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22-Elec-B7 Power Systems Engineering: December 2015

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

  1. Question 1 Ferranti Effect and the Long-Line Model of a 765 kV Circuit
  2. Question 2 Excitation State and the Two-Reaction Salient-Pole Generator
  3. Question 3 Transformer Losses versus Frequency and a 50 Hz Unit Run at 60 Hz
  4. Question 4 Shunt Compensation and a Two-Bus Power Flow
  5. Question 5 Consequences of Short Circuits and a Bolted Fault on a Meshed Network
  6. Question 6 Per-Unit Sequence Networks and a Line-to-Line Fault Mid-Line
  7. Question 7 Equal-Area Criterion and the Critical Clearing Angle

Start with Question 1 →

Paper format. National Exams, December 2015 — 07-Elec-B7 Power Systems Engineering. Open-book, 3 hours. Seven problems are printed; any five constitute a complete paper and all questions are of equal value (25 points each). All seven are solved in full below, because the set is a study resource rather than a timed sitting.

Reference texts. The syllabus for this code follows M. E. El-Hawary, Electrical Power Systems: Design and Analysis (IEEE Press) — the notation used throughout this paper (the cantilever transformer model, the ABCD two-port, the two-reaction salient-pole construction) is his. Corroborating references: J. D. Glover, M. S. Sarma and T. J. Overbye, Power System Analysis and Design, 6th ed.; J. Grainger and W. Stevenson, Power System Analysis; and, for the machine chapters, S. J. Chapman, Electric Machinery Fundamentals, 5th ed. Canadian practice references where grounding and protection are discussed: CSA C22.1 Canadian Electrical Code, Part I and CSA C22.3 No. 1 for overhead systems.

Check: two points read off the printed figures. (i) Figure (1) of Problem 4 prints the line admittance as y = −j10 pu, i.e. a series reactance of j0.10 pu. The negative sign is the physically correct one for an inductive line and is used here. (ii) In Figure (3-a) of Problem 6, transformer T2 carries its delta on the generator side and T1 carries its delta on the motor side; both line-side windings are wye with a solidly earthed neutral. That reading governs the zero-sequence network built in Problem 6(a).