SOPD SCADA Systems 3

Question 1

In a SCADA-based energy management system (EMS), what does the State Estimator function determine?

Accepted Answer

The most probable operating state of the power system using available measurements

Answer

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.

Question 2

What action should an operator take when SCADA shows a 'communication failure' alarm for a critical substation RTU?

Accepted Answer

Verify the last known status and contact field personnel to confirm actual equipment state

Answer

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.

Question 3

Which SCADA feature allows operators to prevent a control command from being sent to field equipment accidentally?

Accepted Answer

Select-before-operate (SBO) control scheme

Answer

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.

Question 4

What is 'topology processing' in an Energy Management System?

Accepted Answer

Determining the electrical connectivity of the network based on current breaker and switch positions

Answer

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.

Question 5

How does DNP3 unsolicited reporting differ from polling in SCADA operations?

Accepted Answer

Unsolicited reporting allows the RTU to send data to the master when changes occur without waiting to be queried

Answer

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.

(SOPD) System Operator/Power Dispatching Practice Test

(SOPD) System Operator/Power Dispatching Practice Test

SOPD SCADA Systems 3