Wildfires and the fragility of PG&E's electrical circuits causing power outages

To give you an example of the fragility of PG&E circuits, we have a report to the CA Public Utilities Commission (CPUC) from a consultant in 2013 stating that PG&E had in service about 22,000 circuit miles of small bare copper wire. It is very common to find multiple repair splices in a single span, as in this picture below. The yellow circles are wire repair splices.

To use this small fragile bare wire as a power conductor anywhere is asking for trouble.

To suspend it though tall forests is worse. But this wire is used all across Northern CA, both in forests and on city streets. This #6 wire is fully in compliance with CA Public Utilities Commission code. The Commission appears to have ignored both its own staff and outside consultant’s comments about this wire.

If you wonder why such defective regulations exist, you could ask our Governor. He appoints the five Commissioners who oversee the CPUC. General Order 95 allows the use of even smaller wire than this.

After a power outage PG&E must inspect every mile of power line for damage before it can safely turn the power back on again. Their linemen must locate and correct the problem that tripped off the power. Otherwise the company may start another wildfire or possibly electrocute someone. If PG&E had better situational awareness on its grid, then locating electrical fault problems might not take them so long. PG&E has limited SCADA (System Control and Data Acquisition). SCADA is an old technology.

So you know what is tripping off your electricity, we include this photo (below) of a PG&E recloser. It’s the large grey box with ceramic insulators on top. PG&E uses at least three different types of reclosers. These may not be the only switch gear involved with Fast Trip power outages.

A recloser is a three phase circuit breaker. They were designed to reduce power outages by auto re-closing to test if an electrical fault had cleared. Many faults are transitory. This re-closing happens three to four times. Perhaps that fault was a squirrel that died and fell off the power pole, so the electrical problem was resolved?

But in 2017 it was found that reclosers were re-energizing downed power lines and starting fires.

Reclosers don’t distinguish what the fault is, and so reclosing or re-energizing without knowing why a circuit tripped off is too dangerous for wildfires during the dry season. Fast Trip does reduce fire ignitions. But there are better ways to accomplish this.

Reclosers are mounted on power poles and in sub-stations. In general principle, reclosers shut off power similarly to the circuit breakers in your house. Recloser devices are usually magnetic rather than thermal or heat operated. House circuit breakers are thermal. But both open a circuit during a power overload.

Sometimes bare powerlines swing in the wind and arc to each other, making flash sparking contact that showers pieces of molten metal. This is a powerful phase to phase arc fault. A line slap lasts only a moment. Reclosers were designed to turn the power on again after the power lines separated.

With Fast Trip, reclosers are being used for something they were not really intended for. That is: to open (or turn off) on low threshold overloads, and then not re-energize.

In 2017 during the “Wine Country Fires”, it was determined that reclosers were starting fires by re-energizing downed powerlines. A downed powerline can arc to earth, start a fire, and not be shut off by any fuse or recloser on a standard setting. This older equipment just detects or fails to detect overloads. New computer equipment can distinguish between nearly every type of electrical fault. These devices can be mounted on power poles.


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