Siemens SDV-4A Instruction Manual
15.5kV, 25.8kV and 27.6kV
Power Circuit Breaker
Type SDV-4A
Instructions
Installation
Operation
Maintenance
SGIM-3788F
Hazardous voltages and high-speed moving parts.
Will cause death, serious injury or property damage.
Always de-energize and ground the equipment before
maintenance. Read and understand this instruction
manual before using equipment.
Maintenance should be performed only by qualified
personnel. Use only Siemens parts in the repair of the
equipment. Do not allow tampering with the equipment. Follow all safety instructions contained herein.
IMPORTANT
The information contained herein is general in nature and not intended for
specific application purposes. It does not relieve the user of responsibility
to use sound practices in application, installation, operation, and maintenance of the equipment purchased. Siemens reserves the right to make
changes in the specifications shown herein or to make improvements at
any time without notice or obligations. Should a conflict arise between the
general information contained in this publication and the contents of drawings or supplementary material or both, the latter shall take precedence.
QUALIFIED PERSON
For the purpose of this manual a qualified person is one who is familiar
with the installation, construction or operation of the equipment and the
hazards involved. In addition, this person has the following qualifications:
(a) is trained and authorized to de-energize, clear, ground, and tag cir-
cuits and equipment in accordance with established safety practices.
(b) is trained in the proper care and use of protective equipment such as
rubber gloves, hard hat, safety glasses or face shields, flash clothing,
etc., in accordance with established safety practices.
(c) is trained in rendering first aid.
NOTE
These instructions do not purport to cover all details or variations in equipment, nor to provide for every possible contingency to be met in connection with installation, operation, or maintenance. Should further information be desired or should particular problems arise which are not covered
sufficiently for the purchaser’s purposes, the matter should be referred to
the local sales office. The contents of this instruction manual shall not become part of or modify any prior or existing agreement, commitment or
relationship. The sales contract contains the entire obligation of Siemens
Power Transmission & Distribution Inc. The warranty contained in the contract between the parties is the sole warranty of Siemens Power Transmission & Distribution Inc. Any statements contained herein do not create new
warranties or modify the existing warranty.
15.5kV, 25.8kV and 27.6kV Power Circuit Breaker
Table of Contents
Introduction and Safety ....................................................... 2
Introduction ............................................................................. 2
Qualified Person ...................................................................... 2
Signal Words ........................................................................... 2
Hazardous Procedures ............................................................ 2
Field Service Operation ........................................................... 2
General Description .............................................................. 3
Introduction ............................................................................. 3
Scope ...................................................................................... 3
General Description ................................................................ 3
Receiving, Handling & Storage ............................................ 4
Receiving ................................................................................ 4
Inspection ............................................................................... 4
Shipping Damage Claims ........................................................ 4
Lifting and Moving .................................................................. 5
Lifting Power Circuit Breaker with Crane ................................ 5
Storage .................................................................................... 5
Installation ............................................................................. 6
Location .................................................................................. 6
Preparation for Installation ...................................................... 6
“X” Bracing Installation Instructions
(for High Seismic Applications Only) ............................... 6
Foundation-General Requirements ......................................... 7
Electrical Connections .......................................................... 8
Primary Lead Connections ...................................................... 8
Ground Connections ............................................................... 8
Secondary Control Wiring ....................................................... 8
Instrument Transformers ..................................................... 9
Current Transformers .............................................................. 9
Installation Checks and Initial Functional Tests ............... 10
Introduction ........................................................................... 10
Inspections, Checks, And Tests Without Control Power ...... 10
Spring Discharge Check ........................................................ 10
Physical Inspections .............................................................. 11
Manual Spring Charging Check ............................................. 11
As-Found and Vacuum Check Tests ...................................... 11
Automatic Spring Charging Check ........................................ 11
Final Mechanical Inspection and
Testing Without Control Power ..................................... 11
Inspection ............................................................................. 11
Testing ................................................................................... 12
Interrupter/Operator Description ...................................... 13
Introduction ........................................................................... 13
Vacuum Interrupters ............................................................. 13
Stored Energy Operating Mechanism ................................... 13
