3 ms·

There's a fairly simple way to protect them, but no utility does it. You mean a faraday cage? Will wrapping it with foil work?

by ky3 14y ago

deleted 14y ago
[deleted]
pavel_lishin 14y ago
> First, the intense magnetic field variations in the magnetosphere induce electric fields and currents over large areas of Earth's surface. In turn, this geoelectric field creates what are known as geomagnetically induced currents, or GICs, which flow in any available conductor, including high-voltage transmission lines, oil and gas pipelines, railways, and undersea communications cables. These interconnecting networks essentially act as giant antennas that channel the induced currents from the ground. Hit with a 300-ampere GIC, a high-voltage transformer's paper tape insulation will burn, its copper winding will melt, and the transformer will fail, either right then and there or in the future. > There is a quick and relatively cheap fix to help protect these transformers from geomagnetically induced currents: They can be retrofitted to block the inflow of GICs. But no utilities anywhere routinely protect their multimillion-dollar transformers in this way.
- mseebach 14y ago
  So this is basically just fusing the transformer, right? The grid will still be down?
  - PeterisP 14y ago
    Well, if both the transformers and actual long distance wires survive the event, then the grid can be brought back up. Most of grid 'defenses' involve some temporary disconnection of components; the robustness question is how quickly you can reconnect again - is it an automatic switch after half a second, or does it require sending repair squads to thousand remote locations.
  - ars 14y ago
    It'll go down, but at least it won't be destroyed. Storms last less than a day, so you can get power back on then, rather than months later.
ars 14y ago
People suggest faraday cages all the time, but they will not work for things like this! Faraday cages only work for high frequencies, but geomagnetic storms and EMP's are low frequency, and will pass right through a faraday cage. (Unless you made an incredibly thick one.) You need Mu-metal for this kind of shielding. (Not that it would work here anyway - the currents are induced in the long powerlines, not in the transformer.) Also, foil it very thin, so it only works for frequencies above 50Mhz or so.

There's a fairly simple way to protect them, but no utility does it. You mean a faraday cage? Will wrapping it with foil work?

by ky3 14y ago

There's a fairly simple way to protect them, but no utility does it. You mean a faraday cage? Will wrapping it with foil work?

deleted 14y ago

[deleted]

pavel_lishin 14y ago

> First, the intense magnetic field variations in the magnetosphere induce electric fields and currents over large areas of Earth's surface. In turn, this geoelectric field creates what are known as geomagnetically induced currents, or GICs, which flow in any available conductor, including high-voltage transmission lines, oil and gas pipelines, railways, and undersea communications cables. These interconnecting networks essentially act as giant antennas that channel the induced currents from the ground. Hit with a 300-ampere GIC, a high-voltage transformer's paper tape insulation will burn, its copper winding will melt, and the transformer will fail, either right then and there or in the future. > There is a quick and relatively cheap fix to help protect these transformers from geomagnetically induced currents: They can be retrofitted to block the inflow of GICs. But no utilities anywhere routinely protect their multimillion-dollar transformers in this way.

mseebach 14y ago
So this is basically just fusing the transformer, right? The grid will still be down?
- PeterisP 14y ago
  Well, if both the transformers and actual long distance wires survive the event, then the grid can be brought back up. Most of grid 'defenses' involve some temporary disconnection of components; the robustness question is how quickly you can reconnect again - is it an automatic switch after half a second, or does it require sending repair squads to thousand remote locations.
- ars 14y ago
  It'll go down, but at least it won't be destroyed. Storms last less than a day, so you can get power back on then, rather than months later.

ars 14y ago

People suggest faraday cages all the time, but they will not work for things like this! Faraday cages only work for high frequencies, but geomagnetic storms and EMP's are low frequency, and will pass right through a faraday cage. (Unless you made an incredibly thick one.) You need Mu-metal for this kind of shielding. (Not that it would work here anyway - the currents are induced in the long powerlines, not in the transformer.) Also, foil it very thin, so it only works for frequencies above 50Mhz or so.