The Two Perth Subsea Outages: Indigo West & Indigo Central
These two Subco-owned cable systems have experienced ongoing outages that started August 8th. Each has a shunt fault located very near the other in the Perth cable protection zone. This zone extends from shore to a depth of 2000 meters and is over 100 kilometers long. These protection zones can backfire because their width is usually just a nautical mile. So the cables are packed together like sardines and if a ship drags its anchor, then multiple outages are pretty much guaranteed. It raises the question of whether cable protection zones are really a good idea since the level of shipping pretty guarantees cable damage. In a way, cable protection zones violate the principle of resiliency via physical diversity. The most likely suspect in this case is a ship that dragged its anchor across the two cables and damaged the sheath protecting the power conductor from water. A ship has been identified that was in the area at the time the outages began. Cable repairs are slated to be complete A...