Protection Relays & Controls
Neutral-Grounding-Resistor Monitoring
SE-330, SE-330HV SERIES
Neutral-Grounding-Resistor Monitor - New Revision
Description
The SE-330 is an advanced ground-fault and neutral-grounding-
resistor monitoring relay. It measures neutral current, neutral-to-
ground voltage, and neutral-to-ground resistance. It provides
continuous monitoring of the neutral-to-ground path to verify
that the neutral-grounding resistor (NGR) is intact. This is of
utmost importance—an open NGR renders current-sensing
ground-fault protection inoperative and could result in a false
belief that the system is functioning properly. The SE-330 can be
used with low- and medium-voltage transformers and
generators with low- or high-resistance grounding used in
processing, manufacturing, chemical, pulp and paper, petroleum,
and water-treatment facilities. For high-voltage applications, use
the SE-330HV. For applications that require conformance to
Australian standard AS/NZS 2081.3:2002, use the SE-330AU.
Simplified Circuit Diagram
Resistor Monitoring
The SE-330 combines the measured values of resistance,
current, and voltage to continuously determine that an NGR
is intact. It is able to detect a resistor failure with or without
a ground fault present. Sensing resistors are matched to the
system voltage and are used to monitor NGRs on systems up
to 72 kV.
CT
B
ER SERIES
(Sensing Resistor)
SE-330 SERIES
L1
L2
(NGR Monitor)
Ground-Fault Monitoring
The SE-330 uses an application-appropriate current transformer
to reliably detect ground-fault currents as small as 100 mA. DFT
filtering ensures that false trips due to harmonic noise from
adjustable-speed drives do not occur. Should the resistor open
and a ground fault subsequently occur, the SE-330 will detect
the fault through voltage measurement, while other current-only
sensing relays would be ineffective.
NGR
A
For detailed wiring diagram, see adjacent page.
Ordering Information
ORDERING
NUMBER
POWER
SUPPLY
COMM
K4 UNIT HEALTHY
CONTACT
SE-330
-
X
X
-
0
X
Pulsing Ground-Fault Location
The SE-330 is capable of controlling a pulsing contactor, which is
used to switch the NGR resistance in a pulsing-compatible NGR
package. The resulting ground-fault current is distinguishable
from charging currents and noise and will only appear upstream
of the ground fault, making fault location fast and easy, even
without isolating feeders or interrupting loads.
SE-330
for all apps.
35 kV or less
SE-330HV
for 72 kV
apps.
0=USB Only
1=DeviceNet
3=EtherNet
(Dual RJ45)
4=EtherNet
0=120/240 (SC Fiber & RJ45)
Vac/Vdc 5=EtherNet
(Dual SC Fiber)
2=48 Vdc 6=IEC61850
(Dual RJ45)
7=IEC61850
(SC Fiber & RJ45)
8=IEC61850
(Dual SC Fiber)
REQUIREMENT
0=Normally Open
1=Normally Closed
Accessories
A
ER Series Sensing Resistor
Required interface between the power system
and the SE-330/SE-330HV. Eliminates hazardous
voltage levels at the relay.
EFCT Series Ground-Fault Current Transformer
Sensitive ground-fault current detection (5 A primary).
SE-CS30 Series Ground-Fault Current Transformer
NOTE: For Australian applications, see the SE-330AU.
B
ACCESSORIES
ER Series Sensing Resistor
Current Transformer
SE-IP65CVR-G
SE-MRE-600
RK-332
NGRM-ENC
PGA-0520
SE-330-SMA
Required
Required
Optional
Optional
Optional
Optional
Optional
Optional
Sensitive ground-fault current detection (30 A primary).
Other Current Transformer
For low-resistance NGRs choose a CT primary
approximately equal to the NGR rating. Inputs
are provided for 1- and 5- A- secondary CTs.
SE-IP65CVR-G Hinged Transparent Cover
Watertight cover, tamper resistant, IP65 protection.
Littelfuse reserves the right to make product changes, without notice. Material in this document is as accurate as known at the time of publication. Visit Littelfuse.com for the most up-to-date information.
