Bender NGRM500 User manual

Manual EN
NGRM500 (HRG) / NGRM550 (LRG)
Neutral Grounding Resistor Monitor
NGRM5xx_D00373_08_M_XXEN/02.2024

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NGRM500 (HRG) / NGRM550 (LRG)
Table of Contents
1General information......................................................................................................... 5
1.1 How to use this manual................................................................................................................................5
1.2 Indication of important instructions and information.......................................................................5
1.3 Signs and symbols...........................................................................................................................................5
1.4 Service and Support....................................................................................................................................... 5
1.5 Training courses and seminars...................................................................................................................6
1.6 Delivery conditions......................................................................................................................................... 6
1.7 Inspection, transport and storage.............................................................................................................6
1.8 Warranty and liability.....................................................................................................................................6
1.9 Disposal of Bender devices..........................................................................................................................7
1.10 Safety.................................................................................................................................................................... 7
2Product description.......................................................................................................... 8
2.1 Intended use......................................................................................................................................................8
2.2 Device features NGRM...................................................................................................................................8
2.3 Functional description...................................................................................................................................9
2.4 Recommended minimum value RNGR (tripping level 50 %).......................................................... 10
3Mounting......................................................................................................................... 12
4Connection...................................................................................................................... 15
4.1 Connection requirements..........................................................................................................................15
4.2 Connection descriptions of CD-series coupling device..................................................................15
4.3 Recommended connecting cable coupling device CD…..............................................................16
4.4 Star connection..............................................................................................................................................16
4.5 Connection current transformer..............................................................................................................19
4.6 Connection of relays.................................................................................................................................... 20
4.7 Connection to the X1 interface............................................................................................................... 20
4.7.1 X1: Input I1…3............................................................................................................................................... 20
4.7.2 X1: Output Q1…2......................................................................................................................................... 21
4.7.3 X1: Analogue output....................................................................................................................................22
5User interface.................................................................................................................. 23
5.1 Operating elements......................................................................................................................................23
5.2 Standard display............................................................................................................................................24
5.3 Fault indication (active).............................................................................................................................. 24
5.4 Fault indication (inactive)...........................................................................................................................24
5.5 Acknowledging a fault message............................................................................................................. 25
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Table of Contents
5.6 History memory............................................................................................................................................. 25
6Menu................................................................................................................................ 26
6.1 Overview...........................................................................................................................................................26
6.2 Navigating through the menu.................................................................................................................27
6.3 Changing settings.........................................................................................................................................27
6.4 Data measured values (menu 1)............................................................................................................. 27
6.5 Harmonics (menu 2).....................................................................................................................................28
6.6 History (menu 3)............................................................................................................................................28
6.7 Pulser (menu 4)..............................................................................................................................................28
6.8 Display (menu 5)........................................................................................................................................... 29
6.9 HRG, LRG settings (menu 6)......................................................................................................................29
6.10 Device settings (menu 7)........................................................................................................................... 35
6.11 Commissioning (menu 8)...........................................................................................................................39
6.12 Info (menu 9).................................................................................................................................................. 39
6.13 Alarm (menu 10)............................................................................................................................................40
7Commissioning................................................................................................................41
7.1 Response values.............................................................................................................................................41
7.2 Output relays operating modes.............................................................................................................. 42
7.3 RMS trip signal, fundamental, harmonics............................................................................................44
7.4 Filter NGR measurement............................................................................................................................ 45
7.5 Initial measurement..................................................................................................................................... 45
8Interfaces......................................................................................................................... 46
8.1 Analogue output (menu 6.5.4).................................................................................................................46
8.2 Digital outputs (Q1, Q2)..............................................................................................................................46
8.3 Digital input.....................................................................................................................................................47
9Test cycle......................................................................................................................... 48
10 Technical data................................................................................................................. 49
10.1 Factory settings..............................................................................................................................................49
10.2 Error codes.......................................................................................................................................................51
10.3 Technical Data NGRM500/550..................................................................................................................52
10.4 Standards, approvals, certifications........................................................................................................58
10.5 Ordering details............................................................................................................................................. 59
10.5.1 NGR Monitor....................................................................................................................................................59
10.5.2 Accessories.......................................................................................................................................................59
10.6 Document revision history........................................................................................................................ 61
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NGRM500 (HRG) / NGRM550 (LRG)
1 General information
1.1 How to use this manual
ADVICE
This manual is intended for qualified personnel working in electrical engineering and electronics! In
addition to this manual, the “Safety Instructions for Bender Products” package insert is also part of the
device documentation.
ADVICE
Read the operating manual before mounting, connecting and commissioning the device. Keep the
manual within easy reach for future reference.
1.2 Indication of important instructions and information
DANGER
Indicates a high risk of danger that will result in death or serious injury if not avoided.
WARNING
Indicates a medium risk of danger that can lead to death or serious injury if not avoided.
CAUTION
Indicates a low-level risk that can result in minor or moderate injury or damage to property if not
avoided.
ADVICE
Indicates important facts that do not result in immediate injuries. They can lead to malfunctions if the
device is handled incorrectly.
Information can help to optimise the use of the product.
1.3 Signs and symbols
Disposal Protect from moisture Protect from dust
Temperature range Recycling RoHS directives
1.4 Service and Support
Information and contact details about customer service, repair service or field service for Bender devices are
available on the following website: Fast assistance | Bender GmbH & Co. KG.
NGRM5xx_D00373_08_M_XXEN/02.2024 5

