Navigator LM | Navigator LM HV

Overhead faulted circuit indicator with different reset options

The Navigator faulted circuit indicator is an electronic device which is designed for medium voltage utility overhead lines.

The indicator is provided with a self-adjusting load-dependent control of the trip current level. This function allows the indicator to continuously sample the load current on overhead lines and automatically set a corresponding trip value for fault detection as a function of the load current. The maximum load current sampled by the indicator, is kept in a memory for a period of at least 72 hours. Thus, the indicator is most favourably adapted to the network to be monitored, even if low load is currently present.

The indicator is provided with a built-in battery control. When the battery capacity decreases from a total indicating time of 500 hours to a residual time of 50 hours, the yellow LED of the display starts flashing for a period of 6 months.

The Navigator LM can differentiate between two subsequent short-circuit detections. Upon the detection of a first short-circuit, the LED indicator light starts flashing at equal rates. The detection of a second short-circuit (e. g. after an automatic re-closing) switches the LED to double flashing mode.

  • Fault detection
  • LED indication with 360 degrees of visibility
  • Double-flashing mode upon detection of a second fault
  • Battery status indication
  • Reset depending on type: manual, current restoration, voltage restoration
  • Mounting on live overhead lines possible
  • Navigator-LM HV: permissible voltage ≤161 kV

Technical specifications

Short-circuit trip current

≥100 A / ≥100 ms, load-dependent self-adjustment

Response delay short-circuit -
Accuracy ±10 % @ 20 °C
Self-adjustment ≥30 A load current
Trip factor 4 – 6 x load current
Adjustment delay

60 s

Peak load memory 72 h
Indication (short-circuit/earth fault)

4 red LEDs (>5,000 mcd resp. 7000 mLm each LED)

2 yellow LEDs (>5,000 mcd resp. 7,000 mLm each LED)

Visibility >50 m / day, >150 m / night, 360 degrees of visibility
Flash rate 30 flashes per minute, total indication time >500 h
Manual reset

With magnet (Version A, B, C, E)

Automatic time reset

4 h ±10 % (2 or 8 h) (Version A, B, C, E)

Remote reset -
Reset on current restoration

>3 A load current (Version A)

Red LEDs turn off, yellow flash until manual or time reset (Version C)

Reset on voltage restoration

≥5 kV line voltage (Version E)

Current measurement accuracy -
Tripping -
Power supply

Lithium battery, replaceable, shelf life ≥20 years

Battery check

1 yellow LED, flash rate: 6 per minute, 6 month

Max. permissible voltage

Navigator LM: ≤46 kV / 50 Hz or 60 Hz

Navigator LM HV: ≤161 kV / 50 Hz or 60 Hz

Withstand current

Navigator LM: 25 kA / 3 s

Navigator LM HV: 40 kA / 1 s

Event reporting -
Remote monitoring -
Communication -
Cellular (WAN) -
Server -
Remote maintenance -
Installation -
Pairing -

UV resistant polycarbonate / polyamide, IP68

Clamping yoke: stainless steel

Temperature range –30 to +75 °C (IEEE 495: −40 to +85 °C)
Cable diameter

Navigator LM: 8 – 29 mm

Navigator LM HV: 13 – 36 mm

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