The LLT-360 AutoRANGER® Overhead Faulted Circuit Indicator Sensor shall indicate and distinguish between temporary and permanent faults when mounted on an overhead bare conductor. Its purpose is to reduce fault locating times and improve system reliability. Specific requirements are:
The AR360 sensor shall use a microprocessor to determine system current by measuring the output of an open-core current transformer inductively coupled to an overhead conductor. The sensor is held on an overhead conductor by a spring clamp that is energized to the conductor’s line potential. A microprocessor detects the voltage gradient formed between the spring clamp and an electrostatically coupled metallic plate near the face of the sensor to determine the presence of system voltage. Circuit logic distinguishes between higher or lower circuit loading conditions, temporary faults (flashing amber LEDs) after a successful reclose, and permanent faults (red-amber LED rotating flash sequence) after a sustained outage.
The sensor shall have a true inrush restraint algorithm to ensure it will not falsely trip on inrush following a reclose operation by activating the loss-of-current and/or voltage circuitry when the recloser opens.
The sensor shall be capable of monitoring a single-phase conductor of an overhead three-phase radial system.
The sensor shall automatically select one of eight discrete trip levels based on measured load current. The sensor shall not lower its trip value unless it detects sustained load current and primary voltage, thereby preventing false tripping from low trip values after an extended outage.
The sensor shall be applicable to an overhead radial distribution circuit with a system voltage within the range of 4160 V to 34.5 kV.
The sensor shall have six ultra-bright, wide-angle LEDs to indicate a temporary or permanent fault. The LED display shall provide 360-degree visibility. The sensor shall indicate temporary faults (self-clearing faults) by flashing amber LEDs. Permanent faults shall be indicated by a rotating flash sequence of red and amber LEDs.
The sensor shall be single hot stick installable on overhead conductors of overhead distribution circuits with conductor diameters inclusive of 0.406 cm to 3.81 cm (0.160 in to 1.50 in).
The sensor shall be suitable for continuous operation over a temperature range of –40° to +85°C (–40° to +185°F).
The sensor can be manually test activated and reset using an optional magnetic test tool.
The sensor shall have a true timed reset function which automatically resets the device upon expiration of factory-set time period.
The sensor shall detect temporary and permanent faults in the 50 to 60 Hz frequency range.
The sensor shall be appropriate for at least 15-year exposure in an outdoor environment.
The sensor shall be powered and be capable of sustaining 1800 flashing hours of operation. It shall incorporate a power-saving feature which will extend the product’s operational life by limiting power to LEDs when a phototransistor detects decreased ambient lighting conditions.
The sensor has a five-year warranty.