General information
1.5 Training courses and seminars
Regular face-to-face or online seminars for customers and other interested parties:
www.bender.de > know-how > seminars.
1.6 Delivery conditions
The conditions of sale and delivery set out by Bender GmbH & Co. KG apply. These can be obtained in printed
or electronic format.
The following applies to software products:
Die Elektroindustrie
“Software clause in respect of the licensing of standard software as part of deliveries,
modifications and changes to general delivery conditions for products and services in the
electrical industry”
1.7 Inspection, transport and storage
Check the shipping and equipment packaging for transport damage and scope of delivery. In case of
complaints, notify the company immediately, see “www.benderinc.com > service & support.”.
The following must be observed when storing the equipment:
1.8 Warranty and liability
Warranty and liability claims for personal injury and property damage are excluded in the case of:
•Improper use of the device.
•Incorrect mounting, commissioning, operation and maintenance of the device.
•Failure to observe the instructions in this operating manual regarding transport, commissioning, operation
and maintenance of the device.
•Unauthorised changes to the device made by parties other than the manufacturer.
•Non-observance of technical data.
•Repairs carried out incorrectly.
•The use of accessories or spare parts that are not provided, approved or recommended by the
manufacturer.
•Catastrophes caused by external influences and force majeure.
•Mounting and installation with device combinations not approved or recommended by the manufacturer.
This operating manual and the enclosed safety instructions must be observed by all persons working with the
device. Furthermore, the rules and regulations that apply for accident prevention at the place of use must be
observed.
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NGRM500 (HRG) / NGRM550 (LRG)
1.9 Disposal of Bender devices
Abide by the national regulations and laws governing the disposal of this device.
For more information on the disposal of Bender devices, refer to
www.benderinc.com > service & support.
1.10 Safety
If the device is used outside the Federal Republic of Germany, the applicable local standards and regulations
must be complied with. The European standard EN 50110 can be used as a guide.
DANGER Risk of electrocution due to electric shock!
Touching live parts of the system carries the risk of:
•An electric shock
•Damage to the electrical installation,
•Destruction of the device
Before installing and connecting the device, make sure that the installation has been de-energized.
Observe the rules for working on electrical installations.
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Product description
2 Product description
2.1 Intended use
The NGRM500 is only intended for use in high-resistance grounded systems. The NGRM550 is only intended for
use in low-resistance grounded systems.
In these systems, the device of the NGRM family monitors
•the current through the neutral grounding resistor (NGR),
•the voltage between the star point of the transformer and ground (voltage drop across the NGR),
•the condition of the neutral grounding resistor (NGR),
•line-to-line and line-to-ground voltages.
Systems with a resistance-grounded star point can be used when an interruption of the power supply
would involve excessive costs due to production stoppage (e.g. automotive production, chemical
industry). The ground fault that occurs between a phase and ground does not lead to a failure of the
power supply in these systems.
A ground fault must be detected and eliminated as quickly as possible, since the occurrence of another
ground fault in a second phase would lead to a tripping of the overcurrent protective device.
In order to meet the requirements of applicable standards, customised parameter settings must be made on
the equipment in order to adapt it to local equipment and operating conditions. Please heed the limits of the
range of application indicated in the technical data. Intended use includes following all the instructions in this
manual.
Any other use than that described in this manual is regarded as improper.
2.2 Device features NGRM
•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
•Web server
•Language selection (German, English GB and US, Spanish, French)
•Test button (internal, external) with/without tripping
•FFT analysis of neutral current and voltage
•Pulser control for manual ground fault location
•Relay outputs for detection of ground faults and resistor faults
•Relay output for shutdown of the installation after a configurable time
•Can be combined with RCMS… for automatic shutdown of feeders
•Graphical user interface
•Integrated wide-range power supply unit for operating the NGR monitor (AC/DC 24…240 V)
•Range of use up to 2000 m AMSL
•Fault/History memory
•Analogue output of measured values (0…10 V, 4…20 mA etc., selectable parameter)
•Password protection
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NGRM500 (HRG) / NGRM550 (LRG)
•Tripping on RMS, fundamental component signal or harmonics
•Detection of AC and DC ground faults
•Variants High Resistance Grounded (HRG), Low Resistance Grounded (LRG)
HRG LRG
NGRM500 NGRM700 NGRM550 NGRM750
UsysLL 400...25000 V
INGRnom 0.5...100 A 10...2000 A
RNGRnom 15...5000 Ω0.1...200 Ω
2.3 Functional description
The NGRM monitors NGR resistance RNGR, neutral voltage UNGR and current INGR. The NGR resistance is
monitored using an active and a passive procedure:
active The device generates an active test pulse and measures RNGR even if the
installation is de-energized..
passive The resistance RNGR is determined when INGR or UNGR exceeds an internal
threshold. The device measures the existing current and voltage and
calculates RNGR.
In the case of the “auto” method, monitoring switches automatically between “active” and “passive” when the
measured current or voltage value exceeds or falls below the internal threshold. The threshold is 15 % of the
nominal value and can be adjusted by Bender if required.
A shorted or open NGR is reliably detected in an energized as well as a de-energized installation with the active
measurement method.
When the “passive” method is selected, no switching of the monitoring takes place. The NGR is not monitored
if the installation is shut down or the current and voltage are too low.
The measurement method can be selected as a set point or via the configurable digital input I1 if the NGR
method “external” has been selected (for software versions from July 2021).
Should the use of frequency inverters lead to interferences with the RNGR measured value during the active
measurement, a filter for active resistance measurement can be added. To this end, 3 pre-defined filters (weak,
medium, strong) have been implemented. In addition, the filter parameters can be adapted individually in the
setting “Customer- specific”.
The NGR-fault relay switches from the operating state (selectable as fail-safe or non-failsafe) to the alarm state
when the measured resistance RNGR is outside of the configured thresholds.
A ground fault is signalled via the corresponding ground-fault relay when INGR or UNGR exceeds the selectable
thresholds. After the adjustable time delay has elapsed, the trip relay operates.
A connection to installations ranging from 400 V to 25 kV is possible via the appropriate CD-series coupling
device.
INGR is measured with measuring current transformers with a 5 A or 50 mA secondary rating.
NGRM5xx_D00373_08_M_XXEN/02.2024 9

