Load Dispatching Flashcards
7 cards from real SOPD practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Load Dispatching flashcards as text
What is the primary purpose of economic dispatch in power system operations?
Answer: Minimize total generation cost while meeting load demand
Economic dispatch allocates load among generators to minimize total fuel or operating cost while satisfying system demand and constraints.
A dispatcher observes that the system frequency has dropped from 60 Hz to 59.8 Hz. Which immediate action is most appropriate?
Answer: Increase generation output from online units
A frequency drop indicates generation is insufficient to meet load, so the dispatcher must increase MW output from available online generators.
What does 'area control error' (ACE) represent in an interconnected power system?
Answer: The difference between actual and scheduled net interchange plus frequency bias
ACE is calculated as the difference between actual net interchange and scheduled net interchange, adjusted by the area's frequency bias setting.
When a large industrial load trips unexpectedly, the system frequency begins to rise. What does this indicate?
Answer: Generation is now in excess relative to remaining load
A frequency rise after load loss means generators are producing more power than the remaining load requires, creating a surplus of generation.
Which dispatch strategy is used when system reliability is threatened and cost is secondary?
Answer: Security-constrained dispatch
Security-constrained dispatch overrides purely economic solutions to ensure transmission limits and reliability criteria are maintained.
A dispatcher is asked to evaluate 'spinning reserve.' What does this term specifically refer to?
Answer: Generation capacity that is synchronized and can increase output within 10 minutes
Spinning reserve is capacity from synchronized (online) generators that can be rapidly increased to cover sudden loss of generation or unexpected load increases.
What is the significance of the 'lambda' (λ) value in classical economic dispatch?
Answer: It represents the system marginal cost, at which all generators should operate for optimal dispatch
Lambda is the system incremental cost ($/MWh) at which the incremental cost of each participating generator is equalized for an optimal economic dispatch solution.