Utility Relay Company AC-PRO-II, Instruction Manual

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AC-PRO-II
®
Instruction Manual www.utilityrelay.com
Page 31
During normal operation, the trip unit display screen will be
off and in its power saving mode. See Section 3.0 for trip
unit power information. When the “DISPLAY” button is
pressed during normal operation (no trips, errors, alarms,
etc), the trip unit will display current and line-to-neutral
voltage (if equipped with VDM) readings. The neutral and
GF currents will only be displayed if neutral or GF protective
functions are turned on. See below. The “XXXX” digits will
display actual readings.
Figure 13.1: Main (“Readings”) Screen
•
The left column displays Currents in Amps for
Phases A, B, C, Neutral and Ground Fault.
•
The right column displays Line-to-Neutral Voltages
for Phases A (“Van”), B (“Vbn”), and C (“Vcn”).
Breaker Current Less than 10% of CT Rating:
When the currents are less than about 10% of the CT rating,
the display will display “LOW” for currents.
Breaker Current Greater than 10% of CT Rating:
If the breaker current is greater than about 10% of the CT
rating, the current readings will be displayed.
Line-to-Neutral Voltages (if equipped with VDM):
“LOW” will be displayed if the Line-to-Neutral voltage is 50V
or below.
“N/A” will be displayed if the Voltage cannot be determined,
most likely because system voltage (i.e. 480V) is not present
at the VDM.
Note: If voltages and voltage labels (“Van, Vbn, Vcn”) do not
display, the AC-PRO-II is either not equipped with a VDM, or
the VDM is not properly connected to the AC-PRO-II.
Contact URC.
Figure 13.2: Power Screen #1:
Instantaneous Power
•
The left column displays real power in Kilowatts (KW) per
phase, total
(∑ KW), and Power Factor (PF).
•
The right column displays apparent power KiloVolt-
Amperes (KVA) per phase and total (∑ KVA).
Figure 13.3: Power Screen #2: Energy
•
KWHr = KiloWatt-Hours (real power usage)
•
KVAHr = KiloVolt-Ampere-Hours (apparent power
usage)
Instantaneous Power Values (if equipped with VDM):
•
“LOW” is displayed for the per-phase KW and KVA
values if an associated phase current or voltage is
“LOW”.
•
“N/A” will be displayed for the per-phase KW and KVA
values if the Voltage on the associated phase cannot be
determined, most likely because system voltage (i.e.
480V) is not present at the VDM.
•
The
∑
symbol represents the three phase power totals.
If a particular phase is “LOW”, then zero is included for
that phase in the three-phase sum.
•
“PF” is the total Power Factor calculation.
•
The KW values are affected by the direction of the power
flow, and the Power Flow Direction user setting. See
Section 11.7.
Energy Values (if equipped with VDM):
•
Energy values increment if the current for a particular
phase is above 3% of the CT rating and the phase
voltage is above 50V.
•
The KWHr value increments and decrements depending
on the power flow direction and Power Flow Direction
user setting. See Section 11.7.
•
The KVAHr value only increments.
•
Note: Energy values can increment even when the
Instantaneous Power values displayed are “LOW”
A "primary injection" test is recommended as the final test of
the AC-PRO-II retrofit.
If residual GF is used, it must be temporarily turned off when
testing the other trip functions.
Before proceeding with the normal primary injection tests,
the trip unit must be commissioned to make it functional. See
Section 11.0 for the commissioning procedure.
It is best to use the final pick-up and time delay settings if
they are known. If not, use typical settings for the primary
injection test.
If residual GF is used, make sure it is temporarily turned off.
To test the LT Pick-Up, increase the current until the “Pick-
Up” LED illuminates.
The injected current should correspond to the programmed
LT pick-up setting. Verify that the correct phase is indicated
on the display.
To test the LT trip time, first calculate the trip time based on
the value of the test current that will be applied. Use the
formula in Section 18.1 or the chart in Section 15.3.
**** NOTE ****
A simple shortcut is to note that the trip time (center
of the curve) at 3 times the LT pick-up current is 4
times the LT Delay setting.
For example:
If LT Pick-Up is 1600A and Delay is 10.0S, then the
trip time at 4800A (3 times 1600A) is 40 sec. (4 times
10 sec).
13.0 Normal Operations & Readings
14.0 Testing
14.1 Commission the Trip Unit
14.2 Long Time Trip Test