Samco Engineers design a method (GFAL) and instrument
(GFAL-A, GFAL-B)
to analyze and locate DC ground faults on
ungrounded DC battery multi-feeder
distribution systems.
The design was very successful, and today we have is
an instrument capable
of quickly locating these DC ground faults.
Abstract
The GFAL-A/B instrument has been used for
many years in stations,
substations and nuclear power plants to troubleshoot
their DC systems
ground faults and has beeneffective in locating
the faults without ever
causing a system trip, or taking a unit off-line.
GFAL-B (tracking unit)
*
Does not require system interruption *
Locate DC ground faults with
this hand held portable instrument *
Protect your sensitive electronic
equipment *
Unique design reduces system
outages
*
No need to be connected to the AC main to operate
*
New: Will detect how much fault
exist on each branch
GFAL-B
OVERVIEW
Traditional methods of indicating
DC ground faults are ineffective when two or more faults
are in opposite polarities of the DC multi-feeder
distribution
system.
Samco engineering has created a new
method that quickly will identify these faults on each polarity.
However once a fault has been identified,
the fault must be located in order to be corrected.
Locating a DC ground fault is currently
done in two ways. The first method consists of opening
circuit breakers or disconnecting branches
and interrupting
the system until the fault is cleared, a procedure that is
time consuming inaccurate and costly, since it requires shutting
down the system..
The second method to locate DC ground
fault injects an AC signal with respect to ground into the DC
system. This process can inadvertently
damage sensitive
electronic equipment or cause expensive nuisance trips.
THE GFAL EXPLAINED
The GFAL-A (interrupter) and
GFAL-B (receiver) are battery operated portable instruments
that utilizes a DC tracking signal
create by the
interrupter
and the fault resistance.
A Hall Effect magnetic Sensor Assembly
is attach to the GFAL-B that wrap around the conductors
to track the tracking signal.
There are three
mayor components that make the GFAL-A/B instrument.
Item 1) The interrupter
unit GFAL-A creates a DC interrupted tracking signal
utilizing the fault resistance.
Item 2) The hand held unit GFAL-B house the
microprocessor and the
analog electronics and
track the tracking signal.
Item 3) The magnetic sensor assembly (MSA)
detect the magnetic field
produce by the tracking
signal.
This MSA wrap around
the conductors under test and is connected
to the GFAL-B.
Carrying Case
PROVEN
RESULTS
Below is a partial list of users that
have benefited from the innovative method implemented by
the GFA-A/B
Plant Bowen 3,540 MW (GA)
Plant Scherer 3,564 MW (GA)
Ray Olinger Plant 420 MW (TX)
City of Anaheim (250 KV) Substation (CA)
El Segundo GS 684 MW (CA)
ExxonMobil Refinery (CA)
Callaway Nuclear Plant (MO)
Comanche Peak Nuclear Plant (TX)
Wolf Creek Nuclear Plant (KS)
Brunswick Nuclear Plant (NC)
Diablo Canyon Nuclear Plant (CA)
Palo Verde Nuclear Plant (AZ)
Hatch Nuclear Plant (GA)
Vogtle Nuclear Plant (GA)
Three Mile Island Nuclear Plant (PA
Minimum specification
of the GFAL-B
Sensitivity:
............................................3mA, will locate
up to 40,000 Ohms fault in a 130VDC distribution system.
Operating DC range...............................12
to 240 VDC
Impedance range....................................No load
to the DC distribution system
Accuracy ...............................................10
% (full scale)
Environmental........................................30
to 125 Degrees F
Power adapter input .............................
+ 12-18 VDC
Internal battery operation........................More
than 24 hr (Rechargeable)
Display...................................................Alphanumeric
16 characters
Dimensions ............................................10”
x 11” x 4.3”
Weight ...................................................4
Lb.
Case (2 colors) .....................................Gray
and yellow
Warranty...............................................1
yr. Parts and Labor
If you need more information, please
contact us at:
Samco Engineering
Fountain Valley, CA 92708
Phone: (714) 235 - 5901
E-mail: samcoeng@aol.com
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