The SE-330 is an advanced ground-fault and neutral-groundingresistor monitoring relay. It measures neutral current, neutral-toground 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, see the SE-330AU.
The SE-330 combines the measured values of resistance, current, and voltage to continuously determine that the 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.
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.
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.
Features & Benefits
Continuous NGR monitoringDetects resistor failure within seconds, reduces transient-overvoltage risk, removes risk of ground-fault-detection failure
Ground-fault detectionMain or backup protection to detect a ground fault anywhere on the monitored system
Adjustable pickup (2-100%)Select greatest sensitivity without false operation
Adjustable time delay (0.1-10 s)Adjustable trip delay allows quick protection and system coordination
Universal CT compatibilityAllows the use of a CT that gives required ground-fault settings
Output contactsTwo Form C (Ground Fault and Resistor Fault), Two Form A (Trip/Pulse, Healthy)
Analog output (4-20 mA)Allows for connecting an optional PGA-0500 meter or control system
Pulsing output (SE-330 only)Control the operation of a pulsing ground-fault-location circuit
Data loggingOn-board 10-event recorder helps with system diagnostics
Harmonic filtering (DFT)Eliminate false trips due to harmonic noise from ASDs
Local communicationsRS-232 port to view measured values, log to a PC and check event records
Network communicationsRemotely view measured values and event records, reset trips, and cause a remote trip
SoftwarePC-interface software (SE-MON330) is included
Selectable contact operating modeSelectable fail-safe or non-fail-safe operating modes allows connection to shunt or undervoltage breaker coil or alarm circuit
Selectable reset modeSelectable latching or auto-reset operation
Calibrate push buttonEnsures resistor-failure sensitivity is correct
Unit-healthy outputVerifies SE-330 is operating correctly
Conformal coatingInternal circuits are conformally coated to protect against corrosion and moisture
SE-330 PCN Document
SE-330 Datasheet - Previous Revision
SE-330HV Datasheet New Revision
SE-330HV Manual - New Revision
SE-330HV Manual - Previous Revision
SE-330 DeviceNet Manual - Previous Revision
SE-330 EthernetIP Manual - Previous Revision
SE-330 Profibus Manual - Previous Revision
SE-MON330 Software Manual
- IEEE Device Numbers: Ground Fault (50G/N, 51G/N, 59N), Checking Relay (3), Lockout Relay (86)
- Input Voltage: See ordering information
- Dimensions: H 213 mm (8.4"); W 98 mm (3.9"); D 132 mm (5.2")
- GF Trip-Level Settings: 2-100% of CT-Primary Rating
- GF Trip-Time Settings: 0.1-10 s
- Vn Trip-Level Settings: 20-2,000 Vac (≤5 kV systems) 100-10,000 Vac (>5 kV systems)
- Contact Operating Mode: Selectable fail-safe or non-fail-safe (K1)
- Harmonic Filtering: Standard feature
- Reset Button: Standard feature
- Output Contacts: Two Form A and two Form C
- Pulsing Circuit: 1.0-3.0 s in 0.2 s increments (SE-330 only)
- Approvals: CSA certified, UL Listed (E340889), CE (European Union) optional, C-Tick (Australian)
- Communications: RS-232; (standard) DeviceNet™, Profibus®(1), Ethernet (optional)
- Analog Output: 4-20 mA, self or loop powered
- Conformally Coated: Standard feature
- Warranty: 5 years
- Mounting Panel: and Surface
|ORDERING NUMBER||POWER SUPPLY||COMM||CERTIFICATION||K4 UNIT HEALTHY CONTACT|
SE-330 for all apps. 35 kV or less
SE-330HV for 72 kV apps.
|0=RS-232 1=RS-232 & DeviceNet™ 2=RS-232 & Profibus® (1) 3=RS-232 & EtherNet/IP™ & Modbus® TCP|
1=CSA, UL, CE, C-Tick
|ER Series Sensing Resistor||Required|
ER Series Sensing Resistor
Required interface between the power system and the /wwHV. 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
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.