© 2015 Littelfuse Protection Relays & Controls
Littelfuse.com/se-330 Littelfuse.com/se-330hv
Rev: 4-D-092915
Based on SE-330 Manual Rev: 10-K-090815
Based on SE-330 HV Manual Rev: 5-I-091115
Protection Relays & Controls
Neutral-Grounding-Resistor Monitoring
SE-330, SE-330HV SERIES
Neutral-Grounding-Resistor Monitor - New Revision
Features & Benefits
FEATURES
Continuous NGR monitoring
Ground-fault detection
Adjustable pickup (2-100%)
Adjustable time delay (0.1-10 s)
Universal CT compatibility
Output contacts
Analog output (4 - 20 mA)
Pulsing output (SE-330 only)
Trip records
Harmonic filtering (DFT)
Local communications
Data Logging
IEEE #
3
50G/N, 51G/N,
59N
BENEFITS
Detects resistor failure within seconds, reduces transient-overvoltage risk, removes risk of ground-fault-detection failure
Main or backup protection to detect a ground fault anywhere on the monitored system
Select greatest sensitivity without false operation, adjustable in 1% increments (MEM setting)
Adjustable trip delay allows quick protection and system coordination
Allows the use of a CT that gives required ground-fault settings
Two Form C (Ground Fault, Resistor Fault), Two Form A (Trip/Pulse, Healthy)
Connect an optional PGA-0520 meter or control system
Control the operation of a pulsing ground-fault-location circuit
On-board 100-event (with date and time) recorder helps with system diagnostics
Eliminate false trips due to harmonic noise from ASDs
Mini USB port to view measured values, configure settings, and check event records
On-board microSD card (included) can be used for long-term data logging
Remotely view measured values and event records, reset trips, and cause a remote trip
Available Protocol Options:
IEC 61850 -
with dual RJ45, SC Fiber and RJ45, or Dual SC Fiber Interface
Modbus TCP and Ethernet/IP
- with dual RJ45, SC Fiber and RJ45, or Dual SC Fiber Interface
DeviceNet -
with CAN interface
PC-interface software (SE-MON330) is available at Littelfuse.com/RelaySoftware
Selectable fail-safe or non-fail-safe operating modes allows connection to shunt or undervoltage breaker coil
or alarm circuit (Trip, Ground Fault, Resistor Fault relays)
Selectable latching or auto-reset operation
Ensures resistor-failure sensitivity is correct
Verifies SE-330 is operating correctly
Internal circuits are conformally coated to protect against corrosion and moisture
Network communications
Software
Selectable contact
operating mode
Selectable reset mode
Calibrate push button
Unit-healthy output
Conformal coating
Typical Values
SYSTEM
VOLTAGE
(VOLTS)
480
600
2,400
4,160
7,200
14,400
NEUTRAL-GROUNDING RESISTOR
CURRENT
(AMPERES)
5
5
5
5
10
15
RESISTANCE
(OHMS)
55
69
277
480
416
554
MODEL
ER-600VC
ER-600VC
ER-5KV
ER-5KV
ER-15KV
ER-15KV
SENSING RESISTOR
RESISTANCE
(SWITCH S5 SETTING)
20 k
Ω
20 k
Ω
20 k
Ω
20 k
Ω
100 k
Ω
100 k
Ω
GROUND-FAULT
PICKUP LEVEL
(AMPERES)
2.5
2.5
2.5
3
2
3
V
N
PICKUP LEVEL
(VOLTS)
170
200
800
1,700
170 x 5 = 850
340 x 5 = 1,700
DISCLAIMER:
The above table is for illustrative purposes only. Actual values may differ based on a variety of individual system considerations, such as capacitive charging current and coordination study results.
Wiring Diagram
CONTROL
POWER
POWER SYSTEM
NEUTRAL (X0)
1
2
3
15
Specifications
UNIT
HEALTHY
12
13
RESET
SENSING RESISTOR
ER SERIES
NEUTRAL-GROUNDING-
RESISTOR MONITOR
SE-330 SERIES
ANALOG
OUTPUT
4-20 mA
16
17
+24 Vdc
18
PULSE
(SE-330 ONLY)
ENABLE
(required)
N
R
6
7
R
G
+
19
20
G
A
0 V
21
TRIP OR
PULSING
(K1)
CURRENT TRANSFORMER
22
23
IEEE Device Numbers
Input Voltage
Dimensions
GF Trip-Level Settings
GF Trip-Time Settings
Vn Trip-Level Settings
Contact Operating Mode
Harmonic Filtering
Reset Button
Output Contacts
Pulsing Circuit
Approvals
Communications
Analog Output
Conformally Coated
Warranty
Mounting
EFCT FAMILY
8
EFCT
1A
5A
COMMON
9
24
(required)
GROUND
FAULT
(K2)
25
26
27
B
10
11
RESISTOR
FAULT
(K3)
28
29
Ground Fault (50G/N, 51G/N, 59N), Checking Relay (3), Lockout Relay (86)
See ordering information
H
213 mm (8.4");
W
98 mm (3.9");
D
132 mm (5.2")
2-100% of CT-Primary Rating in 1% increments
0.1-10 s
20-2,000 Vac (≤5 kV systems) 100-10,000 Vac (>5 kV systems)
Selectable fail-safe or non-fail-safe (K1, K2, K3)
Standard feature
Standard feature
Two Form A and two Form C
1.0-3.0 s in 0.2 s increments (SE-330 only)
CSA certified, UL Listed (E340889),
CE (European Union), C-Tick (Australian)
Mini USB (standard); DeviceNet (optional), IEC 61850 (optional),
Modbus TCP and EtherNet/IP (optional)
4-20 mA, self or loop powered
Standard feature
5 years
Panel and Surface (optional)
Littelfuse reserves the right to make product changes, without notice. Material in this document is as accurate as known at the time of publication. Visit Littelfuse.com for the most up-to-date information.
© 2015 Littelfuse Protection Relays & Controls
Littelfuse.com/se-330 Littelfuse.com/se-330hv
Rev: 4-D-092915
Based on SE-330 Manual Rev: 10-K-090815
Based on SE-330 HV Manual Rev: 5-I-091115
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