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Welcome
DESIGN AN EFFICIENT TRANSMISSION LINEREDUCING CORONA EFFECT
Presented by
Aysha SiddikaRoll-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
16,January.2014
OverviewIntroduction
• Electrical transmission system• Corona Effect• Purpose of research
EHVDC DesignCorona loss calculationResultConclusionFuture plan
16,January.2014
Introduction
Outline of Transmission System:
Power Plant Step up substationHigh voltage
over head line
The functions of a transmission system are:1. To transport electric power from a generating source 2. To transport power in bulk quantities from a central point to wholesale delivery points 3. To act as tie points with interconnecting transmission lines from other power systems for emergency or economic reasons.
16,January.2014
Corona:The phenomenon of violet glow, hissing noise and production of ozone gas in an overhead transmission line is called corona
Propose of my Research:A significant power loss due to corona reductionTo construct high and long transmission lineTo increase efficiency of transmission line
16,January.2014
EHV Overhead Transmission Line Design Map of Bangladesh
Project name: EHVDC TransmissionLocation: Khulna to Dhaka, 335kmPower rating :500 MW, monopolar.Voltage levels :400 kV DC
16,January.2014
Corona Loss CalculationAccording to peek’s formulas, under fair weather condition power loss due to corona:
0 50 100 150 200 250 3002
3
4
5
6
7
8x 10
4
Spacing between conductors in cm
coro
na lo
ss in
fair w
eathe
r con
dition
in kw
Fig. 1power loss due to corona loss versus the spacing between conductors
16,January.2014
0 0.1 0.2 0.3 0.4 0.5 0.6 0.710
20
30
40
50
60
70
80
90
Radius of conductor in cm
Voltag
e in kv to nutra
l
Visual Corona Voltage
Disrupt CriticalVoltage
Fig. 2: Corona voltage at different value of conductor radius
0 0.1 0.2 0.3 0.4 0.5 0.6 0.71.8
1.9
2
2.1
2.2
2.3
2.4
2.5
2.6
2.7x 10
4
Radius of conductors in cm
Coro
na lo
ss in
fair wea
ther
in kw
Fig.3: power loss versus size of the conductor
16,January.2014
0 10 20 30 40 50 60 70 800.5
1
1.5
2
2.5
3
3.5
4
4.5
5x 10
4Co
rona
loss
in kw
Disrupt Critical Voltage
In stormy weather
In fair weather
Fig. 4: power loss under stormy and
fair weather conditions
0 100 200 300 400 500 6000
1
2
3
4
5
6
7
8x 10
4
Cor
ona
loss
in fa
ir w
eath
er c
ondi
tion
in k
w
Line voltage in kv
Fig. 5: corona loss versus the line voltage
0 10 20 30 40 50 600
1
2
3
4
5
6
7
8
9
10x 10
4
Power l
oss in
kw in f
air wea
ther co
ndition
Frequency in Hz
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.
16,January.2014
16,January.2014
Experimental Result
From the simulation and experimental results:By using EHVDC we can decrease corona loss 66% than EHVACBy increasing spacing between conductor we can decrease corona lossBy decreasing diameter of conductor we can decrease corona loss and at 0.1cm its minimumCorona loss is more in stormy weather condition than fair weather condition
ConclusionFrom 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.
Future Plan The proposed design of EHVDC has a great scope in power system of Bangladesh and will help scheme for conversion of exciting AC transmission lines to EHVDC.
Thank you all