SCADA Systems 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 SCADA Systems flashcards as text
In a SCADA-based energy management system (EMS), what does the State Estimator function determine?
Answer: The most probable operating state of the power system using available measurements
The State Estimator uses redundant measurements and network topology to calculate the most likely real-time operating state, filtering out bad data and filling measurement gaps.
What action should an operator take when SCADA shows a 'communication failure' alarm for a critical substation RTU?
Answer: Verify the last known status and contact field personnel to confirm actual equipment state
With lost RTU communications, the operator must treat the last known data as potentially stale and dispatch or contact field personnel to verify actual conditions before taking action.
Which SCADA feature allows operators to prevent a control command from being sent to field equipment accidentally?
Answer: Select-before-operate (SBO) control scheme
The select-before-operate scheme requires two distinct steps—a select command followed by an operate command within a timeout window—to prevent unintended control actions.
What is 'topology processing' in an Energy Management System?
Answer: Determining the electrical connectivity of the network based on current breaker and switch positions
Topology processing uses real-time breaker and switch status from SCADA to build a current electrical network model that reflects which buses and lines are energized and connected.
How does DNP3 unsolicited reporting differ from polling in SCADA operations?
Answer: Unsolicited reporting allows the RTU to send data to the master when changes occur without waiting to be queried
In unsolicited reporting mode, the RTU initiates transmission to the master station whenever a significant change occurs, reducing latency and communication overhead compared to cyclic polling.
What is the significance of the SCADA system's 'scan rate' for critical power system measurements?
Answer: It controls how frequently the master station updates field measurements, affecting real-time situational awareness
The scan rate determines the update frequency of field measurements in the SCADA database; faster scan rates provide more current data for operators monitoring dynamic power system conditions.
In SCADA systems, what is a 'calculated point' or 'pseudo-point'?
Answer: A derived value computed mathematically from other measured points
Calculated or pseudo-points are values derived by applying mathematical formulas or logic to other measured inputs—for example, summing multiple MW flows to get a total interchange.