Refference 4
Refference 4
Abstract- The advanced application of Artificial Neural in operation and their total length. These lines are exposed to
Network was introduced recently in Protection of Transmission faults [2] due to lightning, short circuits, faulty equipments,
lines in Electric Power Systems. In this proposed research, the miss operation, human errors, overload, and aging. Many
application of ANFIS and ANN for Distance Relay Protection electrical faults manifest in mechanical damages, which must
for short and long Transmission line, under different loading be repaired before returning the line to service. It is
conditions, in Electrical Power systems will be introduced and
practically impossible to avoid consequences of natural
discussed. Considering different loading conditions, the
events, physical accidents, and equipment failure or miss
suggested and proposed technique deals with fault detection,
operation which results in the loss of power; voltage dips on
classification, and location in short and long Transmission lines.
All these tasks will be addressed in details in this article. It the power system. The protective relay is preventive device
considers; firstly, detecting the fault occurrence in very short which operates after a fault has occurred and it helps in
time and isolate the faulty section of the short and long minimizing the duration of trouble and limiting the outage
transmission lines. Secondly to classify the fault type and deduce time and related damage. The protective relays can be
which of the three phases are exposed to the fault. Finally, electromechanical, solid-state or digital [3]. Natural events
locating the fault will be achieved easily. The input training data can cause short circuits i.e. faults which can either be single
of the detection units are firstly derived from the fundamental
phase to ground or phase to phase or phase to phase to ground
values of the voltage and current measurements (using digital
or a three phase fault [4] . The transmission line is modeled by
signal processing via Discrete Fourier Transform (DFT». These
various techniques according to, mainly, its length.
measurements were simulated considering different loading
conditions.
Therefore, there are three main types to represent the
transmission line [5], Short T.L (less than 80 km or 50 miles)
index Terms- ANFIS, ANN, Artificial Intelligent
, medium T.L (from 80 to 240 km or from 50 to 150 miles)
Techniques, Distance Protection, Fault Detection, Fault
and long T.L (longer than 240 km or 150 miles). When faults
Classification, Fault Location, short and Long
occur in the power system, they usually provide significant
Transmission Lines
changes in the system quantities like over-current, over or
I. INTRODUCTION
under-power, power factor, impedance, frequency and power
An electric power system comprises of a number of
or current direction. These abnormalities, faults and
power-generating plants, transmission lines, and substations.
intolerable conditions must provide a distinguishable
Electric power is normally generated at II-25kV in a power
difference from the normal operating or tolerable conditions.
station. To transmit over long distances, it is then stepped-up
In this paper, the captured faulted voltage and current signals
to 220kV / 500kV levels as necessary. Power is carried
from instrument transformers have to be filtered and analyzed
through a transmission network of high voltage lines.
using digital signal processing tools. Then, the filtered signals
Usually, these lines run into hundreds of kilometers and
are used for detection, classification, and location of the fault.
deliver the power into a common power pool called the grid.
Fault detection, classification and location have been a goal
The grid is connected to load centers (cities / towns) through a
of power system engineers since the creation of distribution
sub-transmission network of normally 33kV / 66kV lines.
and transmission systems. Quick fault detection can help
These lines terminate into a substation where the voltage is
protect equipment by allowing the disconnection of faulted
stepped-down to 22kV / IIkV / 6.6kV etc., for power
lines before any significant damage is done. Accurate fault
distribution to load points through a distribution network of
classification and location can help utility to remove
lines. This can be shown in Figure (1) [1]:
Color I<ey:
Black: Generation
persistent faults and locate areas where faults regularly occur,
,I�r-rF-'-----' sUbg��;;,���'UlUS reducing the frequency and length of power outages. For
Blue: Transmission
Green: Distribution
Fig I : Typical Power System adequate protection especially for the transmission lines and
they can be employed for initiating the protection reaction
The rapid growth of electric power systems over the past few
after the fault inception as soon as possible. On the other
decades has resulted in a large increase of the number of lines
hand, this protection scheme requires more accurate and
sophisticated computation routines due to the increasing
complexities of modem power system networks [8, 9] . Thus,
Manuscript received March 1, 2013.
