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2BOTHER FUNCTIONS
PROTECTION, CONTROL AND METERING FUNCTIONS
From such expression the imaginary part is taken to eliminate the term that involves
the fault resistance and the resulting expression is:
(
)
(
)
"
*
"
*
Im
Im
I
K
I
Z
m
I
K
V
L
=
Then the expression used by the algorithm for the fault distance calculation is:
(
)
(
)
"*
*
"*
*
Im
Im
I
K
I
Z
I
K
V
m
L
=
If the factor K is represented in its polar form the expression is:
(
)
(
)
α
α
j
L
j
e
I
I
Z
e
I
V
m
−
−
=
"*
"*
Im
Im
Here the angle
α
represents the angular relationship between two current components
one unknown
F
I
and the other known
"
I
so that it is not possible to know its value
using information from only one end of the line. To eliminate this factor Takagi assumes
α
= 0 (this means that every impedance in the system has the same X/R ratio), so:
( )
(
)
"*
"*
Im
Im
I
I
Z
I
V
m
L
=
The expression for m represents the per unit value if the length of the line where the
fault is located. Three possible outcomes are thus possible:
M is positive and smaller than one. This indicates that the fault is located in the
forward direction of the line and inside its length so that the results are correct.
M is negative and its absolute value is smaller than 1. Here the algorithm has to
be reevaluated considering the parameters of the line with backward adjustments
in the proART. After this new assessment which must also return a negative value
the conclusion can be that the location is correct but in the reverse direction.
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...