Eaton QD5 User Manual

METERING: In a co-generation environment, when current
level is above the Reverse Current Sense Threshold in the
forward direction, metering will be recorded for forward
current flow. When current flow is below the Reverse
Current Sense Threshold in the forward direction, the
control will use a test tap strategy and sample changes in
voltage to determine a true current flow direction. Metering
will be recorded for the current direction last determined by
the sampling mechanism to be correct. See Figure36.
Current Level
OTOT
0
Test taps determine true
System power flow direction.
Metering direction matched
by true power flow direction.
Normal Forward
Metering
Reverse Power off
Reverse Forward
OT=Operating Threshold, FC 57, 1-5%
Figure36. Bias co-generation metering
OPERATION: When the control is set for Bias
Co-Generation, if the current flow exceeds the Reverse
Current Sense Threshold in the forward direction, the
control will regulate voltage as normal for forward current
flow. If the current flow drops below the Reverse Current
Sense Threshold, the control must determine current
direction. To do this, it will use a test tap strategy similar
to the Bias Bi-directional mode. The control will utilize two
quick test taps and sample changes in voltage. The current
flow direction will be indicated by the direction of voltage
change seen during the test taps.
If the test tapping and sampling determines a reverse
power flow is due to co-generation, the control will perform
forward voltage regulation using reverse settings for set
voltage (FC 51), bandwidth (FC 52), time delay (FC 53),
and line drop compensation (FC 54 and FC 55). If the
test tapping and sampling determines that a true current
reversal has occurred, the control will begin to operate in
an alternate bias co-gen mode as selected by the user.
The alternate bias co-gen modes are 1) Locked Reverse,
2)Neutral Idle , and 3) Reverse Co-generation. In this case,
it will also use the basic reverse power settings (FC 51 - FC
55). See Figure37.
Because reverse power through the regulator is possible
in a co-generation scenario without a true current flow
reversal, the control must continue to use the test tap and
sampling strategy to determine current flow whenever the
current flow in the forward direction is below the Reverse
Current Sense Threshold.
Current Level
0
Test taps determine true
System power flow direction.
If forward flow, regulates like
standard Co-Gen. If reverse, uses
Alternative Bias Co-Gen mode.
Forward regulation
with Forward settings
Reverse Forward
OTOT
OT=Operating Threshold, FC 57, 1-5%
Figure37. Bias co-generation operation
133
INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS MN225003EN April 2018
CL-7 Voltage Regulator Control

Eaton QD5 Specifications

General

Brand	Eaton
Model	QD5
Category	Cables and connectors
Language	English