I know you all are waiting for an explanation of why about 85% of the Town experienced a power outage last night. As I am sure is the case for all of you, I was shocked and highly irritated that it happened. That is bad news. The good news is that our emergency response team, the Fire Department, and Alan Welch, with support from the PBSO deputies on duty, did a great job in securing the site and getting FPL on stations to restore power.
So, the question is what happened and why: One of the electric transmission main overhead feeder wires broke lose on the corner of Atlantic and Bravado. This caused two small explosions; one when the wire broke loose and one when it hit the ground. These were the flashes and bangs that many residents near the site heard or saw. This event tripped the main distribution transformer that feeds 85% of the Town. The FPL response team bypassed the downed wire and reset the transformer to restore power. The restoration process, from start to finish took about 45 minutes.
Why did it happen? FPL does not yet know why the wire failed. They are in the process of failure mode analysis. The reasons for the near-total outage are as follows:
- Some 85 percent of the Town is fed from the transformer at the southwest end of the Inlet, near the Anchorage. This was the feeder line transformer that tripped when the wire broke.
- Although the Town has three main feeder lines (One on Lake and Blue Heron, one on Blue Heron and Park and one on the Inlet), because the undergrounding process is not yet completed these do not switch automatically. When one fails, the switch to another must be done manually. When the undergrounding project is completed, this will change to a fully automated, computerized switching system. This means if one feeder line fails, the other will immediately compensate. This arrangement won’t happen immediately upon completion of the project, but it will happen.
- The overhead feeder lines have not yet been de-energized. Because of this, when the overhead feeder line failed, the entire system failed, except Bamboo and the north side of Sandal, which are energized by the northern feeder lines. (As a side note, most of the lines running in the rear of our homes have been de-energized, the exceptions being from the Parkway to Ocean Ave between Edwards and Cascade and between Bamboo and Sandal (a lateral feeder line.)
What will happen next? Viking has three small conduit connections to complete. (Two are communication – AT&T and Comcast - distribution boxes that were not called out on the master conversion plan done by the Town consulting engineer.) The other is a small conduit run at the Seaspray. These will be completed this week. FPL will then begin the de-energizing of the feeder lines on Monday, August 17. They will work from North to South, which is a change in plans. They originally were going to switch the main load transformer on the Inlet and work North, but after this outage incident, they have decided that the load on this transformer is too large to do first. So, they will now work north to south. Once de-energizing is done, the FPL portion of the undergrounding project will be done. HOWEVER, the automatic switch over will not yet be in place; meaning that if one feeder line goes down, the others will not automatically compensate. It will take a bit more time to put this change in place and this will require a computer program change. Also, as a side note, the Lake and Park feeder lines, although underground, connect to above-ground lines running east/west on Blue Heron, so they are still vulnerable during hurricanes. But, with automatic switching, the risk of an outage will be reduced.
Hopefully, the foregoing will give you all a clear picture of what happened, why it happened, and what is being done to correct the issues. If you have any questions please email me or Alan Welch, who has taken over as the Undergrounding Project Manager.