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Due to RMS continuous product improvement policy this information is subject to change without notice. 1S30/Issue G/18/07/11 - 1/5
Features
Compact rugged design
One or two optical detectors
High speed arc detection
Heavy duty 6m termination
cable
Optional 20m & screened
cables
Simple flush panel mounting
outside or inside switchgear
compartment
Integrated sensor circuit
supervision
Very low sensitivity to ambient
light levels to avoid nuisance
tripping even in direct sunlight
Sealed module for harsh
environments
Optional metal reinforced
mounting shield
Application
Arc fault protection is a relatively new
technique employed for the fast clearance
of arcing faults on BUS bars & within
metal clad switchgear & associated cable
boxes. The arc is detected using an
optical sensor & the signal input to a
protection device which also monitors the
load current on the system. A trip signal
can be achieved in less than 10ms using
arc detection.
RMS manufactures a protection class arc
fault optical sensor & monitoring system
suitable for both low & medium voltage
switchgear and BUS bar applications.
1S20
3 sensor, 2 zone Arc Fault Monitor
1S25
8 sensor, 4 zone Arc Fault Monitor
1S26
1S25 with integrated current check
1S30
Optical Arc Fault Sensor
While the high intensity flash caused by an
electrical arc will be reflected within the
metal clad switchgear, it is recommended
that one or more sensors be mounted in
each enclosed switchgear compartment.
For BUS bar protection applications
multiple sensors are required to achieve
adequate coverage along the length of the
BUS. A sensor version with two optical
detectors “looking” in opposite directions is
available for this purpose (Refer figure 3
for generic layout).
Technical Bulletin
1S30
Optical Arc Fault Sensor
1S30 Arc Fault Sensors
Through panel mounting detector
Front panel view of dual detector
View depicted at left
version depicted at right
Description
Made in Australia
The 1S30 is an optical sensor that responds to the flash of light emitted during the
incidence of an arcing fault. Onset of the light flash & detection by the 1S30 occurs in a few
ms.
Each arc fault sensor consists of one or two silicon PIN photo diode light detectors
mounted on a circuit board together with the associated detection circuit (Figures 1 & 2).
The detector monitors a wide space angle. A broad spectral response in the visible region
is provided as depicted in figure 5.
Sensitivity of the arc sensor has been set to a low level to reduce the possibility of mal
operation under high ambient lighting conditions. This is made possible due the high
intensity of light emitted under arc fault conditions. Additional security can be incorporated
by way of a current check stage as described in the 1S20 Arc Fault Monitor Technical
Bulletin.
In stand by mode the 1S30 sensor presents a high resistance to the 12V DC control signal
provided by the 1S20, 1S25 or 1S26 Arc Fault Monitors. This allows a small circulating
current to flow for continuous supervision of the 1S30 connection circuit. When an arc is
detected, the resistance presented by the 1S30 drops to a level where the current flow
increases to approximately 20mA. This increased current flow is instantaneously detected
by the Arc Fault Monitor & its trip output contacts closed. Refer to the 1S20 Arc Fault
Monitor Technical Bulletin for further details.
