LINETRAXX® NGRM550

The NGRM550 Neutral Grounding Resistor Monitor detects grounding-resistor failures and ground faults. It is intended for use in low-resistance grounded transformers and generators used in commercial and industrial power systems. This versatility makes the NGRM550 an essential component in enhancing ground fault protection and electrical safety. In these systems, the NGRM550 monitors:

  • Current through the neutral-grounding resistor
  • Voltage between the star point of the transformer and ground (voltage drop across the NGR)
  • NGR failure (open), including failure of connections between neutral and ground

A benefit to many users is the multilingual user interface that allows the comfort of reading values and programming in your native language.

It is an ideal solution that is easy to retrofit into existing LRG (low resistance grounding) applications or factory-install in new LRG packages. If customers prefer, they can easily program the relay via the built-in webserver.  NGRM550’s can easily connect to a supervisory system with Modbus TCP/IP or RTU communications. Capabilities extend to 25 kV and 2,000 A.

Questions? Contact us!

[Translate to Canadian English:] NGRM550

The NGRM550 Neutral Grounding Resistor Monitor detects grounding-resistor failures and ground faults. It is intended for use in low-resistance grounded transformers and generators used in commercial and industrial power systems. This versatility makes the NGRM550 an essential component in enhancing ground fault protection and electrical safety. In these systems, the NGRM550 monitors:

  • Current through the neutral-grounding resistor
  • Voltage between the star point of the transformer and ground (voltage drop across the NGR)
  • NGR failure (open), including failure of connections between neutral and ground

A benefit to many users is the multilingual user interface that allows the comfort of reading values and programming in your native language.

It is an ideal solution that is easy to retrofit into existing LRG (low resistance grounding) applications or factory-install in new LRG packages. If customers prefer, they can easily program the relay via the built-in webserver.  NGRM550’s can easily connect to a supervisory system with Modbus TCP/IP or RTU communications. Capabilities extend to 25 kV and 2,000 A.

Questions? Contact us!

Features

  • Determination of RNGR with passive and active measurement methods
  • Continuous monitoring of the RNGR even if the installation is de-energized
  • Alarm or trip on ground fault
  • Monitoring of the current INGR
  • Monitoring of the voltage UNGR
  • Ethernet communication
  • Webserver
  • Language selection (English, German, Spanish, French)
  • Test button (internal, external) with/without tripping
  • FFT analysis of the measuring signals
  • Relay for detection of ground faults and resistor faults
  • Relay for shutdown of the installation after a configurable time
  • Can be combined with RCMS… for automatic shutdown of feeders
  • Graphical user interface
  • Wide supply voltage range
  • Range of use up to 2,000 m AMSL
  • Fault/history memory
  • Analog output of measured values (0…10 V, 4…20 mA, etc., selectable parameters)
  • Password protection
  • Tripping on RMS, fundamental component signal or harmonics
  • Detection of AC and DC ground faults

LINETRAXX® NGRM550 Variant(s)

TypeSupply voltage US / Frequency range HzArt. No.
NGRM550AC 48…240 V, 40…70 Hz
DC 48…240 V
B94013550

Optional Accessories for LINETRAXX® NGRM550

CD-series coupling device

TypeVoltage UsysArt. No.
CD1000400…690 VB98039010
CD1000-2400…1000 VB98039053
CD50001000…4200 VB98039011
CD144004300…14550 VB98039054
CD2500014551…25000 VB98039055

Measuring current transformer

TypeVoltage/CurrentArt. No.
CTAC35
CTAC60
CTAS50
CTAS80
CTAS120
AC up to 30 AB98110007
B98110017
B98110009
B98110010
B98110011
CTUB103-CTBC35AC/DC up to 10 AB78120030
CTUB103-CTBC60
CTUB103-CTBC120
AC/DC up to 25 AB78120031
B78120032
CTB31…CTB51 seriesAC > 30…1000 AB980860xx

Voltage supply for measuring current transformers CTUB103…

Typemax. connected measuring current transformersArt. No.
STEP-PS/1 AC/24 DC/0.52B94053110
STEP-PS/1 AC/24 DC/1.757B94053111
STEP-PS/1 AC/24 DC/4.217B94053112

Downloads for LINETRAXX® NGRM550

NameCategorySizeLanguageTimestampD-/B-Number
NGRM5x0 SW 2024-04 Software 13.8 MB EN2024/04/1919.04.2024
NGR Product Comparison Flyers 630.6 KB EN2022/07/1818.07.2022
NGRM…-Modbus Manuals 443.2 KB EN2022/06/0909.06.2022D00292
NGRM500/NGRM550 Datasheets 1.2 MB EN2023/06/2020.06.2023D00373
NGRM500/NGRM550 Quickstarts 1.1 MB EN2024/02/0707.02.2024D00373
NGRM500/NGRM550 Manuals 1.1 MB EN2024/02/2626.02.2024D00373
NGR Checklist (US) Technical Information 245.3 KB EN2022/11/0707.11.2022