Modes Of Operation - Discussion ......................................... 14
Spring Charging Mode .......................................................... 14
Closing Mode ........................................................................ 15
Trip Free Mode ...................................................................... 15
Opening Mode ...................................................................... 15
Rapid Auto-Reclosing Mode ................................................. 15
Closing And Tripping Springs ................................................ 15
Trip Free Operation ............................................................... 16
Damper ................................................................................. 16
Manual Spring Charging ........................................................ 16
Spring Charging Motor .......................................................... 17
Close Solenoid, Trip Solenoid and Anti-Pump Relay ............. 17
Auxiliary Switch ..................................................................... 17
Limit Switches ...................................................................... 17
Standard Schematic Diagrams .............................................. 17
Capacitor Trip Device (Optional) ............................................ 18
Maintenance ........................................................................ 21
Inspection and Maintenance Intervals .................................. 21
Recommended Hand Tools ................................................... 21
Recommended Maintenance and Lubrication ...................... 21
De-energize the Circuit Breaker ............................................ 22
Checks Of Primary Power Path ............................................ 22
Cleanliness Check ................................................................. 22
Checks of the Stored Energy Operator Mechanism ............. 23
Maintenance and Lubrication ................................................ 23
Fastener Check ..................................................................... 23
Manual Spring Charging And Contact Erosion Checks ......... 23
Vacuum Interrupter Stroke Check ......................................... 24
Damper Assembly Check ..................................................... 25
Electrical Control Checks ...................................................... 25
Check Of The Wiring And Terminals ..................................... 25
Automatic Spring Charging Check —
Control Power Required................................................ 25
Electrical Close And Trip Check —
Control Power Required................................................ 26
Checks Of Spring Charging Motor ........................................ 26
High Potential Tests .............................................................. 26
Vacuum Integrity Check ........................................................ 26
High Potential Test Voltages ................................................. 26
Vacuum Integrity Test Procedure .......................................... 27
As-Found Insulation and Contact Resistance Tests .............. 27
Insulation and Contact Resistance Test Equipment .............. 27
Insulation and Contact Resistance Test Procedure ............... 27
Inspection And Cleaning Of Breaker Insulation .................... 28
Functional Tests .................................................................... 28
Relays and Instruments ........................................................ 28
Equipment Surfaces .............................................................. 28
Operator Adjustments ........................................................ 29
Spring Charging Adjustment ................................................. 29
Spring Release Latch “Bite” Adjustment ............................. 30
Overhaul .............................................................................. 31
Introduction ........................................................................... 31
Circuit Breaker Overhaul ....................................................... 31
Replacement At Overhaul ..................................................... 31
Replacement Of Closing Springs .......................................... 31
Replacement Of Opening Spring .......................................... 32
Replacement Of Closing and Tripping Solenoids
(Devices 52SRC and 52T) ............................................. 32
Replacement of Anti-Pump Relay (Device 52Y) .................... 32
Replacement of the Auxiliary Switch .................................... 32
Replacement of Motor Cutoff Switch (Device LS1)
and Spring Charged Switch (LS2) ................................. 33
Replacement of Trip Latch Reset Check Switch
(Device LS3) .................................................................. 33
Replacement of Damper Assembly ...................................... 34
Replacement of Spring Charging Motor (Device 88) ............ 34
Replacement of Vacuum Interrupters ................................... 34
Index of Figures and Tables .................................................. 34
Recommended Hand Tools ................................................... 34
Preparation ............................................................................ 35
Vacuum Interrupter Removal ................................................ 35
Vacuum Interrupter Replacement ......................................... 35
Periodic Maintenance and Lubrication Tasks ................... 39
Troubleshooting .................................................................. 40
Ordering Replacement Parts ................................................. 42
Appendix .............................................................................. 43
Cover 2074-98
1
Introduction and Safety
Introduction
The SDV (generic family name for SDV-4A) vacuum breakers are designed to meet all applicable ANSI, NEMA, and
IEEE standards. Successful application and operation of
this equipment depends as much upon proper installation
and maintenance by the user as it does upon the careful
design and fabrication by Siemens.
The purpose of this instruction manual is to assist the user
in developing safe and efficient procedures for the installation, maintenance and use of the equipment.
Contact the nearest Siemens representative if any additional
information is desired.
Hazardous voltages and high-speed moving
parts.
