SWP Power Grid & Ground-Based Infrastructure Impacts 2

Question 1

NERC's standard TPL-007 was developed specifically to address:

Accepted Answer

Geomagnetic disturbance vulnerability assessment and mitigation for bulk electric systems

Answer

NERC TPL-007 requires transmission planners to assess transformer vulnerabilities to GICs and implement mitigation measures for extreme geomagnetic disturbance scenarios.

Question 2

GIC neutral blocking devices protect transformers by:

Accepted Answer

Inserting capacitors in the neutral-to-ground connection to block DC while passing AC

Answer

Neutral blocking capacitors break the DC/quasi-DC path to ground that allows GICs to flow through transformer neutrals, while presenting negligible impedance to the 60 Hz AC current.

Question 3

The October 2003 'Halloween storms' were significant for power infrastructure because they:

Accepted Answer

Produced the largest GIC ever recorded in North America and caused transformer damage in South Africa

Answer

The Halloween storms produced large GICs worldwide; South Africa's Eskom reported severe transformer damage because its power grid lies at sub-auroral latitudes and uses long transmission lines over resistive rock.

Question 4

Why are Extra High Voltage (EHV) transformers particularly difficult to replace after GIC damage?

Accepted Answer

They are custom-built to site specifications, weigh hundreds of tons, and have lead times of 12–18 months

Answer

Large power transformers are custom units, often 300–500 tons, manufactured in limited quantities globally, making replacement after a major GIC event a months-to-years-long process.

Question 5

Which geomagnetic index is most commonly used in GIC risk assessments for power grid operators?

Accepted Answer

Local K-index from nearby magnetometers

Answer

Local K-indices from magnetometer stations near grid infrastructure provide site-specific data on geomagnetic activity intensity more relevant than global indices like Kp.

SWP - Space Weather Professional Certification Exam Practice Test

SWP - Space Weather Professional Certification Exam Practice Test

SWP Power Grid & Ground-Based Infrastructure Impacts 2