Distribution Systems Fault Analysis

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Distribution Systems FaultAnalysis

Laurentiu Nastac and Anupam Thatte

Concurrent Technologies Corporation (CTC )

May 25, 2006



2

Objective

• Integrate an intelligent, operational, decision-support (fault locator) software tool to predict

the location of low impedance, momentary andpermanent (more than one minute) faults indistribution power systems



3

Background:

Identified Simulation and Modeling Tools

www.pscad.comManitoba Research Center (PSCAD)

www.tekla.comTekla Corporation (Tekla Xpower)

www.otii.comOptimal Technologies (AEMPFAST)

www.rtds.comRTDS Technologies (RTDS)

www.cyme.comCYME International (CYMDIST)

www.pti-us.comSiemens PTI

(PSS/E™ and PSS/ADEPT ™)

www.samsixedd.comElectrical Distribution Design (EDD)

Distribution Engineering Workstation (DEW)

www.dmsgroup.co.yuDistribution Management System

Application Software Group (DMS)

Company URLCompany / Software Product Name



4

• Stand alone tool – Easily integrated in network fault analysis software platform

as a post-processing tool

– Easily integrated as module (.dll - dynamic link library) inDEW/AEMPFAST/PSCAD/CYMDIST

• Combined heuristic/genetic algorithm (GA) – Rule-based approach – Use GA to minimize errors between measurements and

expected parameters – Quick runs – Adequate quality (experimentally validated)

• Operational decision-support tool

– Uses real time data for • Load conditions• Recorded currents• Recloser status• Customer (trouble) calls

Fault Locator Software Integration:

Features



5

• Thevenin-Norton (e.g., Thevenin) analysis to predictthe fault currents in circuit components [1, 2]

• Measured faulted circuit data from DTE used tovalidate network fault analysis method – Approximately 10% typical errors exist in predicting the fault

currents for distribution systems [1, 2]

– Preload-conditions & fault impedance accounted for [1, 2]

– Accuracy in predicting fault currents does not significantlydepend on the distance from the fault location to thesubstation [3]


Technical Approach

[1] L. Nastac et al., 8th IASTED International Conference on Power and Energy Systems,PES2005, October 24-26, 2005, Marina del Rey, CA.

[2] L. Nastac et al ., IEEE 37th North American Power Symposium , October 23-25, 2005, Ames, Iowa.[3] L. Nastac, Personal Communication , DTE, December 29, 2005.



6


Network Fault Analysis with DEWComparison (% Err) of measured (DTE faulted data) and predictedresults with DEW*

% Err = 100 * (Meas I c – Calc I c ) / Meas I c

Calc I c – calculated post-fault phase C currentMeas I c – measured post-fault phase C current

*Post-fault current includes both fault current and load current

1.41

-9.8075%

-2.11

-12.90100%

Err [%]

Arcing [Ohm]

Pre-faultLoading



7

• Algorithm Rules

– Rule #1: Compare predicted fault currents with measured /recorded fault currents (from the substation,modern reclosers, etc.)

– Rule #2: Recloser status (open/close)

– Rule #3: Recloser V&I RMS values (if available) – Rule #4: Customer (trouble) call input file (if available)

– Rule #5: Time synchronized phase angles and waveformsas well as transient RMS current and voltagevalues (if available)


Technical Approach



8


Procedures

4. Knowledge-based engineDatabase of signature libraryHeuristic rules / GA minimization

5. Customer (trouble) calls?

2. Compute load and fault currents in theselected branch componentsCompare them with recorded currents

1. Read input data:Distribution System & Component dataRecorded currents at substationRecloser information & Trouble call records

6. Perform back-trackingfrom customers to narrowdown fault locations

3. Use recloser information to determinecircuit branches related to fault region

7. Plot fault locationsWrite fault location report

YES

NO

A

A



9

• Evaluating a GA to perform a minimization for eachcircuit branch to narrow down the possible faultlocations


Technical Approach

Substation -relay

Recloser –fault

location

Substation -relay

Recloser –fault

location

Fault

Customer call

Recloser Branch #1

Branch #2

Branch #3

Branch #4

Branch #5



10

Fault Locator Software Implementation:

DTE’s Orion Circuit

Zoom area

LegendBlue – Circuit componentsBlack – Fault currentsRed – Predicted faults locations

Simulated

Experimental



11

LegendBlue – All components (1078)Black – Fault currents (≤10% Error) = 88Red – Possible faults locations = 43Green – Recloser Light Blue – Customer (trouble) call

a) No faults b) Fault currents c) + Recloser & trouble calls


Predictions of Faults (DTE’s Orion)Recloser Trouble call Fault location



12


Predicted Results

Phase II43Phase II67881078(all components

selected)

6500Orion #2July 4, 2003

6500

Distancefromfault

locationto

substation[ft]

Phase II9Phase II19231078(125 selected*)

Orion #2July 4, 2003

Rule #5

Other intelligences(GA, ANN,waveforms,

phase angle)

Rule #4

Customer trouble

callinput file

Rule #3

Recloser current/voltageRMS

values

Rule #2

Recloser status

Rule #1

Current

Number of system

components

DTEFaulted

Circuit Name

Predicted numbers of possible fault locations

*Selected components were defined by DTE as the most likely components to failduring an outage event



13

2401

1078

1078

2300

Number of system

components

19100

6500

6500

6900

Distancefromfault

locationto

substation[ft]

Phase II4Phase II823169Mac

Phase II9Phase II1923125Orion#2

Phase II6Phase II1721125Orion#1

Phase II3Phase II812188Clark

Rule #5c

Other

intelligences(GA, ANN,waveforms,

phase angle)

Rule #4

Customer

(trouble)call

input file

Rule #3

Recloser

current/voltage(RMS

values) b

Rule #2

Recloser

status

Rule #1

Current

Number of selected

components

DTE

Circuit

namea

Notes: a. DTE’s Orion circuit – two different faults that occurred in different times at the same locationb. Rule #3 will be validated in Phase IIc. Rule #5 will be implemented in Phase II

Predicted numbers of possible fault locations

Fault Locator: Predicted ResultsPredicted number of possible permanent fault locations, assuming 10% errors in estimating

fault currents (recorded fault locations were captured in all predictions)



14

Project Budget with Milestones

• Phase I (FY06, July 05 – June 06): DistributionSystems Fault Analysis

– Budget: $135K

– Milestones and deliverables

• April 30, 2006: Completed integration of the fault locator

software tool for predicting the locations of permanentfaults in distribution power systems

• May 31, 2006: Validate fault locator with DTE measureddata

• June 20, 2006: Show results of validation to DTE• June 30, 2006: Final report



15

Project Budget with Milestones (Contd.)

• Phase II (FY07, July 06 – June 07): AdvancedFault Analysis System (AFAS)

– Budget: $158K – Milestones and deliverables

• July 31, 2006: Communicate with AEP on possibleinvolvement and extension of fault data for longer

distribution line applications• March 26, 2007: Complete integration of AFAS software for

predicting faults in distribution power systems

• May 31, 2007: Validate AFAS with additional measured

data from DTE• June 15, 2007: Show results of validation to DTE and other

possibly utility stakeholder

• June 30, 2007: Final report



16

Interactions & Collaborations

• Phase I (FY06)

– DTE Energy (Stakeholder)

– Optimal Technologies (AEMPFAST Software)

– EDD Inc. (DEW Software)

• Phase II (FY07) – DTE Energy (Stakeholder) and other possible utility

stakeholder

– Optimal Technologies (AEMPFAST Software)

– EDD Inc. (DEW Software)

– Nayak Corporation (PSCAD software) (Subcon)



17

Technical and Economic Benefits

• Distribution systems fault analysis software willsignificantly enhance ability of distribution utilities toprovide protection, operational and planning personnel

with – Improved fault diagnosis technologies that enable anticipating,

locating, isolating and restoring faults/failures with minimumhuman input and fast response time

• Specifically, current fault analysis software can give: – Improved system analysis (protection, planning and

operational)

– Reduced outage time (improved restoration time)

– Increased service and component reliability



18

• CTC identified and assessed several modeling andsimulation tools that can be successfully applied toanalyze, monitor, manage and control large andcomplex energy systems at the distribution level