Will cause death, serious injury or property
damage.
To avoid electrical shock, burns and entanglement in moving parts this equipment must be
installed, operated and maintained only by
qualified persons thoroughly familiar with the
equipment, instruction manuals and drawings.
Read and understand this instruction manual
before using equipment.
Qualified Person
For the purpose of this manual a Qualified Person is one
who is familiar with the installation, construction or operation of the equipment and the hazards involved. In addition, this person has the following qualifications:
Caution - indicates a potentially hazardous situation which,
if not avoided, may result in minor or moderate injury.
Caution (without safety alert symbol) - indicates a potentially hazardous situation which, if not avoided, may result in property damage.
Hazardous Procedures
In addition to other procedures described in this manual
as dangerous, user personnel must adhere to the following:
1. Always work only on a de-energized breaker. The breaker
should be isolated, grounded, and have all control power
removed before performing any tests, maintenance or
repair.
2. Always perform maintenance on the breaker after the
spring-charged mechanisms are discharged (except for
test of the charging mechanisms). Check to be certain
that the indicator flags read OPEN and DISCHARGED.
3. Always let an interlock device or safety mechanism perform its function without forcing or defeating the device.
Field Service Operation
Siemens can provide competent, well-trained Field Service
Representatives to provide technical guidance and advisory assistance for the installation, overhaul, repair and
maintenance of Siemens equipment, processes and systems. Contact regional service centers, sales offices or the
factory for details, or telephone Siemens Field Service at
1-877-742-3309.
• Training and authorization to energize, de-energize, clear,
ground and tag circuits and equipment in accordance
with established safety practices.
• Training in the proper care and use of protective
equipment such as rubber gloves, hard hat, safety
glasses, face shields, flash clothing, etc., in accordance
with established safety procedures.
• Training in rendering first aid.
Signal Words
The signal words “Danger”, “Warning” and “Caution” used
in this manual indicate the degree of hazard that may be
encountered by the user. These words are defined as:
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.
2
General Description
The instructions included in this manual are provided to
aid you in obtaining longer and more economical service
from your Siemens Circuit Breakers. For proper installation and operation, this information should be distributed
to your operators, engineers and maintenance personnel.
By carefully following these instructions, difficulties should
be avoided. However, the instructions are not intended to
cover all details of variations that may be encountered in
connection with the installation, operation and maintenance
of this equipment.
Should additional information be desired, including replacement instruction books, contact your Siemens representative.
Scope
These instructions cover the installation, operation and
maintenance of Siemens type SDV power circuit breakers
using vacuum interrupters. The equipment described in
this manual consists of free standing outdoor power circuit breakers for application up to 27.6kV. A typical breaker
is shown in Figure 1. All diagrams, descriptions and instructions apply to all above types and designs unless noted
otherwise.
2075-98
Figure 1. Typical Power Circuit Breaker, Type SDV-4A.
Introduction
The successful performance and application of Power Circuit Breakers depends as much on proper installation,
maintenance and correct application as it does on good
design and careful manufacture .
Siemens Type SDV outdoor power circuit breakers are precision built units designed to function efficiently under
normal operating conditions. They are designed and manufactured to operate within the limits established in the ANSI
C37 and NEMA standards for Power Circuit Breakers. Performance requirements of these standards have been met
or exceeded by these designs. Specific Standards which
apply include:
Standard construction details of the circuit breaker are given
in the appropriate sections. Special mechanical and electrical devices, furnished in accordance with purchase order requirements, are covered by supplementary instructions submitted with this instruction manual.
The equipment furnished has been designed to operate in
a system having the circuit capacity specified by the purchaser. If for any reason the equipment is used in a different system, or if the short-circuit capacity of the system is
increased, the momentary rating and interrupting capacity
of the circuit breaker must be checked. Failure on the part
of the user to receive approval of intended changes from
Siemens may cause voiding the warranty.
General Description
The power circuit breaker described in this manual is the
AC high-voltage circuit breaker type, as defined in ANSI
C37 and NEMA SG 4. All high voltage parts excluding the
roof bushings are completely enclosed within grounded
metal barriers. Secondary control compartment and primary circuits are isolated from each other by barriers.
