GE G30 - Loss of Excitation

GE Multilin G30 Generator Protection System 9-7
9 APPLICATION OF SETTINGS 9.1 SETTING EXAMPLE
9
The minimum operate time of stage 1 will be set to 0.25 seconds, the maximum operating time will be 10 minutes, and the
reset time will be set to 4 minutes.
Stage 2 is typically set lower than stage 1 with a time delay to prevent nuisance alarms for external faults that are normally
cleared by system protection. For the application example, the pickup setting is:
(EQ 9.6)
Source 2 will be chosen for this element. The settings are as follows:
9.1.6 LOSS OF EXCITATION
For the example system, we have the following values:
(EQ 9.7)
(EQ 9.8)
(EQ 9.9)
(EQ 9.10)
(EQ 9.11)
(EQ 9.12)
(EQ 9.13)
(EQ 9.14)
The voltage supervision setting will be determined by a system study and may be disabled on either element if required. VT
fuse failure should supervise this element.
Pickup 70% I
2
capability× 0.70 8%× 5.6%===
Z
b sec()
base kV
2
base MVA
---------------------------
CT ratio
VT ratio
---------------------
×
18 kV()
2
211.765 MVA
------------------------------------
1600
157.5
---------------
× 15.54 Ω== =
X
d
′(sec) X
d
′ Z
b
(sec)× 0.216 15.54 Ω× 3.36 Ω== =
X
d
sec()X
d
Z
b
sec()× 1.967 15.54 Ω× 30.57 Ω== =
CENTER 1
Z
b
sec()X
d
′(sec)+
2
-------------------------------------------------
15.54Ω 3.36Ω+
2
-------------------------------------------
9.45 Ω===
RADIUS 1
Z
b
sec()
2
--------------------
15.54 Ω
2
----------------------
7.77 Ω== =
PICKUP DELAY 1 0.06 seconds=
CENTER 2
X
d
sec()X
d
′(sec)+
2
-------------------------------------------------
30.57Ω 3.36Ω+
2
-------------------------------------------
16.97 Ω===
RADIUS 2
X
d
sec()
2
---------------------
30.57 Ω
2
----------------------
15.28 Ω== =