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Overcurrent Protection for the

IEEE 34 Node Radial Test FeederHamed B. Funmilayo, James A. Silva and

Dr. Karen L. Butler-PurryTexas A&M University

Electrical and Computer Engineering Department

1

Po

werSystemAu

tomationLab


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Introduction

Major use of the benchmark radial test

feeders -- provide load-flow data for validating

load-flow results from existing/novel load-

flow algorithms

Extend Current IEEE 34 node test feeder

Provide overcurrent protection, considering off-

the-shelf protective devices

Make available for studies under new scenarios

(such as DG impact)

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Work Reported in This Paper

Model of Test feeder in DIgSILENT

PowerFactory 13.1 and conduct LF and

SC studies

Coordination studies for temporary and

permanent faults for various fault

situations

Select OCP devices for the test feeder

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Over Current Protective Devices

Modeled in DIgSILENT

1 recloser, 12 fuses

Fuse saving for fuses 1, 2, 3, 4, 6, 7, 8, and 11

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Maximum and Minimum Fault Currents

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Comparison of Maximum FaultCurrent to IEEE TF Results

Faulted IEEE* DIgSILENT DIgSILENT

Node (A) (A) % Error

800 718.60 678.60 5.57

808 526.50 510.20 3.10

816 335.40 329.94 1.63

824 313.00 310.50 0.80

854 272.90 276.40 1.28

832 223.10 217.70 2.42

858 217.70 213.30 2.02

834 211.30 208.40 1.37

836 206.90 204.40 1.21840 206.10 203.61 1.21

890 406.50 440.10 8.27

Comparison of Minimum FaultCurrent to IEEE TF Results

Faulted IEEE* DIgSILENT DIgSILENT

Node (A) (A) % Error

800 479.30 459.00 4.24

808 309.40 322.26 4.16

816 213.50 205.49 3.75

824 195.10 194.06 0.53

854 175.90 173.68 1.26

832 146.20 140.55 3.86

858 143.00 138.06 3.45

834 139.30 135.19 2.95

836 136.50 132.71 2.78840 136.00 132.27 2.74

890 94.10 87.94 6.55


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Recloser and Fuses Types

Recloser

Recloser's coordination range must provide adequate time to sense all

downstream faults.

Fuse Saving mode used

A triple single-phase electronic recloser was used

Load side fuses

Similar types of fuse links were selected for all branches within the

same nominal current range

Voltage rating equal to or higher than the maximum bus voltage at thefuse location

Interrupting current rating larger than the maximum symmetrical fault

current at the fuse location

Type K, T and X expulsion fuse links

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Step Down Transformer (XMF-1) Fusing

A type T external expulsion cutout on the primary side

The voltage rating equal to or greater than the voltage at transformer's

location

The ampere rating equal to or greater than the anticipated normal

loading level The symmetrical short-circuit interrupting rating equal to or greater

than the maximum fault current

Be able to withstand the inrush current generated when

transformer is energized

Be able to protect against transformer faults and secondary

side faults (through faults)

Serve as backup device by coordinating with the OCP device

downstream of the lateral

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Capacitor Bank Fusing

Group fusing method is used. (One fuse

protects the capacitor bank)

Promptly isolate the failed capacitor unit on

the line prior to any other protective device

on the system

1-phase grounded fault current without fault

impedance is assumed as the capacitor fault

value.

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Settings for Recloser and Load Side Fuses

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Minimum Fault Current Observed at the Recloser

For The Minimum Fault At Each Lateral

Recloser Faulted Lateral If recloser (A)

Node Node number DIgSILENT

800 810 1 321.79

800 822 2 168.90

800 826 3 218.89

800 856 4 179.82

800 888 5 61.08

800 864 6 126.36

800 848 7 165.82

800 838 8 166.88800 Cap- 844 7 167.93

800 Cap- 848 7 165.82

800 840 11 165.88

No. of Instantaneous Trips 1

No. of Delay Trips 2

Nominal Voltage 14.4 kV, L-N

Minimum trip rating 100 A

Instantaneous trip curve type 103

Delay trip curve type 134

Recloser Settings

Nominal Voltage Rating24.9 kV, L-L or

4.16 kV, L-L

Nominal Current Rating of Each

Fuse

Based on each

branchs current

Load Side Fuse Settings


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Coordination Studies

Two terms for OCP operation

Primary device

Near to the fault and first to clear the fault

Secondary (backup device)

Backup of the primary device

Coordination between recloser and fuse

For temporary fault, K factor is used

For permanent fault, fuse operates prior to reclosersdelay trip

Coordination between fuse and fuse Max clearing time of primary fuse will not exceed 0.75 times the

minimum melting time of the secondary fuse

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Fault Case Studies

Fault on main feeder

Fault on ordinary laterals

Fault on laterals with reactive compensation Faults on laterals with step-down transformer

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Fault on ordinary laterals

Recloser operates on its

instantaneous trip for

temporary fault

For permanent fault,

fuse operates to clear

the fault and isolates the

lateral

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Instantaneous trip of recloser

Fuse melting time

Delayed curve of recloser (backup)

Recloser-Fuse coordination for min fault at 810


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Discussion of Results

RECLOSER-FUSE COORDINATION TIME INTERVALS FROM DIGSILENT

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OPD List for the Test Feeder

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Summary/Conclusions

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A conventional overcurrent protection and

coordination scheme was implemented on IEEE 34

Node Test Feeder computer model in DIgSILENT

The final list of selected OCP was provided Coordination was achieved for different cases

This may be used for easy comparison and

assessment of future overcurrent protection studiesregarding radial distribution system with or without

additions such as DG


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Acknowledgement

The authors would like to thank F. J. Verdeja

Perez, J. Mendoza, S. Duttagupta, M. Marotti,

K. Mansfield, T. Djokic, and H. E. Leon for their

contributions, along with the assistance ofProf. W. H. Kersting.

This work was supported in part by the U.S.

National Science Foundation under Grant ECS-02-18309.

Paper no. TPWRD-00792-2007.

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Contact information:

Dr. Karen L. Butler-Purry

Email: [email protected]

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