Siemens power circuit breakers carry a type designation
as shown in Table 1. This designation may appear on draw-
ings and familiarity with them will simplify communications with the factory.
C37.04 AC High-Voltage Circuit Breakers - Basis of Rating
C37.06 AC High-Voltage Circuit Breakers - Preferred Ratings
C37.09 AC High-Voltage Circuit Breakers - Test Code
SG 4 Alternating-Current High-Voltage Circuit Breakers
Table 1. Power Circuit Breaker Designation
DESIGN TYPE
Bolted Cabinet SDV-4A
3
Receiving, Handling & Storage
Receiving
Each type SDV circuit breaker is securely blocked and
braced for shipment. Every precaution is taken to insure
its safe arrival. Relatively delicate instruments may be included and the circuit breakers must be handled carefully
when unloading and moving.
Inspection
Inspect the equipment as soon as possible after receiving
for any damage that may have occurred in transit. Before
unloading, make a physical inspection of the circuit breaker,
checking for shipment damage or indications of rough handling by the carrier. Check the shipping manifest to be certain that all items have been received. If there is a shortage, make certain it is noted on the freight bill and contact
the carrier immediately. Notify the Siemens sales office of
any shortage or damage.
Shipping Damage Claims
IMPORTANT: The way visible shipping damage is
treated by consignee prior to signing the delivery
receipt can determine the outcome of the damage
claim to be filed.
Notification to carrier within the 15 day limit on concealed
damage is essential if loss resulting from unsettled claims
is to be eliminated or minimized.
1. When shipment arrives, note whether equipment is
properly secured for transit. Note trailer number on
which the equipment arrived. Note blocking of
equipment. During unloading, make sure count agrees
with delivery receipt.
2. Make immediate inspection for visible damage upon
arrival, and prior to unloading. When total inspection
cannot be made on vehicles prior to unloading, close
inspection during unloading must be performed and
visible damage noted on the delivery receipt. Take
pictures if possible.
3. Any visible damage must be noted on the delivery receipt
and acknowledged with the driver’s signature. The
damage should be detailed as much as possible. It is
essential that a notation “Possible internal damage,
subject to inspection” be included on delivery receipt.
If the driver will not sign the delivery receipt with damage
noted, the shipment should not be signed for by the
consignee or his agent.
4. Notify the Siemens sales office immediately of any
damage.
5. Arrange for a carrier inspection of damage immediately.
IMPORTANT: Do not move equipment from the
place it was set when unloading. Equipment must
be inspected by carrier prior to handling after
receipt. This eliminates loss due to claims by carrier
that equipment was damaged or further damaged
on site after unloading.
6. Be sure equipment is properly protected from any further
damage by covering it properly after unloading.
7. If practical, make further inspection for possible
concealed damage while the carrier’s inspector is on
site. If inspection for concealed damage is not practical
at the time the carrier’s inspector is present, it must be
done within 15 days of receipt of equipment. If concealed
damage is found, the carrier must again be notified and
inspection made prior to taking any corrective action to
repair. Also notify Siemens sales office immediately.
8. Obtain the original of the carrier inspection report and
forward it along with a copy of the noted delivery receipt
to the Siemens sales office. Approval must be obtained
by Siemens from the carrier before any repair work can
be performed. Before approval can be obtained,
Siemens must have the documents. The carrier
inspection report and/or driver’s signature on the delivery
receipt does not constitute approval to repair.
Note: Any adverse judgment as to whether the equipment
was properly loaded or properly prepared by shipper for
over-the-road travel cannot be made at the destination.
Shipments are not released from the factory without a clear
bill of lading. Approved methods are employed for preparation, loading, blocking and securing of the equipment
before it leaves the Siemens factory. Therefore, if the equipment is received in a damaged condition, this damage to
the equipment had to occur while enroute due to conditions beyond Siemens control. If the procedure outlined
above is not followed by the consignee, purchaser, or his
agent, Siemens cannot be held liable for repairs. Siemens
will not be held liable for repairs in any case where the
work was performed prior to authorization from Siemens.
4
Receiving, Handling & Storage
Heavy weight with a high center of gravity.
Can cause death, serious injury or property
damage.
Observe all handling instructions in this
instruction manual to prevent tipping or
dropping of equipment.
