Distribution Line Earth Fault Indicator Monitoring Device for Underground Networks

The DJX-FF-C Earth Fault Indicator for MV Power Distribution Network is used in 6~35KV Cable line power distribution networks, usually installed in Ring Main Unit, Cable Distribution Box, Switch Cabinet, enable the electricity distribution network engineers to quickly identify the faulty section of network and restore power supplies to customers on healthy sections in the shortest time possible.

Features

Short Circuit Warning Current: 200-2000A Selectable (accuracy:±10%); Delay 20-300ms; Customer could select before production; Default Settings: 800A/20ms

Earth Fault Warning Current: 10-150A Selectable (accuracy:±10%); Delay 20-300ms; Customer could select before production; Default Settings: 20A/20ms

Short circuit sensor mounted cable diameter: outside diameter≤Φ40mm (other specifications shall be customized)

Earth fault sensor mounted cable diameter: outside diameter≤Φ120mm (other specifications shall be customized)

Working Ambient Temperature: -40℃-75℃

Relative Humidity: ≤95%RH

Working Power Supply: The sensors are powered by the CT when the flowing current above 10A, when the current under 10 A, will powered by the backup Lithium battery; The display unit is powered by the Lithium Battery

Remote Signal Communication Reset Method: Manual reset / Auto reset

Automatic Reset Time: 1-48H Selectable (accuracy:±1%); Customer could select before production; Default Settings: 12H

Suitable for medium voltage below 35KV rating system.

System Composition

The system is composed of 3 pcs short circuit sensor, 1 pcs earth fault sensor, and 1 pcs Display Unit.

1. Sensor

4pcs/SET, include 3 pcs short circuit sensors and 1 pcs earth fault sensor. 3 pcs short circuit sensors respectively installed in A,B,C three phase Cable Line, 1 pcs earth fault sensor installed on the bifurcation unshielded part of three-phase cable.

2. Display Unit

Receive fault signal from sensors and display immediately as light flashing. The sensors and the display unit is connected by the fiber optic.

Operation Worked Example

1. Short circuit indication:

On detection of flowing current value exceed the fault sensitivity threshold, the Short circuit sensor will send fault signal through fiber optic to the Display Unit. The Display Unit will respond by light flashing in the short circuit indicator.

2. Earth fault indication:

On detection of the zero sequence current value exceed fault sensitivity threshold, the earth fault sensor will send fault signal through fiber optic to the Display Unit. The Display Unit will respond by light flashing in the earth fault indicator.

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Distribution Line Earth Fault Indicator Monitoring Device for Underground Networks