Eaton COOPER POWER SERIES Manual

Type PST Model-9 Automatic Source Transfer Switchgear with iST
Control; Installation, Operation, and Maintenance Instructions
COOPER POWER
SERIES
Underground
Distribution Switchgear
MN285002EN Effective April 2019
Supersedes April 2018

ii INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS MN285002EN April 2019
DISCLAIMER OF WARRANTIES AND LIMITATION OF LIABILITY
The information, recommendations, descriptions and safety notations in this document are based on Eaton Corporation’s
(“Eaton”) experience and judgment and may not cover all contingencies. If further information is required, an Eaton sales
office should be consulted. Sale of the product shown in this literature is subject to the terms and conditions outlined in
appropriate Eaton selling policies or other contractual agreement between Eaton and the purchaser.
THERE ARE NO UNDERSTANDINGS, AGREEMENTS, WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING WARRANTIES
OF FITNESS FOR A PARTICULAR PURPOSE OR MERCHANTABILITY, OTHER THAN THOSE SPECIFICALLY SET OUT IN ANY
EXISTING CONTRACT BETWEEN THE PARTIES. ANY SUCH CONTRACT STATES THE ENTIRE OBLIGATION OF EATON. THE
CONTENTS OF THIS DOCUMENT SHALL NOT BECOME PART OF OR MODIFY ANY CONTRACT BETWEEN THE PARTIES.
In no event will Eaton be responsible to the purchaser or user in contract, in tort (including negligence), strict liability or
other-wise for any special, indirect, incidental or consequential damage or loss whatsoever, including but not limited to
damage or loss of use of equipment, plant or power system, cost of capital, loss of power, additional expenses in the use of
existing power facilities, or claims against the purchaser or user by its customers resulting from the use of the information,
recommendations and descriptions contained herein. The information contained in this manual is subject to change without
notice.

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INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS MN285002EN April 2019
Contents
DISCLAIMER OF WARRANTIES AND LIMITATION OF LIABILITY ....................................II
SAFETY INFORMATION .................................................................... V
Safety instructions...............................................................................v
PRODUCT INFORMATION....................................................................1
Introduction ....................................................................................1
Acceptance and initial inspection ...................................................................1
Handling and storage.............................................................................1
Standards .....................................................................................1
Quality standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
PST MODEL-9 OVERALL DESCRIPTION ........................................................1
Vacuum interrupters .............................................................................2
Bushings ......................................................................................2
Standard cabinet features .........................................................................2
Interrupter duty cycle ............................................................................4
Switch test sequence ............................................................................4
Nameplate .....................................................................................4
Operating handles ...............................................................................4
Weight ........................................................................................4
RATINGS AND SPECIFICATIONS ..............................................................5
LOAD TRANSFER FUNCTIONALITY ............................................................5
iST control operation ............................................................................5
Operation of interval timer ........................................................................9
CI switch .....................................................................................10
Operating modes ..............................................................................10
CI operating sequences .........................................................................10
Manual operation of CI switches...................................................................11
OVERCURRENT PROTECTION FUNCTIONALITY ................................................11
Vacuum fault interrupters (VFI) ....................................................................12
Manual VFI operation............................................................................12
Opening VFI switches ...........................................................................13
Resetting VFI switches ..........................................................................13
Closing VFI switches ............................................................................13
INSTALLATION PROCEDURES ...............................................................13
Initial mechanical operation check ..................................................................14
Initial electrical operation check....................................................................15
Initial iST control operation check ..................................................................16

iv INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS MN285002EN April 2019
MAINTENANCE ...........................................................................17
Maintenance inspection procedure .................................................................17
Internal inspection and repair .....................................................................18
Insulating fluid maintenance ......................................................................18
Frequency of maintenance .......................................................................19
Types of fluid samples...........................................................................19
Fluid sampling guidelines ........................................................................19
Fluid fill guidelines ..............................................................................20
Fluid testing...................................................................................21
Dissolved gas analysis...........................................................................21
TESTING ................................................................................22
High-potential withstand testing of vacuum interrupters ................................................22
REPLACEMENT PARTS .....................................................................22

