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In The Name of GOD SIMULTANEOUS VOLTAGE CONTROL OF SEVERAL LOADS ON FEEDERS OF A DISTRIBUTION...
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Transcript of In The Name of GOD SIMULTANEOUS VOLTAGE CONTROL OF SEVERAL LOADS ON FEEDERS OF A DISTRIBUTION...
In The Name of GOD
SIMULTANEOUS VOLTAGE CONTROL OF SEVERAL LOADS ON FEEDERS OF A
DISTRIBUTION SUB-STATION USING
FUZZY MODELING AND FUZZY OPTIMIZATION
A. Ebrahimi A. Zolfaghari S.Mohseni
Electrical and Comp. Eng. Department
Isfahan University of Technology, IRAN
Barcelona 12-15 May 2003
A.Ebrahimi_ir_Session3_block1_slide1
Scope of this paper
• A new algorithm for simultaneous voltage control of several loads located on various feeders of a distribution sub-station
• Using Fuzzy Modeling and Fuzzy Optimization
• According to actual limitations
Barcelona 12-15 May 2003
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Usual Methods for Load Voltage Regulation
• Using Automatic switched shunt capacitors.
• Using Dynamic voltage regulators.• Using A.V.R. & Tap Changer Systems at
Distribution Substations.
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Limitations:
• Variation of loads and their power factor • The loads are distributed along the feeder • High voltage drop during peak and over voltage
during off-peak hours• Different behaviors of various loads• Different sensitivity of loads to voltage deviations• ِِ��At last but not least : No Remote Controlled
Switch and no Monitoring Systems are usually available
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There is an Optimization Problem!
Max : D = Min [i1 (Vi ) , i2 (Vi )]
S.T. : VA = Vi + Ri Ii COS Øi + Xi Ii SIN Øi
VAmin VA VA
max
For all i =1, 2,…, n
D is the decision fuzzy set defined as the intersection of fuzzy sets i
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Why Fuzzy Modeling
& Optimization?
• Fuzzy nature of loads and voltage variations
• Approximate data and rare of information
• No measurement and monitoring systems are available at most load points
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The Proposed Algorithm
• By FLP and some approximations:
VA = Vi + Ri Ii COS Øi + Xi Ii SIN Øi
• VA is the magnitude of low voltage side of transformer at sub-station
• Vi is the voltage of load i
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Triangular Membership Function
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WhyTrapezoidal membership functions?
• Representing a more realistic modeling for flexible constraints.
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Especial loads &
Their Priority in Voltage Regulation
• By priority factors (i ) multiplied to membership functions
• Decreasing acceptable bound of membership function
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Case Study
• A distribution sub station with 4 radial feeders• Loads assumed constant and at the end of feeders• Using triangular and trapezoidal membership
functions for voltage fuzzy sets• Using several priority factors
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• A symbolic view of the test system
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CONCLUSIONS
• Simultaneous voltage control of loads located at several distribution feeders
• Priorities for especial loads considered
• Useful and applicable in systems without remote controlled switches and monitoring system
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Thanks For Your Attention
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33Bridge-Isfahan-Iran