Free sample: 2 of 45
Answer each one before you open the explanation. On the exam there's no explanation, and you have about 77 seconds a question on RC and BT, 90 on TO and BI.
A steady-state contingency analysis run checks flows and voltages. How may a Reliability Coordinator assess instability, Cascading and uncontrolled separation for the Contingencies it studies?
- A. By predetermined stability limits or offline analysis
- B. By the same steady-state run that checks the flows
- C. By the state estimator's bad-data and residual checks
- D. By the Undervoltage Load Shedding Program's settings
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Answer A By predetermined stability limits or offline analysis
FAC-011-4 states that assessments of instability, Cascading and uncontrolled separation may be performed with real-time stability assessments, predetermined stability limits or other offline analysis techniques. A steady-state solution reports flows and voltages only, and the methodology is barred from leaning on Undervoltage Load Shedding Programs when stability limits are established.
Reference: FAC-011-4 R6, footnote 1; R4, Part 4.7
A bus sits at 0.97 per unit before the Contingency and at 0.91 per unit after it, against an emergency low limit of 0.92 per unit. How deep is the exceedance?
- A. 0.06 per unit below the emergency limit
- B. 0.01 per unit below the emergency limit
- C. 0.05 per unit below the emergency limit
- D. 0.01 per unit above the emergency limit
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Answer B 0.01 per unit below the emergency limit
The post-Contingency voltage is what the emergency limit is tested against: 0.92 - 0.91 = 0.01 per unit below the limit. The 0.06 per unit figure is the drop from the pre-Contingency voltage and 0.05 per unit is the pre-Contingency margin, and neither is the exceedance.
Reference: FAC-011-4 R6, Part 6.2.2; power system fundamentals