Type PST Model-9 Automatic Source Transfer Switchgear with iST Control
Safety for life
Eaton meets or exceeds all applicable industry standards relating to product safety in its Cooper Power™ series products.
We actively promote safe practices in the use and maintenance of our products through our service literature, instructional
training programs, and the continuous efforts of all Eaton employees involved in product design, manufacture, marketing, and
service.
We strongly urge that you always follow all locally-approved safety procedures and safety instructions when working around
high-voltage lines and equipment, and support our “Safety For Life” mission.
Safety information
The instructions in this manual are not intended as a
substitute for proper training or adequate experience in the
safe operation of the equipment described. Only competent
technicians who are familiar with this equipment should
install, operate, and service it.
A competent technician has these qualifications:
 Is thoroughly familiar with these instructions.
 Is trained in industry-accepted high- and low-voltage safe
operating practices and procedures.
 Is trained and authorized to energize, de-energize, clear,
and ground power distribution equipment.
 Is trained in the care and use of protective equipment
such as arc flash clothing, safety glasses, face shield,
hard hat, rubber gloves, clampstick, hotstick, etc.
Following is important safety information. For safe
installation and operation of this equipment, be sure to read
and understand all cautions and warnings.
Hazard Statement Definitions
This manual may contain four types of hazard statements:
DANGER
Indicates an imminently hazardous situation which, if
not avoided, will result in death or serious injury.
WARNING
Indicates a potentially hazardous situation which, if not
avoided, could result in death or serious injury.
CAUTION
Indicates a potentially hazardous situation which, if not
avoided, may result in minor or moderate injury.
NOTICE
Indicates a potentially hazardous situation which, if not
avoided, may result in equipment damage only.
Safety instructions
Following are general caution and warning statements that
apply to this equipment. Additional statements, related to
specific tasks and procedures, are located throughout the
manual.
DANGER
Hazardous voltage. Contact with hazardous voltage will
cause death or severe personal injury. Follow all locally-
approved safety procedures when working around high-
and low-voltage lines and equipment. G103.3
WARNING
Before installing, operating, maintaining, or testing this
equipment, carefully read and understand the contents
of this manual. Improper operation, handling, or
maintenance can result in death, severe personal injury,
and equipment damage. G101.0
WARNING
This equipment is not intended to protect human
life. Follow all locally-approved procedures and safety
practices when installing or operating this equipment.
Failure to comply can result in death, severe personal
injury, and equipment damage. G102.1
WARNING
Power distribution and transmission equipment must
be properly selected for the intended application. It
must be installed and serviced by competent personnel
who have been trained and understand proper safety
procedures. These instructions are written for such
personnel and are not a substitute for adequate training
and experience in safety procedures. Failure to properly
select, install, or maintain power distribution and
transmission equipment can result in death, severe
personal injury, and equipment damage. G122.2
!
SAFETY
FOR LIFE
!
SAFETY
FOR LIFE
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Type PST Model-9 Automatic Source Transfer Switchgear with iST Control
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vi INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS MN285002EN April 2019