• Comparisons of predicted fault currents with DEWand AEMPFAST software tools with recorded

measurements from DTE were acceptable – Differences within 10% for pre-fault load current ranging

from 50–100% and for arcing impedance ranging from0.5–1 ohm

– Accuracy in predicting fault currents does not significantlydepend on the distance of the fault location from thesubstation

Concluding Remarks



19

• Fault Locator Software: Very promising operational,decision-support tool that can be used to predictmost likely fault locations in power systems

– Numerical predictions were fully validated againstmeasured data from DTE

– The numbers of possible fault locations were narroweddown significantly by the fault locator software

– Recorded fault locations were captured in all predictions

– The following benefits are anticipated by using this tool

• System analysis improvements at protection, planning andoperational levels

• Reduction in outage time due to shorter restoration times

• Increase in service and component reliability

Concluding Remarks (Contd.)



20

• Predictive capabilities of the fault analysis softwarewill be significantly enhanced

• PSCADTM software as well as other advanced toolsand algorithms (e.g., fuzzy logic, genetic algorithms,neural tools, etc.) will be utilized in next phases – Phase II (July 06–June 07) of the Distribution Systems

Fault Analysis project (i.e., Advanced Fault Analysis

System or AFAS) – All algorithm rules will be implementedinto AFAS to accurately predict fault locations

– Phase III (July 07–June 08) – AFAS will additionally usetransient analyses and data to intelligently anticipatemomentary and permanent faults

Future Work



21

Acknowledgments

• Concurrent Technologies Corporation conducted thiswork under DOE cooperative agreement DE-FC02-04CH11241. Such support does not constitute anendorsement by DOE of the views expressed in this

presentation. Approved for public dissemination;distribution is unlimited.• DTE Energy, Detroit, MI – R. Lascu, D. Costyk, N.

Carlson, R. Sequin and H. Asgeirsson

• Optimal Technologies Inc., Benicia, CA – R. Schoettle,S. Kuloor and T. Mellik• EDD Inc., Blacksburg, VA – R. Broadwater and M. Dilek• Nayak Corporation, Princeton, NJ – O. Nayak and M.

Griffin• Carnegie Mellon University, Pittsburgh, PA – M. Ilic andM. Prica



22

Principle Investigator:

Dr. Laurentiu Nastac

Concurrent Technologies Corporation,

425 Sixth Avenue, Regional Enterprise Tower

Pittsburgh, PA 15219

Email: [email protected]

Phone: 412-992-5361

Co - Principle Investigator:

Anupam Thatte

Email: [email protected]

Phone: 412-992-5376

Contact Information



23

Backup Slides



24

Background:

Assessed Capabilities/Features [1,2] – Basic analysis tools: Load flow, fault analysis, motor

analysis, voltage regulation – More advanced analysis tools: Overcurrent protection,

transient stability, harmonic analysis – Additional features for analysis: GIS, import/export of data,

GUI, help utilities – Optimization tools: Network reconfiguration for loss

minimization via switching, restoration for return supply,optimal active/reactive power flow, capacitor placement, DGplacement

– Equipment/hardware models: Regulators, converters,motors, batteries, fuel cells, transformers

[1] L. Nastac et al., 8 th IASTED International Conference on Power and Energy Systems,PES2005, October 24-26, 2005, Marina del Rey, CA.

[2] L. Nastac et al ., IEEE 37 th North American Power Symposium , October 23-25, 2005, Ames, Iowa.



25

• Thevenin method to compute short-circuit currents for unbalanced faults in unbalanced three-phase system [4]

• Positive, Z + and zero, Z 0, sequence equivalent system

impedances (in ohms,Ω

) are calculated

[3] M. Dilek et al., 2004 Power Systems Conference and Exposition, New York , October 2004.

( ) ( ) +−==

−−

+Z LL

V Z LL

V Z

phase phase MVA MVA 2

23

2

** 1

0

3

V LL – nominal line-to-line voltage in kV of distribution systemMVA – given short-circuit MVA magnitude and angle

• Convert positive and zero sequence impedances into phaseimpedance matrix, Z T

• Thevenin matrices – sum of phase impedance matrices of each device in between circuit voltage source and faultlocation

Technical Approach: Thevenin Method

[4] M. Dilek et al ., 2004 Power Systems Conference and Exposition, New York, October 2004.



