2BOTHER FUNCTIONS
PROTECTION, CONTROL AND METERING FUNCTIONS
The Takagi algorithm multiplies the fault voltage for such a magnitude that the result is a
real number. This magnitude should be measurable by the relay which requires certain
approximations in order to ignore the magnitudes of the remote line terminal
Figure 2-53 shows the prefault (a) and fault (b) equivalent circuits for a simple system
assuming a three phase sort circuit for simplicity. From such circuit the prefault
(
'
'
V
,
I
1) and fault (
''
''
V
,
I
2) components can be calculated. The total fault
magnitudes
V
,
I
can be later calculated using the superposition theorem.
E
A
∠
δ
E
B
∠
0
o
I
V
F
V
(a)
A
Z
B
Z
A
m
Z
L
(1-m
)
Z
L
B
(b)
V
V
F
I
I
F
R
F
Z
B
Z
A
m
Z
L
(1-m
)
Z
L
A
B
F
F
Figure 2-53 Prefault (a) and fault (b) equivalent circuits for a three phase short circuit in a simple
system.
From Figure 2-53 we get:
"
'
I
I
I
+
=
Takagi introduces the term:
"
I
I
Ke
K
F
j
=
=
α
And the fault current can be expressed as:
"
I
K
I
F
=
By multiplying the measured voltage at the end where the fault locator is placed times
the fault current conjugate we get:
*
"
*
"
*
F
F
F
L
I
I
R
I
K
I
Z
m
I
K
V
+
=
Summary of Contents for smART P500
Page 1: ...Instruction Manual Multifunction Protection Relay smART P500...
Page 23: ...2BTABLES INDEX THIS PAGE HAS BEEN LEFT BLANK INTENTIONALLY...
Page 39: ...5BHARDWARE FEATURES INTRODUCTION Figure 1 9 Wye Wye Connection measured neutral...
Page 40: ...5BHARDWARE FEATURES INTRODUCTION Figure 1 10 Wye Wye Connection sensitive neutral...
Page 41: ...5BHARDWARE FEATURES INTRODUCTION Figure 1 11 Open Delta Connection measured neutral...
Page 42: ...5BHARDWARE FEATURES INTRODUCTION Figure 1 12 Open Delta Connection sensitive neutral...
Page 511: ...2BANSI CURVES 0BCURVES FOR TIME CHARACTERISTICS Figure I 6 Moderately ANSI curve...
Page 513: ...2BANSI CURVES 0BCURVES FOR TIME CHARACTERISTICS Figure I 7 Very inverse ANSI curve...
Page 515: ...2BANSI CURVES 0BCURVES FOR TIME CHARACTERISTICS Figure I 8 Extremely inverse ANSI curve...
Page 532: ...4BRECLOSER CURVES 0BCURVES FOR TIME CHARACTERISTICS Figure I 14 Recloser Curves 101 119...
Page 535: ...4BRECLOSER CURVES 0BCURVES FOR TIME CHARACTERISTICS Figure I 15 Recloser Curves 120 142...
Page 538: ...4BRECLOSER CURVES 0BCURVES FOR TIME CHARACTERISTICS Figure I 16 Recloser Curves 151 202...