Product description
2.4 Recommended minimum value RNGR (tripping level 50 %)
Temperature range –40…+60 °C, field calibration at 20 °C
() = Limited temperature range at any field calibration temperature ±20 K. The temperatures must be within
the limits of the operating temperature range of –40…+60 °C .
Recommended RNGR for system voltage Usys T 4300 V
CD1000/CD1000-2 CD1000-2 CD5000
Usys 400 V 600 V 690 V 1000 V 2400 V 4200 V
INGR
1 A 231 Ω 346 Ω 398 Ω 577 Ω 1386 Ω —
5 A 46 Ω 69 Ω 80 Ω 115 Ω 277 Ω 485 Ω
10 A (23 Ω) 35 Ω 40 Ω 58 Ω 139 Ω 242 Ω
15 A (15 Ω) (23 Ω) (27 Ω) 38 Ω 92 Ω 162 Ω
20 A — (17 Ω) (20 Ω) 29 Ω 69 Ω 121 Ω
25 A — — (16 Ω) (23 Ω) 55 Ω 97 Ω
30 A — — — (19 Ω) (46 Ω) 81 Ω
40 A — — — — (35 Ω) 61 Ω
50 A — — — — (28 Ω) (48 Ω)
100 A — — — — — (24 Ω)
Recommended RNGR for system voltage Usys > 4300 V
CD14400 CD25000
Usys 6000 V 6600 V 7200 V 11,000 V 14,400 V 25,000 V
INGR
1 A — — — — — —
5 A 693 Ω 762 Ω 831 Ω 1270 Ω 1663 Ω —
10 A 346 Ω 381 Ω 416 Ω 635 Ω 831 Ω 1443 Ω
15 A 231 Ω 254 Ω 277 Ω 423 Ω 554 Ω 962 Ω
20 A (173 Ω) 191 Ω 208 Ω 318 Ω 416 Ω 722 Ω
25 A (139 Ω) (152 Ω) (166 Ω) 254 Ω 333 Ω 577 Ω
30 A (115 Ω) (127 Ω) (139 Ω) 212 Ω 277 Ω 481 Ω
40 A (87 Ω) (95 Ω) (104 Ω) (159 Ω) 208 Ω 361 Ω
50 A — (76 Ω) (83 Ω) (127 Ω) (166 Ω) 289 Ω
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NGRM500 (HRG) / NGRM550 (LRG)
CD14400 CD25000
Usys 6000 V 6600 V 7200 V 11,000 V 14,400 V 25,000 V
INGR
100 A — — — — (83 Ω) (144 Ω)
NGRM5xx_D00373_08_M_XXEN/02.2024 11

