Power Engineering Electromagnetics ‐ EEE349/EEE350 (2024‐2025)
EEE349/EEE350 – Sem1 ‐ Assignment Introduction
Question 1 [60 marks]
A single core lead sheathed cable with voltage (60+m) kV shown in figure 1 has a conductor radius of R = (15 + m/2) mm and two layers of insulating material with relative permittivity εr1 and εr2, respectively. The radii of layers 1 and 2 are r1 = (30 + m/2) mm and r2 = (35 + m/2) mm respectively. Choose the material of layer 1 as Polypropylene (you can modify the property to match your design). Choose the material of layer 2 as PVC (you can change the property to match your design). The conductor is copper (You can add a new property as a copper conductor and select a valid value for the permittivity of the copper conductor).
Figure 1: Cross section of the underground cable
Hints: Design requirements:
● Choose a planar solution
● Use length units in millimetres
● Depth 1000 mm.
● Add a boundary layer filled with air.
● Choose your mesh not higher than 0.5 mm to improve the solution's accuracy.
In your report,
a‐] Calculate the voltage for each layer [5 marks]
b‐] The maximum and minimum electric field for each layer. [5 marks]
c‐] The capacitance of each layer and the total capacitance [5 marks]
d‐] Using FEMM4.2, Draw the cable including the contour line. Add a picture to your report. [ 5 marks]
e‐] Show voltage distribution on the cable cross‐section, plot the voltage against the contour line, and then measure layers one and two voltages to confirm the analytical results of part [a]. [5 marks]
f‐] Show the electric field distribution and electric field tensor on the cable cross‐section. Plot the electric field against the contour line, then measure the maximum and minimum values of the electric field to confirm the analytical results of part [b]. [5 marks]
g‐] Measure using the FEMM4.02 software the total charge and calculate cable capacitance. Comment on the results with respect to part [c]. [5 marks]
h‐] Repeat parts [d] to [g] for the Square cable shown in figure 2, but plot for both contour line 1 and contour line 2 [10 marks]
i‐] comment between the results of the square cable and cyclindrical one [10 marks]
Figure 2: Cross section of the square cable
Note:
Five marks are allocated for report organisation/presentation.
Question 2 [40 marks]
Figure 2 shows a solenoid system. The coil has a resistance of 2 Ω and the number of turns N = (500+2*m) turns. the air‐gap length has the boundaries (0 < x < 20 mm). The iron material is Mild‐steel M‐50. (Note: The figure is not drawn to scale)
Figure 2: solenoid system
The problem conditions:
‐ Electromagnetic problem
‐ Choose a planar solution,
‐ Length units in millimetres, and
‐ Choose your mesh for not higher than 0.5 mm to improve the accuracy of the solution.
‐ Add boundary to your solution
‐ Consider nonmagnetic sleeve as air
In your report:
a‐] Calculate the coil inductance function of x (Where and is the reluctance). Calculate the value of the inductance at x = 0‐, 10‐, and 20 mm [10 marks]
b‐] Calculate the coil current if the current density is (3.8+0.05m) A/mm2. The filling factor is 55 %. [5 marks]
c‐] Attach a schematic diagram using FEMM4.2 software with the required contour. [5 marks]
d‐] For the solenoid system shown in figure 2, show the flux density and flux tensor for x = 0‐, 10‐, and 20 mm. Plot on the same graph the flux density against the contour line for x = 0‐, 10‐, and 20‐mm. Record the flux density value at the points P and Q for each x value (Note: at x = 0 mm, the point P and point Q are the same point). Comment on the results [15 marks]
Note:
Five marks are allocated for question organisation/presentation