Which of the following has the largest resistance?
Which of the following has the largest reactance?
True/false: Conductor resistance increases as temperature decreases.
To protect against burndown on covered conductors, arc protective devices should be placed where? Mark all that apply.
Which type of fault is most likely to cause conductor slapping.
Mark which of the following are true for conductor slapping?
Which has the larger diameter?
Which has the larger diameter?
Which has the higher ampacity?
Which has the lower weight?
Which of the following may cause radio frequency interference? Mark all that apply.
True/false: Increased phase separation increases the zero-sequence reactance.
For a conductor temperature of 90C and an ambient temperature of 25C, which of the following is true for 336 AAC conductor?
True/false: Conductor annealing from faults is a function of I^{2}t.
True/false: Conductor burndown from faults is a function of I^{2}t.
Mark which of the following are true related to burndowns?
A typical overhead feeder mains positive sequence impedances per mile is:
If Va = 1.02 ∠0°, Vb = 1.0 ∠-119°, and Vc = 1.01∠119°, find V_{1}, V_{2}, and V_{0}. Which is larger, V_{0} or V_{1}?
Calculate the current needed for the “typical burndown” case to burn down 556 AAC in 0.5 sec.
Calculate the current needed to anneal 556 AAC in 0.5 sec.
Find the critical conductor slapping times for both 44- and 56-in spacings for a span length of 300 ft and a fault current of 4 kA.
For 350-kcmil Al conductor with an ampacity of 361 A at an ambient temperature of 25C and a conductor temperature of 75C, find the ampacity at an ampient temp of 30C and a conductor temperature of 90C.
For the following overhead line, find Z_{1}, Z_{0}, Z_{s}, and Z_{m} in ohms/1000ft:
For the parameters in the problem above, find the complete 4x4 impedance matrix of the circuit in ohms/1000ft.
Using these same line characteristics, calculate the phase voltages and the sequence voltages at the load for the following:
[OpenDSS] Repeat the previous question using OpenDSS.
Consider a double-circuit line with the following characteristics:
a1 b1 c1
a2 b2 c2
n
The vertical distance between the phase conductors is 3 ft. The horizontal distance between conductors is 4 ft. The neutral is 8 ft below b2.
For an a1-to-n fault that’s 4 miles from the substation that draws 4 kA, calculate the voltage at the fault location on phase a2. Assume that circuit 2 is a 12.5-kV circuit, and that circuits 1 and 2 have the same phasing. Assume no other loading on either circuit.
Ampacity
Write an ampacity program in R, Matlab, Octave, a spreadsheet, or other tool.
Impedances
Write a program to calculate overhead impedances in R, Matlab, Octave, a spreadsheet, or other tool.
Conductor slapping (challenging)
Write a program to dynamically model conductor slapping.
To the extent possible under law, Tom Short has waived all
copyright and related or neighboring rights to these study
questions. This work is published from the
United States. Please use this material however you want.