By size, within the scope of a big-city system, it was considered a “small” outage – but given that it happened in subfreezing weather, the outage last night in Gatewood/Morgan Junction was huge for hundreds of families. We just talked with Scott Thomsen at Seattle City Light, who explained the cause of the three-hour outage, why it took so long to fix, and why that area seems to be hit by outages frequently: “The area that was affected is served by a 4-kilovolt line – that’s some of the oldest wire in the system – standard (nowadays) is 26 kilovolts.” Scott adds that this is one of some “small pockets” in the city still served by that wire, and what went wrong is that it’s not made to handle the kind of demand placed on it when the temperature went way down and the heat went way up. It took crews a while to figure out the problem: “Ultimately they discovered the relays set up to deliver energy into that area were not set up to handle the increased load demand … as people were keeping their heat on. … So it kept cutting out, and tripping the breaker, and finally went out. They wound up feeding the electricity into that area in a different route to keep it from tripping the breaker, and they will keep that in place for as long as (the cold weather continues).” He says upgrading lines like that is part of the infrastructure investment called for in City Light’s five-year plan, but it’s not cheap – it would require new cable and new transformers – so if you live in that area and are tired of repeated outages, you might want to let the City Council know, since they ultimately hold the purse strings.
West Seattle, Washington
05 Thursday
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