GE LJ1005B010H00C MLJ Digital Synchromism Check
MLJ Digital Synchromism Check
Features and Benefits
RS485. RS232 or fiber comm. available
Configurable auxiliary outputs
V f Hz line and bus metering
Continuous or manual modes
Part of a modular system
Independent 2″ or 4″ modules
1/4 or 1/8 standard 19″ rack case available
3 digit display
Applications
Generator and network synchronism
Bus or line synchronism check
Manual closing of breakers
Protection and Control
Synchronism check operation
Undervoltage supervision
DLDB, DLLB and LLDB indication
Description
The MLJ is a digital synchronism
check relay that measures bus
and line voltages, checking:
voltage differences
frequency slip
phase angle between both volt
ages
The main applications of the MLJ
are:
connection of a generator to the
network
reestablishing the connection
between two parts of the
network
manual closing of breakers
a continuous mode in which it
constantly checks the synchro
nism
the manual mode is activated
when voltage is applied to a
manual digital input, initiating
the synchronism supervision
when voltage is applied by
another check starting digital
input
The synchronism function (with
the presence of line and bar volt
age) can be supervised by two
undervoltage units that permit
the synchronism function when
both voltages are above the set
value.
The relay sends a closing output
to the breaker when all of the
values fall within the set limits
and maintain these values for a
period of time which has been set
by the user. If any of the condi
tions are not met, the relay will
provide a close condition fault
signal.
The relay has two operational
modes:
Additionally, the relay contains
dead line-dead bus (DLDB), dead
line-live bus (DLLB) and live line
dead bus (LLDB) units, with the
ability to select any combination
of them through independent
settings.
The basic relay, MLJ1000. and
the RS-485 communications
model, MLJ1005. are mounted in
a 2″ module that is compatible
with the MID industrial systems.
They can also be provided in an
individual 1/8 rack. The relays
with additional communications
via RS232 and plastic or glass
fiber optics, models MLJ1006 and
MLJ1007. come with an addition
al 2″ card. The set can be
mounted in either a 4″ module for
MID compatibility or a 1/4 rack
case to be used as a stand alone
relay.
Functions
programmable synchronism
verification (voltage, phase and
frequency)
two operating modes: continu
ous and manual
dead line-dead bus (DLDB), dead
line-live bus (DLLB) and live line
dead bus (LLDB) units
real time measuring of line and
bus voltages, voltage difference,
phase difference and slip
registering of the last close
permitted
visual indication of the line and
bus status (live/dead)
configurable auxiliary outputs
local interface with push buttons
and display
RS485. RS232 and fiber optics
communications
self test functions
compatible with MID industrial
systems