Power Switching Centers
General
A metal-enclosed Power Switching
Center incorporating load interrupter
switches and power fuses has one single
assembly rating. All major components
such as switches, fuses, bus, and operating mechanism are coordinated electrically and mechanically, permitting economical high-voltage switching and protection.
A key feature of this system is the
“Building Block” approach to Power
Switching Center design which allows
almost unlimited application flexibility.
This concept provides a simple solution to
specific present and future requirements.
Features:
쐍 Switch interrupter, 600A or 1200A
continuous and load break capability,
with 40 kA or 61 kA close and latch
ratings.
쐍 4.16 kV or 13.8 kV nominal voltages,
60 kV and 95 kV BIL.
쐍 600A and 1200A main bus ratings.
쐍 Available with either current limiting
fuses or expulsion fuses.
쐍 Indoor and outdoor construction.
쐍 Customer or Power Company metering units.
쐍 Electrical operation with automaticthrowover of two incoming sources.
쐍 Design that include potheads, roof
bushings, special terminators and
lightning arresters.
CSI Section 16431
Siemens Electrical Products and Systems
Specification Guide
69
5
Power Switching
Centers
Optional Features and Accessories
쐍 UL Listed Ratings
쐍 Shaft Connected Auxiliary Switches
쐍 Solenoid Instantaneous Open and / or
Close
쐍 Manual Instantaneous Open and / or
Close
쐍 Motor Operators to Close and Open
쐍 Spring Charged Indicator Switch
쐍 Operation Counter
쐍 Key Interlocks
쐍 Lightning Arresters
쐍 Weatherproofing
쐍 Special Terminations
쐍 Mechanical Interlocks to Grounding
Switch
쐍 Grounding Blades
쐍 Automatic Transfer Systems
쐍 CT’s, PT’s, CPT’s — Drawout and
Stationary
쐍 Instrumentation — Ammeter,
Voltmeter, Watthour Meter, etc.
쐍 Anti-Single Phasing
쐍 Mimic Bus
Power Switching Centers
General
A metal-enclosed Power Switching
Center incorporating load interrupter
switches and power fuses has one single
assembly rating. All major components
such as switches, fuses, bus, and operating mechanism are coordinated electrically and mechanically, permitting economical high-voltage switching and protection.
A key feature of this system is the
“Building Block” approach to Power
Switching Center design which allows
almost unlimited application flexibility.
This concept provides a simple solution to
specific present and future requirements.
Features:
쐍 Switch interrupter, 600A or 1200A
continuous and load break capability,
with 40 kA or 61 kA close and latch
ratings.
쐍 4.16 kV or 13.8 kV nominal voltages,
60 kV and 95 kV BIL.
쐍 600A and 1200A main bus ratings.
쐍 Available with either current limiting
fuses or expulsion fuses.
쐍 Indoor and outdoor construction.
쐍 Customer or Power Company metering units.
쐍 Electrical operation with automaticthrowover of two incoming sources.
쐍 Design that include potheads, roof
bushings, special terminators and
lightning arresters.
CSI Section 16431
Siemens Electrical Products and Systems
Specification Guide
69
5
Power Switching
Centers
Optional Features and Accessories
쐍 UL Listed Ratings
쐍 Shaft Connected Auxiliary Switches
쐍 Solenoid Instantaneous Open and / or
Close
쐍 Manual Instantaneous Open and / or
Close
쐍 Motor Operators to Close and Open
쐍 Spring Charged Indicator Switch
쐍 Operation Counter
쐍 Key Interlocks
쐍 Lightning Arresters
쐍 Weatherproofing
쐍 Special Terminations
쐍 Mechanical Interlocks to Grounding
Switch
쐍 Grounding Blades
쐍 Automatic Transfer Systems
쐍 CT’s, PT’s, CPT’s — Drawout and
Stationary
쐍 Instrumentation — Ammeter,
Voltmeter, Watthour Meter, etc.
