INTRODUCING PDV-65
ARRESTER FOR NORMAL
DUTY APPLICATIONS
®
®
POWER SYSTEMS, INC.
Hi-Tension News
Reprinted from
8801-H
Winter 1988
ISO 9001-94
Cert. No. 002196
The Ohio Brass Co.
Wadsworth, OH USA
®
POWER
SYSTEMS, INC.
573-682-5521
ANDERSON
Fax 573-682-8714
®
http://www.hubbellpowersystems.com
®
®
®
UNITED STATES • 210 N. Allen • Centralia, MO 65240 • Phone: 573-682-5521 • Fax: 573-682-8714 • e-mail: hpscontact@hps.hubbell.com
CANADA • 870 Brock Road South • Pickering, Ontario L1W 1Z8 • Phone: 905-839-1138 • Fax: 905-831-6353 • e-mail: jpearl@hubbell-canada.com
MEXICO • Av. Coyoacan No. 1051 • Col. Del Valle • 03100 Mexico, D.F. • Phone: 525-575-2022 • Fax: 525-559-8626 • e-mail: vtasdf@hubbell.com.mx
NOTE: Because Ohio Brass has a policy of continuous product improvement, we reserve the right to change design and specifications without notice.
©
Copyright 2001 • Hubbell/ Ohio Brass
Bulletin EU1425-H
Printed in U.S.A.
Introducing the PDV-65 Arrester
for Normal Duty Applications
T
he Ohio Brass Company
expands its line of polymer-housed
distribution arresters with a normal
duty PDV-65. The PDV-100 arrester
was introduced in 1986 as the first
U.S. non-ceramic arrester for heavyduty applications.
The polymer housing on these
arresters offers many benefits never
before available. For example, the
arrester minimizes the opportunity
for damage from mishandling in
packing. Shipping and installation.
Because the PDV does not have an
internal atmosphere, failure from
“breathing” or “pumping” moisture through minute cracks or other
imperfections is also eliminated.
The application of system
overvoltage, above arrester design
limits, results in failure as with all
arresters. The housing splits or tears
in contrast to the potentially violent
failure mode of porcelain into many
sharp fragments. The potential
danger to nearby equipment and
personnel is reduced drastically.
The PDV arrester has the same
high-quality metal-oxide varistor
formulation used in other Ohio
Brass DynaVar station, intermediate and distribution arresters. The
PDV-65 arrester has all the MOV
advantages such as high temporary
overvoltage capability, contamination resistance, improved surgeduty capability, and excellent
protective characteristics.
2
The PDV-100 (l) and the PDV-65 arrester
for heavy duty and normal duty applications respectively.
Alloy EP Housing
The PDV arrester housing is
made from an alloy EP (ethylene
propylene) material. The improved
EP housing resists tracking from
surface leakage currents. Leakage
distance is exceptionally long.
In addition to the performance
record as an insulator material, EP's
excellent properties have been
confirmed in a series of performance tests that include tracking
resistance, contamination, aging
and seal design. As with polymer
insulators, polymer arresters have
high cantilever and tensile
strengths.
Basic Construction
The polymer housing fits like a
tight elastic glove around the
internal components in contrast to
porcelain housings which are
separated from the varistors. Even
though vacuum pumps can remove
most moisture from the space
inside the porcelain housing, a
source of potential trouble can
develop if small cracks let additional moisture enter the housing.
In the PDV arresters, the varistors are locked in place with tightly
wound layers of fiberglass filament
impregnated with epoxy resin. The
polymer housing design excludes
air and moisture. The inside
diameter of the housing is slightly
smaller than the outside diameter
of the cylindrical element providing
a snug fit.
Stainless Steel
Terminal Stud
Stainless Steel Cap
Alloy EP Rubber Housing
Metal Oxide Varistor
Belleville Washer
Epoxy-Fiberglass Wrap
Metal Oxide Varistor
Live Silicone Interface
End Terminal
PDV-65 Distribution Class Arrester
10 kV Unit
3
The basic PDV-65 arrester is only
six inches long for a 10 kV unit
which is 50 to 60 percent shorter
than the porcelain equivalent.
A great advantage of the PDV
arrester construction is that fault
current withstand capability can be
maintained throughout the voltage
range. In contrast, the fault current
capability of porcelain enclosed
designs is reduced as the housing
lengthens.
The polymer-housed arresters
can be used with all standard
mounting arms and brackets. They
come with all the necessary fasteners, isolators and terminal attachments. A specially designed glassfilled polyester insulating arm
extends from the arrester to the
NEMA crossarm bracket, eliminating the need for installation of a
metal clamping band around the
arrester. The insulating arm not
only eliminates the rust and corrosion sometimes encountered with a
metal clamping band, but also has
been treated with an inhibitor to
resist ultraviolet damage.
