Electric System Reliability

Providing safe, dependable, affordable and efficient electric service to your home is our highest priority. That's why we regularly inspect and test our electric system, making corrections before power-quality problems arise.

We monitor the reliability of our electric system on a daily basis and develop projects to improve electric service reliability for our customers.

Electric Reliability
  • Targeted reliability improvements
    • Tree wire
      Tree-related outages can be reduced by up to 95 percent when smaller diameter wire is replaced with tough, thick-coated wire designed to prevent outages when tree limbs fall into power lines. Tree wire cannot prevent outages caused by large falling trees.

    • Convert existing overhead lines to underground
      After a careful analysis of all specific criteria relating to the reliability issue, we may determine that undergrounding the distribution lines is the best and most prudent solution.

    • Reclosers
      By installing specialized equipment on power lines, the length and size of outages can be minimized. Reclosers sense a fault on a power line and automatically attempt to re-energize the line. If the recloser no longer senses the fault, it will reclose and re-energize the line without needing service personnel to deploy and physically patrol the line.

    • Supervisory Control and Data Acquisition
      Supervisory Control and Data Acquisition (SCADA) is an important aspect of managing the power system. SCADA is a system used for monitoring and controlling equipment remotely that enables faster restoration of power to our customers.
  • System-wide reliability improvements
    • Vegetation management
      Trees are beautiful and an important part of living in the Northwest, but they are a major cause of outages. To mitigate falling trees and limbs, we perform vegetation management on a cyclical schedule, with efforts focusing on achieving a safe and reliable electric system.

    • TreeWatch
      Certified arborists work with communities and property owners to identify and remove “at-risk” trees on private property to prevent tree-related outages.

    • Wildlife protection
      In an effort to avoid wildlife caused outages, special safety equipment is installed when maintenance activities occur to poles, transformers and high-voltage lines.

    • Underground cable replacement
      Some underground electric cable installed up until the 1980s has reached the end of its useful life. Replacing this failing cable greatly reduces localized outages and increases reliability.

    • Pole inspection and replacement
      Failure of utility poles can cause outages. To ensure the continued strength, safety and reliability of our utility poles, we regularly inspect wood poles and treat or replace them as needed.

    • Substation equipment replacement
      Specific types of equipment are proactively replaced in substations annually. These include transmission and distribution breakers, transformer protection devices and circuit switches to maintain system reliability and offset impacts from aging infrastructure.
  • Pilot projects
    • Distribution automation
      In order to further reduce the number of impacted customers when a distribution outage occurs, we are testing fault detection sensors that can better identify and isolate the location of the fault. Electricity can then be routed more quickly around the isolated section to restore power to customers faster.

    • Transmission automation
      We are currently testing automated switching schemes throughout our transmission system as well. These schemes perform much like the distribution automation, allowing large number of customers to have shorter outages.

    • Batteries
      Improvements to large-scale battery systems are making it more practical for utilities to invest in distributed generation systems that capture, store and release energy onto the power grid. We currently have one battery pilot project in operation in Glacier, Wash. During an outage, a battery system releases its stored energy back into the electric grid to keep customers’ lights on. When energy output decreases from wind or solar generation facilities, a battery system can help balance out that decrease.

  • Current projects