How We Restore Power
Power outages can be caused by any number of things, including storms, car wrecks and curious animals. View our outage map to see if your location is affected.
How we restore power depends on the cause, extent and location of the outage. Rural lines may be difficult to reach and repair, while removing a branch from a feeder line can be quick.
After safety needs are met, we prioritize the work that will get the most customers back on line. Then we keep working our way down the system. We appreciate your patience and help pinpointing the outage.
Generally, here’s how we restore power:
- Perform initial assessment: We determine the location and nature of the outage. Based on those factors, we send out appropriate crews and equipment.
- Protect public safety: We clear live power lines and repair equipment that poses a safety hazard. Public health and safety facilities, such as hospitals, clinics and utilities (water, sewer, natural gas and telephone) get first priority.
- Repair transmission lines: Transmission lines supply power from generating facilities, like dams, to one or more substations. They rarely fail, but it is possible. Since trouble on a transmission line affects thousands of customers, it gets attention first.
- Repair substations: We survey any substations involved in the outage to check for abnormalities. If we can fix the issue at the substation, we can get power back on for a large number of customers. Substations act as a distribution and switching station.
- Repair feeder lines: Feeders are like arterial streets. We patrol the individual lines, working our way down the system from the substation. This is often how we find limbs and trees on lines. Feeder lines serve 1,000 to 3,000 customers and are usually the lines affected when you hear of a power outage on the news.
- Repair tap lines: Tap lines move power from feeder lines to individual streets. They feed pockets of 20 to 30 homes each.
- Restore power to individual homes or businesses: This task takes the longest. Sometimes damage can occur on the service line between your house and the transformer on the pole. This may be why your neighbor has power but you do not. This is why we may need you to report your outage multiple times through a multi-day restoration effort as we work our way through the system.
Helpful Outage Information
- A Tacoma Power truck came through my neighborhood, then left without stopping. Why?
There could be several reasons. Crew members could be driving through areas visually assessing damage. That happens when work requires more equipment or additional crew members. Or, a tree crew may be needed to remove fallen trees or branches before other crews can get to work. Rest assured, we haven’t forgotten you. We are working as fast as we can.
- What is cold load?
When large numbers of our customers are out of power, one challenge we face is “cold load,” a high demand on the system as we try to re-energize areas that have been without power for a long time. When customers leave appliances on during an outage, the heavy, immediate demand on a re-energized system can sometimes cause a secondary outage as circuit breakers trip to protect the system from overload.
You can help prevent a second outage by turning off the breaker switch to your furnace, water heater and large appliances during a long-term power outage. When electricity is restored, you can further help by turning on electronics and large appliances slowly, one by one.
- Why did my lights flicker? Is it true three flickers means the power will go out?
Power grids are large networks of wire connected to substations. That flicker you noticed was caused by measures in place to prevent a potential short circuit of the entire grid from a minor event.
Each substation in the network is protected with circuit breakers or fuses. For example, in wind storms, a branch may fall on a power line. If the branch bounces off the line, you’ll notice a flicker, but the power stays on. The protection system triggered to prevent a short circuit, then reset itself when it found the problem cleared.
In a sense, three flickers can mean the power is going out. That flicker allows a select number of attempts in short intervals before power goes out and human intervention is required to fix the outage. That number of attempts is usually around two or three. So, if that same branch fell on the wire and stayed on the wire, you may notice three flickers as the protection system attempts to check three times to see if the problem is big or one that went away on its own. If the system senses a continued issue after three checks, the power will go out.