Benefits
The PDV-65 arrester housing
material excels in tolerance to
weather extremes from desert heat
to arctic cold, and resists damage
from ultraviolet rays and ozone.
Samples of the polymer have
survived the equivalent of over 50
years of accelerated ultraviolet
testing.
4
If the PDV-65 arrester is dropped
or otherwise mishandled, there is
little risk of housing damage, in
contrast to the brittleness of porcelain. Internal parts cannot move.
The risk of vandalism is reduced. A
bullet can penetrate the housing,
causing arrester failure. But polymer does not shatter as does
porcelain, which scatters sharp
fragments.
A PDV arrester weighs less than
its porcelain counterpart, again
making it easier to handle, less
costly to ship. Linemen who carry
the arrester up the pole appreciate
the weight difference.
The PDV-65 arrester is suitable
for a number of different applications, such as transformer mounting, enclosed in switchgear or
underhung in transmission line
protection.
This is an 18 kV DynaVar PDV-65 arrester.
As a non-ceramic arrester, the
PDV-65 offers an imposing list of
benefits. The capability of failing
without endangering equipment
and personnel, durability and ease
of handling lead the list. The PDV
arrester is a worthy addition to the
long list of Ohio Brass surge
arrester innovations - innovations
that have regularly improved
protective levels, lowered costs of
protection, and enabled utilities to
operate equipment with lower basic
insulation levels, with savings of
millions of dollars.
The PDV-65 arrester is constructed with
32mm diameter metal-oxide blocks.
PDV-65 Arrester Design Test Insures
Compliance with ANSI/IEEE C62.11-1987
T
he complete design test series
has been performed on the Ohio
Brass PDV-65 arrester. These tests
include:
I.
II.
Insulation Withstand Tests
Discharge Voltage Characteristic Tests
III. Accelerated Aging Tests
IV. 65 kA High Current, Short
Duration Tests
V. Low Current, Long Duration Tests
VI. Duty Cycle Tests
VII. Internal lonization and RIV
Tests
VIII. Contamination Tests
IX. Fault Current Withstand
Tests
Each of these tests were performed in accordance with ANSI/
IEEE Standard C62.11-1987 for
metal-oxide surge arresters. A brief
outline of some of the more critical
tests is given below.
Figure 1
Discharge Voltage
Characteristic Test
The discharge voltage characteristic test is performed on metaloxide varistors for various current
values and current wave shapes.
This is done to insure that the
arrester complies with the catalog
protective characteristics.
5
Figure 1 shows the results of this
discharge voltage testing. The
catalog discharge voltages are
derived from values on this curve.
Accelerated Aging Test
The accelerated aging test is
performed on metal-oxide varistors
to insure a suitable life under
continuously applied voltage. Since
metal-oxide distribution arresters
are gapless, the metal-oxide varistors are constantly subjected to a 60
cycle voltage. Accelerated aging
tests are performed to insure stable
watts loss characteristics as a
function of time.
This test is performed by energizing sample metal-oxide varistors
in an oven at 115°C for 1000 hours.
During this 1000-hour period the
sample varistors are continuously
energized at the sample MCOV
(maximum continuous operating
voltage).
The watts loss of the varistors are
measured at ambient temperature
before and after the 1000 hour test.
The watts loss measurements at
these times are taken at both
MCOV voltage and duty cycle rated
voltage.
If the watts loss at the end of the
test is less than or equal to the watts
loss at the beginning of the test then
the varistors have shown no
significant aging effects. In this case
all further tests which involve
thermal stability of the arrester may
be run at MCOV.
As Figure 2 summarizes, the
final watts loss for all metal-oxide
varistors tested was less than the
initial watts loss. Therefore the
varistor elements in the PDV-65
demonstrated no adverse aging
effects and all further tests were run
at MCOV.
65 kA High Current,
Short Duration Testing
Sample PDV-65 arresters were
subjected to two 65,000 ampere
discharges with sufficient time
between discharges to allow
cooling. Within five minutes after
the second discharge, the sample
was energized at MCOV to demonstrate thermal stability I .
Not only was thermal stability
demonstrated, but the 5 and 10 kA
protective characteristics of the
sample were measured and neither
of these showed any significant
increase. This demonstrates stable
protective characteristics.
Low Current, Long Duration
Testing
The low current, long duration
test was performed on a sample
PDV-65 arrester. This test consisted
of subjecting the sample to a series
of 75 ampere by 2000 microsecond
discharges. After the 18th discharge
the sample is heated to a temperature of 60°C and subjected to an
additional two discharges.
