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School of Engineering and Architecture

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Uncertainty of line parameters, particularly zero sequence components. 13 ... Sequence Network Diagram for phase A-to-ground fault. 20. Derivation of the equations ... – PowerPoint PPT presentation

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Title: School of Engineering and Architecture


1
School of Engineering and Architecture
LEBANESE AMERICAN UNIVERSITY
  • Location of Transmission Lines Faults
  • presented by Mr. Mohamad Haidar
  • Supervised by
  • Dr. Raymond Ghajar
  • Final Year Project

2
Table of Contents
  • Introduction
  • Faults
  • Types of faults
  • Fault Location Techniques
  • Derivation of Single Line-to-Ground distance
    equation
  • Tested Data
  • Future Work
  • Conclusion

3
Introduction
  • What is a Power System?

4
Faults
  • What is a fault?
  • Causes of Faults(Lightning strikes, sabotage, car
    accidents, wind damage,etc)
  • History
  • Digital Fault Recordershave voltage triggers,
    record 32 or more analogue or digital
    channels,and 720 samples/sec

5
One-Terminal DFR
6
Two-Terminal DFR
7
Types of Faults
  • Single Line-to-Ground faults(SLG)
  • Double Line-to-Ground faults(DLG)
  • Line-to-Line faults(LL)
  • Three Phase faults

8
Single Line-to-Ground(SLG)
  • SLG whenever any one phase touches
  • the ground.

9
Double Line-to-Ground (DLG)
  • DLG Whenever any two phases touches
  • the ground.

10
Line-to-Line (LL)
  • LL Whenever any two phases touches
  • each other.

11
Three Phase
  • Three Phase fault Whenever all phases touches
    the ground.

Phase A
Ifa
Zf
Phase B
Ifb
Zf
Phase C
Ifa
Zf
12
Fault Location Techniques
  • One-Terminal Data Algorithm
  • What effects the accuracy?
  • Load current in presence of high fault resistance
  • Mutual effects on zero-sequence components
  • Untransposed Lines and line charging
  • Inaccurate fault type identification
  • Uncertainty of line parameters, particularly zero
    sequence components

13
Two-Terminal Data Algorithm
14
Benefits of Fault Location and Analysis
  • Help us to identify
  • Causes of both permanent and temporary faults
  • Weak spots in the transmission network
  • Tower footing resistance , this helps to reduce
    future faults in the network, providing other
    benefits such as
  • Improved service reliability
  • Reduced maintenance and operating costs
  • Optimized equipment purchases (such as surge
    arrestors)

15
Comparison between One-Terminal and Two-Terminal
Algorithms
16
Comparison between One-Terminal and Two-Terminal
Algorithms Graphically
17
Derivation of SLG fault Distance Equation
  • Description of the system

18
Assumptions takes into consideration
  • Three phases of a transmission line are assumed
    to be transposed
  • Synchronization between the two terminals not
    needed
  • No shunt capacitances
  • No Load
  • Mutual coupling between phases is ignored
  • Source impedances, distribution factors, and
    prefault currents are not needed by the
    estimation procedures

19
Sequence Network Diagram for phase A-to-ground
fault
20
Derivation of the equations
  • Vax V1x V2x V0x _at_ bus X ..(1)
  • Vay V1y V2y V0y _at_ bus Y ..(2)
  • by KVL
  • V1x Z1xfI1xf V1f (3) V1y Z1yfI1yf
    V1f (6)
  • V2x Z2xfI2xf V2f (4) V2y Z2yfI2yf
    V2f (7)
  • V0x Z0xfI0xf V0f (5) V0y
    Z0yfI0yf V0f (8)
  • Substituting eq.(3) to eq(8) in eq.(1) and eq(2)
    and knowing that Z1xf Z2xf and Z1yf Z2yf
  • And Iaxf I1xf I2xf I0xf (9)
  • Iayf I1yf I2yf I0yf (10)

21
Final Equation
  • Lx L Im(Z1xf) / Im(Zxy)
  • Ly L Im(Z1yf) / Im(Zxy)
  • Where Zxy Z1x Z1y and L length of the
    transmission line and Lx and Ly are the distances
    to the fault from buses X and Y respectively.

22
Simulation of the Program
23
Future Work
  • Expanded to other types of faults
  • Identifying type of faults
  • Building up a network
  • Will be tested on ElectroMagneticTransients
    Program

24
Conclusion
  • In conclusion, Ive talked about the major
    aspects of a power system.
  • Personally, Ive learned a lot throughout this
    project, such as the different fault location
    techniques, and learning a new computer language
    (Visual Basic)
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