SE-330AU-21-01 - SE-330AU Series

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The SE-330AU is an advanced earth-fault and earthing-resistor monitoring relay for low- and medium-voltage transformers and generators. It monitors neutral current, neutral-to-earth voltage, and neutral-to-earth resistance. It provides continuous monitoring of the neutral-to-earth path to verify that the neutral-earthing resistor (NER) is intact. This is of utmost importance—an open NER renders current-sensing earth-fault protection inoperative and could result in a false belief that the system is functioning properly. The SE-330AU earth-fault function complies with AS/NZS 2081.3:2002. For non-AS/NZS 2081 applications, see the SE-330 or SE-330HV.

The SE-330AU New Revision provides these additional features:

  • 100 trip records with date and time stamp
  • A mini-USB interface to view measured values, configure settings and check event records using SE-MON330 v3.2 or later
  • An on-board microSD card (included) can be used for long term data logging and firmware upgrades
  • Earth-fault trip level is adjustable from 0.125 to 5A (EFCT) or 0.75 to 30A (CS30). When set to MEM, the earth-fault trip level is adjustable from 2 to 100% in 1% increments of the CT-primary rating. SE-MON330 V3.2 or later is required.
  • Dual Ethernet ports are optionally available with support for fiber and RJ45 interfaces
  • IEC 61850 protocol is optionally available

Connect the SE-330AU to the network using a standard Ethernet patch cable. Use of a crossover cable to connect the SE-330AU directly to the computer running IP-Config is not recommended. A typical router will assign an IP address to all connected computers that are using DHCP. The SE-330AU does not support the use of DHCP. If the SE-330AU is being set-up for first time, it is recommended to only have one SE-330AU connected to the network to prevent communication errors.

Click here to download the COMPUTER TO RELAY CONNECTION diagram.


Property (Mouseover for details) Value
Analog Output Current mA 4 - 20
Communications USB; DeviceNet
Relay Contacts Config 1 Form A; 1 Form B; 2 Form C
Supply Voltage ac 28 - 52
Supply Voltage dc 36 - 72
New Rev Avail Now
Old Rev Avail No longer available
IEEE Device Numbers 50G - 50N - 51G - 51N - 59N - 86
Relay Contacts Operation Fail-safe
Dimensions 8.4 H x 3.9 W x 5.8 D in.
Weight (lbs/g) 0 Kg
Auto Manual Reset Latching; Autoreset
Conformally coated Standard
Frequency 50; 60; ASD
GF Trip Level A 0.125 - 30.0
GF Trip Time s 0.1 - 0.5
Harmonic Filtering Standard (DFT)
Reset Type Front-panel switch/Remote N.O. Contact
RF Trip Level V 20 - 2000 (systems up to 5 kV); 100 - 10000 (systems over 5 kV)
RF Trip Time s 12
System type Resistance Grounded AC

pdf icon SE-330, SE-330HV, SE-330AU Manual

A high-resistance-grounded system uses a neutralgrounding resistor (NGR) with a low let-through current to limit ground-fault current. This is an improvement over low-resistance- or solidly grounded systems because, in those systems, a ground-fault flash hazard exists and a ground fault can result in substantial point-of-fault damage.

pdf icon SE-330 DeviceNet Manual - Previous Revision

This document describes the Anybus DeviceNet features supported by the SE-330/SE-330AU/SE-330HV.

pdf icon SE-330 EthernetIP Manual - Previous Revision

This document describes the Anybus Ethernet IT features supported by the SE-330/SE-330AU/SE-330HV.

pdf icon SE-330 Profibus Manual - Previous Revision

The Profibus-DP slave interface on the SE-330/ SE-330AU/SE330HV is used to access meter data and provide reset functions. Set points can be read but not written.

SE-MON330 v4.0 Software

This software is used to receive data from SE-330, SE-330AU, and SE-330HV Neutral-Grounding-Resistor Monitors. It will display the relay's set points as well as measured values.

pdf icon SE-MON330 Software Manual

SE-MON330 is a PC-based application designed to access set-points, measured values, and trip records from the SE-330 Neutral-Grounding-Resistor Monitor, the SE-330HV Neutral-Grounding-Resistor Monitor, and the SE-330AU Neutral-Earthing- Resistor Monitor.

ER-15Kv 3D Model

dwg ER-25kv CAD Drawing

dwg ER-600VC CAD Drawing

pdf icon TN RG-01 NGR Monitoring Isolated Ground Beds

pdf icon TN RG-05 SE-330 Guideform Specification

pdf icon TN RG-07 SE-VS50010K Voltage Scaler

pdf icon TN RG-08 SE-330 Settings

pdf icon TN RG-09 Single NGR for Multiple Sources

pdf icon TN-RG11 Voltage Metering on RG Systems

pdf icon TN RG-12 Convert Ungrounded to Resistance Grounded

pdf icon TN RG-14 NGR Package Checklist

pdf icon TN GF-10 Pulsing Ground-Fault Systems

SE-330, SE-330AU, SE-330HV 3D Model

11-1AU Earth-Fault CT Selection Flowchart Australia


pdf icon TN 11-1 Ground-Fault CT Selection Guide

pdf icon 11-2 Locating Phase Conductors in a Zero-Sequence-CT Window

An ideal window-type current transformer responds only to the sum of the currents flowing through its window...

pdf icon 11-4 Trailing Cable Types

pdf icon 11-5 Polycast 200 5 CT Test


pdf icon 11-7 Locating Phase Conductors in a Zero-Sequence CT Window

pdf icon Protection Relays and Controls Catalog - Mandarin

pdf icon SE 330AU Datasheet-New Rev

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