AKA Transformer
Pre-magnetization System
The connection of transformers to
AC buses in marine power plants
limitation can be essential for marine
power plants. Major
can result in inrush currents several components
of the system
times greater than the steady state A method of pre-magnetizing large
full load current. Often this can cause transformers has been successfully
a disturbance on the AC bus, in the
form of a voltage drop. To combat
applied on several vessels in recent
years. This system involves initially
include
this, additional generators may be energizing the secondary windings of • PLC Control Box
brought online prior to transformer the transformer prior to connection
connection. However, the total number of the primary to the main bus. This • HMI Touch screen
of generators is then higher than would has the effect of pre-magnetizing • 10kva Pre-mag Transformer
normally be required to run the plant the transformer’s core and aligning
under steady state conditions, and in a magnetic fields so that inrush is • RTD temperature monitoring
blackout recovery situation this means negligible when the primary feeder
additional time is required for recovery. breaker is closed.
In some situations – for example
where generators are out of service
for maintenance – recovery may be AKA’s
impossible. It is sometimes necessary Pre-Mag
to set generator protection parameters
(eg. differential trip settings) wider System
than the ideal in order to allow for Protect your
transformer connections. These transformers from
inrush currents over time can stress inrush currents.
and eventually damage a transformer.
For these reasons, a method of inrush
E N G I N E E R I N G I N N O VAT I V E S O LU T I O N S
www.aka-group.com • sales@aka-group.com
PRE-MAG SYSTEM
AC Bus
PLC-Based
Pre-Mag Control
Shunt
Trip
Switchboard
UPS
Main Feeder
Breaker
Breaker Control
RTD
Pre-Mag
Transformer
Redundant
Control Power
PLC-Based
Pre-Mag Control
PLC-Based Voltage Monitor
Pre-Mag
Control
Close
Permissive
Touchscreen
HMI
DC Bus
Pre-Charge
Control
(existing)
DC Bus
Benefits and Features
• Inrush current is negligible • Twin control power feeds • PLC control box to supervise and
independently monitored and sequence the pre-magnetization
• Fewer generators required to
alarmed (pre-mag) process and to monitor
compensate for voltage drop
the health of all sub systems involved
• UPS back up feed to maintain PLC in
• Faster blackout recovery times
ready state during blackout
• Hardware-In-The-Loop Testing using
• HMI Touch screen to display AKA’s Pre-Mag System.
dual series contactors to allow the
system to test some key functionality
the status of system elements and Protect your
without actually performing a
monitored values (such as voltages transformers from
complete pre-mag operation.
and temperatures) and alarms. inrush currents.
0000-AKA-E-2027 V4_00
headquarters LOCATIONS Sales info
PO Box 577 North America - Canada +1.902.620.4882
23 Brook Street EU - Germany sales@aka-group.com
Montague, PE Asia - Singapore, China www.aka-group.com
Canada C0A 1R0
