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07 Apr 2025, 08:27
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A space weather event can produce geomagnetically induced currents (GICs) that may be transmitted by surface-connected conductors such as the electric-power grid. When GICs enter the power grid, they act as direct current (DC) sources that flow alongside the normal alternating currents (AC) produced at power plants and transferred along power lines to electrical substations. Basic incompatibilities between DC and AC currents may interfere with the normal functioning and performance of Extra High Voltage (EHV) transformers. The interaction of GICs with these transformers can result in a number of physical effects that, if sufficiently large and not properly managed, may adversely impact the power system.
For example, GIC–transformer interactions can increase reactive power consumption, contributing to voltage instabilities and potentially leading to power outages. They can also cause interference that leads to the improper operation of protective relay equipment (e.g., static compensators) and/or the tripping offline and potentially damaging of generators. It is important to note that this impact pathway is the only one that has to-date been known to trigger space weather–related blackouts.
For example, GIC–transformer interactions can increase reactive power consumption, contributing to voltage instabilities and potentially leading to power outages. They can also cause interference that leads to the improper operation of protective relay equipment (e.g., static compensators) and/or the tripping offline and potentially damaging of generators. It is important to note that this impact pathway is the only one that has to-date been known to trigger space weather–related blackouts.
Improper operation of protective relay equipment
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
81% (02:26) correct
19%
(02:49)
wrong
based on 324
sessions
History
Date
Time
Result
Not Attempted Yet
According to the information provided, which of the following physical effects has been shown—based on past experience—to cause service interruptions in the power grid?
| Improper operation of protective relay equipment | |
| Loss of precision timing | |
| Real power imbalances | |
| Transformer heating | |
| Reactive Power Consumption |
ShowHide Answer
Official Answer
Improper operation of protective relay equipment
Emergency procedures may be needed during both moderate and extreme space weather events.: Not Inferred
Both direct current and alternating current can flow through the electric-power grid to Extra High Voltage transformers.: Inferred
Extra High Voltage transformers are vulnerable to disruption during space weather events.: Inferred
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
65%
(hard)
Question Stats:
50% (02:07) correct
50%
(02:26)
wrong
based on 381
sessions
History
Date
Time
Result
Not Attempted Yet
For each of the following, select Inferred if the statement can be reasonably inferred from the information provided. Otherwise, select Not Inferred.
| Inferred | Not Inferred | |
| Emergency procedures may be needed during both moderate and extreme space weather events. | ||
| Both direct current and alternating current can flow through the electric-power grid to Extra High Voltage transformers. | ||
| Extra High Voltage transformers are vulnerable to disruption during space weather events. |
ShowHide Answer
Official Answer
Emergency procedures may be needed during both moderate and extreme space weather events.: Not Inferred
Both direct current and alternating current can flow through the electric-power grid to Extra High Voltage transformers.: Inferred
Extra High Voltage transformers are vulnerable to disruption during space weather events.: Inferred
Communication satellites: Not Affected
Power generators: Affected
Static compensators: Affected
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
25%
(medium)
Question Stats:
72% (01:26) correct
28%
(01:40)
wrong
based on 330
sessions
History
Date
Time
Result
Not Attempted Yet
For each of the following, select Affected if the information provided supports the conclusion that the item could be negatively impacted by geomagnetically induced currents (GICs). Otherwise, select Not Affected.
| Affected | Not Affected | |
| Communication satellites | ||
| Power generators | ||
| Static compensators |
ShowHide Answer
Official Answer
Communication satellites: Not Affected
Power generators: Affected
Static compensators: Affected
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28 May 2025, 01:30
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Official Solution:
Communication satellites
• Tab 1 explains how geomagnetically induced currents (GICs) affect ground-level electrical infrastructure, including transformers, relay equipment, and power lines. It does not mention satellites or any space-based systems. Therefore, there is no support for the idea that communication satellites are affected by GICs in this context. Not Affected.
Power generators
• Tab 1 states that geomagnetically induced currents can cause the tripping offline and potentially damaging of generators. This confirms that power generators can be negatively impacted by GICs. Affected.
Static compensators
• Tab 1 states that geomagnetically induced currents can interfere with the operation of protective relay equipment, and explicitly gives static compensators as an example. This confirms that static compensators can be negatively impacted by GICs. Affected.
Correct answer:
Communication satellites "No discernible effect"
Power generators "Affected"
Static compensators "Affected"
Bunuel
Communication satellites
• Tab 1 explains how geomagnetically induced currents (GICs) affect ground-level electrical infrastructure, including transformers, relay equipment, and power lines. It does not mention satellites or any space-based systems. Therefore, there is no support for the idea that communication satellites are affected by GICs in this context. Not Affected.
Power generators
• Tab 1 states that geomagnetically induced currents can cause the tripping offline and potentially damaging of generators. This confirms that power generators can be negatively impacted by GICs. Affected.
Static compensators
• Tab 1 states that geomagnetically induced currents can interfere with the operation of protective relay equipment, and explicitly gives static compensators as an example. This confirms that static compensators can be negatively impacted by GICs. Affected.
Correct answer:
Communication satellites "No discernible effect"
Power generators "Affected"
Static compensators "Affected"
23 Jun 2025, 01:30
Kudos
Bookmarks
Official Solution:
Checking the image in Tab 3, under the Service Interruptions column, only Improper operation of protective relay equipment has a black circle—confirming that it has been shown, based on past experience, to cause service interruptions. All other listed effects have open circles, indicating they are not confirmed.
Correct answer:
According to the information provided, which of the following physical effects has been shown—based on past experience—to cause service interruptions in the power grid? "Improper operation of protective relay equipment"
Bunuel
Checking the image in Tab 3, under the Service Interruptions column, only Improper operation of protective relay equipment has a black circle—confirming that it has been shown, based on past experience, to cause service interruptions. All other listed effects have open circles, indicating they are not confirmed.
Correct answer:
According to the information provided, which of the following physical effects has been shown—based on past experience—to cause service interruptions in the power grid? "Improper operation of protective relay equipment"
