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DETECTION OF HIGH IMPEDANCE FAULTS USING ARTIFICIAL NEURAL NETWORKS. By Ibrahim El-Amin Mohammad H. Al-Mubarak. May 2003. Problem Definition. High Impedance Fault (HIF) is a fault on primary distribution (PD) system that cannot be detected by conventional O/C protection - PowerPoint PPT Presentation
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DETECTION OF HIGH IMPEDANCE FAULTS USING ARTIFICIAL NEURAL
NETWORKS
DETECTION OF HIGH IMPEDANCE FAULTS USING ARTIFICIAL NEURAL
NETWORKS
ByIbrahim El-Amin Mohammad
H. Al-Mubarak
ByIbrahim El-Amin Mohammad
H. Al-Mubarak
May 2003
Problem Definition High Impedance Fault (HIF) is
a fault on primary distribution (PD) system that cannot be detected by conventional O/C protection
95% of faults on PD feeders occur on O/H lines
Undetected HIFs may result in public hazard and property damage
Primary motivator to design HIF detectors is public safety
Problem Statement and Paper Objective
O/C relays are set to operate for currents between 125-200% of the normal load current
HIFs draw currents in the range of 0-100 A
Objective of paper is to develop an ANN based HIF detector that can also: Locate the HIF Distinguish HIFs from normal
switching events Identify the faulty phase
Solution Approach
Feeder Simulation with EMTPFeeder Simulation with EMTP
Data Scaling and Preprocessing
Data Scaling and Preprocessing
ANN Trainging and Testing
ANN Trainging and Testing
Fault Diagnosis
Fault Diagnosis
Feeder Simulation
EMTP is used because It can handle switch closing and opening (ideal for
transient analysis or fault simulation) It can simulate unbalanced systems (e.g. single line
to ground faults)Simulation is for 5 cycles (83.33 ms) at a
sampling rate of 0.2778 ms300 samples/phase for each case, i.e. 1800
samples to represent the 3 phases of the current and voltage waveforms
Feeder Simulation (Cont’d)
Feeder Simulation (Cont’d)
Phase-C Current Waveform for Load-4 and C1 Switching
Designing and Testing the ANN
Target Possible Values (Decimal Output)
Target # 1 (Fault Detection) 0, 1
Target # 2 (Fault Location) 0, 1, 2, 3, 4
Target # 3 (Event Type) 0, 1, 2, 3, 4
Target # 4 (Faulty Phase) 0, 1, 2, 3
ANN Targets
Comparison Between the Three ANN Designs
Design No.No. of EMTP Cases for ANN
No. of EpochsTraining Testing
Generalization Check
1D1F
39 13 48414
D1R 335
2
D2F
66 22 24
2872
D2R 844
D2B 404
3
D3F
57 20 36
1812
D3R 1123
D3B 457
Test Results of the ANN Designs w.r.t. Targets
Design No.Overall
Accuracy (%)
Accuracy (%) w.r.t. Target #
1 2 3 4
Te
st Ca
ses
D1F 98.1 100 92.3 100 100
D1R 94.2 100 92.3 92.3 92.3
D2F 97.7 100 90.9 100 100
D2R 96.6 100 86.4 100 100
D2B 86.4 NA NA NA NA
D3F 96.3 100 85 100 100
D3R 100 100 100 100 100
D3B 80 NA NA NA NA
Test Results of the ANN Designs w.r.t. Targets
Design No.Overall
Accuracy (%)
Accuracy (%) w.r.t. Target #
1 2 3 4
Generalization C
heck Cases
D1F 99.3 100 95.2 100 100
D1R 70.3 87.5 52.1 58.3 85.4
D2F 63.5 91.7 45.8 58.3 58.3
D2R 77.1 100 83.3 58.3 75
D2B 86.1 NA NA NA NA
D3F 79.2 100 75 75 83.3
D3R 81.9 100 83.3 66.7 77.8
D3B 81 NA NA NA NA
1
3
2
1 23 4
Conclusions Out of the eight design versions, four are
promising for HIF diagnosis applications. These are D1F, D2B, D3R & D3B
Design D3R is the best because 100% accuracy for all test cases and all targets 100% accuracy for mid-span HIF cases, for extended
feeder cases, for varying fault impedance cases and for varying transmission line impedance cases
All errors are for lightly loaded feeder cases, but none of them is in detecting the HIF occurrence
The design fails to distinguish between two fault events but succeeds in not false-indicating a HIF for normal system operation or vice versa
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