Mohamed .M. Ismail . Faculty of Engineering , Helwan University , 1 while fault detection, classification and location schemes
shref street - Helwan Cairo , Egypt , department of electrical power and have been developed in the past, a variety of algorithms
machines (e-mail: m_m_ismail@yahoo.com ) continue to be developed to perform this task more accurately
M.A.Moustafa . Faculty of Engineering , Cairo University ,Giza , Egypt
and more effectively. Regarding the fault detection and
department of electrical power and machines (e-mail:
mmustafa 98@hotmail.com ) classification, the problem was solved some time ago by
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introducing the traditional relaying principles such as over detecting the fault and the noise that can be obtained from the
current, distance, overvoltage, under voltage, differential, etc. measured signals lead to decreasing the accuracy . Although
All of these principles are based on a comparison between the there are previous researches, as in [12-16], that utilize the
measurements and predetermined setting calculated taking artificial intelligence techniques in fault detection in double
into account only predetermined operating conditions and circuit T.Ls, there isn't any research that deals with the fault
fault events. Consequently, if the actual power system classification and location in these lines using AI tools.
conditions deviate from the anticipated ones, the Moreover, the zero sequence mutual coupling between the
measurements and settings determined by the classical relay parallel lines introduces many complexities in establishing
design have inherent limitations in classifying certain fault the ANFIS fault units. However, this is solved in our paper by
conditions, and the performance of classical protective relays using the zero sequence current to be an input from the inputs
may significantly deteriorate . While for fault location, of the ANFIS and ANN classifier and it is also helpful in
traveling wave phenomena was early employed for its differentiating between the ground and non ground faults.
purposes. However, these schemes suffered from different The previous work obtained in [17-21] is also improved in
shortcomings associated with the propagation and this paper by using ANN technique as well as ANFIS method
economical problems. Then, the impedance-based fault and the simulations in our article was applied on short and
locators were developed depending on the available long of transmission lines
measured quantities at the locator position. Later, the II. TRANSMISSION LINE MODELING
revolution of digital technologies and microprocessor Short Transmission Line
applications [lO] were employed to develop these schemes A single line diagram for the protected T.L is shown in
into their digital forms. However, these digital versions are Figure (2). It is consists of two circuits of 80 km length,
usually structured following almost the same basic functions 66 kV voltage level and 2 GVA short circuit level.
that are used by the conventional schemes. Hence, these new
versions in most cases suffered from the associated
shortcomings with the function essence. Different factors are
�'I ! ::1i--
:---
xom
responsible for these drawbacks as these approaches are
based on deterministic computations on a well defmed model
Fig 2 : Single Line Diagram For The T.L
of the system to be protected. In general, the steps in the
protective relaying algorithm are detecting the fault , Classify Since the T.L is considered a link between the short and
the fault and fmally Locate the fault medium T.Ls, it represented in ATP by single 7[ model so that
In this paper , the proposed distance protective relay was more accurate data can be acquired. The single phase 7[ model
applied on two different transmission , first system is double in ATP is shown in Figure (3) [28] where R, L, and Care
circuit transmission line with 66 kV, 2 GVA, and 80 km and scalar values. The capacitance value Con the branch card is
the second system is Single circuit transmission line with 500 split up into two equal parts and connected to NODE k and
kV, 20 GVA, and 160 km. The fault detectors, classifiers, and NODEm.
