GE Multilin G650, Manual, Page: 241 / 639

5-98 G650 Generator Protection & Control System GEK-113285A
5.5 CONTROL ELEMENTS 5 SETTINGS
5
Table 5–95: LOSS OF MAINS INTERNAL SIGNALS
5.5.10.3 LOSS OF MAINS ALGORITHM IMPLEMENTATION
1. Calculation for the average of positive and negative semi-periods of the signal:
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.
Signal Comment
LOSS OF MAINS 1 (2, 3,) BLOCK Input used to block externally the Loss of mains (1, 2, 3)
element
LOSS OF MAINS 1 (2, 3,) A OP Output used to indicate a loss of mains in phase A in the (1, 2,
3) elements
LOSS OF MAINS 1 (2, 3,) B OP Output used to indicate a loss of mains in phase B in the (1, 2,
3) elements
LOSS OF MAINS 1 (2, 3,) C OP Output used to indicate a loss of mains in phase C in the (1, 2,
3) elements
LOSS OF MAINS 1 (2, 3,) OP Output used to indicate a loss of mains in the (1, 2, 3) elements
∑
=
=
−
=
N i
i
i n
s
s
T
N
T
1
) (
1
∑
=
=
−
=
N i
i
i n
b
b
T
N
T
1
) (
1
ϕ
> −
∑
=
=
−
|
1
|
1
) (
N i
i
i n
b
b
n
T
N
T
ϕ
> −
∑
=
=
−
|
1
|
1
) (
N i
i
i n
s
s
n
T
N
T
ϕ
< −
∑
=
=
−
+
|
1
|
1
) (
1
N i
i
i n
b
b
n
T
N
T
ϕ
< −
∑
=
=
−
+
|
1
|
1
) (
1
N i
i
i n
s
s
n
T
N
T