Modbus
Modbus is a communications protocol used for automation applications.
It is often used in SCADA systems especially in substation
automation. NOJA Power's range of OSM reclosers are supplied
with the Modbus protocol as standard.
OSM - Outdoor Switch Module
The Outdoor Switch Module is an outdoor, pole-mounted, medium
voltage recloser. It features full-directional protection,
current and voltage measurement on all six bushings, no SF6
or oil insulants and is light weight. Full SCADA and communications
features are standard along with programmable digital I/O.
Recloser
A recloser is a circuit breaker incorporating a multishot,
autoclosing relay, installed on a medium voltage feeder. They
are designed to trip when a fault is detected, then automatically
reclose after a set amount of time in an attempt to clear
transient faults on the feeder. They can save considerable
time when restoring power.
Rogowski Sensor
A Rogowski sensor is an air-cored CT design made out of a
helix coil. They are immune to core saturation at high fault
currents, produce safe voltages (millivolts) have an increased
accuracy over a wider range and are very lightweight. NOJA
Power use Rogowski coils for phase and earth current measurement
in the OSM recloser.
RTU - Remote Terminal Unit
Remote control and monitoring unit used in SCADA systems.
SCADA - Supervisory Control And Data
Acquisition
SCADA systems are used to monitor and control a population
of remote devices from a central control room. A communications
protocol is required to receive and transmit alarms and other
data. NOJA Power reclosers are SCADA ready with RS485, RS232
ports and protocols such as DNP3 and Modbus.
SEF - Sensitive Earth Fault
Sensitive Earth Fault is a form of Earth Fault protection
capable of detecting low fault currents. The OSM recloser
can detect SEF from 4 - 80A.
TELUS
TELUS is a software package that allows easy configuration
of an OSM recloser via an RS232 connection. It features a
graphical protection curve tool, I/O mapping tool, SCADA protocol
configuration and can be used to change every setting inside
the control cubicle. TELUS is also used to transfer event
data from the recloser to a pc for off-line analysis of faults,
load profiles, events and other recorded information.
