Utility Relay Company AC-PRO-II, Instruction Manual

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AC-PRO-II
®
Instruction Manual www.utilityrelay.com
Page 27
This setting only applies if the AC-PRO-II is installed
with the optional Voltage Divider Module (VDM).
The Undervoltage (UV) function of the AC-PRO-II utilizes
Line-to-Neutral voltage and a definite time delay, to provide
three-phase UV protection.
The UnderVoltage (UV) function uses voltage magnitude
only, which provides “brownout” protection. “Brownouts” are
when system voltage is still present, but the voltages are
lower than the nominal system voltage. UnderVoltage
protection is not intended to be “Phase Loss” protection and
will not operate reliably in the event of a total phase loss, or
total system outage. This is because voltage can still be
present on the “lost” phase, from the “regenerated voltage”
or “back EMF” from 3-phase motors operating on a single
phase source.
Figure 11.3 for Undervoltage settings notes, ranges, steps,
and options.
The UV function is disabled under the following conditions:
- If a Secondary Injection Test set is connected.
- If the AC-PRO-II is on battery power only or USB power
only
- If (2) Phase currents are “LOW” and (1) Phase current is
not “LOW”.
- After a UV trip, repeated UV trips are blocked until current
is re-established.
**** IMPORTANT ****
For Undervoltage trips and alarms to occur, the following
conditions must be present:
1. At least (2) phase currents must be greater than 10%
of the CT rating.
2. The Phase A-to-B voltage must be greater than 90V.
**** IMPORTANT ****
The Undervoltage function will not operate in the event of
a total phase loss or total system outage. The
UnderVoltage function is not “Phase Loss” protection.
**** IMPORTANT ****
Use caution when using the Undervoltage (UV) Trip
function on Non-solidly grounded systems.
This setting only applies if the AC-PRO-II is installed
with the optional Voltage Divider Module (VDM).
The Overvoltage (OV) function of the AC-PRO-II utilizes
Line-to-Neutral voltage and a definite time delay, to provide
three-phase OV protection.
Figure 11 . 3 for OV settings notes, ranges, steps, and
options.
The OV function is disabled under the following condition:
- After an OV trip, repeated OV trips are blocked until current
is re-established.
**** IMPORTANT ****
Use caution when using the Overvoltage (OV) Trip
function on Non-solidly grounded systems.
The Sluggish Breaker setting range is 20ms – 80ms. The
default setting is 33ms.
The following steps are recommended for determining the
Sluggish Breaker setting on a recently serviced breaker with
a mechanism in good operating condition:
1. Perform primary Injection to initiate a ST or LT trip; or
use the SAFE-T-TRIP device to initiate a trip. If using
SAFE-T-TRIP on a breaker that does not have primary
current flowing through it, a 52a or 52b contact must be
wired to AC-PRO-II.
2. Use the trip history menu to review the recorded
breaker mechanism times of the trip initiated in step 1
above. The breaker mechanism times should be in the
20ms to 80ms range. The total trip time (different than
breaker mechanism time) should conform to the Time
Current Curve in Figure 18.1.
3. URC recommends setting the Sluggish Breaker time to
be 17ms greater than the recorded mechanism time
from step 2.
See Figure 11.4 for Sluggish Breaker setting screen.
See Section 10.0 for additional information about the
Sluggish Breaker feature.
11.20 Configurable Alarm Relay Settings
The alarm relay configuration occurs via two alarm relay
settings screens, where the alarm relay can be set to
operate for any combination of events. If the setting is “ON”,
the relay will operate for that particular event/condition. See
Figure 11.4 for alarm relay settings options and notes.
Refer to Section 5.3.1 and Table 5-A for additional
information about the configurable alarm relay.
If a breaker position contact is wired to the AC-PRO-II, the
contact type is set at this screen. If the breaker contact is
open when the breaker is open, select 52a. If the breaker
contact is closed when the breaker is open, select 52b. If a
breaker contact is not wired into the trip unit, this setting
should be OFF. See Figure 11.4.
Note that this setting affects the Sluggish Breaker detection
method. See Section 10.0.
Once the last setting is entered, the “Save Settings?” screen
will appear. The save settings screen also provides a
reminder that if the “Save” button is pressed, the settings will
be saved, logged, and time stamped as a “Settings Change”.
The settings change time stamp is stored and available via
Modbus communications.
Pressing “Exit” will return to the Main screen.
Pressing “Back” will return to the previous setting screen.
11.23 Settings Verification
Once the settings are saved, the “REV” and “OK” buttons
are available at the “Settings Saved” screen.
Pressing “REV” will lead to the review settings sequence.
Pressing “OK” will lead to the main screen.
To complete the entering or changing settings process,
press “REV” to review and confirm all settings entered.
The settings review sequence is very similar to the settings
change sequence, except the settings are only viewed and
cannot be changed. The existing settings are viewed and
navigated with the “Next” and “Back” buttons.
See below and Figure 6.2.
11.17 Undervoltage (UV)
11.18 Overvoltage (OV)
11.19 Sluggish Breaker Setting
11.21 Breaker Position Contact Type Setting
11.22 Saving Settings