2. Presented by
Aysha Siddika
Roll-117
Supervised by
Engr. Muhammad Shamsul Haque
Instructor (Electronics),
Mymensingh Polytechnic Institute,
Guest Teacher, Mymensingh Engineering
College,
Mymensingh
Electrical and Electronics Engineering
Department of Engineering
Mymensingh Engineering College, Mymensingh
16,January.2014

3. 16,January.2014

4. High voltage
over head line

5. The phenomenon of violet glow, hissing noise and
production of ozone gas in an overhead transmission
line is called corona

6. 16,January.2014

7. 0 50 100 150 200 250 300
2
3
4
5
6
7
8
x 10
4
Spacingbetweenconductorsincm
coronalossinfairweatherconditioninkw
Fig. 1power loss due to corona loss versus the spacing between conductors

8. 16,January.2014
Fig. 2: Corona voltage at different value of conductor radius

9. Fig. 4: power loss under
stormy and fair weather
conditions
Fig. 5: corona loss versus the
line voltage

10. Fig. 6: power loss versus
frequency
Figure 3 shows that the higher the supply frequency, the higher the
corona loss. The d.c. corona loss is less than that of a.c corona loss. The
effect of corona on a.c. lines generates third harmonic components that
increase the corona loss.

12. From calculation we see that EHVDC is more efficient than EHVAC for
reducing corona effect. Although EHVDC is not popular in our country, for
reducing loss and increasing efficiency of power system new advanced
EHVDC should be adopted. It is quite conceivable that with changed
circumstances in the electricity industry, the technological developments, and
environmental considerations, EHVDC would be the preferred alternative in
many more transmission projects.