Rockwell Automation 1407-CGCM Combination Generator Control Module - Manual (Page 57)

Rockwell Automation Publication 1407-UM001G-EN-P - April 2013 57
CGCM Unit Operation Chapter 3
Loss of Excitation Power (PMG) (27)
If voltage to the PMG excitation power inputs falls below 10V AC for
approximately 400 ms or more, a Loss of Excitation power fault occurs. When
single phase PMG is selected, the CGCM unit senses phases A and C for this
function. This function is disabled when Shunt excitation is selected, the
EngineIdle
tag is set, or the host Logix controller is in Program mode. If this fault
occurs, tag LossPMGFlt = 1 in the Scheduled Read table.
Reverse VAR (40Q)
When the Reverse VAR level exceeds the characteristic curve for an amount of
time you set, a Reverse VAR fault occurs. The characteristic curve is a line that
begins at the pickup setting you defined at zero real power and extends toward
positive reactive power at an angle of 8°. Once the VARs increase above the
threshold, the Reverse VAR fault timer is reset. If this fault occurs, the CGCM
unit shuts down excitation and sets tag RevVARFlt = 1 in the Scheduled Read
table.
The Reverse VAR Characteristic graph shows more details.
Figure 35 - Reverse VAR Characteristic
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
-1.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
Lagging
Leading
Reactive Power
, per Unit
Generator
Characteristic
Curve
Trip Region
Reverse VAR
Trip Setting
Real Power, per Unit
8˚