Littelfuse SE-325 Series - Manual

Protection Relays & Controls
© 2013 Littelfuse Protection Relays & Controls Rev: 4-A-050213
Based on Manual Rev 12
Neutral-Grounding-Resistor Monitoring
SE-325 SERiES (PGM-8325)
Neutral-Grounding-Resistor Monitor
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.
ORdERiNG NuMbER cONtROl POwER
SE-325 120 Vac
SE-325D 120 Vac/Vdc
SE-325E 240 Vac
Ordering Information
Simplified Circuit Diagram
NGR
L2
CT
L1
SE-325 SERIES
ER SERIES
(Sensing Resistor)
(NGR Monitor)
A
FEatuRES bENEFitS
Continuous NGR
monitoring
Detects resistor failure within seconds, reduces
transient-overvoltage risk, removes risk of ground-
fault-detection failure
Ground-fault
Detection
Main or backup protection to detect a ground
fault anywhere on the monitored system
Adjustable pickup
(0.5 - 4 A)
Select greatest sensitivity without
false operation
Adjustable time delay
(0.1 - 2 s)
Adjustable trip delay allows system coordination
Output contacts Form A output contact
Selectable contact
operating mode
Selectable fail-safe or non-fail-safe operating
modes allows connection to shunt or undervoltage
breaker coil or alarm system
Features & Benefits
B
accESSORiES REquiREMENt
CT200 Series Required
ER Series Required
SE-MRE-600 Optional
Rk-325, Rk-325I, Rk-302 Optional
Rk-13 Optional
NGRM-ENC Optional
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
CT200 Series Current Transformer
Required CT detects ground-fault current. B
Accessories
A
ER Series Sensing Resistor
Required interface between the power
system and the SE-325. Eliminates
hazardous voltage levels at the monitor.
RK Series Remote Indication and Reset
Optional panel-mounted remote indication
and reset assemblies. Available in NEMA 1 or
NEMA 4 configurations.
Consult manual online for additional ordering options.
Littelfuse.com/se-325