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.
PRC-024-3 applies to the frequency protection on several parts of a generating Facility. Which protection does the standard expressly exempt?
- A. Protection on auxiliary equipment within the generating Facility
- B. Protection on the generator step-up transformer of a BES resource
- C. Protection on the high side of a unit auxiliary transformer
- D. Protection on the individual dispersed power producing resources
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Answer A Protection on auxiliary equipment within the generating Facility
Facilities Section 4.2.2 exempts protection on all auxiliary equipment within the generating Facility. The generator step-up transformer, the high side of a generator-connected unit auxiliary transformer and individual dispersed power producing resources all sit inside the standard's scope under Section 4.2.1.
Reference: PRC-024-3 Applicability 4.2.1 and 4.2.2
The Underfrequency Performance Characteristic in PRC-006-5 Attachment 1 is f = 0.575 log(t) + 57.83 Hz for times between 2 and 60 seconds. Where does that boundary sit 20 seconds into a simulation?
- A. 58.38 Hz
- B. 58.58 Hz
- C. 59.30 Hz
- D. 58.00 Hz
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Answer B 58.58 Hz
The log of 20 is 1.301, and 0.575 x 1.301 = 0.748, so the curve sits at 57.83 + 0.75 = 58.58 Hz at 20 seconds, and simulated frequency must stay above it. The 58.38 Hz value comes from the Generator Underfrequency Trip Modeling curve, which uses 57.63 in place of 57.83.
Reference: PRC-006-5 Attachment 1
