Littelfuse PGN User Manual

Protection Relays & Controls

Pulsing High-Resistance Grounding

PGN SERIES

Pulsing High-Resistance-Grounding System

Description

The PGN Pulsing High-Resistance-Grounding Systems are used to ground power systems
by inserting a resistor between system neutral and ground to lower the ground-fault
current to a predetermined value.

Properly sized Resistance Grounding Systems solve two problems of ungrounded
systems—transient overvoltages and the difficulty of locating ground faults. They also
significantly reduce damage caused by ground faults on solidly grounded systems. The
current limitation eliminates the Arc-Flash Hazards associated with the first ground fault.
The hazards associated with phase-to-phase electrical faults must still be mitigated by
using current-limiting fuses and other methods. High-Resistance Grounding Systems
include all necessary components to convert to a resistance grounded system.

Options include a pulsing circuit and SE-701 Ground-Fault Monitors to provide a method
for locating ground faults.

Applications

High-resistance grounding is typically applied on transformers and generators where
safety and continuity of service are paramount. Since the ground-fault current is typically
5 A or less, there is no Arc-Flash Hazard associated with the first ground fault and the
faulted feeder can remain in operation until it is safe to repair the fault, when allowed by
the electrical code.

Benefits

g

Eliminate phase-to-ground arc-flash incidents

g

Eliminate transient overvoltages

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Reduced point-of-fault damage

g

Pulsing ground-fault current to aid in fault location

Features

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Pulsing current 5 A above the selected resistor current is standard; other pulsing

options available upon request

g

All PGN systems include resistor monitoring, ground-fault detection, and integrated

pulsing control with the SE-330 NGR Monitor

g

ER-series Sensing Resistor and Current Transformer required for NGR monitoring come

pre-installed inside the enclosure

g

Optional test circuit to simulate a ground fault

g

Continuous-rated resistors

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Stainless steel resistor elements prevent corrosion

Ordering Information

CONFIGURATION SYS. VOLTAGE RES. CURRENT ENCLOSURE TYPE # OF FEEDERS CUSTOM

PGN – 3 X X X – X X – XXX

0 = Other 0 = Other 0 = Other 0 = Other 0 = 0 000 = Standard

W = Wye 1 = 240 V 1 = 5 A N = No Enclosure 1 = 1 XX X = Drawing #

D = Delta 2 = 480/277 V 2 = 10 A F = Outdoor Free Standing 2 = 2

3 = 600/347 V 3 = 15 A W = Outdoor Wall Mount 3 = 3

4 = 2400/1390 V 4 = 20 A 4 = 4

5 = 4160/2400 V 5 = 25 A 5 = 5

6 = 6

7 = 7

8 = 8

9 = Other

© 2013 Littelfuse Protection Relays & Controls
Littelfuse.com/pgn

Rev: 4-A-050213