쐍 Anti-Single Phasing
쐍 Mimic Bus
Power Switching Centers
Switch Components
햲 Stationary Contacts
Hinge and jaw contacts are heavy
castings capable of absorbing and
dissipating the heat from the large
short circuits which may be encountered. The contact pressure is maintained on these contacts with
spring washers especially adapted
to maintain suitable pressure. The
retaining nuts prevent joint loosening due to vibration, shock, and
operation. Special sealing designs
effectively prevent the entrance of
dust or dirt into the contact making
area. The contact area maintains
optimum current carrying ability and
decreases heating.
햳 Arcing Chambers
Stationary arcing contacts are located inside the arc chutes. They
remain at the same potential as the
main stationary contact. As the
quick break blade is withdrawn
from the arc chute, it parts with the
stationary arcing contacts inside the
chute. The chute is made from a
specially prepared compound that
evolves a gas to quickly extinguish
the arc.
햴 Switch Insulators
The insulating support for the main
hinge and jaw contacts has excellent dielectric characteristics, is nontracking, non-combustible, nonhygroscopic, won’t age, and is easy
to clean.
햵 Stored Energy Mechanism
The opening and closing springs
provide for quick make (rated fault
closing) and quick break (rated load
interruption). The switch mechanism shaft is driven by a chain and
sprocket from the front operating
handle. As the handle is rotated, it
is directly connected to a sprocket
which in turn chain drives the opening spring to a “charged” position.
As the operator continues to rotate
the handle, the charged spring is
General
driven off-center by the chain and
releases its energy into rotating the
operating shaft to operate. The
switch blades will not move, in
either a closing or opening direction, until the closing spring causes
rotation in the operating shaft. Antifriction bearings provide for a
smooth operating performance. The
handle housing has provisions for
multiple padlocking. The handles
are non-removable, self-latching and
padlockable in the open or closed
positions. “Telltale” indicators show
the switch position.
햶 Structure
Welded frame design provides
greater structural strength.
햷 Quick Break Blade
The quick-break arcing blade is
made of a special high-strength,
high-conductivity material tipped
with a tungsten arcing material. A
quick-break spring charging mechanism is mounted on the blade that
with an assist from the arcing
chamber stationary contacts, prevents the opening until after the
main contact gap is at the proper
clearance spacing. Arcing blades
and tips are designed to prevent
arcing blades from hanging up in
the stationary arcing contacts.
햸 Main Moveable Blades
These blades are made of hard
drawn copper bars, silver-plated at
the contact points for long dependable operation.
Power Switching
Centers
5
70
Siemens Electrical Products and Systems
Specification Guide
CSI Section 16431
Power Switching Centers
Ratings
Table 5.1
Technical
Indoor Air Interrupter Switch Ratings
Voltage Ratings햲 햳
Nominal
kV, RMS
햲
햳
Current Ratings햲 햳
Maximum
Design
kV, RMS
1-Min.
Power Frequency
Withstand
kV, RMS
1.2 × 50
Impulse
Withstand
kV, BIL
4.16
4.76
19
60
7.2
8.25
26
75
13.8
15.0
36
95
14.4
15.5
50
110
23.0
25.8
60
125
34.5
38.0
80
150
34.5
38.0
95
200
Continuous
Amperes
RMS
600
1200
600
1200
600
1200
600
1200
600
1200
600
1200
600
1200
Load
Interrupt
Amperes
RMS
600
1200
600
1200
600
1200
600
1200
Short-Time Ratings
Momentary
Asymmetrical
kA, RMS
40
61
40
61
40
61
40
61
2-Sec
kA, RMS
25
38
25
38
25
38
25
38
FaultClose
Asymmetrical
kA, RMS
40
61
40
61
40
61
40
61
600
40
25
40
600
40
25
40
600
40
25
40
Ratings apply to Stored Energy Operated Switches.
Special ratings available — consult Siemens.
UL and MET listings for specific application — consult Siemens.
Table 5.2
Power Fuses
Max
Design
KV
System
KV
Interrupting Ratings
RMS
Symmetrical
Amperes
Maximum Continuous Current
Nom. Equiv.
