I.E.S COLLEGE OF ENGINEERING

CHITTILAPPILLY, THRISSUR

POWER UPGRADING OF TRANSMISSION LINE

BY COMBINING AC-DC TRANSMISSION

GUIDED BY:

EDISON A.J

ASST.PROFESSOR

EEE DEPT.

IESCE

PRESENTED BY:

GROUP NO. 10

DHANESH K.N (09)

JASIM N.C (17)

MUKHTHAR U.P (34)

SULFATH N.P (52)

VEENA VIVEK (55)

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OVERVIEW

• OBJECTIVE

• INTRODUCTION

• SCHEMATIC DIAGRAM

• MATLAB SIMULINK MODELS

• SIMULATION GRAPHS

• ANALYSIS

• ADVANTAGES

• CONCLUSION

• PROJECT REVIEW

• BIBLIOGRAPHY

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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.

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BASIC SCHEME FOR COMPOSITE AC-DC

TRANSMISSION

SIMULATION OF EHV-AC TRANSMISSION

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RESULT

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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

𝑃′𝑡𝑜𝑡𝑎𝑙 ≈ 3𝑉𝑝ℎ2 sin 𝛿 /X

• AC current per phase per circuit of the line.

𝐼𝑎 = V (sin 𝛿/2)/X.

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

• Total power = 𝑃𝑎𝑐 + 𝑃𝑑𝑐.

• Power transfer through AC-DC combined line

𝑃𝑡𝑜𝑡𝑎𝑙 ≈ 3𝑉𝑝ℎ2 sin 𝛿 /X+ 2𝑉𝑑 𝐼𝑑.

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MASTERCONTROL

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• The Master Control system generates the current reference for both

converters.

• Initiates the starting and stopping of the DC power transmission.

• The protection systems can be switched on and off.

• At the rectifier, the DC fault protection detects a fault on the line and takes

the necessary action to clear the fault.

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SIMULATION OF RECTIFIER SIMULATION OF INVERTER

AC FILTER

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Reactive power ,

𝑄𝑐 = (𝑉2/ 𝑋𝑐 )·𝑛2/((𝑛2 – 1)

Tuned harmonic order,

n= 𝑓𝑛/ 𝑓1.

Quality factor,

Q = n 𝑋𝐿 /R = 𝑋𝑐 /(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

AC VOLTAGE

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AC CURRENT

AC TRANSMISSION

SENDING END POWER

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RECEIVING END POWER

ACTIVE

REACTIVE

ACTIVE

REACTIVE

COMBINED AC –DC

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VOLTAGE

CURRENT

DC CURRENTS

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RECTIFIER AND INVERTER DC CURRENTS

SENDING END POWER

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RECEIVING END POWER

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ANALYSIS

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Power (MW)

Thermal limit 0f 115kV 615

Power transfer of double circuitAC line

328

Power transfer of combinedAC-DC system

607

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 % .

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PROJECT REVIEW

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MONTH STATUSJune 2013 Proposal & finalisation of topic

July 2013 Research for thesis

August 2013 Zeroth Presentation

September 2013 Data collection

October 2013 1st review presentation

December 2013 Simulation of AC started

January 2014 Output obtained

February 2014 Simulation of AC DC started

April 2014 project completed

BIBLIOGRAPHY

• Basu and B. H. Khan-Simultaneous ac-dc power transmission.

• H. Rahman and B. H. Khan, ―Enhanced power transfer by Simultaneous

transmission of AC-DC: a new FACTS concept.

• T.Vijay Muni, T.Vinoditha, D.Kumar Swamy - ―Improvement of Power System

Stability by Simultaneous AC-DC Power Transmission

• N. G. Hingorani, ―FACTS—flexible A.C. transmission system,‖ in Proc. Inst.

Elect. Eng. 5th. Int. Conf. A.C. D.C. Power Trans- mission

• L. K. Gyugyi et al., ―The unified power flow controller; a new approach to

power transmission control,‖ IEEE Trans. Power Del., vol. 10, no. 2, pp. 1085–

1097, Apr. 1995.

• Kundur, Power System Stability and Control. New York: Mc-Graw-Hill, 1994.

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THANK YOU