Lifting and Moving
There are a number of methods that can be used in handling the breaker, which when properly employed, will not
damage the breaker. The handling method used will be
determined by conditions and available equipment at the
installation site. Refer to the breaker nameplate for the
weight. Lifting with a crane by the use of sling and lifting
lugs is the preferred method of handling; however, overhead obstructions often dictate the method to be used. Fork
lift trucks may be used prior to removal of wooden skids.
Be sure that the forklift blades pass completely under the
breaker.
60.0"
Refer to Figure 2 for lifting of the breaker using a sling.
Each power circuit breaker has provisions for attaching lifting cables. Lifting lugs are provided on each side of the
breaker, which are designed for use with a sling or hooks
of the proper size and a crane of adequate height and capacity. Refer to the breaker nameplate for the weight.
Lifting Power Circuit Breaker with Crane
Recommended lifting of power circuit breakers is by means
of cables connected to an overhead crane. The cables are
connected to the lifting lugs on the top of the breaker as
illustrated in Figure 2. A crane with sufficient height should
be used so the load angle (from horizontal) on the lifting
cable will be at least 63 degrees, when viewed from the
front or the rear. The minimum recommended cable length
to achieve proper load angle is 134 inches hook end to hook
end. A lesser angle (shorter cable) could cause damage to
the equipment.
Figure 2. Lifting Power Circuit Breaker - with Crane.
Storage
When it is necessary to store a power circuit breaker in an
area exposed to the weather or under humid conditions,
energize the space heaters provided and make certain that
any vents are uncovered to allow air to circulate. If at all
possible, install the breaker at the permanent location even
though it may be some time before the equipment is used.
It is also recommended that the breaker receive periodic
inspection during storage.
Access to the heater circuit is gained by opening the door
to the instrument panel compartment. Refer to wiring diagram drawing for space heater circuit connections. Lubricate hinges and other moving parts.
5
Installation
Location
The breaker should be located so that it is readily accessible for manual operation and inspection. Ample clearance should be provided for doors and panels to swing
open, or to be removed for servicing the breaker.
Preparation for Installation
Prior to installation of a power circuit breaker, study this
instruction book and the breaker drawings, such as outline, CT diagram, elementary diagram, connection diagram,
relay panel diagram and electrical bill of material, and
nameplate engraving. Special attention should be given
to the foundation information contained in this manual as
well as the information provided on the equipment drawings. Be sure that the foundation conforms to the requirements described in this manual and the outline drawing.
SDV breakers are shipped with the legs positioned for shipment. The legs must be removed, turned to the proper
position and set to the desired height. Directions are given
in the notice decal.
“X” Bracing Installation Instructions (for High Seismic
Applications Only)
Once the SDV breaker is set in place at the correct height
with the legs correctly installed, “X” bracing must be added
to each of the four sides. Figure 3 shows appropriate installation for the breaker at its highest elevation. Other
breaker heights will use a similar configuration. The bracing is to run from the first hole below (nearest) the cabinet
on one leg to the bottom hole of the opposite leg. When
both braces are installed on any side of the breaker, they
form the letter “X”.
The bracing is to be attached to each leg using 1 set of 0.5
inch SAE Grade No. 5 hardware (torqued to 50-75 ft-lbs.).
The “X” bracing bars have a series of overlapping holes to
allow appropriate length adjustment. The two bars forming each brace will use 2 sets of 0.5 inch SAE Grade No. 5
hardware (torqued to 50-75 ft-lbs.) installed in the overlapping holes. Refer to Figure 3 for hardware requirements.
Figure 3. “X” Bracing Installation (High Seismic Applications Only).
6
Installation
Foundation-General Requirements
Prior to installation of the breaker, careful design, planning
and construction of the foundation or base on which the
breaker will rest must be made. A thorough analysis and
careful construction may alleviate many problems at the
time of installation, and during operation. It is important
that a relatively level surface be provided capable of supporting the weight of the breaker, and 0.75 inch diameter
anchor bolts are recommended. Figures 4 illustrates typical locations for anchor bolts. No special leveling procedures are required.
Figure 4. Anchoring SDV-4A Power Circuit Breaker.
7
Electrical Connections
Hazardous voltages.
Will cause death, serious injury, and
property damage.