Type PST Model-9 Automatic Source Transfer Switchgear with iST Control
Product information
Introduction
Service Information MN285002EN provides installation
instructions, operation information, maintenance
procedures, and testing information for Eaton's Cooper
Power™ series Type PST Model-9 Underground Distribution
Automatic Source Transfer Switchgear with iST Control.
Before installing and operating this control, carefully read
and understand the contents of this manual.
For additional information, refer to the following applicable
service information bulletins:
 S275-10-1 Type CI Three-Phase Fault Interrupters
Installation and Operation Instructions
 MN285006EN Type VFI, Fluid Insulated, Vacuum Fault
Interrupter; Installation, Operation, and Maintenance
Instructions
Read this manual first
Read and understand the contents of this manual and follow
all locally approved procedures and safety practices before
installing or operating this equipment.
Additional information
These instructions cannot cover all details or variations
in the equipment, procedures, or process described, nor
provide directions for meeting every possible contingency
during installation, operation, or maintenance. For additional
information, please contact your Eaton representative.
Acceptance and initial inspection
The PST switchgear is completely assembled, tested, and
inspected at the factory. The switchgear is filled to the
correct level with insulating fluid. It is in good condition
when accepted by the freight carrier for shipment.
1. Upon receipt, inspect the unit thoroughly for damage
and loss of parts or fluid incurred during shipment.
If damage or loss is discovered, file a claim with the
carrier immediately.
2. Check for fluid leakage.
Handling and storage
The switchgear should remain on its shipping pallet until it is
installed. When handling the switchgear, always use a fork
truck that has adequate lifting capacity and forks that extend
the entire length of the pallet. Improper handling can cause
damage to the switchgear.
If the switchgear is to be stored for any appreciable time
before installation, provide a clean, dry storage area.
Be careful during handling and storage to minimize the
possibility of mechanical damage. Do not stack other
material on the switchgear.
Standards
PST Model-9 Underground Distribution Switchgear products
are designed and tested in accordance with standards: IEEE
Std C57.12.28™-2005 and IEEE Std 386™-2006.
Quality standards
ISO 9001 Certified Quality Management System.
PST Model-9 overall description
Type PST Model-9 Automatic Source Transfer Switchgear
provides both loss-of-source health and overcurrent
protection for critical loads for 15, 25, and 35 kV
underground systems.
PST Model-9 units are self-contained, steel constructed
underground distribution enclosures containing mineral oil
or Envirotemp™ 200™ as a dielectric insulating medium.
They are shipped fully assembled and filled with insulating
fluid. PST Model-9 switchgear is designed for outdoor
mounting on a concrete pad. Power is fed to, and from, the
switchgear from underground through openings in the pad.
Deadfront construction minimizes the high voltage safety
hazards for both the operator and the general public.
Loss-of-source health protection functionality is provided
by an iST control system and two three-phase Type CI
motor-operated, source-side vacuum interrupter switches
(Figure 1).
Eaton's Cooper Power series iST control monitors the
preferred and alternate line voltages and provides the timing
and control logic required to perform the automatic load
transfer in the event of a source health loss. The control
commands the operations of the two Type CI vacuum
interrupter switches during auto transfer. Manually operated
levers enable manual trip and close of source-side CI
interrupter switches during power outages. Operational
power (120 Vac) for the transfer control and vacuum
switches is derived from system line levels via internally
mounted potential transformers; no external source of
power is required.
Eaton's Cooper Power series VFI Interrupters and iST control
provide independent overcurrent protection of the two
PST taps. Both taps are independently served by separate
controls commanding the operations of a dedicated VFI
vacuum fault interrupter on each tap (Figure 1).
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INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS MN285002EN April 2019

Type PST Model-9 Automatic Source Transfer Switchgear with iST Control
Control Control
PTs PTs
Fault Block Signal
Overcurrent
Protection
Overcurrent
Protection
iST-921
Voltage Input
Figure 1. PST Model-9 functional diagram
Overcurrent sensing, timing, and tripping functions are
performed by the iST control system. Sensing CTs,
mounted internally on each phase of the tap connections,
are used by the iST control system to monitor load current.
If the current monitored is greater than the phase or ground
minimum trip level, the control begins a user selected time-
current curve (TCC) delay sequence. At the completion of
the programmed TCC delay, a signal is issued to trip the VFI
on the respective load tap.
Vacuum interrupters
Load-break switching and fault interruption takes place
within sealed vacuum interrupters. Vacuum interrupters
provide fast, low energy arc interruption and produce no
arcing by-products to contaminate the insulating fluid.
Use of vacuum interruption significantly reduces the
maintenance required of this equipment.
Figure 2. Vacuum interrupter assembly
Bushings
Bushings are mounted horizontally in-line and located a
minimum of 24 inches above the pad.
Depending on the rating of the PST Model-9 unit, bushings
may be furnished in different configurations and ratings.
200A interfaces are provided as either 200A bushing wells
or 200A one-piece loadbreak bushings. 600A deadbreak
aluminum type bushings are furnished for PST Model-9
units rated for 600A continuous current operation. All
bushings conform to IEEE Std 386™-2006.
Standard cabinet features
Standard features (Figure 3 and Figure 4) include a fluid
level indicator on each front plate, automatic pressure-relief
valve, operation one-line diagrams on the doors, fluid fill
plug, fluid drain and sampler, and a standoff bracket for each
bushing. Standard grounding provisions include a 1/2-13
UNC stainless steel ground nut for each bushing.
Cabinet padlocking provisions
Provisions are included for padlocking the cabinet in order
to prevent unauthorized door opening. The cabinet must
be locked at all times to prevent accidental contact with
hazardous voltage.
Cabinet construction
Type PST Model-9 switchgear features deadfront, tamper-
resistant, low-profile construction. It is suitable for operation
in demanding indoor and outdoor applications. Cabinets
meet the enclosure security requirements of IEEE Std
C57.12.28™-2005 standard.
Tank construction is of 7- or 10-gauge steel, and cabinets
are made of 12- or 13-gauge steel. Recessed lifting
provisions are provided at each corner of the tank for a
balanced lift.
Side-hinged, cabinet style doors are provided with door
stays and fitted with stainless steel hinges. Both source and
tap doors can be fully open at the same time. Each door
has a floating lock pocket with padlock provisions and penta-
head silicon bronze door bolt.
Cabinet finish
PST Model-9 switchgear is finished in a green color, which
conforms to Munsell 7GY 3.29/1.5 Green.
The coating conforms to the following specifications: IEEE
Std C57.12.28™-2005, ASTM B117 24-hour 5% salt spray
corrosion test, ASTM D2247 1000-hour humidity test, ASTM
G53 500-hour ultraviolet accelerated weathering test, and
ASTM D2794 impact test.
2INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS MN285002EN April 2019

