A Study on the Protection Relay Test and Analysis Method ...protection relay has been developing...
Transcript of A Study on the Protection Relay Test and Analysis Method ...protection relay has been developing...
Journal of Energy and Power Engineering 14 (2020) 179-186 doi:10.17265/1934-8975/2020.06.001
A Study on the Protection Relay Test and Analysis
Method of AC Electric Railway Substation
Dae-Seok Kang1, Woo-Sik Won1, Byung-Lib Ahn1 and Byeong-Gon Lee2
1. EntechWorld, Inc., 196 Gasan Digital 1-ro, Geumcheon-gu, Seoul 08502, Korea
2. Korea Railroad Corporation, 240 Jungangno, Dong-gu, Daejeon 34618, Korea
Abstract: Since opening of the Korean high-speed railway in 2004, the rate of electrification has been increasing rapidly, and safety of the supply of AC railways has become very important. And the digital protection relays in railway feeding system need more attention with the expansion of unmanned SSs (substations) and digital SSs. For accident prevention, it is necessary to develop accurate modeling and simulation technology for railway feeding devices of electric railway. And it is also important to continuously improve test methods and develop excellent relay algorithms and apply them to the protection system to prepare for unexpected accidents. In this study, after reduced modeling the AC railway power supply system using PSCAD/EMTDC (Power Systems Computer Aided Design/Electromagnetic Transient DC Analysis), the results were compared and verified with the numerical calculation using the symmetric coordinate method. It also presents a method of using the verified results for simulation and education for various railway accidents. This study result will be used for the construction of new lines as well as existing lines in the future railway business. Key words: Electric railway, digital protection relay, modeling, PSCAD/EMTDC.
1. Introduction
With the opening of the high-speed railway in 2004
in Korea, electric railway technology for safety has
also rapidly developed. However, more fundamental
countermeasures are needed for large and small
accidents that may occur in large-scale personnel
transportation [1]. AC electric railway SSs (substations)
are installed at intervals of about 50 km, and SP
(Section Post) and SSP (Sub-Section Post) are installed
between each SS. The SP and SSP installed between
each SS are for division and extension of the electric
feeding section. These electric rail power supply
devices are monitored in real time by a protection relay
for safety. The protection relay used in the AC electric
railway power system is mostly dependent on foreign
products.
Digital protection relay operation algorithms used for
power system protection are classified into various types
Corresponding author: Woo-Sik Won, Technical Research
Center in Entechworld Inc., research fields: protection relay, fault locator and power quality management.
according to application targets such as transmission
lines, transformers, buses and generators. Recently, the
protection relay has been developing rapidly, but the
relay algorithm currently applied is not perfect yet. In
particular, since the electric train is a moving load, it is
necessary to prepare for unexpected accidents, and to
continuously improve test methods and develop
excellent relay algorithms and apply them to the
protection system. In order to prevent malfunction of
the protection relay and fault locator installed for the
safety of the railway power supply system, modeling
and simulation reflecting the actual field system are
required. In addition, it is necessary to develop various
solutions to increase users’ accident analysis abilities.
In this paper, we investigated the operation and test
method of the electric railway power system protection
relay. And we have developed the new protection relay
for the power supply system evaluation solution based
on PSCAD/EMTDC (Power Systems Computer Aided
Design/Electromagnetic Transient DC analysis). The
developed protection relay evaluation system can be
used for various accident simulation and education.
D DAVID PUBLISHING
A
180
2. Electric
2.1 AC Railw
There are
AT (Auto T
power supp
supplied thr
line, and in t
the feeder l
below.
Fig. 1 is
method. The
and the dista
AT method
SSs are ins
distance betw
is about 10 k
Fig. 1 BT ele
Fig. 2 AT el
In additio
of electric r
called IED
important d
power suppl
is an intelli
Study on the
c Railway D
way Protectio
e BT (Boost
Transformer)
ly method. I
rough the ca
the AT metho
line. The tw
the BT me
e distance bet
ance between
is Korean AC
stalled at int
ween SPs an
km.
ectrical railwa
ectrical railwa
on, there are v
railways, and
(Intelligent E
device for th
ly. IED of a
gent comput
e Protection R
Digital Prot
on Relay
er Transform
method for
In the BT m
atenary line a
od, power is
wo methods a
ethod and Fi
tween BT SS
n AT SSs is
C Railway’s
tervals of ab
d SSPs instal
ay power system
ay power system
various devic
d the digital
Electronic D
he safety of
recent trend
tational relay
Relay Test an
tection Rela
mer) method
electric rail
method, powe
and the sub-
supplied thro
are compared
ig. 2 is the
Ss is about 30
40~100 km.
