GE Multilin G650 Manual page 241

5.5 CONTROL ELEMENTS
Table 5–95: LOSS OF MAINS INTERNAL SIGNALS
Signal
LOSS OF MAINS 1 (2, 3,) BLOCK
LOSS OF MAINS 1 (2, 3,) A OP
LOSS OF MAINS 1 (2, 3,) B OP
LOSS OF MAINS 1 (2, 3,) C OP
LOSS OF MAINS 1 (2, 3,) OP
5.5.10.3 LOSS OF MAINS ALGORITHM IMPLEMENTATION
1. Calculation for the average of positive and negative semi-periods of the signal:
5
where N value is 10
2. If a) and b) are fulfilled we will be talking about a phase leap.
a)
b)
where ϕ value is value set in Loss of mains Angle.
First condition checks that something has occurred in the semi cycle and b) condition is used to differentiate between a
phase displacement from a frequency change.
5-98
Comment
Input used to block externally the Loss of mains (1, 2, 3)
element
Output used to indicate a loss of mains in phase A in the (1, 2,
3) elements
Output used to indicate a loss of mains in phase B in the (1, 2,
3) elements
Output used to indicate a loss of mains in phase C in the (1, 2,
3) elements
Output used to indicate a loss of mains in the (1, 2, 3) elements
=
i N
1
∑
=
s
T T
N
=
i 1
=
i N
1
∑
=
b
T T
N
=
i 1
=
i N
1 ∑
−
b
b
| T T
( n
n
N
=
i 1
=
i N
1
∑
−
s
s
| T T
( n
n
N
=
i 1
=
i N
1
∑
−
b
b
| T T
+
n 1
N
=
i 1
=
i N
1 ∑
−
s
s
| T T
+ (
n 1
N
=
i 1
G650 Generator Protection & Control System
s
−
( n i )
b
−
( n i )
ϕ
>
|
−
i )
ϕ
>
|
−
i )
ϕ
<
|
−
( n i )
ϕ
<
|
−
n i )
5 SETTINGS
GEK-113285A