Potentials - January/February 2016 - 40
A sampling rate of 3 kHz is selected,
and various wavelets are separately
employed as the mother wavelet. From
this value of sampling frequency, the
signal is decomposed into four levels
by passing through the MRA filter
bank. Figure 2 depicts the stages of
decomposition and the detail coefficients up to four levels.
As shown by Chanda et al., in the
event of fault occurrence, the second
and third harmonics in the transient
signal are dominant and can therefore be used to detect the fault. This
feature also provides useful information for the process of fault classification. From Fig. 2, it is observed
that the fourth-level detail coefficient
(d4) gives the frequency components
(100-150 Hz) corresponding to second and third harmonics.
In the process of transmission line
fault analysis, the information located
in these frequency bands provides im-
portant clues that help in the detection and classification of faults. By
randomly shifting the point of fault on
the 300-km transmission line, simulations are carried out using MATLAB. Thus based on the fourth-level
detail coefficients of the time domain
current signals at both buses, a fault
classification algorithm based on the
wavelet MRA technique is presented
in the next section, "Algorithm for
fault classification."
algorithm for fault classification
Wavelet MRA has been used to
obtain the fourth-level detail coefficients of the fault current signals
from each phase of the three-phase
transmission line. These coefficients are used for the fault classification procedure in the following
manner. The summation of the
wavelet coefficients for each phase
is performed.
Let M r1, M y1, M b1 be the summation of fourth-level detail coefficients
of the transient current signals line
(near bus 1) for phases R, Y, and
B, respectively, of the three-phase
transmission line. Similarly, let
M r2, M y2, M b2 be the summation of
fourth-level detail coefficients of the
transient current signals (near bus
2) for r, y, and b phases, respectively.
From the above coefficients, the following notations are derived.
D r12 = absolute (eM r1 e - eM r2 e),
D y12 = absolute (eM y1 e - eM y2 e),
D b12 = absolute (eM b1 e - eM b2 e),
M r12 = M r1 + M r 2,
M y12 = M y1 + M y2,
M b12 = M b1 + M b2 .
The value of fault inception angle (FIA) has an effect on the phase
current samples obtained and,
therefore, also on the output of the
wavelet transform of the post-fault
signals. The signals are periodic,
Check If
OMr1 - Mr2K c 0 Yes
Fault Is
Y - B Fault
No
Fault Is
L-L
or
L-L-L
Check If
OMy1 - My2K c 0 Yes
No
Begin
Get
Mr1, My1, Mb1,
Mr2, My2, Mb2.
Calculate
Dr12 = KKMr1K- OMr2KK
Check If
OMb1 - Mb2K c 0 Yes
Check If
Yes
(Mr12 + My12 +
No
Mb12) c 0
Dy12 = KKMy1K- O(My2KK
Mr12 = Mr1 + Mr2,
My12 = My1 + My2,
Mb12 = Mb1 + Mb2
No
Check If
Dr12 c Dy12
Db12 = KKMb1K- O(Mb2KK
Check If
Dy12 c Db12
fig3 A flowchart showing the fault classification algorithm.
