Any preparation done for GIC (Geo-magnetically Induced Currents)?

[Beengineer]

2010-2012 is the period of solare storm that results in Geo-magnetically Induced Currents (GIC). It occurs in a cycle of 11-12 years.

I am interested to know what other companies are doing to pretect their transformers from GIC.

Thanks

 

[marks1080]

I don't think there's a whole lot that you can do... Cross your fingers and maybe rethink some reclose settings?

 

[tlrols]

Install series capacitors everywhere? Mostly joking, but about the only thing you can really do technically speaking...

 

[prc]

During these solar storms,DC current will be induced on lines and can flow to ground through the winding neutral,thereby saturating the core.This will result in extremely high excitation currents,overheating of winding ,overfluxing in core etc.One solution tried is a filter between transformer neutral and ground which will block DC current.

 

[electricuwe]

Can anyone post information on damages caused in the solar storm period around 1990 ?

I can not remember any issues at that time.

 

[Beengineer]

Highest levels were recorded on March 13, 1989

Up to 150 Amperes on the PSE&G system

Caused failure of one shell form of an old design, gassing of a # of transformers in the NE of USA area, and an 8 hr blackout of the HQ system

Has caused overheating / gassing in other large power transformers - In S. Africa, Sweden, and Finland in 2000 / 200

 

[stevenal]

I deleted the email, but I recall reading that the US Congress is on top of this. They will give FERC more authority to deal with solar storms as well as cyber intrusions. No worries.

 

[ProtectionEngineer]

Here is the NERC Link for the Electromagnetic Pulse


Report of the Commission to Assess the Threat to the
United States from Electromagnetic Pulse (EMP) Attack.
April 2008.

http://www.empcommission.org/docs/A2473-EMP_Commission-7MB.pdf

NERC System Disturbance Analysis: 1989 Geomagnetic
Storm. August 1990.

http://www.nerc.com/files/1989-Quebec-Disturbance.pdf

Thanks
Alex

 

[cranky108]

PRC said "current will be induced on lines", is this true, or will current be induced into the earth plain causing a potential differentce across the path of transmission lines?

Eather way it's the same results. I just want to know.

 

[mgtrp]

We have capacitors installed in the neutrals of a number of our transformers to protect against GIC.

 

[prc]

Cranky ,Iam not sure.If DC current is induced in ground,why it should move over to lines through transformer neutral?Of course there will be induction on ground.

GIC is a problem only in arctic or near to those areas. We have seen similar problem in other areas where in HV DC system when one line is charged under ground return mode,DC current moves through ground.Where resistivity is high, Dc current will move in to neutrals of nearby transformer and move over transmission lines and come out of receiving end transformer neutral to ground, as it is relatively less resistive to current flow.

 

[cranky108]

I would think the transmission lines are more conductive than rock.

If capacitors work, have you had any problems with arrestors?

 

[mgtrp]

No issues with surge arrestors to the best of my knowledge, although to be fair, I haven't made too many enquiries.

 

[magoo2]

You've got a mixed bag of advice - some of which I would seriously question. There are a number of things that you can do.

The Artic may be more susceptible but that factor relates more to the level of induced currents which are greater closer to the poles. As previously noted, PSE&G (NJ) lost a GSU transformer back in 1989. Hydro Quebec had their system shut down for a good number of hours on the same day mainly because a number of their transmission capacitor banks tripped off.

We had a couple of our capacitor banks trip off on the same day due to harmonics. Harmonics are a result of transformer saturation. A number of neighboring East-coast utilities reported tripping of their cap banks on the same day. Again we're talking about transmission banks.

The main path of GIC is east-west. Long transmission lines that run in an east-west direction are most susceptible.

Some things can be done. The simplest is to replace transmission capacitor bank protective relaying with a type that is less sensitive to harmonics. This is a fairly inexpensive thing to do. We replaced a number of older GSU transformers with ones that are more tolerant of GIC. That is a solution even though it is expensive.

You can also install monitors at critical transformer locations. That will give you an early warning - maybe 30 minutes or so. The trick is to decide what you want to do given that you have a high current level on one of the monitored transformers. Think about that for a minute.

There is also a YouTube clip of a U.S. senior energy expert that predicts doom and gloom for the 2010-2011 solar storm. It remains to be seen whether it will be as bad as 1989 or not.