SE-325 Datasheet, PDF (1/1 Pages) Littelfuse – The SE-325 Neutral-Grounding-Resistor Monitor

Protection Relays and Controls
Neutral-Grounding-Resistor Monitoring
SE-325 SERIES (PGM-8325)
Neutral-Grounding-Resistor Monitor
Simplified Circuit Diagram
CT
B
NGR
ER SERIES
(Sensing Resistor)
A
SE-325 SERIES
(NGR Monitor)
L1
L2
Ordering Information
ORDERING NUMBER
CONTROL POWER
SE-325
120 Vac
SE-325D
120 Vac/Vdc
SE-325E
240 Vac
Consult manual online for additional ordering options.
ACCESSORIES
CT200 Series
ER Series
SE-MRE-600
RK-325, RK-325I, RK-302
RK-13
NGRM-ENC
REQUIREMENT
Required
Required
Optional
Optional
Optional
Optional
© 2016 Littelfuse Protection Relays & Controls
Littelfuse.com/se-325
Description
The SE-325 Neutral-Grounding-Resistor Monitor is used on
resistance-grounded systems up to 25 kV to monitor the
integrity of the neutral-to-ground path and to detect ground
faults. It measures current and voltage in a transformer or
generator neutral-to-ground connection and continuity of the
neutral-grounding resistor (NGR). The SE-325 coordinates
these three measurements to detect a loose connection,
corrosion, ground fault, or NGR failure, and provides one alarm
or trip output contact.
Features & Benefits
FEATURES
Continuous NGR
monitoring
Ground-fault
Detection
Adjustable pickup
(0.5 - 4 A)
Adjustable time delay
(0.1 - 2 s)
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 trip delay allows system coordination
Output contacts
Selectable contact
operating mode
Form A output contact
Selectable fail-safe or non-fail-safe operating
modes allows connection to shunt or undervoltage
breaker coil or alarm system
Accessories
A
ER Series Sensing Resistor
Required interface between the power
system and the SE-325. Eliminates
hazardous voltage levels at the monitor.
B
CT200 Series Current Transformer
Required CT detects ground-fault current.
RK Series Remote Indication and Reset
Optional panel-mounted remote indication
and reset assemblies. Available in NEMA 1 or
NEMA 4 configurations.
Specifications
IEEE Device Numbers
Ground Fault (50G/N, 51G/N),
Overvoltage (59N), Lockout Relay (86),
Checking Relay (3)
Input Voltage
See ordering information
Dimensions H 150 mm (5.9"); W 109 mm (4.3");
D 100 mm (4.0")
GF Trip Level Settings 0.5-4.0 A
GF Trip Time Settings
0.1-2.0 s
RF Trip-Level Settings 20-400 Vac (≤5 kV systems)
100-2,000 Vac (>5 kV systems)
Contact Operating Mode Selectable fail-safe or non-fail-safe
Reset Button
Standard feature
Output Contacts
Form A
Approvals
CSA certified, UL Listed (E340889),
C-Tick (Australian)
Conformally coated
Standard feature
Warranty
5 years
Mounting
Surface
Rev: 4-B-102214
Based on Manual Rev:13-C-092314