standard and
bout 50km.
lled between
m.
m.
ces for the sa
protection r
Device) is a v
electric rail
of multifunc
y, which sam
nd Analysis M
ay
and
lway
er is
feed
ough
d as
AT
0 km
The
d AT
The
SSs
afety
relay
very
lway
ction
mples
an i
digi
faul
T
loca
mai
curr
und
Tab
AN
Ov
Un
Ov
Un
Dis
Dif
Fau
V
SP
Tab
Recsec
Tra
Feesec
In
burn
occ
and
prob
failu
due
circ
freq
sect
Method of AC
input at a pre
ital value, an
lt or not by in
Table 1 sum
ations of AC
in AC protec
rent relays, o
dervoltage rel
ble 1 AC railw
NSI device
ercurrent
dercurrent
ervoltage
dervoltage
stance
fferential curren
ult locator
Various accid
and SSP are
ble 2 SS prote
Fa
ceiving ction
ShGr
ansformer InOv
eding ction
ShGrUn
n the electri
nout of trans
ur due to ove
d ground fa
blems of ca
ure due to in
e to overvol
cuit, ground
quent failure
tion [3, 4].
Electric Rail
edetermined p
nd compares
nternal algorit
mmarizes the
C railway prot
tion relays us
overcurrent re
lays and dista
way protection
Numbers
#50/51(O
#37(UCR
#59(OVR
#27(UVR
#21
nt #87
#99(FL)
dents occurrin
summarized
ection relay fai
ault type
hort circuit round fault
nternal problem vervoltage
hort circuit round fault ndervoltage
ic railway s
sformers and
ercurrent acci
aults. In ad
apacity reduc
sulation brea
ltage in the
fault, and un
es in the ca
way Substati
period and co
and determi
thm.
e names and
tection relay
sed in SSs ar
elays, overvo
ance relays [2
n relay.
s Remark
OCR) Feeding
R) SP/SSP
R) Receivi
R) Receivi
Feeding
Transfo
Feeding
ng in electric
in Table 2.
ilure.
Symptoms
Overcurrent
Short circuit
Overcurrent Overvoltage Unable norm
substation, a
d peripheral
idents due to
ddition, there
ction and po
akdown and w
transformer
ndervoltage a
se of the p
ion
onverts it to a
ines whether
d installation
system. The
re differential
oltage relays,
2].
k
g section
P
ing section
ing/Feeding
g section
ormer section
g section
c railway SS,
mal operation
problem of
devices may
short circuits
e are some
ower supply
winding short
r. The short
accidents are
ower supply
a
r
n
e
l
,
,
f
y
s
e
y
t
t
e
y
A
2.2 AC Prote
The diffe
relay #21 o
short circuit
the train to
finding the c
describes the
relay. Fig. 3
the ratio diff
Fig. 3 Test o
In Korea
transformers
#87 is intend
case of an
transformer
primary side
the external
train operati
The differ
between the
transformer
coil in the
transformer
operation. T
suppression
differential c
Study on the
ection Relay
rential curren
operate in the
t accident in
block the fa
cause of the
e differential
3 explains th
ferential relay
of differential c
’s AC powe
s are used. T
ded to protec
n internal fa
protection re
e, the transfo
fault of the
ion.
rential curren
e primary an
in the suppr
e relay for
to determin
Table 3 descr
current co
current relay.
e Protection R
Operation
nt relay #87
e event of a
the power s
ault current a
failure. The
current relay
he operating c
y.
current protec
er railway SS
The different
ct the Scott tra
ault of the
elay should b
rmer should
transformer
nt relay detec
nd secondary
ression coil a
internal pr
ne whether
ribes the cor
orrection con
Relay Test an
and the dista
a ground faul
supply system
and contribut
following bri
y and the dista
characteristic
ction relay.
S, Scott and
tial current r
ansformer. In
transformer,
be cut off on
be inoperativ
or to the nor
cts the differe
y currents of
and the opera
rotection of
the relay is
rrection ratio
nditions of
nd Analysis M
ance
lt or
m of
te to
iefly
ance
cs of
AT
relay
n the
the
n the
ve to
rmal
ence
f the
ation
the
s in
and
the
Tab
Set
Pic
Slo
Slo
HO
F
dist
rela
curr
(pot
outp
dete
the
circ
Fig.
