Working to be Wrong

Right now I have an odd  after hours task: proving myself wrong. The issue is what a Carrington Event would do to the power grid. For those who may not have heard of it, the Carrington Event was a Coronal Mass Ejection (CME) that hit the earth in 1859. It caused huge auroras all across the globe – auroras are the result of charged particles from the sun interacting with the earth’s magnetosphere and spraying the upper atmosphere. It also caused spectacular damage to telegraph systems, with operators reporting arcing, and in some cases fires. Others were able to disconnect batteries and run from what’s now called Geomagnetic Induced Current (GIC). For all this interaction with the earth’s magnetic field induces electrical currents, and those during the Carrington Event packed a wallop.

It’s generally claimed that a Carrington Event would practically destroy the electric grid due to GIC frying substation transformers that takes so long to build. When asked for how many, one person said 50%. To this I go “Eh.” The grid has protection devices known as lightning arresters, fuses, and reclosers (essentially a type of breaker). Protective equipment disconnects generation when it senses instability to the grid. Since the charged particles follow the earth’s magnetic field, they tend to be more intense at the poles, which is why Canadian utilities have dealt with power going out due to GIC during a solar storm. That this doesn’t destroy their infrastructure each time it happens is a strong argument that a Carrington Event would cause global cascade outages without significant damage to infrastructure.

That said, GIC does damage transformers. It can produce hot spots in transformer windings, causing insulation break down and internal failure. It has taken substation transformers out of operation. My contention is that while a Carrington Event would trip protective devices, it would be require smaller events, those where protection devices failed to operate, for transformers to be damaged. It’s sort of like a seat belt that lets you lean forward, but catches you in a sudden stop.

Moreover, the grid is subject to lightning. Lightning weighs in at around 30,000 amps or higher, at around 1,250,000 volts. That’s a good bit more punch than a Carrington Event would pack.

There’s also a noticeable lack of knowledge on power restoration in these apocalypse scenarios. Such as changing feeds and connecting tie-lines, and things like mobile substations, distributed generation, including portable generators the size of semi-trailers. Once a diesel electric locomotive was used in a pinch. These aren’t usually mentioned in a Carrington Event scenario, maybe because those predicting such aren’t aware they exist. Electrical Engineering is a broad field, and it’s very possible for an EE not to be aware of what’s done to restore power.

For all these reasons, I fear a series of smaller solar events more than a Carrington Event. I base my opinion on over thirty years experience at an electric utility, including power restoration. I know something about how things in the business works.

I also could be terribly wrong.

The problem is that the field is so broad. I pooh-pooh doomsday assessments based on what I know, but what I know isn’t all inclusive. Just like the doomsday assessments that don’t take into account what utilities can do to get power restored, I might not be taking into account things that could make a Carrington Event a nightmare.

That’s why this is becoming an obsession. The question isn’t so much do you trust an Engineering Tech with over thirty years experience over a gloom and doom EE, but how well this difference of opinion matches the numbers. Line protection device characteristics are well known; so is GIC. Anything that doesn’t open protection devices can cause problems. And there’s the issue of transformers that were damaged by GIC even with protection. What will the numbers show, and how to go about it?

This means I’m working to prove myself wrong. That might strike some as disingenuous, but it’s the nature of the business. If I’m right, all well and good. If I’m wrong but there are ways to limit damage, we ought to apply them. If we can’t be assured of limiting damage, we should plan for power restoration in a worse possible case.

So I’m going to be looking at GIC and the Carrington Event with the goal of proving myself wrong, and likely posting some of the stuff that turns up. And we shall see what we shall see.

Advertisements