Type PST Model-9 Automatic Source Transfer Switchgear with iST Control
Nameplate
Potential Transformer Dead-break Disconnect Switch Source 2 Bushings
Source 1
Bushings
iST 921 Control
Enclosure
Interrupting Switch
Manual Spring Charge Operator
CI Switch S2 Manual
Operating Lever
CI Switch S1 Status
Indicator
CI Switch S1
Manual Operating
Lever
Interrupting Switch
Spring Charge Indicator
CI Switch S1 Operation
Counter
iST 901 Control Enclosure
Figure 3. PST Model-9 source-side features
Fluid Level
Indicator
Fluid Drain Plug and Sampler
(located behind the sill)
Tap 2 Bushings
Tap 1 Bushings
VFI Operating Handle
VFI Operating Handle
Fluid Fill Plug Pressure Relief Valve
1/2 - 13UNC Stainless Steel
Ground Nut - Typ. (located behind the sill)
Figure 4. PST Model-9 tap-side features
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INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS MN285002EN April 2019

Type PST Model-9 Automatic Source Transfer Switchgear with iST Control
Interrupter duty cycle
The VFI mechanism conforms to the duty cycle
requirements of IEEE Std C37.60™-2003 standard.
Switch test sequence
The VFI operating mechanism conforms to the switch test
sequence requirements of IEEE Std C37.60™-2003.
Nameplate
Prior to installation, check the nameplate ratings. Verify the
overall current and voltage ratings, transformer ratings, and
one-line diagrams are correct for the planned installation.
Operating handles
WARNING
Hazardous voltage. Never rely on the open position of
the operating handle or the contact position indicator;
it does not ensure that the line is de-energized. Follow
all locally approved safety practices. Failure to comply
can result in contact with high voltage, which will
cause death or severe personal injury. G123.1
Type PST Model-9 switchgear is equipped with hotstick-
operable loadbreak switch handles for operation of the CI
source-side and VFI tap-side switches.
The operating handles of CI switches provide incremental
travel between the trip, close, and reset positions of the
switch (Figure 5). CI trip-reset levers may be padlocked in
the tripped position.
The Type VFI interrupters are equipped with hotstick-
operable handles that are located on the tap-side of the
unit. VFI operating handles are factory configured for
ganged three-phase operation (all three phases operated
simultaneously with a single handle). The operating handle
(Figure 6) provides convenient push-to-close and pull-to-
open operation. VFI operating handles may be padlocked in
the open position.
Figure 5. CI switch trip-reset lever
Figure 6. VFI operating handle, three-phase ganged
operation
Weight
The weight of the switchgear is shown on the nameplate.
Make sure that lifting equipment used is rated sufficiently
to safely handle the switchgear.
4INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS MN285002EN April 2019