De-energize and properly ground high
voltage conductors before working on or
near them. The user must adjust the breaker
height to ensure compliance with safety
codes for electrical clearance.
Primary Lead Connections
The primary leads should be brought down from above
the breaker if possible, with adequate clearance to other
parts, and with the proper supports so that the breaker
bushings are not subjected to excessive strains.
The leads should be sized to have a capacity at least equal
to the maximum operating current of the circuit and within
the rating of the breaker. Connections are to be made to
the bolted terminals of the bushings and must be securely
tightened to a clean, bright surface to assure good contact.
Ground Connections
Diagonally opposite grounding pads are provided for connecting the cabinet to ground, using at least a 4/0 AWG
conductor on each pad. A good low-resistance ground is
essential for adequate protection and for proper functioning of electronic components such as protective relays.
Provision for connecting to ground pads must be made in
such a manner that a reliable ground connection is obtained. Consult latest National Electrical Code or National
Electric Safety Code for ground connection standards.
Secondary Control Wiring
All secondary control wiring installed by the factory is neatly
routed and secured in place. Make all field connections in
a similar manner. Check that the relay panel (if so equipped)
clears any additional wiring installed.
A conduit panel opening is provided in the bottom of the
relay and control compartment for the connection of control circuits. The control wires should be run separately
from high voltage wiring to prevent inductive coupling
between them and should be sized for full operating current to avoid a drop in voltage below that specified on the
nameplate. All conduits should be sealed off at their entrance to the relay and control compartment.
Terminal blocks are provided inside the relay and control
compartment for the connections necessary for the control wiring, bushing current transformers and relay panel
(if so equipped). These terminal blocks are located inside
the control compartment immediately behind the control
compartment access door.
Connection diagrams are provided with each breaker and
will be found in the pocket inside the control compartment
door.
8
Instrument Transformers
Current Transformers
Figure 5 illustrates bushing (toroidal) current transformers
installed in the primary compartment of a circuit breaker.
The circuit breaker roof bushings pass through the transformers. Type BCM current transformers are of the toroidal type mounted in the circuit breaker primary compartment. Up to two current transformers may be mounted
around each roof bushing. The bushing current transformer
connections are wired to separate terminal blocks located
in the control and relay compartment.
Hazardous voltage.
Will cause death, serious injury, and
property damage.
Current Transformers must not be operated
with an open circuit and must be either
connected to a burden or short circuited and
grounded at the terminal blocks.
2088-98
Figure 5. Type BCM CT’s Installed in primary compartment.
View shown is looking up into cabinet roof
from below
9
Installation Checks and Initial Functional Tests
Introduction
This section provides a description of the inspections,
checks and tests to perform on the circuit breaker prior to
operation.
Inspections, Checks, And Tests Without Control Power
Vacuum breakers are normally shipped with the primary
contacts open and the springs discharged. However, prior
to starting the inspection process, it is critical to
first
verify
that the control power is de-energized and the springloaded mechanisms are in the discharged condition.
De-energizing Control Power in a Power Circuit Breaker To de-energize the control power, open the disconnect device in the secondary control compartment. Figure 6 shows
the location of this disconnect in a standard breaker.
The control power disconnect device is located on the control panel in the secondary control compartment. Figure 6
shows a knife switch with fuses. Opening the knife switch
de-energizes control power to the circuit breaker. In some
breakers pullout type fuse holders or molded case breakers are used in lieu of knife switches. Removal of the fuse
holder or opening the molded case breaker accomplishes
the same result: control power is disconnected.
Spring Discharge Check (Figure 7)
Hazardous voltages and high-speed
mechanical parts.
Will cause death, serious injury or property
damage.
Read instruction manuals, observe safety
instructions and use qualified personnel.
The spring discharge check consists of simply performing
the following tasks in the order given. This check assures
that both the tripping and closing springs are fully discharged.
1. De-energize control power.
2. Press Trip pushbutton.
3. Press Close pushbutton.
4. Again press Trip pushbutton.
5. Verify Spring Condition Indicator shows DISCHARGED.
2078-98
6. Verify Main Contact Status Indicator shows OPEN.
Manual
Trip
Manual
Close
2082-98
Figure 7. Operator Control Panel of Power Circuit Breaker.
