Distribution System Reliability

By Brent Bischoff

Last fall, I wrote about transmission grid reliability and how the principles of redundance and resilience improve electric system reliability. Redundance and resilience are built into the Coos-Curry Electric Cooperative distribution system, too.

CCEC’s long-range plan and five-year capital work plan identify aging equipment that needs to be replaced. Ideally, we replace equipment near the end of its useful life but before it fails. These plans also identify key projects to build new reliability into the electric plant. I’ll give an overview of two projects we are completing to improve redundance, resilience and reliability.

CCEC owns a mobile substation. It is a substation power transformer on a semitrailer. There are 13 substations in the CCEC distribution system where large power transformers reduce electricity from the 115,000-volt transmission system to 12,500 volts for distribution. The mobile substation is a redundant, or backup, power transformer in case a substation power transformer fails. Substation transformers are built to order, and lead times are one to three years for delivery. The mobile substation can also serve an area during a scheduled substation upgrade when an old substation transformer is replaced.

CCEC has owned the mobile substation for many years, and it needed extensive maintenance and refurbishment. It is in the shop now and will be ready for service again this summer.

Some CCEC substations do not have space to set up the mobile substation. In these cases, the reliability plan is to build a distribution tie line from the nearest substation.

With some substations, the distance to the adjacent substation and ruggedness of the terrain make it too expensive to build a distribution tie between substations. The Pistol River Substation is an example of this. A Gold Beach to Pistol River distribution tie line is identified in the long-range plan but has been too expensive to build.

With the construction of the Beacon Broadband fiber network, a fiber path between Pistol River and Gold Beach is necessary. We used this opportunity to share costs and build the Pistol River to Gold Beach electric distribution tie and fiber network path at the same time. The line is being built underground rather than overhead to improve resilience and wildfire mitigation.

The federal and state governments recently announced grant programs to improve electric system resilience in rural areas. CCEC is actively pursuing these grant opportunities to fund more projects that will strengthen our local power grid.

Most of us take electricity for granted and don’t think about what makes the power grid reliable. At CCEC, we like it that way because it indicates we are accomplishing our mission to serve you the energy that powers your life.