SYNERGY INSTITUTE OF ENGINEERING AND TECHNOLOGY

SEMINAR ON:DE-ICING OF TRANSMISSION LINE BY dielectric losses

Under the guidance of:-Mr. AUROBINDO BEHERA(Asst.prof.)

Presented By:-Bhabani Sankar CharanEE-12-921201230197Electrical engineering

DEPARTMENT OF ELECTRICAL ENGINEERING

CONTENTS1. Introduction2. Need of deicing3. What is dielectric loss? 4. Application of high frequency5. Types of De-icing process6. Principle of ice dielectric heating7. Additional consideration8. Advantages9. Disadvantages10. Conclusion11. References

INTRODUCTION

When accretion of ice takes place over the conductor then icing occurs.

Icing of power transmission lines during winter storms is a persistent problem, causing outages and costing millions of rupees in repair expenses.

Deicing is a process in which ice can removed from the iced wire.

For de-icing of high voltage transmission lines a high frequency excitation at approximately 100kHz proposed.

NEED OF DEICINGEquipment failure

Tilting and collapsing of tower

Economic loss

DIELECTRICA material that conducts electricity poorly or

not.However ,under certain condition ,dielectric

material can breakdown and conduct current.When electric field applied, flow of electron

occurs for that time only.As soon as electric effect is reamed, dipole

condition settles down and again becomes insulator.

What is DIELECTRIC LOSS??A portion of the energy of an alternating

electric field in a dielectric medium that Leads to heat evolution.

Dielectric losses depends on frequency and the dielectric material.

APPLICATION OF HIGH FREQUENCY

Fig 1-De-icing of power lines by applying high frequency high voltage

TYPES OF DE-ICING PROCESS

Deicing using roller

Dielectric heating

Skin effect heating

DE-ICING USING ROLLER

Fig 2-De-icing process using roller

DIELECTRIC HEATING

Fig 3-Equivalent circuit for ice-coated transmission line

Ice modeled as a dielectric material, the equivalent Circuit for a short section of transmission line Coated with ice is shown in figure.

The dielectric properties become sufficiently lossy to generate significant heating.

SKIN EFFECT HEATINGThe crowding of

current near the conductor surface is called skin effect.

Fig 4- Skin effect heating

ACHIEVING UNIFORM HEATING

Fig 5-Combined ice dielectric and skin-effect heating at 60 KHz

Fig 6-Combined ice dielectric and skin-effect heating at 100 kHz, where we estimate the two effects are optimally balanced

ADDITIONAL CONSIDERATION

EMI

CORONA

ADVANTAGESIn this study we get a cost effective approach.This technique is applicable for live line

conductors.It reduces the tension produced by icing.

DISADVANTAGESIt can cause interference with radio

communication system.

CONCLUSIONCombined di-electric heating and skin-effect

heating can be used to achieve uniform heating , and thus dielectric loss takesplace.

The application of 100 kHz electric fields to melting ice on power transmission lines appears promising.

REFERENCES

1. To deice transmission line with 100khz high voltage excitation by Charles R. Sullivan and victor F. Petrenko .Thayer school of engineering.

2. Principles of power system by V.K Mehta and Rohit Mehta.

3. www.brighthub.com