T
each
In
und
mar
Method of AC
ble 3 Differen
tting range
ck-up current
ope 1
ope 2
OC
Fig. 4 describ
tance protect
ay calculates
rent input thr
tential trans
puts TRIP
ermining the
relay install
cuit or ground
. 4 Test of dis
Table 4 descr
h protection
order to p
der-reach in d
rgin of about
Electric Rail
ntial current pr
Differential current (%)
15%
35%~40%
70%
70% of shor
bes the opera
tion relay (#
impedance
rough CT (cu
sducer), and
signal. That
direction and
ation locatio
d fault [5].
stance protecti
ribes the dista
zone of the
prevent mal
distance rela
20% is reflec
way Substati
rotection relay
rt circuit
ating characte
#21). Distanc
value from
urrent transdu
d determines
t is, it is
d electrical d
n to the poin
ion relay.
ance and time
distance prot
lfunction of
ay operation,
cted.
ion 181
y setting.
Restrain current (pu)
1.0
5.0
≥ 10.0
≥ 10.0
eristics of the
ce protection
voltage and
ucer) and PT
s error and
operated by
distance from
nt of a short
e settings for
tection relay.
f over- and
a correction
e
n
d
T
d
y
m
t
r
.
d
n
A
182
Table 4 Diff
Dist
Zone 1 Dist
Tim
Zone 2 Dist
Tim
Zone 1 is
and it is typ
length. Zon
there is no
Operating ti
cycle. Zone
primary line
exact fault
120%~125%
provides su
fault impeda
should note
protection to
3. Protecti
3.1 AC Railw
The digita
and dynamic
test, a simpl
usually ev
characteristi
system accid
Hardware-In
or dynamic c
relay is relat
very comple
so the test m
In electric
involve larg
simulate the
compare it w
Study on the
ferential curre
tance relay setti
tance 85
me 0.0
tance 12
me 0.2
s meant for p
pically set to
ne 1 provide
intentional ti
ime of Zone
1 does not c
e because it
location. U
% of primary
ufficient marg
ance and othe
e that Zone
o a part of the
ion Relay T
way Protectio
al protection r
c characterist
le characteris
valuated, w
ic test, it is us
dents or malf
n-the-Loop (H
characteristic
tively simple
ex accident an
method is also
c railway po
ge fault curren
e fault curre
with the actua
e Protection R
ent protection r
ing P
5%~90% P
05s
20%~125% E
2s
protection of
o cover 80%~
es fastest pro
ime delay as
e 1 can be o
cover the ent
is difficult to
Usually Zon
line impedan
gin to accou
er errors in re
e 2 also pr
e adjacent line
Test and M
on Relay Test
relay test is d
tics. In the sta
stic of the pr
whereas in
sed to check t
functions. Fig
HIL) test pro
cs. The static
but the dyna
nalysis has a
o quite difficu
ower systems
nts. So it is v
ent by each
al value.
Relay Test an
relay setting.
Purpose
Prevent error
Expand protect
the primary
~95% of the
otection bec
ssociated wit
of the order o
tire length of
o distinguish
ne 2 is set
nce Zone 1.
unt for non-
elaying. Also
ovides back
e.
Modeling
t
divided into s
atic character
rotection rela
the dyna
the occurrenc
g. 5 describes
ocedure for s
test of protec
amic test used
variety of inp
ult.
s, most accid
very importan
fault mode
nd Analysis M
tion
line
line
ause
th it.
of 1
f the
h the
t to
This
zero
one
k up
tatic
ristic
ay is
amic
ce of
s the
tatic
ction
d for
puts,
dents
nt to
and
Fig.
F
stat
rela
the
site
amp
pow
stor
CO
In
cha
exte
Om
Fig.
Method of AC
. 5 Protection
Fig. 6 introdu
tic and dyna
ay. The simul
data stored i
e are input
plifier to dete
wer system s
rage data i
MTRADE fi
the test of
annels applied
ernal analo
micron-CMC3
. 6 Protection
Electric Rail
n relay HIL-tes
uces several
amic characte
lation result o
in the protec
to the prote
ermine wheth
imulation ou
is played b
ile and used
this study,
d to the pro
og amplifier
356 (protectio
n relay test syst
way Substati
st procedure.
methods fo
eristics of th
of RSCAD o
ction relay at
ection relay
her there is a
utput data or
back in th
for accident
there were
otection relay
r and the
on relay test s
tem.
ion
r testing the
he protection
or PSCAD or
the accident
through an
a failure. The
the accident
he form of
analysis [6].
two signal
y. One is an
e other is
set).
e
n
r
t
n
e
t
f
.
l
n
s
A
3.2 Electric
The electr
and simulat
V-source an
order to test
V1 and I1
output termi
In the 6-te
between vo
following E
AC electric
Fig. 7 Linea
Power is
sources, tran
time, a vo
impedance o
is %Z, whic
of the line
percentage.
expressed b
the reference
The follo
circuit and
system of th
receives 154
Power Corp
transformer.
