IB ATS-C103
For more information visit: www.eaton.com
Instructional Booklet
Effective: March 2012
Page
19
Instructions for Installation, Operation and Maintenance of the
Eaton ATC-800 Closed/Open Transition Transfer Switch Controller
•
History information:
Source 1 Engine Run Time
Source 2 Engine Run Time
Source 1 Available Time
Source 2 Available Time
Source 1 Connected Time
Source 2 Connected Time
Load Energized Time
Number of Transfers
All history information is in hours and minutes. Each individual
value is resettable over IMPACC.
•
Time-stamped history (time/date/reason) for all previous trans-
fers.
•
Capability to initiate an engine test.
•
Updates the ATC-800 real-time clock.
4.9 Closed/In-phase Transition
Closed Transition is a feature that will temporarily parallel two live
sources in a make-before-break scheme when performing a trans-
fer. This achieves a transfer between sources with no power
interruption. Both sources must be synchronized in frequency,
phase, and voltage before the transfer is initiated.
In-phase Transition is a feature that will allow a transfer between
two live sources only when the phase difference between the two
sources is near zero. This is an open transition transfer that pre-
vents in-rush currents from exceeding normal starting currents in
the case where motor loads are being transferred.
The following sequence of transitions is implemented: If Closed
Transition does not occur in a specified amount of time, we will
proceed to In-phase Transition. If this transition does not occur
within a specified amount of time, we will then perform an Open
Transition with the Time Delay Neutral or Time Delay Load Sense
feature.
4.9.1 Closed Transition
The Closed Transition transfer switch will close the breakers for
both sources for a maximum time of 100 milliseconds after the
sources are synchronized. The breaker for the Normal source will
then be opened.
The closed transition scheme is anticipatory in that the breaker
close command is initiated before the sources are exactly in-
phase. This phase angle is called the advance angle. The
advance angle compensates for the closing time of the breaker.
The advance angle is calculated based on the frequency differ-
ence between the two sources and also the response time of the
breaker. This results in the optimum reconnect angle of 0 degrees
for all of the frequency difference values.
The criteria for closed transition require that both sources be
available and synchronized in voltage, frequency, and phase. The
frequency difference must be less than the closed transition fre-
quency difference set point (0.0 to 0.3 Hz). The voltage differ-
ence must be less than the closed transition voltage difference
setpoint (1 to 5%). When these conditions are met, the ATC-800
will monitor the phase difference between the two sources. The
synchronization timer will count down and be displayed as
“TSCT” while waiting for synchronization to be detected. When
the phase difference is within the advance angle window, the
“breaker close” command is given. When the breaker closes, the
two Sources are paralleled and then the first source is discon-
nected. The parallel time is less than 100 milliseconds.
If the synchronization does not occur within a specified amount of
time, the transfer will take place under in-phase transition or
delayed transition. If a closed transition transfer is performed and
the Normal source is not opened within 100 milliseconds, then
the Emergency source is opened and the alarm relay is energized.
4.9.2 In-Phase Transition
In-phase transition is an open transition with both sources in-
phase. The same anticipatory scheme used for closed transition
is also used for in-phase transition. The advance angle is calcu-
lated based on the frequency difference between the two sources
and also the response time of the breaker. This results in the opti-
mum reconnect angle of 0 degrees for all of the frequency differ-
ence values.
The criteria for in-phase transition are similar to closed transition.
Both sources must be available and the frequency difference must
be less than the in-phase transition frequency difference setpoint
(0.0 to 3.0 Hz). When these conditions are met, the ATC-800
will monitor the phase difference between the two sources. The
synchronization timer will count down and be displayed as “TSIP”
while waiting for synchronization to be detected. When the
phase difference is within the advance angle window, the “trans-
fer” command is given. This is an open transition but both
sources will be in phase when the transfer occurs.
If the synchronization does not occur within a specified amount of
time, the transfer will take place under delayed transition.The
Alarm relay will energize and the failure will be logged into the
Transfer History as either “Sync Fail - Freq” or “Sync Fail - Phase”
depending on whether the frequency difference or the phase dif-
ference was excessive.
NOTICE
IF THE ATC-800 RUN/PROGRAM SWITCH IS IN THE PROGRAM POSI-
TION, THE SETPOINTS CANNOT BE DOWNLOADED OVER IMPACC.
