Failure Mode Percentage of Failures

High Resistance Ground
Fault Protection with the
PulserPlus.Net TM
Chris Small – Post Glover
John Levine – L 3 , Inc.

Failure Mode
Percentage of Failures
Line to Ground 98%
Phase to Phase < 1.5%
*Three Phase < 0.5%
*Most three phase faults are man-made:
i.e. accidents caused by improper operating
procedure.

The massive energy released in a ground fault
rapidly vaporizes the metal conductors involved,
blasting molten metal and expanding plasma
outward with extreme force.
5-10 Arch Flash Explosions in US per day
Over 2000 Arc Flash & Blast injuries & deaths a
year in US
Surfaces of nearby people and objects absorb
this energy and are instantly heated to
vaporizing temperatures.
Source: NFPA, CapSchell

HRG
AØ
Source
(Wye)
N
BØ
CØ
Advantages
◦ Limits Ground Fault current
to 10 Amps or less
◦ Allows faulted circuit to
continue operation
◦ Eliminates 95% of arc flash
potential
◦ Significantly decreases
shock potential

Can be connected via RS-485 or Ethernet
Accessible via IP address (pre-loaded, but can
be edited)
Remote viewing possible
Incorporate into Network Protection Scheme

Alarm Table – stores 200 alarms with value,
time and date
Events Table – stores 200 events such as
faults cleared, pulsing started/stopped,
password activities, etc with time and date
Tables for charging current, passwords,
timers and system data

Up to 2 GB SD card for back-up storage
Pulser software can be reloaded in the field
Individual settings can be cloned to other
units
Data Tables can also be backed up

Tables can be accessed remotely through
customer’s LAN.
Data Logging will record all alarms, events
and parameter changes
◦ Allows customer to track/trend faults
◦ More easily allows customer to locate intermittent
faults

- Used to determine
resistor failure
- Can also indicate
broken connection to
neutral
Ω

Monitors each phase and indicates which
phase is faulted
Knowing the faulted phase can assist with
troubleshooting and repair

In ungrounded systems, a
voltage is held on the system
capacitance after a fault. In an
arcing or intermittent fault, this
can lead to a significant voltage
build-up.
In a high resistance grounded
system, the resistance must be
low enough to allow the system
capacitance to discharge
relatively quickly.

1. Press the CHRGNG
CURRENT button
2. One phase shorted
through 55 Ω resistor
3. Current in fault and thru
neutral are measured
Charging current = Square Root (Fault Current 2 – Resistor Current 2 )

• Much easier for
installers and field
technicians to
change fault and
pulse taps
Terminal Block

Password protection to avoid unauthorized
access
Re-alarm if condition not cleared within time
delay
System Test & Charging Current
Measurement disabled during fault
Lamp test

Pulser Plus
Digitally filters out (ignores)
harmonics in your system to
measure only the fundamental
frequency where ground faults
occur
Capable of measuring and storing
more parameters, including both
voltage and current monitoring.
Analog
Unless an actual signal filter is in
place to filter out the harmonics,
this system is very susceptible to
nuisance tripping
Typically only measures either
voltage OR current, not both, for
monitoring. This could lead to an
situation where there is a problem
with the resistor (open) and the
system will not detect it.

PulserPlus.Net TM
Competitors
Data Logging 200 alarms and 200
events with real
time/date stamp
Loss of Ground
Protection
Charging Current
Measurement
Ethernet
Communications
Offers built in
monitoring as well as
current and voltage
measurement for
redundancy
Standard
Standard
Not available
Optional
Not available
Not available

Stand Alone Unit
Wall Mount Unit
OEM Kit
Retrofit Kit

www.postglover.com
www.l-3.com/private/post_glover