Study on the
Railway Pow
rical power sy
ted as a cir
nd I-source b
t electrical fa
of the input
inal, it can be
rminal netw
oltage and c
q. (1), and is
rail power su
ar four-port ne
V1
V1'
I1
I1'
=
a11aa21aa31aa41a
s supplied t
nsmission lin
ltage drop
of each devic
h is importan
voltage drop
Conversion
y Eq. (2) wh
e capacity is
%Z = Q
V2
owing Fig.
simulation c
he AC railro
4 kV from
p.) and transfo
.
e Protection R
wer System M
ystem can be
rcuit configu
based on a 4
aults of the sy
t terminal an
e expressed as
work model,
current is ex
s used for mo
upply system.
twork.
a12a13a14
a22a23a24
a32a33a34
a42a43a44
V2
V2'
I2
I2'
to the load
nes and trans
occurs due
ce. The imped
nt in modeling
p and the ra
of %Z and
hen the line v
Q.
Z2 × 100%
8 shows re
circuit of th
oad. The ele
the KEPCO
forms it into
Relay Test an
Modeling
e simply mod
uration of R
-port networ
ystem. Assum
nd V2, I2 of
s shown in Fi
the relation
xpressed as
odeling the ac
2
2 (1)
through po
sformers. At
to the spe
dance at that t
g. %Z is the r
ated voltage
d ohm value
voltage is V
educed mode
he power sup
ectric railway
(Korea Elec
55 kV in a S
nd Analysis M
deled
RLC,
rk in
ming
f the
ig. 7.
nship
the
ctual
ower
this
cific
time
ratio
as a
es is
and
(2)
eling
pply
y SS
ctric
Scott
(a) M
(b)
Fig.
T
3-ph
M-p
diff
T
tran
to t
betw
rail
sup
resp
In
the
spe
num
met
PSC
ana
Method of AC
Modeling of e
Simulation cir
. 8 Modeling
The Scott tra
hase power
phase and T
ference as sin
The AT rece
nsformer, tran
the feeding li
ween the cate
is connected
plies 27.5 kV
pectively.
n power syste
simulation v
cific acciden
merical calcu
thod and
CAD/EMTDC
alysis.
Electric Rail
electric railwa
rcuit using PS
circuit for AC
ansformer rec
and outputs
T-phase have
ngle-phase ou
eives the 55
nsforms it int
ine. The auto
enary line an
d to its center
V to the cat
em modeling
value were c
nt in the tra
lation using t
the simu
C are compar
way Substati
ay substation
SCAD/EMTD
railway system
ceives KEPC
two 55 kV.
e only 90 d
utputs.
kV output
to 27.5 kV, an
otransformer
nd the feeder
r. In other w
enary-rail an
g, the calculat
compared by
ain feeding
the symmetri
ulation res
red and used
ion 183
DC
m.
CO’s 154 kV
The 55 kV
degree phase
of the Scott
nd supplies it
is connected
line, and the
words, the AT
nd feeder-rail
ted value and
y assuming a
system. The
ic coordinate
sults using
d for accurate
3
V
V
e
t
t
d
e
T
l
d
a
e
e
g
e
A Study on the Protection Relay Test and Analysis Method of AC Electric Railway Substation
184
Table 5 shows the impedance values for the
calculation of 154 kV single line-to-ground fault
current. The numerically calculated single
line-to-ground fault current (Ig) is shown in Eq. (3).
Table 5 154 kV single line-to-ground fault impedance.
Z = R + jX Ω R X
Zero sequence component 1.0296 5.2232
Positive sequence component 0.5853 3.8554
Negative sequence component 0.5853 3.8554
Combined component 2.202 12.934
IG=3E
Z0+Z1+Z2=
3
13.12×
154kV
√3=20.33kA (3)
3.3 Protection Relay Evaluation System Development
RTDS (Real Time Digital Simulator) based
real-time simulators, which have recently attracted
attention as power system simulators, have economic
and technical difficulties. So, in this study, we
developed a relatively simple PSCAD based IED
(Intelligent Electronic Device ; protection relay)
simulator as a pre-test tool prior to RTDS based
simulation as a new solution, and in the future it can
be also used for field education. Fig. 9 is an HIL-test
hardware configuration of the IED simulator for
electric railways developed based on PSCAD in this
study [7, 8].
Fig. 9 HIL-test configuration of IED simulator.
