Rockwell Automation 1407-CGCM Combination Generator Control Module - Manual (Page 60)

60 Rockwell Automation Publication 1407-UM001G-EN-P - April 2013
Chapter 3 CGCM Unit Operation
Synchronizing Connection Schemes
The CGCM unit provides information that its host Logix controller uses to
synchronize the generator output voltage, frequency, and phase to a reference
power system, or bus. 3-phase, dual bus, and single-phase connection schemes are
described below.
• 3-phase
In this scheme, the 3-phase output of the generator and all three phases of
the reference system are connected to the CGCM unit. This lets the
CGCM unit match voltage, frequency, phase, and phase rotation of the
generator to the reference system. The 3-phase scheme provides the
CGCM unit with the most power system data, allowing it to perform the
most thorough synchronization.
To enable a 3-phase connection, the user selects the Generator and Bus VT
Configurations as two-transformer open-delta, three-wire wye or
four-wire wye.
When synchronizing delta systems, the CGCM unit uses line-to-line
voltage for voltage, frequency and phase matching. When synchronizing
wye systems, the CGCM unit uses line-to-line voltage for voltage and
frequency matching, and line-to-neutral voltage for phase matching.
• Dual Bus
The CGCM unit has the ability to synchronize a generator to either one
of two reference busses. The CGCM unit supports this by monitoring one
line-to-line phase of the two reference busses. The user must select the
appropriate bus for synchronization. It is not possible to synchronize to
two different busses at the same time. For dual-bus synchronization, the
3-phase output of the generator and a single phase from each reference bus
are connected to the CGCM unit. This lets the CGCM unit match
voltage, frequency, and phase, but not phase rotation of the generator to
the reference system.
However, the CGCM unit verifies that the generator output phase
rotation matches the user-configured selection of ABC or ACB.
To enable the dual-bus mode, select the Bus VT Configuration as Dual
Breaker.
• Single-phase
The CGCM unit is also capable of synchronizing where only a single
line-to-line input is available from the generator or bus. This is the case for
single-phase systems or in systems where only one phase has a transformer
connected for synchronizing purposes. The CGCM unit can perform no
phase rotation check on the generator output with single-phase generator
voltage sensing. The reference bus connection can be either single or
3-phase.