Utility Relay Company AC-PRO-II, Instruction Manual

Page: 35 / 56

AC-PRO-II
®
Instruction Manual www.utilityrelay.com
Page 33
Figure 14.1 and Figure 14.2
show a method to verify that the
breaker CT polarities match. The setup in Figure 14.1
verifies that the CT polarities of Phase A and Phase B
match. The setup in Figure 14.2 verifies that the CT
polarities of Phase B and Phase C match.
It is only necessary to inject a current slightly greater than
the GF Pick-Up setting and to verify that a GF trip does not
occur.
To Test Set
Breaker
Jumper load side of Phase A & B poles
"A" "B" "C"
CTs
Apply current slightly greater
If Phase A & B phasing match,
a GF trip will not occur.
than GF Pick-Up to the breaker line side.
Figure 14.1: Phase A & B, CT Polarity Test
To Test Set
"B" "A"
Jumper load side of Phase B & C poles
Breaker
CTs
than GF Pick-Up to breaker line side.
a GF trip will not occur.
If Phase B & C phasing match,
Apply current slightly greater
"C"
Figure 14.2: Phase B & C, CT Polarity Test
If a GF trip does occur, determine which CT has the
reversed polarity. Reverse the secondary connections at the
CT to correct the reversed polarity.
The breakers shown in the Figures above have the CTs on
the load side. Use exactly the same method if the CTs are
on the breaker line side or if they are staggered.
If a neutral CT is used, its polarity must match the polarity of
the breaker mounted CTs.
To test QT-I the AC-PRO-II QUICK-TRIP switch module
must be connected to the trip unit as shown in Figure 7.1.
With QT- I pick-up set to the required value and the
QUICK-TRIP selector switch turned to the on position, test all
three breaker poles in the same manner as the normal
Instantaneous function.
To test the UV trip or alarm function, a primary injection
current test set, a voltage source, and a timer is needed.
Since both a current test set and a voltage source will be
used, ensure the AC-PRO-II voltage connections are
isolated from the breaker poles by removing the fuses from
the fuse block that feeds the VDM (Voltage Divider Module).
Make the temporary testing connections shown in Figure
14.3. The voltage source can be 120VAC (voltage must be
at least 90VAC). Verify that the Phase A voltage is indicated
on the display. Reminder: voltage measurement and
settings are for Line-to-Neutral voltages (i.e. 277V is the
Line-Neutral voltage on a 480V 3-phase system).
The UV delay feature can be tested with a timer. The UV
function is “definite time”, so the delay remains the same
regardless of the severity of the undervoltage.
From Primary Injection
"A" "B" "C"
CTs



Current Test Set
From Voltage
Source
"Hot" Neutral







AC-PRO-II
VDM
Voltage
Divider
Module
A B C G
Figure 14.3: Undervoltage Test temporary
connections
Undervoltage Test Notes:
1) In addition to the voltage source, current must be above
10% of the CT rating on any two phases for a UV Trip or
Alarm to occur.
2) UV is disabled if a Secondary Injection Test Set is
connected.
3) After a UV trip occurs, repeated UV trips are blocked
until current is re-established.
4) If a UV alarm occurs, it is latched and must be reset
using the display and push buttons.
5) Refer to Section 11.17 for additional Undervoltage
information.
**** 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.
Undervoltage Test Procedure:
1) Set the AC-PRO-II UnderVoltage Trip or Alarm setting to
ON.
2) Apply 120VAC across terminals A & B. (must be at least
90VAC)
3) Apply current greater than 10% of the CT rating on two
phases and start the timer.
NOTE: as soon as current is applied to any two phases,
the AC-PRO-II internal UV pickup timer will start since
the voltages applied to Phases B & C are both “Low”.
4) The UV trip or alarm should occur /- 0.25
seconds of the UV time delay setting.
14.9 QT-I Trip Test
14.10 Undervoltage (UV) Test