J a n u a r y/Febr uar y 2016
Fault Is
B - G Fault
Yes
Fault Is
R - G Fault
Yes
Fault Is
Y - G Fault
Fault Is
R - Y- B Fault
Db12
R - Y- G
Fault
IEEE PotEntIals
Dy12
B - R- G
Fault
No
No
n
Yes
Fault Is
R - Y Fault
No
Fault Is
L-G
or
L-L-G
Check If
Db12 c Dr12
40
Fault Is
R - B Fault
Minimum of
(Dr12, Dy12, Db12)
Dr12
Y-B-G
Fault
Table of Contents for the Digital Edition of Potentials - January/February 2016
Potentials - January/February 2016 - Cover1
Potentials - January/February 2016 - Cover2
Potentials - January/February 2016 - 1
Potentials - January/February 2016 - 2
Potentials - January/February 2016 - 3
Potentials - January/February 2016 - 4
Potentials - January/February 2016 - 5
Potentials - January/February 2016 - 6
Potentials - January/February 2016 - 7
Potentials - January/February 2016 - 8
Potentials - January/February 2016 - 9
Potentials - January/February 2016 - 10
Potentials - January/February 2016 - 11
Potentials - January/February 2016 - 12
Potentials - January/February 2016 - 13
Potentials - January/February 2016 - 14
Potentials - January/February 2016 - 15
Potentials - January/February 2016 - 16
Potentials - January/February 2016 - 17
Potentials - January/February 2016 - 18
Potentials - January/February 2016 - 19
Potentials - January/February 2016 - 20
Potentials - January/February 2016 - 21
Potentials - January/February 2016 - 22
Potentials - January/February 2016 - 23
Potentials - January/February 2016 - 24
Potentials - January/February 2016 - 25
Potentials - January/February 2016 - 26
Potentials - January/February 2016 - 27
Potentials - January/February 2016 - 28
Potentials - January/February 2016 - 29
Potentials - January/February 2016 - 30
Potentials - January/February 2016 - 31
Potentials - January/February 2016 - 32
Potentials - January/February 2016 - 33
Potentials - January/February 2016 - 34
Potentials - January/February 2016 - 35
Potentials - January/February 2016 - 36
Potentials - January/February 2016 - 37
Potentials - January/February 2016 - 38
Potentials - January/February 2016 - 39
Potentials - January/February 2016 - 40
Potentials - January/February 2016 - 41
Potentials - January/February 2016 - 42
Potentials - January/February 2016 - 43
Potentials - January/February 2016 - 44
Potentials - January/February 2016 - 45
Potentials - January/February 2016 - 46
Potentials - January/February 2016 - 47
Potentials - January/February 2016 - 48
Potentials - January/February 2016 - Cover3
Potentials - January/February 2016 - Cover4
https://www.nxtbook.com/nxtbooks/ieee/potentials_20190102
https://www.nxtbook.com/nxtbooks/ieee/potentials_20181112
https://www.nxtbook.com/nxtbooks/ieee/potentials_20180910
https://www.nxtbook.com/nxtbooks/ieee/potentials_20180708
https://www.nxtbook.com/nxtbooks/ieee/potentials_20180506
https://www.nxtbook.com/nxtbooks/ieee/potentials_20180304
https://www.nxtbook.com/nxtbooks/ieee/potentials_20180102
https://www.nxtbook.com/nxtbooks/ieee/potentials_111217
https://www.nxtbook.com/nxtbooks/ieee/potentials_091017
https://www.nxtbook.com/nxtbooks/ieee/potentials_070817
https://www.nxtbook.com/nxtbooks/ieee/potentials_050617
https://www.nxtbook.com/nxtbooks/ieee/potentials_030417
https://www.nxtbook.com/nxtbooks/ieee/potentials_010217
https://www.nxtbook.com/nxtbooks/ieee/potentials_111216
https://www.nxtbook.com/nxtbooks/ieee/potentials_091016
https://www.nxtbook.com/nxtbooks/ieee/potentials_070816
https://www.nxtbook.com/nxtbooks/ieee/potentials_050616
https://www.nxtbook.com/nxtbooks/ieee/potentials_030416
https://www.nxtbook.com/nxtbooks/ieee/potentials_010216
https://www.nxtbook.com/nxtbooks/ieee/potentials_111215
https://www.nxtbook.com/nxtbooks/ieee/potentials_091015
https://www.nxtbook.com/nxtbooks/ieee/potentials_070815
https://www.nxtbook.com/nxtbooks/ieee/potentials_050615
https://www.nxtbook.com/nxtbooks/ieee/potentials_030415
https://www.nxtbook.com/nxtbooks/ieee/potentials_010215
https://www.nxtbook.com/nxtbooks/ieee/potentials_111214
https://www.nxtbook.com/nxtbooks/ieee/potentials_091014
https://www.nxtbook.com/nxtbooks/ieee/potentials_070814
https://www.nxtbookmedia.com