Figure 6.
2089-98
Control Power Disconnects in Power Circuit Breaker.
10
Installation Checks and Initial Functional Tests
Physical Inspections
1. Verify that the rating of the circuit breaker is compatible
with the system.
2. Perform a visual shipping damage check. Clean the
breaker of all shipping dust, dirt and foreign material.
Manual Spring Charging Check
1. Insert the manual spring charging lever into the manual
charge handle socket as shown in Figure 8. Operate the
lever up and down until the spring condition indicator
shows the closing springs are Charged, and remove the
lever from the socket.
2. Repeat the Spring Discharge Check.
3. Verify that the springs are discharged and the breaker
primary contacts are open by observing the indicator
positions.
connected to the circuit breaker. (Refer to the specific wiring information and rating label for your circuit breaker to
determine the voltage required and where the control voltage signal should be applied.) When control power is connected to the breaker, the closing springs should automatically charge if the control power disconnect (see Figure 6)
is closed.
The automatic spring charging features of the circuit
breaker must be checked. Control power is required for
automatic spring charging to take place.
1. Use the manual Close and Trip controls (Figure 7) to first
Close and then Open the circuit breaker contacts. Verify
contact positions visually by observing the Open/Closed
indicator on the circuit breaker.
2. Open control power circuit by opening knife switch
shown in Figure 6.
3. Perform the Spring Discharge Check again. Verify that
the closing springs are discharged and the primary contacts of the circuit breaker are open.
Final Mechanical Inspection and Testing
Without Control Power
Before the circuit breaker is energized, it must be thoroughly
inspected and tested. Correct any deviations before
energization.
2090-98
Figure 8. Manual Charging of Closing Springs.
As-Found and Vacuum Check Tests - Perform and record
the results of both the As-Found insulation test and the
vacuum check high-potential test. Procedures for these
tests are described in the Maintenance Section of this
manual.
Automatic Spring Charging Check
Note: A temporary source of control power and test leads
may be required if the control power source has not been
Inspection
Check the following points:
1. Make a final mechanical inspection of the circuit breaker.
Verify that the contacts are in the Open position, and
the closing springs are Discharged.
2. Make sure the breaker is properly set up and reason-
ably level on its foundation and appropriately anchored
to the foundation.
3. Check the tightness of all hardware on the cabinet, ad-
justable legs, bushings, bus bars and operator mechanism.
4. See that the operating mechanism has been properly
lubricated.
5. Blocking, supports and other temporary ties removed
from breakers, instruments, relays, etc.
6. Proper fuses correctly placed.
7. Temporary wiring jumpers (used on the secondaries of
current transformers wired to external devices, as
shown on wiring diagrams) removed.
8. Ground connections properly made.
11
Installation Checks and Initial Functional Tests
9. Incoming primary and secondary connections properly
made and checked for shorts or undesired grounds.
10. See that all covers, and bolted connectors are securely
fastened.
11. Relays coordinated with other relays and protection devices on the system. Refer to relay instructions before
making any adjustments.
12. Examine the vacuum interrupters for damage, and wipe
the interrupters and other insulating parts with a clean,
dry cloth.
13. All filters in vent areas are clean and free of shipping or
construction material.
14. Retouch any paint that has been damaged during installation.
Shipping bracing and tag between phase barriers (on units
so equipped) may damage circuit breaker.
May result in damage to equipment.
Remove bracing and tag (on units so equipped) before
energizing breaker high voltage.
Testing
High Potential tests employ hazardous
voltages.
Will cause death or serious injury.
Follow safe procedures, exclude unnecessary
personnel and use safety barriers. Keep away
from the breaker during application of test
voltages. After test completion, ground both
ends and the middle ring (if visible) of the
vacuum interrupter to dissipate any static
charges.
Note: No hazardous X-radiation is produced with closed
contacts, or with open contacts with rated operating voltage applied.
Excessive test voltages.
May result in damage to equipment.
Do not perform dielectric tests at test voltages exceeding the
ratings of the tested equipment.
1. An insulation resistance test is advisable on the control
circuit to be sure that all connections made in the field
are properly insulated.
2. A dielectric test, if possible, should be made on the high
voltage circuit for one minute at the following voltages
corresponding to the rated voltage of the equipment.