locators of both lines are firstly instituted by the ANN and
ANFIS training, and then they are tested in variety of system R L
the power system. Distance relays are normally used to Fig 3 : Single Pi Model in ATP
protect transmission lines,. They respond to the impedance Long Transmission Line
between the relay location and the fault location. Distance After the implementation of the proposed protection scheme
relays are preferred than over current relays in the line on short transmission line with 66 kV considering constant
protection because they are not nearly so much affected by loading conditions, the proposed algorithm will now utilized
changes in short-circuit-current magnitude as over current for protecting actual overhead transmission line in Egypt. The
relays are, and, hence, are much less affected by changes in T.L is single circuit 500 kV and 160 km in length. It connects
generating capacity and in system configuration. This is between the two substations; Abu Zabal and the Suez. Since
because distance relays achieve selectivity on the basis of all the 500 kV T.Ls in Egypt are single circuits up till now,
impedance rather than current. The main distance relay likewise the selected one, the difficulty of the mutual
schemes could be classified in [9-11]. Our work is an coupling between parallel lines is vanished. Therefore, the
improvement of [12], [13], [14] , [15] and [16] such that we proposed protection relaying is applied on this line to
are using short and long transmission line at different loading accomplish the three fault tasks at a verity of loading
conditions with two techniques ANFIS and ANN, also in this conditions even though this line is twice the length of the first
article we can locate the fault with very good accuracy and we line and it is at much higher voltage level. The MATLAB
are using digital signal processing for filtering the noise , program represents the transmission lines by either
while the previous work deal only with classification and distributed parameter line method or a series combination of
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U2013 Proceedings of Intemational Conference on Modelling, Identification & Control (ICMIC)
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pi models. In this paper the latter method is used because the Switching in the power systems , Faults in the power systems
selected line is considered a medium T.L. Therefore, even a with their different types , non linear elements in the power
single pi model could be sufficient. However, in order to get systems; e.g. static shunt compensators, and magnetic
more accurate results from the T.L model, a series saturations in the transformers , Shunt capacitance of long
combination of pi models is adopted. In spite of this, it is transmission lines , dc-components in the power systems due
found that the adequate number of pi models that required to to the energy stored in the inductance that decays
emulate the T.L. is depending on the maximum frequency of exponentially in the system resistances. In most studies in the
the harmonics that are imposed on the fundamental power system analysis, the necessitated voltage and the
components and the length of the transmission line. There is current measurements are the fundamental components of the
a fonnula that relates this maximum frequency and the voltage and current signals. Therefore, several steps, as
number of pi models [14], which is shown in Figure (6), such that Analog to digital conversion,
Nv Digital low pass filter , Fourier analysis and Scaling.
fmax =--
�.r-C::::::: :::::::: :::::::: :::: �:: ���: :::::::::: :::::::: ::::::::::: D�su, ��
500kV·160kmTransmissionline
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U2013 Proceedings of International Conference on Modelling, Identification & Control (ICMIC)
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COlltrol The training data used to train the ANFIS of the fault
detection unit are taken at the no fault conditions and fault
conditions. The fault conditions are carried out at all different
Ullit fault types at fault distance (Dr) 5%, 40% and 80% of the line
with inception fault time (Tc) 5 msec. and fault resistances
Activatioll (Rr) 0 and 100 ohms. The output data from ANN and ANFIS
are 0 for no fault conditions and 1 for fault conditions. Table
1 is the testing data for fault detection , Tr is the fault
inspection time, Rr is the fault resistance , Dr is the fault
distance in Km. . The impedance of the three phase are Za ,
Zb and Zc And O/P1 is the ANFIS output and O/P2 is the
ANN output .
Table 1: Testing Data of the Fault Detection Unit for the Fault
Conditions
Since that the ATP is used to model the T.L and also to create
both the training and testing data, therefore, the training
procedure of fault classification (FC) and fault location (FL) ,
o - ....
units are established separately from that of fault detection ;:,
.... - o
00
o :... o '" .... :...
.... 00 :... ....
u.
....
(FD) unit. This is because of the difficulties which will be
inserted to the model in ATP to implement different DSP
processes in the same model at the same running cycle.
However, these separated training procedures allow
instituting the distance protection scheme at much variety of
the system conditions.
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U2013 Proceedings of Intemational Conference on Modelling, Identification & Control (ICMIC)
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:.-
== Table 3: Testing Data of the Fault Classification Unit for the SLO Faults
,
0
;:, �
t-J 0 ...
-
0 N
'" 0 U; -
:; ;;> ;:, ;:, ... '" N
0
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0 Q<, '" '" Q<,
N N t
� "'l N
.. "0 0 0
-
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N N N I' �
... �
-I
...., ::::
....,
-c
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q
-c
'"
.£
-c
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.E.
'?
�
-c
.n.
