SOPD Load Dispatching 2

Question 1

What is the primary purpose of economic dispatch in power system operations?

Accepted Answer

Minimize total generation cost while meeting load demand

Answer

Economic dispatch allocates load among generators to minimize total fuel or operating cost while satisfying system demand and constraints.

Question 2

A dispatcher observes that the system frequency has dropped from 60 Hz to 59.8 Hz. Which immediate action is most appropriate?

Accepted Answer

Increase generation output from online units

Answer

A frequency drop indicates generation is insufficient to meet load, so the dispatcher must increase MW output from available online generators.

Question 3

What does 'area control error' (ACE) represent in an interconnected power system?

Accepted Answer

The difference between actual and scheduled net interchange plus frequency bias

Answer

ACE is calculated as the difference between actual net interchange and scheduled net interchange, adjusted by the area's frequency bias setting.

Question 4

When a large industrial load trips unexpectedly, the system frequency begins to rise. What does this indicate?

Accepted Answer

Generation is now in excess relative to remaining load

Answer

A frequency rise after load loss means generators are producing more power than the remaining load requires, creating a surplus of generation.

Question 5

Which dispatch strategy is used when system reliability is threatened and cost is secondary?

Accepted Answer

Security-constrained dispatch

Answer

Security-constrained dispatch overrides purely economic solutions to ensure transmission limits and reliability criteria are maintained.

(SOPD) System Operator/Power Dispatching Practice Test