The graphic plots in Fig. 10 are the protective relay
(#87, #21) simulation results obtained from the
HIL-test program developed in this study.
Fig. 10 HIL-test configuration of IED simulator.
The differential current relay (#87) monitors the
current ratio of the primary and secondary sides of the
Scott transformer to check for abnormalities. And the
distance relay (#21) measures and monitors the
impedance of the feeding section to check whether it
is fault or not.
3.4 Fault Simulation of Electric Railway SS
Fig. 11 is a simulation result of accident currents
that may occur in AC railway SS, and these results are
compared with numerical values. It shows the
simulation results using PSCAD/EMTDC, targeting
154 kV single line-to-ground current, 3-phase short
circuit current, 55 kV line-to-line short circuit current,
and 27.5 kV single line-to-ground current.
A
(a) Single lin
(c) Line-to-li
Fig. 11 AC r
Table 6
values of th
kV single
consistency,
was 97.8%,
was 92.9%,
current was Table 6 Fau
Unit: kA (Reference : 100 MVA)
(A)Calculation
(B)Simulation(A)/(B)
The follo
current of th
of the ‘Non
Honam Lin
confirmed th
through the
showed 96.2
in the simula
Study on the
ne-to-ground
ine short circu
railway fault c
compares th
he symmetric
line-to-grou
, the 154 kV
the 55 kV lin
, and the 27
97.0%.
ult simulation c
154 kV
Single line -to-ground
n 20.33
n 22.00 92.4%
owing Fig.
he 27.5 kV c
nsan ~ Bongm
ne in Korea
hat the groun
COMTRAD
2% agreemen
ation.
e Protection R
(b) 3-phase s
uit (d) Single
current simulat
he calculated
coordinate m
und current
V 3-phase sho
ne-to-line sho
7.5 kV singl
current.
154 kV 53-phase Short circuit
InSc
23.04 2
23.56 297.8% 9
12 shows th
catenary line
myeong’ sect
a. The faul
nd fault curre
E file stored
nt with the 5
Relay Test an
short circuit
e line-to-groun
tion result.
d and simul
method. The
showed 92
ort circuit cur
ort circuit cur
le line-to-gro
55 kV 27.5 knternal
Short circuit
Single-to-gro
2.60 5.201
2.80 5.3692.9% 97.0%
he ground f
at the substa
tion of the K
lt current v
ent was 5.57
in the relay,
5.3 6kA obta
nd Analysis M
nd
lated
154
2.4%
rrent
rrent
ound
kV
e lineound
%
fault
ation
KTX
value
7 kA
and
ained
Fig.
4. C
In
incr
quic
con
and
perf
rela
for
PSC
occ
a r
sho
sho
line
27.5
con
calc
circ
but
agre
grou
In
dev
situ
Ac
T
Infr
Rai
Method of AC
. 12 Ground
Conclusion
n a situation
reases and be
ckly and acc
ntinuous data
d software
formance eva
ays was condu
each type
CAD/EMTDC
urring in the
esult, the 15
wed 92.4%
rt circuit cu
e-to-line shor
5 kV single
nsistency. In
culations and
cuit accidents
almost iden
eement with
und fault of
the future,
velopment are
uation analysi
knowledgm
This study wa
rastructure a
ilway Techno
Electric Rail
fault current o
n
where the sc
comes more c
curately resp
accumulation
development
aluation syst
ucted, and sim
along with
C for analys
AC railway
54 kV singl
consistency
urrent show
rt circuit curr
line-to-groun
n the com
d simulations
s, they tend n
ntical. In add
the actual m
the 27.5 kV
the results
e expected to b
is and field tra
ments
as conducted
and Transpor
ology-Project
way Substati
of 27.5 kV cate
cale of the p
complex, it is
ond to incid
n. In this stud
t required
tem for digit
mulations we
reduced mo
sis of vario
power supply
le line-to-gro
y, the 154
wed 97.8%,
rent was 92.
nd current sh
mparison of
for ground fa
not to be 100
dition, it sho
measurement
V catenary lin
s of this r
be used for va
aining.
by the Mini
rt’s Research
(20RTRP-B
ion 185
enary line.
power system
s necessary to
dents through
dy, hardware
to build a
tal protection
ere conducted
deling using
us accidents
y system. As
ound current
kV 3-phase
the 55 kV
.9%, and the
howed 97.0%
f numerical
ault and short
0% identical,
owed 96.2%
result of the
ne of the SS.
esearch and
arious failure
stry of Land,
h Project on
146034-03).
5
m
o
h
e
a
n
d
g
s
s
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A Study on the Protection Relay Test and Analysis Method of AC Electric Railway Substation
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