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