Woodward HighPROtec MCDLV4, Руководство пользователя

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Protective Elements
Tripping curve
The restrained percentage phase differential protection tripping characteristic can be expressed mathematically as:
∣ ⃗
I
d
∣
≥
∣ ⃗
I
dmin
∣
+
K
1
⋅
∣ ⃗
I
s
∣
⏟
I
s
>
I
s ( Idmin )
und I
s
<
I
s1
+
K
2
⋅
∣ ⃗
I
s
∣
⏟
I
s
⩾
I
s2
+
d
(
H , m
)
Where
∣ ⃗
I
d
∣
=
∣
⃗
I
W1
' ' '
+⃗
I
W2
' ' '
∣
is defined as fundamental differential current.
∣ ⃗
I
s
∣
=
0.5
⋅
∣ ⃗
I
W1
' ' '
−⃗
I
W2
' ' '
∣
is defined as fundamental restraining current, and it is also called the through-current
for normal load and external faults.
∣ 
I
dmin
∣
is the minimum differential current scaled to the base current.
K
1
and
K
2
are slope factors for two slope sections on the operating curve respectively.
d

H , m

is the temporary restraining current (see diagram “Temporary Dynamic Rise of the Static Tripping
Characteristic”), which is a configurable multiple of the base current
I
b
.
⃗
I
W1
' ' '
and
⃗
I
W2
' ' '
are the corresponding compensated secondary current phasors, which are scaled from the
uncompensated primary phase current phasors
⃗
I
pri,W1
and
⃗
I
pri,W2
flowing into the protected object.
Under normal conditions, the differential current should be below
∣ 
I
dmin
∣
. When an internal fault occurs, the
different current will raise above the restraining current to trip. To establish a correct trip criterion, two currents
flowing into the protected object must be matched by compensating their magnitudes and phases.
605 MCDLV4 DOK-HB-MCDLV4-2E
Id
_Z
0
7
Trip Range
Operating Range
Static Base Curve
Is/Ib
Is1 Is2
Id[Is2]
Id[Is1]
Id[Is0]
Id min
Slop
e1
Sl
op
e2
Id/Ib
Is0 = 0