POWER UPGRADING OF TRANSMISSION LINE BY COMBINING AC-DC TRANSMISSION

GUIDED BY:

MR. GAURAV PANDEY

EE DEPT.

PRESENTED BY:

GROUP NO. 21 AMIT TRIPATHI MOHD. MUJAHID VINEET RANJAN

EE-7

4SR

MG

PC

OVERVIEW

• OBJECTIVE

• INTRODUCTION

• SCHEMATIC DIAGRAM

• MATLAB SIMULINK MODELS

• SIMULATION GRAPHS

• ANALYSIS

• ADVANTAGES

• CONCLUSION

• PROJECT REVIEW

• BIBLIOGRAPHY1

OBJECTIVE

• Power transfer enhancement , without any alteration in

the existing Extra High Voltage AC line.

• To utilize the advantage of parallel ac–dc transmission

by loading the line close to its upper thermal limit.

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INTRODUCTION

• Long extra high voltage (EHV) ac lines cannot be loaded to

their thermal limits in order to keep sufficient margin against

transient instability.

• In simultaneous ac-dc power transmission system, the

conductors are allowed to carry dc current superimposed on

ac current.

• The added power flow does not cause of any transient

instability.3

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BASIC SCHEME FOR COMPOSITE AC-DC TRANSMISSION

SIMULATION OF EHV-AC TRANSMISSION

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SIMULATION OF EHVAC-DC TRANSMISSION

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DESIGN

• 115kV, 50Hz, 450 km D/C AC transmission line

• The total power transfer through the circuit line

sin /X

•AC current per phase per circuit of the line.

= V (sin /2)/X.

• Transfer reactance per phase, X = 74.4435 ohm/ph.

• Total power = + .

• Power transfer through AC-DC combined line

sin /X+ 2 .7

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SIMULATION OF RECTIFIER SIMULATION OF INVERTER

AC FILTER

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Reactive power , = (/ )·/(( – 1)

Tuned harmonic order, n= / .

Quality factor, Q = n /R = /(n R)

Where, fn – tuning frequency f1- fundamental frequency

SIMULATION GRAPHS

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AC ALONE:

• AC VOLTAGE: SENDING END, RECEIVING END

• AC CURRENT: SENDING END, RECEIVING END

• SENDING END POWER: ACTIVE, REACTIVE

• RECEIVING END POWER: ACTIVE, REACTIVE

AC-DC COMBINED:

• VOLTAGE: SENDING END, RECEIVING END

• CURRENT: SENDING END, RECEIVING END

• DC CURRENT: RECTIFIER, INVERTER

• SENDING END POWER: ACTIVE, REACTIVE

• RECEIVING END POWER: ACTIVE, REACTIVE

ADVANTAGES

• Conductors can be loaded close to their thermal limit.

• The power flow does not impose any stability problem.

• No alterations of conductors, insulator strings or towers of the original line are needed.

• Helps to improve stability and damping out of oscillations.

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CONCLUSION

• The merits to convert existing double circuit ac transmission line to

composite ac-dc transmission line for substantial power upgrading

have been demonstrated.

• Studied that there is substantial increase in the load ability of the

line.

• The load ability further increases with increase in the length of line.

• The line is loaded near to its thermal limit with the superimposed dc

current.

• The capacity of the transmission line is increased by 85.06 % .12

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THANK YOU