Mounting
3 Mounting
Only qualified personnel are permitted to carry out the work necessary to install, commission and run a
device or system.
DANGER Risk of electrocution due to electric shock!
Touching live parts of the system carries the risk of:
•An electric shock
•Damage to the electrical installation,
•Destruction of the device
Before installing and connecting the device, make sure that the installation has been de-energized.
Observe the rules for working on electrical installations.
Dimension diagram NGRM5...
108 (4.25)
110 (4.33)
Figure 3-1: Dimension diagram NGRM5…; Dimensions in mm (in)
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NGRM500 (HRG) / NGRM550 (LRG)
Enclosure view
SERVICE
TRIPPED
NGR FAULT
GROUND FAULT
ON
MENU
RESET
DATA
INFO
TEST
NGR Monitor
OK
NGR = 265 W
I NGR = 0,01A
NGRM500
LINETRAXX®
Ω
A
V
C
5
E
R S
R
ETH
X1
50m
11 12 14
21 22 24
31 32 34
Ground fault
NGR fault
Trip
NGRM500
Figure 3-2: Enclosure view: Front (left), Top (right), Bottom (right bottom)
Screw mounting
Figure 3-3: Screw mounting; dimensions in mm (in)
1. Fix the three mounting clips delivered with
the device (two of them packed separately)
manually or using a tool, as illustrated below.
2. Drill the mounting holes for the M4 thread
according to the drilling template.
3. Fix the device with three M4 or #10 screws.
NGRM5xx_D00373_08_M_XXEN/02.2024 13

Mounting
DIN rail mounting
Figure 3-4: DIN rail mounting
Fix the mounting clips delivered with the device as
illustrated.
1. Snap the device on the DIN rail.
2. Press the device lightly onto the DIN rail.
3. Fix the device to the DIN rail by pushing the
mounting clips until they you hear them click
into place.
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NGRM500 (HRG) / NGRM550 (LRG)
4 Connection
4.1 Connection requirements
Only qualified personnel are permitted to carry out the work necessary to install, commission and run a
device or system.
DANGER Risk of electrocution due to electric shock!
Touching live parts of the system carries the risk of:
•An electric shock
•Damage to the electrical installation,
•Destruction of the device
Before installing and connecting the device, make sure that the installation has been de-energized.
Observe the rules for working on electrical installations.
CAUTION Provide line protection!
According to DIN VDE 0100-430, a line protection shall be provided for the supply voltage.
Check proper connection. Prior to commissioning of the installation, check that the device has been
properly connected and check that the device functions.
For UL applications:
•Use 60/70 °C copper lines only.
•For UL and CSA applications, the supply voltage must be protected via 5A fuses.
4.2 Connection descriptions of CD-series coupling device
NConnection to star point
G1, RSConnection to RS of the NGRM
G, E Connection to E of the NGRM7
Rs
E
N
CD1000-2
CD14400
CD25000
PE
G1
PE
N
CD1000
CD5000
G
PE Connection to the protective earth
conductor of the installation
NGRM5xx_D00373_08_M_XXEN/02.2024 15

