SE-330 Datasheet, PDF(1/2 Page) Littelfuse – The SE-330 is an advanced ground-fault

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 importanceâan 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.

NGR

ER SERIES

(Sensing Resistor)

SE-330 SERIES

(NGR Monitor)

For detailed wiring diagram, see adjacent page.

Ordering Information

ORDERING

NUMBER

POWER

SUPPLY

COMM

K4 UNIT HEALTHY

CONTACT

SE-330 - X

-0

0=USB Only

SE-330

for all apps.

35 kV or less

SE-330HV

for 72 kV

apps.

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)

0=Normally Open

1=Normally Closed

NOTE: For Australian applications, see the SE-330AU.

ACCESSORIES

ER Series Sensing Resistor

Current Transformer

SE-IP65CVR-G

SE-MRE-600

RK-332

NGRM-ENC

PGA-0520

SE-330-SMA

REQUIREMENT

Required

Optional

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.

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.

Accessories

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

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.

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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