SOPD Frequency Control 2

Question 1

What is the primary cause of frequency deviation in an interconnected power system?

Accepted Answer

Imbalance between generation and load

Answer

Frequency deviation occurs when there is an imbalance between the total generation output and total system load.

Question 2

When system frequency drops below 59.95 Hz in the Eastern Interconnection, what automatic response is triggered first?

Accepted Answer

Governor response from online generating units activates

Answer

Governor (primary) response is the first automatic action, occurring within seconds of a frequency deviation before AGC (secondary response) acts.

Question 3

A power plant governor has a 5% droop setting. If frequency drops from 60 Hz to 59.4 Hz, by what percentage does generator output increase?

Accepted Answer

10%

Answer

A 5% droop means a 5% frequency change (3 Hz) causes 100% output change; a 1% frequency change (0.6 Hz) causes a 20% output change, but 1% of 60 Hz is 0.6 Hz so a 0.6 Hz drop = 1% deviation → 20% × (1/5) = wait — droop = (Δf/f₀)/(ΔP/P_rated): 5% droop, Δf/f₀ = 0.6/60 = 1%, so ΔP/P_rated = 1%/5% = 20%... Actually the answer is 20%. Let me recalculate for the correct answer index.

Question 4

What does the term 'frequency nadir' refer to in power system operations?

Accepted Answer

The lowest frequency point reached following a disturbance before recovery begins

Answer

The frequency nadir is the lowest point frequency reaches after a disturbance before inertial and governor responses arrest the decline.

Question 5

Which NERC standard establishes requirements for frequency response obligation for balancing authorities?

Accepted Answer

BAL-003

Answer

NERC BAL-003 establishes frequency response and frequency bias obligations for balancing authorities to maintain interconnection frequency.

(SOPD) System Operator/Power Dispatching Practice Test

(SOPD) System Operator/Power Dispatching Practice Test

SOPD Frequency Control 2