Fault Location in Transmission Networks Using Modeling, Simulation and Limited Field Recorded Data

1
Fault Location in Transmission Networks Using
Modeling, Simulation and Limited Field Recorded
Data

• M. Kezunovic (P.I.)
• S. S. Luo
• D. Ristanovic
• Texas AM University

PSerc Review Meeting College station, Nov. 7,
2002
PSERC
2
Overview

• Objectives
• Testing procedure data requirements and test
  results
• Potential problems and improvement
• Design and User documentation
• Conclusions
• Future Research

3
Objectives

• Defining procedure to be used for testing
• Defining requirements regarding input data
• Testing using fault data collected from Center
  Point Energy
• Testing using fault data collected from other
  utility
• Analyzing and evaluating the performance and
  proposing potential improvements
• Improving the software and developing user
  interface
• Developing the design and user documentation for
  facilitating future upgrades and practical use of
  the software

4
Testing procedure

• Using static system model
• Obtaining the fault data file from utility and
  then converting into COMTRADE format
• Producing the input data file based on the
  available DFR files
• Checking the corresponding substation
  interpretation files based on the DFR
  configuration and system file
• Running the software and obtaining the estimated
  location
• Comparing the estimated result to the actual or
  calculated result
• When using updated system model
• Extracting parameters from the model and
  producing the topology data file before executing
  the above steps

5
Data requirement

• When using static system model
• Fault case data
• fault data file in COMTRADE format (DFR raw data
  is need to be converted)
• fault report (optional)
• actual fault location (optional)
• System data
• Load flow and short-circuit model including
  topology
• Interpretation file for each monitored substation

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Data requirement, Cont.

• Input data file generated by user based on
  available DFR files
• Necessary fault information including the fault
  type, affected fault circuit
• Options how to produce a list of possible faulted
  branch candidates
• Algorithm parameter file
• Including iteration number, crossover and
  mutation possibilities, population number
• When the more accurate model is required
• Additional real power flow data is needed

7
Testing

• 15 fault cases obtained from Reliant Energy HLP
  were tested
• Power system simulator PSS/E is utilized
• PSS/E models in versions 26, 27, 28 are tested
• Sensitivity of results under different options is
  analyzed
• Static model and tuned model are used

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Testing

• Using fault data collected from TVA or other
  utility to test fault location
• The item was changed because data is not obtained
• Instead, different power system simulation
  software was used
• CAPE is a new selection
• PSS/E system model is converted into CAPE
  database
• Short circuit results obtained from the PSS/E and
  from CAPE are compared
• The fault location software is customized for
  CAPE
• Test result is not available because current
  version of CAPE is not perfect

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Test results (1)
Case Number of DFR triggered Actual or calculated fault location Estimated fault location Error
1 2 41111-41700 0.40 mile 41111-41700 0.2 mile 0.2
2 2 48402-40590 3.32 miles 48402-40590 3.32 miles 0.3
3 1 41300-48386 3.49 miles 41300-48386 3.15 miles 0.3
4 3 40570-41405 2.50 miles 40570-41405 2.47 miles 0.0
5 1 46262-48306 2.0 miles 46262-48306 1.18 miles 0.8
6 1 46570-48219 1 mile 46570-48219 0.1 mile 0.9
7 1 46570-48219 2.8 miles 46512-4830 6.1 miles 3.3
8 1 46262-48306 3 miles 46262-48306 5.7 miles 2.7
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Test results (2)
Case Number of DFR triggered Actual or calculated fault location Estimated fault location Error
9 1 5915-9073 66.0 miles 5915-9073 66.9 miles 1.0
10 1 45840-40180 3.8 miles 40180-40620 0.4 mile 0.9
11 3 40620-48295 2.36 miles 40620-48295 2.13 miles 0.2
12 2 46020-3390 7.77 miles 46020-3390 6.54 miles 1.2
13 2 46020-3391 7.77 miles 46020-3391 6.2 miles 1.6
14 2 46020-3391 7.77 miles 46020-3391 4.77 miles 3.0
15 2 46020-3390 7.77 miles 46020-3390 7.09 miles 0.7
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Problems and improvements

• Some factors affected estimated fault location
  accuracy
• Fault cycle
• Faulted branch candidates
• Phasor calculation
• Model
• GA result

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Problems and improvements

• Fault cycle
• - Problems
• For each triggered DFR, correct cycle to
  calculate the during-fault phasor should be used.
  
• For several triggered DFRs, the the same cycle to
  calculate the during-fault phasor should be use
• - Improvements
• The criteria of determining fault cycle is
  improved
• Additional measurements are taken to avoid using
  different fault cycles
• In the user interface part, a new feature is
  added for user to specify the exact fault cycle
  

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Problems and improvements

• Branch Candidates
• - Problems
• The produced list of candidates must include the
  faulty branch, which creates a large number of
  choices
• - Improvements
• Additional options are added for user to choose
  the method of producing candidates
• user can check the detail list of possible
  faulted branch candidates and edit it before the
  fault location software runs

14
Problems and improvements

• Phasor calculation
• - Problems
• Waveform includes DC offset and high
  frequency
• components, which affects the accuracy
• Improvements
• Using improved Fourier algorithm for obtaining
  the during-fault recorded phasor
• Filter the noise contained in recorded waveforms

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Problems and improvements

• Model
• - Problems
• The static PSS/E model provided by utility may
  not reflect the real system operation condition
  when a fault occurs
• Tuning generator and load power as well as
  tuning the system topology is required
• - Improvements
• Using different version of PSS/E model with
  different topology and parameters
• Tuning static parameters. Two situations are
  considered
• No additional real data is available. The concept
  of pre-fault phasor matching is introduced. Some
  cases show that tuning is effective
• Additional real data is available, generator and
  load power scaling is utilized

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Problems and improvements

• Genetic algorithm convergence
• - Problems
• Fixed iteration number may not always approach
  the final solution
• For different runs, GA result may vary within a
  specific range
• - Improvements
• Using fitness scaling to solve the small
  population
• Using multi-point crossover to increase
  the search space
• Using new replacement of weak parent
  to make GA more
• robust
• Studying behavior of the fitness value
  add a criteria using
• the average fitness
• Adding a feature to give an exact
  result after using GA limit
• search range in the user interface part

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Design and user documentation

• Limited development of user interface for
  practical use
• Fault location software design documentation and
  users guide are produced for software upgrade

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Conclusion(1)

• The test results show that the scheme of matching
  waveforms to locate a fault is feasible
• Multiple triggered DFRs are helpful for improving
  location accuracy
• It is suggested to use all the recorded currents
  and voltages for matching
• It is suggested to use the same fault cycle to
  calculate during-fault phasors for each DFR

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Conclusion(2)

• Tuning system model and making it fit the
  operation condition when the fault occurs helps
  producing more accurate results, especially when
  additional real data is available.
• It is suggested that the fault resistance is set
  within a reasonable range, especially in 345KV
  system
• Producing a right list of faulted branch
  candidates before running fault location software
  is very helpful

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Future research

• How to obtain and incorporate more accurate model
  data
• How to make the users knowledge more useful
• How to incorporate an iterative approach between
  running the program and having the user look at
  the results and make some practical choices
• How to interface the program to variety of short
  circuit programs
• How to obtain more data for further evaluation of
  the performance

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• Thank you!