26

I b =0

I c

V anf

V bnf

V cnf

n –

I a

Z f I f Post-fault

System

Model

Phase-to-Phase Fault

f f

f

cn

f

an f c a b Z I V V and I I I I =−=−== ,0

Z f – arcing impedance

Technical Approach: Thevenin Method



27


Network Fault Analysis with AEMPFAST

6.01000.5

0.8500.5

-4.800.5

-1.91000

-6.0500

-11.700

Err [%]

Pre-faultLoading

[%]

Arcing[Ohm]

Comparison (% Err) of measured (DTE faulted data) and predictedresults with AEMPFAST



28

• Working with DTE Energy - Several faulted circuits for integrating, testing and validating the software

• Current Implementation: QuickWin Application (Fortran 90)• Final implementation: Lotus Domino Developer v7 Application

Fault Locator Software Implementation

Strategy



29

Fault ReportFault Report for the Circuit = Orion #2 (1078 components)

A) Fault Current Comparison Using Error [%] = 10

Fault Type No. X Y Status Current3 8 2293331 466782 100 2526 22913 9 2293302 466822 100 2503 22913 10 2293297 466878 100 2503 22913 11 2293324 466605 100 2463 22913 12 2293355 466263 100 2429 22913 13 2293880 465094 100 2086 22913 16 2293642 465426 100 2205 22913 17 2293427 465461 100 2249 22913 18 2293414 465286 100 2222 22913 20 2293395 465618 100 2291 22913 23 2292612 466125 100 2107 2291

3 24 2292640 465894 100 2148 22913 25 2292691 465493 100 2146 22913 26 2293382 465933 100 2359 22913 29 2293373 466145 100 2406 22913 34 2294334 466424 100 2324 22913 35 2294014 466193 100 2427 22913 37 2294192 464546 100 2121 22913 39 2294312 463919 100 2041 22913 101 2294373 464168 100 2088 22913 102 2294150 465150 100 2231 22913 106 2294080 465594 100 2305 22913 108 2294011 466439 100 2496 2291

Number of possible fault locations = 23



30

Fault Report (Contd.)

B) Recloser Type X Y Current1 1 2293355 466263 0

Fault Type No. X Y Status Current3 12 2293355 466263 100 2429 22913 13 2293880 465094 100 2086 2291

3 16 2293642 465426 100 2205 22913 17 2293427 465461 100 2249 22913 18 2293414 465286 100 2222 22913 20 2293395 465618 100 2291 22913 23 2292612 466125 100 2107 22913 24 2292640 465894 100 2148 22913 25 2292691 465493 100 2146 22913 26 2293382 465933 100 2359 2291

3 29 2293373 466145 100 2406 22913 34 2294334 466424 100 2324 22913 35 2294014 466193 100 2427 22913 37 2294192 464546 100 2121 22913 39 2294312 463919 100 2041 22913 101 2294373 464168 100 2088 22913 102 2294150 465150 100 2231 2291

3 106 2294080 465594 100 2305 22913 108 2294011 466439 100 2496 2291




31

C) Call No. Comp. No. X Y

1 25 2292691 465493

2 25 2292691 465493

3 25 2292691 465493

4 25 2292691 465493

5 25 2292691 465493

6 25 2292691 465493

7 25 2292691 4654938 25 2292691 465493

9 25 2292691 465493

10 25 2292691 465493

11 25 2292691 465493

12 25 2292691 465493

13 25 2292691 465493

Fault Type No. X Y Status Current

3 12 2293355 466263 100 2429 2291

3 13 2293880 465094 100 2086 2291

3 16 2293642 465426 100 2205 2291

3 17 2293427 465461 100 2249 2291

3 18 2293414 465286 100 2222 2291

3 20 2293395 465618 100 2291 2291

3 23 2292612 466125 100 2107 22913 24 2292640 465894 100 2148 2291

3 25 2292691 465493 100 2146 2291


Fault Report (Contd.)

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Distribution Systems Fault Analysis

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