Connection
4.3 Recommended connecting cable coupling device CD…
CD… Connection CD… Cable lug Metrical Imperial
CD1000 N, G1, G — 1.5 mm² AWG 16
N, RS, E — 1.5 mm² AWG 16
CD1000-2
PE M4 # 1 .5 mm² AWG 16 or bigger
G1, G — 1.5 mm² AWG 16
N M8 oder M10 # 1 .5 mm² AWG 16 or biggerCD5000
PE M6 # 1 .5 mm² AWG 16 or bigger
RS, E — 1.5 mm² AWG 16
N M5 oder M10 # 1 .5 mm² AWG 16 or bigger
CD14400 CD25000
PE M5 # 1 .5 mm² AWG 16 or bigger
4.4 Star connection
Connection
Cirquit breaker
NGR fault
Ground fault Trip
Figure 4-1: Star configuration
The “N” connection of the CD-series coupling device should be as close to the transformer star point as
possible.
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NGRM500 (HRG) / NGRM550 (LRG)
Connection with Pulser
Cirquit breaker
NGR fault
Ground fault Trip
Figure 4-2: Connection with pulser
The “N” connection of the CD-series coupling device should be as close to the transformer star point as
possible.
An intermediate relay may be required between the power contactor of the pulser and the digital output
X1.
NGRM5xx_D00373_08_M_XXEN/02.2024 17

Connection
Artificial neutral (delta connection)
If no star point is available, the following circuit can create an artificial neutral.
Cirquit breaker
NGR fault
Ground fault Trip
Figure 4-3: Artificial neutral with a zigzag transformer
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NGRM500 (HRG) / NGRM550 (LRG)
4.5 Connection current transformer
Choose a measuring current transformer suitable for the network to be monitored. All common measuring
current transformers (50 mA or 5 A on the secondary side) can be used. The following table helps you with the
choice:
System type AC + DC AC AC AC
INGR 0.5…25 A 5…30 A 5…1000 A 10…2000 A
f0…3800 Hz 42…3800 Hz 50/60 Hz 50/60 Hz
Transformation ratio,
Bender CT
Measuring ranges (see
CTUB103 manual)
5 A 100:1
10 A 200:1
25 A 500:1
600:1
max. 30 m max. 40 mConnecting cable
provided cable or
0.75…1.5 mm² / AWG 18…16
max. 25 m: 4 mm² / AWG 12
max. 40 m: 6 mm² / AWG 10
Idn
Type CTUB103 CTAC…
CTAS…
CTB31…51 Any standard current
transformer can be used.
CT terminal k NGRM: 50 mA NGRM5…: 50 mA NGRM5…: 5 A NGRM5…: 5 A
CT terminal l NGRM5…: C NGRM5…: C NGRM5…: C NGRM5…: C
NGRM5xx_D00373_08_M_XXEN/02.2024 19

Connection
4.6 Connection of relays
Groud-fault relay NGR-fault relay Trip relay
The delay times of the various relays are not the same. See table “Trip times”, Page 42.
4.7 Connection to the X1 interface
Pin assignment X1 interface
I1 Digital 1 (configurable: pulser, NGR method)
I2 Reset IN
I3 Test IN
A Modbus RTU (A)
B Modbus RTU (B)
Common
M+ Analogue output
Q2 Open Collector: Pulser OUT
Q1 Open Collector: Device health
+ Output for supply of external relays (+24 V, max. 100 mA)
4.7.1 X1: Input I1…3
The input is only detected as “activated” after the contact has been activated for at least 150 ms. This way,
short interference pulses are ignored.
Input I1…3: Potential-free contact to ground or 0 V and 24 V in conjunction with a PLC
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