Power Engineering Electromagnetics ‐ EEE350 (2024‐2025)
EEE350 – Sem1 ‐ Assignment
Introduction
‐ This assignment depends on Sem 1 material.
‐ The assessment will be based on FEMM4.2 software
‐ The assignment might contain elements that have not been covered in the lectures. ‐ You should provide all workings and explanations in your solutions. Also, justify your
design selection, if any. These will variously count towards achieving full marks in this assessment.
Submission Details
You can complete your answers as a word‐processed document or as handwritten sheets (The word document is preferred). Please save or scan these respectively into a pdf file. Copy any graphs into a word document, then save them into a pdf file. Also, copy any figures or graphs from FEMM4.2 into a word document. As this submission is considered a formal report, The first‐page template is added to the same folder. Convert the first page into pdf format and merge your documents into one pdf file.
This assignment has two questions. Question 1 is an electrostatic problem, while question 2 is an electromagnetic problem. It is recommended to add a summary page for your answer.
Upload and submit your work as one pdf file via MOLE (BlackBoard) under the content area' Sem1‐Assignment 2024‐2025'; Please do not zip your pdf.
The deadline for submission is 23:59 on Sunday, February 23rd 2025.
Grades and feedback will be released after the Easter break.
The report will be marked out of 100
Question 1 is out of 55 marks
Question 2 is out of 35 marks
Ten marks for organisation and presentation (5 marks for each question)
This assignment is a MUST‐PASS ELEMENT. The minimum grade to pass is 40 %.
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 r1 and r2, 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 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)
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 L and ℜ is the reluctance).
ℜ
Calculate the value of the inductance atx = 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: atx = 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