ACCELERATED AGING TEST RESULTS
Varistor
Sample
Initial Watts
Loss at MCOV
Final Watts
Loss at MCOV
Initial Watts
Loss at Duty
Cycle Rated
Voltage
1
2
3
.35
.34
.35
.31
.31
.31
.64
.68
.72
Figure 2
6
Final Watts
Loss at Duty
Cycle Rated
Voltage
.49
.49
.51
Within five minutes of the 20th
discharge the sample was energized
at MCOV to demonstrate thermal
stability. In addition to this, the 5
and 10 kA protective characteristics
of this arrester were measured and
neither of these were affected by the
low current, long duration duty.
Again this demonstrates a highly
stable product.
Cycle Test
The duty cycle test was performed on a sample PDV-65
arrester. This test sample was
energized at duty cycle rated
voltage and subjected to 20-5 kA 8/
20 discharges spaced one minute
apart. After the 20th discharge the
sample was preheated to 60°C and
then subjected to two additional 5
kA 8/20 discharges.
Within five minutes after the
22nd discharge the test sample was
energized at MCOV for 30 minutes
to demonstrate thermal stability,
and also the 5 and 10 kA protective
characteristics were measured. The
sample demonstrated thermal
stability with no significant change
in the 5 and 10 kA protective
characteristics.
Fault Current Withstand Test
The fault current withstand tests
were performed by placing a fuse
wire between the metal-oxide
varistors and the fiberglass wrap.
Figure 3 summarizes the results of
the fault current withstand testing.
Conclusions
The design test series performed
on the PDV arrester highlights two
of the PDV-65 arrester's major
benefits.
PDV Arresters
Fault Current Withstand Ratings
Current
Magnitude
(Amps-Sym rms)
PDV-65 Arrester
Test
Duration
(Cycles)
500
2,500
5,000
10,000
120
60
30
10
Figure 3
First, the metal-oxide arrester has
extremely stable protective characteristics with repetitive high energy
duty. This is in contrast to silicon
carbide arresters which could, as
allowed by standards, have protective characteristics change by as
much as 10 percent after these types
of tests. This increase in protective
characteristics in the case of the
silicon carbide arresters could lead
to diminished or non-existent
protective margins.
Second, the PDV-65 fault current
withstand capability will provide
increased safety for equipment and
personnel.
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Hardware Attachments for PDV
Surge Arresters
T
he table below describes the
standard hardware items which are
available on Ohio Brass Type PDV
arresters. The hardware described
in this table is suitable for the PDV100 (heavy duty) and the PDV-65
(normal duty) surge arresters.
Ohio Brass PDV arresters are
specified by the six digit catalog
numbers which describes the
MCOV (maximum continuous
operating voltage) rating of the
arrester. For example, the PDV-65
arrester 8.4 kV MCOV is Catalog
Number 217259. However, this six
digit catalog number is not sufficient to completely specify the
surge arrester. In addition the basic
arrester the optional hardware
attachments which are required
must also be specified. The optional
hardware attachments are specified
by the use of a four digit suffix code
beginning with the Number 7.
The three digits following 7
specify in turn the top end hardware, the mounting hardware, and
the bottom end hardware.
For example, if you need an 8.4
kV MCOV PDV-65 arrester with a
nut, wire clamp and protective cover
on the top end, the insulating base
bracket and NEMA crossarm bracket
as the mounting attachment and the
isolator, nut and wire clamp as the
lower end hardware, then this
arrester would be specified by code
217259-7324.
217259-7324
POPULAR OPTION FOR PDV ARRESTERS
Top Terminal Hardware
7100
3⁄ " Stud
8
(No Option)
7200
Term. Nut
& Wire Clamp
7300
Nut, Wire Clamp
& Prof. Cover
7400
Adjustable
(1-5")
Gap Electrode
7500
Nut, Wire Clamp
Protective Cap,
& 18" Wire Lead
7600
Ext. Gap
Under 12kV
Duty Cycle Rated
7700
Ext. Gap 12kV &
Above Duty
Cycle Rated
7030
Insulating
Base Bracket
and Transformer
Bracket
No. 271881-4001
7040
Insulating
Base Bracket
and NEMA
Angle Bracket
7050
Insulating
Base Bracket
and NEMA 6 x 6
X-Arm Hanger
7060
Metal Base
Mounting
Strap
7070
Metal Base
Mounting
Strap and
NEMA 4 x 5
X-Arm Hanger
7003
Isolator,
Ground Strap
& Nut
7004
Isolator, Nut
& Wire Clamp
7005
Isolator, Nut
Wire Clamp &
Prot. Cover
7006*
Ground Strap
& Nut, &
Lockwasher
7007*
Nut, Flatwasher
& Lockwasher
Mounting Hardware
7010
Insulating
Base
Bracket
7020
Insulating
Base Bracket
and NEMA 4 x 5
X-Arm Hanger
Lower Terminal Hardware
7001*
3⁄ " Stud
8
(No Option)
7002*
Term. Nut
& Wire Clamp
*Must be ordered in conjunction with codes 7060 and 7070.
8