-c �
*
= I' C: I' C:
Fault classification unit: N N
"0 0;;
Fault Classification Unit is the subsequent unit to be
activated from the Fault Detection Unit in case of fault.
0
b -
;;> .... 0 .... 0 '" 0 N
The output of ANN and ANFIS fault classification unit is ;:,
0
0 e
0J0 �
N
Q<,
;:,
....
0J0
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'"
0J0 !" '"
... 0
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....
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� N N N
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�
...., q i: .E. � .n.
::l :::: -c -c
'"
-c -c -c -c
C: C: C: I' C: I' C:
�
N N
..0 "'"0
:;-
;0
0 0 0 0 .... .... 0
Fig 9 : Control Circuit (C.C) ;:, N
0J0 N
0J0 Cl ;; ;:,
Q<,
;-I
....
E
'"
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-
;:,
'"
Q<,
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f- f-
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0
0 0 -.J 0 0 0
-.J � Vo
Vo
00
'='
0 00 :..., '=' '=' 00 :...,
Fig JO : Contents of Each Subsystem in C.C IV '" '" :,. IV :..., :;;: '0 -.J
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U2013 Proceedings of Intemational Conference on Modelling, Identification & Control (ICMIC)
Cairo, Egypt, 31stAug.- 2ndSept. 2013
Vab
o o o
Iabc
'"
'" '"
'" :::;
0
0 0 0 0 0
0
'" :x; '" '" 00
'" N
00 ...
:;;: V. -..l
:.. 00 ;:;; ;:;; 101'
ActivatiOl\ or
0
Deactivation
"N0 0 0
0
...., N N N I' � �
...
.E. � .n.
....,
-I
� 'C
'? 'C '?
i:: " I' i:: I' "
N N
"0 "'"
0
-..l
...
...
o
:...
...
o
The input data to the ANFIS and ANN detection units are the
impedances of the three phases (magnitude and phase i.e. 6
inputs) after the digital signal processing is achieved as
b) Long transmission line shown previously. While the output data from ANFIS and
ANN units are 0 for no fault conditions and 1 for fault
For the long transmission line that indicated in figure 8. The conditions.
complete line system with the protection algorithm is Fault classification units:
indicated in figure 11. The Fault Classification and Fault The input data to the first ANFIS and ANN classification
Location units apply DSP for only power cycle during the units are the impedances of the three phases (magnitude and
fault existence. This process is shown in Figure (12) where it phase) and the zero sequence components of the currents, i.e.
is regulated by three control blocks which are The "Fault 7 inputs, after the digital signal processing is achieved.
Instance" block which is responsible for the occurrence of the While the output data from it are 1 for single phase to ground
fault at 5 msec by taking in consideration the phase voltage of faults., 2 for double phases to ground faults and 3 for three
phase A is the reference , The "FD Control" block which phases to ground faults.
allows the continuous DSP of the training data for the ANFIS On the other hand, the input data to the second ANFIS and
detectors and The "FC and FL Control" block implements ANN classification units are the impedances of the three
the DSP of the training data for the ANFIS classifiers and phases (magnitude and phase i.e. 6 inputs) after the digital
locators for only one power cycle during fault condition, i.e. signal processing is achieved. While the output data from it
20 msec. are 1 for double phases faults and 2 for three phases faults.
__ -,f�
l:U.tt loclll o n Fault location units:
·�t
Training data for fault location units:
I �
.�� The training data used to train the ANFIS and ANN of the
Fault Location Units are as same as those of Fault
�
Abu l� Sub:stwUlm :iOO kV· 160 t:m TrlnlmluJon line �
-, Classification Units and they also classified into different
� RlidIlII lllUt d,=====,.:a
: : �:. :�:bJt� section depending on either if the zero sequence current is
' --------. , ======� fl ..... -- ., .-- .. oe=----...roc
zero or not.
• "'t.J
...
.:1 · t
The input data to the ANFIS and ANN Location units are the
tl� "--=-1
impedances of the three phases (magnitude and phase i.e. 6
inputs) after the digital signal processing is achieved. While
" --. the output data from ANFIS locators are the nonnalized fault
distance value.
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