Allen-Bradley 1407-CGCM-DLR User Manual page 168

Chapter 7 Troubleshooting
Table 23 - Compensation Modes - Droop
Symptom
Voltage does not change with
changes in reactive load while not
connected to the grid
Reactive power does not change
with adjustments to the voltage
setpoint while connected to the grid
Voltage and / or reactive load is
unstable when operating in droop
Table 24 - Compensation Modes - Cross Current
Symptom
VARs share but not equally; even
when the system load changes
VARs do not share at all and when a
voltage adjust is made, nothing
happens
168
Most Likely Cause
Droop not selected/active
Cross current mode is
enabled/selected
Metering error
Droop not selected/active
PF or VAR control enabled/selected
Metering error
AVR Gains misadjusted
Metering error
Most Likely Cause
Gain mis-adjustment
CT or input impedance mismatch
Cross current mode is not
enabled/selected
Gain misadjustment
Wiring error
Rockwell Automation Publication 1407-UM002B-EN-P - February 2019
Diagnostic Action
Check tag Droop_Ened
Check Droop_CCCT_Select tag
See Metering troubleshooting
Table 30
Check tag Droop_Ened
Check tag PF_VAR_Control
See Metering troubleshooting
Table 30
Check voltage stability when
operating isolated from load and if
possible in constant voltage control
See Metering troubleshooting
Table 30
Diagnostic Action
Check CCCT Gain
Verify CT selection and measure
input impedance to each AVR
Check Droop_CCCT_Select tag
Check CCCT Gain
Measure voltage at ID+/- terminal
and adjust reactive power/voltage
Corrective Action
If not active, check/correct logic for
mode selection
If active, check/correct logic for
mode selection
See Metering troubleshooting
Table 30
If not active, check/correct logic for
mode selection
If active, check/correct logic for
mode selection
See Metering troubleshooting
Table 30
Calculate/correct AVR gains if
necessary
See Metering troubleshooting
Table 30
Corrective Action
Correct as required
Correct or replace CTs as required.
Add resistors as required to match
AVR input resistance
If not active, check/correct logic for
mode selection
Correct as required
Correct wiring as required if voltage
signal from CCCT circuit is not
observed