The voltage should be raised gradually and the circuit
under test should sustain the voltage for one minute.
When the test is performed with the breaker open, the
integrity of the vacuum interrupter will also be verified.
If these levels cannot be sustained and there is no other
source for the failure, the interrupter must be replaced.
Rated
Maximum
Voltage
kV (rms)
15.5
25.8, 27.6
Power
Frequency
Withstand
kV (rms)
50
60
Field Test Voltage
kV (rms) kV (dc)
37.5
45
53
63.6
Note: The DC test voltage is given as a reference only. It
represents values believed to be appropriate and approximately equivalent to the corresponding power frequency
withstand test values specified for each voltage rating. The
presence of this column in no way implies any requirement
for a DC withstand test on AC equipment or that a DC withstand test represents an acceptable alternative to AC withstand tests. When making DC tests, the voltage should be
raised to the test value in discreet steps and held for a period of one minute.
Vacuum interrupters may emit X-radiation.
Can cause serious injury.
X-rays can be produced when a high voltage
is placed across two circuit elements in a
vacuum.
Keep personnel more that six (6) feet away
from a circuit breaker under test. All normal
metallic doors and panels must be installed
during tests.
Field Dielectric Tests are recommended when new units
are installed, or after major field modifications. The equipment should be put in good condition prior to the field test.
It is not expected that equipment shall be subjected to these
tests after it has been stored for long periods of time or has
accumulated a large amount of dust, moisture, or other
contaminants without being first restored to good condition.
12
Interrupter/Operator Description
Introduction
Type SDV circuit breakers include three vacuum interrupters, a stored energy operating mechanism and necessary
electrical controls. On some circuit breaker ratings, insulating barriers are located between the vacuum interrupters.
This section describes the operation of each major subassembly as an aid in the operation, installation, maintenance
and repair of the type SDV vacuum circuit breaker.
Vacuum Interrupters
The operating principle of the vacuum interrupter is simple.
Figure 9 is a cutaway view of a typical vacuum interrupter.
The entire assembly is sealed after a vacuum is established.
The interrupter stationary contact is rigidly attached to the
end cap which serves as one terminal of the interrupter.
The interrupter movable contact is free to move in a guide,
and is connected to the operating mechanism by a system
of linkages. The metal bellows assembly provides a secure seal around the movable contact, preventing loss of
vacuum while permitting movement of the contact.
Fixed
Contact
Current
Connection
When the two contacts separate, an arc is initiated which
continues conducting up to the following current zero. At
current zero, the arc extinguishes and any conductive metal
vapor which has been created by and supported the arc
condenses on the contacts and on the surrounding vapor
shield. Contact materials and configuration are optimized
to achieve arc motion and to minimize switching disturbances.
The arc drawn in the vacuum breaker is not cooled. The
metal vapor plasma is highly conductive and the resulting
arc voltage only attains values between 20V and 200V. For
this reason and because of the short arcing times, the arc
energy developed in the breaker is very small. This also
accounts for the long life expectancy of the vacuum interrupter.
Phase barriers are provided on all 25.8kV and 27.6kV class
type SDV units as shown in Figure 10. These plates of insulating material are attached to the circuit breaker housing and provide suitable electrical insulation between the
vacuum interrupter primary circuits. Phase barriers are not
required in 15.5kV class type SDV units, but are available
as an option.
Ceramic
Insulator
Arc Shield
Fixed
Contact
Moving
Contact
Ceramic
Insulator
Metal
Bellows
Guide
Moving
Contact
Current
Connection
Figure 9. Cutaway View of SDV Vacuum Interrupter.
2097-98
Figure 10. Breaker with Interphase Barriers.
Stored Energy Operating Mechanism
The stored energy operating mechanism of the SDV circuit
breaker is an integrated arrangement of springs, solenoids
and mechanical devices designed to provide a number of
critical functions. The energy necessary to close and open
the contacts of the vacuum interrupters is stored in powerful tripping and closing strings. These springs are normally
charged automatically, but there are provisions for manual
charging. The operating mechanism that controls charging, closing and tripping functions is fully trip-free, i.e.,
spring charging does not automatically change the position of the primary contacts, and the closing function may
be overridden by the tripping function at any time.
13
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