-assessment personnel.
Then, early in the morning in mid-November, wind started to pick up, a thunderstorm front rolled in, and temperatures dropped. Consumers Energy made its first request for mutual assistance on that Sunday night, and then again on Monday and Tuesday. Overall, 218 three-person crews supported the mutual assistance effort. The linemen came from a wide variety of contractors and utilities from Kentucky, North Carolina, South Carolina, Ohio, Tennessee, Virginia, Oklahoma, Maryland and Missouri. The company had 163 company crews and 105 in-state contractor crews along with 150 contractor forestry crews who responded to the storm-restoration effort.
As part of the Great Lakes Mutual Assistance Group, Consumers Energy requested support from other member utilities when the high wind event hit Michigan. The utility set up a conference call with the other utilities, discussed its need for crews, and then the other utilities offered their support. Because the storm struck Michigan and most of the Midwest, they were only able to get limited nearby support, and as such, had to go beyond this group to the non-Midwestern utilities to secure resources.
Before the linemen started working in the field in many areas, the utility performed a damage assessment. From past storms, the utility learned the importance of conducting this assessment prior to sending linemen out in the field to the extent possible. That way, they minimized the problem of sending too many workers into an area with minimal damage. Consumer Energy analyzed the outage orders coming in and then pinpointed the location of the outages and the areas where wire was down.
Consumers Energy also engaged some of the work groups in the wire-down program, while the linemen focused on isolating as much of the damage as possible on the substation circuit. That way, they could restore power to as many customers as possible in a timely manner.
The level of damage varied widely from one end of the utility’s service territory to the other. For example, in Grand Rapids, Michigan, about 45 poles went down, while 70 miles away in Battle Creek, Michigan, the linemen had to replace 100 poles. Statewide, more than 1,000 wooden poles were broken, with the worst damage occurring in the southern part of the state.
For this particular storm event, trees and crossarms fell on the high-voltage distribution lines, causing a lot of damage. In fact, the utility experienced 21 line lockouts on its high-voltage distribution system. Fortunately, the company’s high-voltage distribution system is looped in most areas, and as a result, the linemen and system operators were able to isolate the damage more quickly. In some cases, where they had the structures down but didn’t have the opportunity to isolate the power and redirect it, linemen had to repair or replace poles and crossarms prior to restoring power.
Accessing the Storm-Stricken Areas
Because so many poles were broken in the deep rights-of-way, the field crews had to use a lot of flex track equipment to reach the work site. These digger derrick units featured a flexible track drive system, which allowed linemen to use them in farmland and wet and swampy areas.
The linemen also relied on backyard machines to carry poles into backyards or into tight quarters. These machines featured an auger and a pin-on bucket, and the linemen were able to haul the pole in, auger the new hole, set the pole in and use the bucket at the end of the boom to perform the work.
Because one of the downed lines crossed the river, the linemen had to take a boat to the other side. They then had to pull the conductor across to replace the damaged conductor.
For the first time in its history, Consumers Energy was also able to deploy its three mobile material trailers to the storm-restoration zones. The utility built these portable storm rooms earlier this year and deployed them to three different areas. These trailers contained all of the equipment necessary to rebuild an installation including crossarms, transformers, connectors, insulators, wire spools and hardware. The utility delivered the trailers to shopping center parking lots near damaged areas. That way, out-of-town contractor or mutual assistance crews could go to the mobile storm rooms and stock up rather than going to the nearest service center, saving valuable time.
Two days after the historic wind storm swept across Michigan, Consumers Energy linemen and mutual assistance crews had already made significant progress in getting the lights back on for the hundreds of thousands without power. Overall, the utility had 1,400 linemen respond to the wind event, including 500 from Consumer Energy. About 1,200 support, supply chain, customer operations and other personnel also helped with the effort.
After all of the customers’ power was restored, the crews permanently repaired those services that were temporarily fixed. By partnering with linemen from across the United States, the linemen were able to replace broken poles and get the lights back on for their customers.
Consumers Energy | www.consumersenergy.com
Sidebar: Communication Is Key to Successful Storm-Restoration Effort
Here are five ways that Consumers Energy kept in close contact with its field crews and its customers.
- Keep the lines of communication open. Consumers Energy needed to know where all of its workers were at all times, who was on shift, and the status of the equipment, lines and substations. To ensure everyone was on the same page, the managers attended regular conference calls throughout the event and participated in status calls three times a day.
- Assign field leaders/guides. Consumers Energy also assigned a field representative to the outside mutual assistance crews. This person served as the communications conduit as well as a field guide who could work with the outside crews, answer their questions about the system and make sure they were performing the work in the assigned areas.
- Connect the dispatchers with the field resources. The dispatchers were on the radio with field resources. In addition, field control was assigned to field leaders who took responsibility for sub circuits and operated as their own dispatchers responsible for all the crews and execution.
- Make information available to local restoration personnel. Consumers Energy representatives also could access the catastrophic crew database, which included information on resources available to use during the storm-restoration effort.
- Provide an outage map. Another valuable tool was the outage map, which was made available to Consumers Energy employees and customers. By clicking on the state of Michigan, they could see where the outages were occurring and whether or not their area was affected. They also could view estimated restoration times, which is a new feature just added within the last year.
Sidebar: Six Steps to Storm Response
Consumers Energy crews follow these six steps when a storm hits their service territory:
- Monitor the weather to identify significant weather threats
- Prepare and plan for the severe weather event
- Mobilize office and field resources
- Execute the storm-restoration plan
- Communicate with the public and governmental agencies
- Perform a post-storm assessment of the performance of the organization to improve the response for the next event.
Sidebar: System Hardening
Like many other electric utilities, Consumers Energy is making its infrastructure more robust to withstand severe weather events and improve reliability. Here are a few ways that the utility is guarding itself against Mother Nature’s wrath:
- Replacing aging poles
- Installing tree-resistant aerial spacer cable conductor
- Upgrading motor-operated air-break switches
- Focusing on forestry clearing
- Removing unnecessary limbs and growth threatening lines that impact the most customers in the three-phase distribution and high-voltage distribution system.