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Sigma D++

Directional fault indicator

Product Features

  • CT powered directional short-circuit and directional earth fault indicator for all distribution networks / neutral point treatments
  • Earth fault detection with up to 5 different earth fault detection methods, also in combination
  • Only 3 single-phase current sensors needed for all earth fault detection methods

  • Clear indication and signalling of fault direction

  • Fully automatic voltage calibration
  • Easy and flexible parameter setting via DIP switch or USB port
  • Event memory for fault evaluation
  • Multicolour LED status display
  • Remote signalling via freely programmable relays
  • Wide-range power supply 24 V to 230 V AC/DC
  • Sigma Explorer Software: Commissioning and parameterisation via front accessible USB port

The Sigma D++ is a combined directional short-circuit and directional earth fault indicator for medium voltage distribution networks. The device is current sensor powered, thus no auxiliary supply is required. For the current measurement single-phase current sensors resp. a summation current sensor are required.

For the transient earth fault method only 3 single-phase current sensors are needed, but auxiliary supply is mandatory. The connection of a summation current sensor is optional.
The auxiliary supply is not needed if only the cos φ or sin φ method – without the transient earth fault method – is used for the fault direction indication.

The voltage information will be taken from an integrated voltage detecting system, either Wega 1.2 C, Wega 2.2 C or Wega 1.2 C vario. Optionally, the voltage information can be taken from an HR interface or capacitive insulators.
The Sigma D++ provide additional earth fault detection methods for compensated and isolated  neutral networks. The calculation or measurement of the summation current is chosen via DIP switches for all earth fault detection methods.
The variants differ in regard of the transient earth fault method.

Equipment set:

  • 1 Display unit (plug-in housing)
  • 3 Single-phase current sensors
  • 1 Summation current sensor
  • (optional)


Note Item Number


Item Number37-6200-001

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