What causes power outages?
Power outages can be caused by many factors including high demand on the power grid, aging equipment, damage to local equipment from extreme weather, a fallen object such as a tree or a vehicle accident. Metallic and shiny Mylar balloons that come in contact with a power line or float into substation equipment can cause a surge of electricity that short-circuits equipment and can lead to a power outage. Critters such as birds, rats, squirrels and raccoons can also cause power outages when they come in contact with high-voltage power lines or other electrified equipment. Much like a metallic balloon can trigger an electrical arc or flash, animals that climb or land on electrical equipment can serve as a conductor of electricity that can short transformers, trip circuit breakers, melt electrical equipment or cause a fire. Once a circuit breaker opens, it can cause the breaker or protective equipment to automatically shut-off to prevent damage to the rest of the system. When a system shut-off occurs, what was initially an outage impacting a limited number of customers can end up impacting a much larger number of customers.
There are three power delivery points in Ashland: the BPA substation on Mountain Avenue which is owned and maintained by the BPA (Bonneville Power Administration), the PPL (Pacific Power and Electric) substation on Nevada Street and the PPL substation at Oak Knoll are both owned and maintained by Pacific Power and Electric. Each substation provides power to a distinct area of Ashland.
In addition to serving PPLís own customers, PPL is contractually bound to deliver a part of the Cityís BPA power through the Nevada Street and Oak Knoll substations. PPL operates the substation equipment, the City operates distribution control equipment to both receive power and protect the Cityís distribution system.
When a failure occurs at one of these substations Ashland electric crews transfer the electric load, in stages, to the other substations until repairs are completed by either BPA or PPL electric crews at the substation.
May 20, 2017: The outage was caused by a catastrophic equipment failure at the Nevada Street substation. While PPL worked to replace the equipment, Ashland electric crews determined the best solution was to transfer the electric load to the Mountain Ave. substation. The switching process requires a methodical execution of steps carefully coordinated with crews in the field. The outage lasted 3 and a half hours.
April 30, 2017: The outage was caused by a drunk driver who crashed into a transformer. The transformer had to be replaced. The outage lasted two hours.
April 14, 2017: The outage was caused by an animal at the Nevada Street substation. Ashland Electric crews transferred power to the other substations while PPL repaired the damaged equipment at the Nevada Street substation. The outage lasted three hours.
Why canít measures to taken to prevent animals from coming into contact with power equipment?
Animals trigger 11 percent of power outages across the nation and Electric Utilities around the world face the same challenges as Ashland. Many techniques have been tried to deter animals from entering a substation: inflatable decoy owls to scare off potential prey, noise makers, ultrasonic bird deterrents, air horns, plastic screens over insulators to allow animals to safely pass, animal proof perimeter fencing and more. Most treatments have no effect and many are disruptive in residential areas.
The Ashland substation are owned by non-Ashland organizations. The Ashland Electric Utility works closely with both PPL and BPA to mitigate outages due to animals. The three substations in Ashland are maintained to deter animals: no food, no cover, no water. And, the equipment is outfitted with animal guards to prevent animals coming into contact with energized equipment. Despite these precautions, animals still occasionally find contact with energized equipment.
The City is redesigning the City operated control area to increase the distance between controls and energized lines, thus decreasing the likelihood of an animal causing another incident. Longer term the City will be evaluating moving the City-owned control equipment away from the privately owned substations.
Equipment upgrades to the substations by both PPL and BPA are phased in over time.