SOPD Load Forecasting & Energy Scheduling 2 — Questions and Answers
Question 1: Which factor most commonly causes a load forecast to UNDERESTIMATE actual demand during a heat wave?
- Overestimating industrial load
- Underestimating residential air conditioning saturation (Correct answer)
- Using too long a forecast horizon
- Applying peak shaving algorithms
Correct answer: Underestimating residential air conditioning saturation
Residential AC saturation is often underestimated, causing significantly higher-than-forecast cooling loads during extreme heat events.
Question 2: A system operator receives a day-ahead forecast showing a 15% demand increase at 5 PM due to a major sporting event. Which action is MOST appropriate?
- Ignore the forecast since events are unpredictable
- Pre-position additional spinning reserves before the event (Correct answer)
- Wait until 4:45 PM to dispatch additional generation
- Reduce scheduled interchange exports by 50%
Correct answer: Pre-position additional spinning reserves before the event
Pre-positioning spinning reserves ensures the system can respond quickly to the anticipated demand surge without relying on slow-start units.
Question 3: In energy scheduling, the term 'economic dispatch' refers to:
- Dispatching generators based solely on voltage support capability
- Allocating generation output to minimize total fuel cost while meeting load (Correct answer)
- Scheduling energy imports to minimize wheeling charges
- Distributing load equally among all online generators
Correct answer: Allocating generation output to minimize total fuel cost while meeting load
Economic dispatch allocates generation among committed units to meet system load at the lowest possible total production cost.
Question 4: A short-term load forecast for the next 4 hours shows demand declining steadily. Which generation scheduling action is MOST appropriate?
- Commit additional baseload units for reliability margin
- Begin decommitting peaking units according to their minimum down-time constraints (Correct answer)
- Increase spinning reserve requirements by 20%
- Dispatch units at maximum output to build energy reserves
Correct answer: Begin decommitting peaking units according to their minimum down-time constraints
As forecast demand declines, operators de-commit peaking units while respecting minimum down-time constraints to avoid mechanical damage.
Question 5: What is the primary purpose of a 'load pocket' analysis in energy scheduling?
- To identify areas where generation exceeds transmission capacity
- To locate transmission-constrained areas that require local generation (Correct answer)
- To schedule pumped storage hydro operations
- To calculate reactive power compensation needs
Correct answer: To locate transmission-constrained areas that require local generation
Load pocket analysis identifies areas electrically isolated by transmission constraints, requiring local generation that may be more expensive to dispatch.
Question 6: Which of the following is a key difference between a 'firm' and 'non-firm' energy schedule?
- Firm schedules cannot be curtailed, while non-firm can be interrupted during congestion (Correct answer)
- Firm schedules are always cheaper than non-firm schedules
- Non-firm schedules have priority during emergency conditions
- Firm schedules apply only to renewable generation
Correct answer: Firm schedules cannot be curtailed, while non-firm can be interrupted during congestion
Firm energy schedules are contractually protected from curtailment, while non-firm schedules may be interrupted when transmission congestion occurs.
Question 7: When a load forecast model uses weather normalization, the purpose is to:
- Adjust forecasts to account for daylight saving time changes
- Remove the effect of abnormal weather to reveal underlying load trends (Correct answer)
- Normalize voltage across the service territory
- Scale load forecasts to match historical peak demand records
Correct answer: Remove the effect of abnormal weather to reveal underlying load trends
Weather normalization removes the influence of unusual temperatures or humidity so operators can analyze true load growth trends independent of weather anomalies.
SOPD Load Forecasting & Energy Scheduling 2
Which factor most commonly causes a load forecast to UNDERESTIMATE actual demand during a heat wave?