3Ø-MVA햲
Single
Barrel
Double
Barrel
Triple
Barrel
200E
200E
200E
125E
125E
125E
125E
125E
125E
125E
125E
400E
400E
400E
250E
250E
250E
250E
250E
250E
250E
250E
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
600E
750E
—
—
—
—
—
—
—
—
Current Limiting Fuse
5.5
15.5
5.5
15.5
2.4
4.16
4.8
6.9
7.2
11.5
12.0
12.47
13.2
13.8
14.4
2.4
4.16
4.8
4.8
4.8
4.8
6.9
7.2
11.5
12.0
12.47
13.2
13.8
14.4
50,000
50,000
50,000
40,000
40,000
40,000
40,000
40,000
40,000
40,000
40,000
60,000
60,000
60,000
60,000
50,000
50,000
50,000
50,000
40,000
40,000
40,000
40,000
40,000
40,000
208
360
416
480
500
800
830
860
910
955
1000
250
430
500
500
500
500
596
620
800
830
860
910
955
1000
10E
through
150E
—
—
—
10E
through
100E
175E
through
450E
—
—
—
—
125E
through
200E
Expulsion Fuse — S & C Type SM or Westinghouse Type RBA
15.5
17
17,200
37,500
14,000
12,500
25,000
34,000
125
270
335
300
600
815
200E
400E
200E
200E
400E
400E
—
720E햳
—
—
—
—
—
—
—
—
—
—
5
Power Switching
Centers
15.5
4.8
4.4
14.4
14.4
14.4
13.8
The 3 phase MVA = 1.73 × (kV) × (fuse interrupting kA)
햳 Double Barrel Fuse. Consult Siemens for dimensions.
햲
CSI Section 16431
Siemens Electrical Products and Systems
Specification Guide
71
Power Switching Centers
Non-UL / ANSI Standards
The following figures depict the basic
standard units available. For most applications, 42 in. (1067 mm) deep front
accessible units will be adequate. The
Dimensions
58 in. (1473 mm) deep front and rear
accessible unit will be required for the
following conditions:
쐍 Upfeed with main bus at top
쐍
쐍
Downfeed with pothead cable
terminations
Both current and potential transformers in a switch unit
42 Inch (1067 mm) Deep Units (Front Accessible)햲 Downfeed 5kV and 15kV
Figure 1
Entrance Unit
No Switch햳
Figure 4
Feeder Unit
Unfused Switch
Figure 3
Entrance Unit
Fused Switch햴
Figure 2
Entrance Unit
Unfused Switch
Figure 5
Feeder Unit
Fused Switch
42 Inch (1067 mm) Deep Units (Front Accessible)햲 Upfeed 5kV and 15kV
Figure 6
Entrance Unit
No Switch햳
Figure 8
Entrance Unit
Fused Switch
Figure 7
Entrance Unit
Unfused Switch
Figure 9
Feeder Unit
Unfused Switch햵
Figure 10
Feeder Unit
Fused Switch햴
햵
햲
42 Inch (1067 mm) Deep Units (Front Accessible) Tie and Metering 5kV and 15kV
Figure 11
Tie unit
Unfused Switch
Figure 12
Tie unit
No Switch
Figure 13
Metering Unit햶
Figure 14
Transition to Motor Control
or Metal-Clad Switchgear햷
58 Inch (1473 mm) Deep Units (Front and Rear Accessible)햸 Miscellanous 5kv and 15kv
Figure 15
Feeder Unit-Upfeed햸
Unfused Switch
Power Switching
Centers
5
햲
Figure 16
Feeder Unit-Upfeed햸
Fused Switch
Switch units can be furnished with up to 3 current
transformers or 2 potential transformers and 3 distribution class surge arresters. Contact Siemens for
dimensional information.
햳 If cable terminations are potheads, a 58 in. (1473 mm)
deep unit is required with rear access to the potheads.
햴 Current limiting fuses only.
72
Figure 18
Cable-In-Out Unit
Fused Switch
Figure 17
Cable-In-Out Unit
Unfused Switch
햵
A feeder unit with upfeed cable can be finished in a 42
in. (1067 mm) deep unit with the main bus at the bottom (See Figures 9 and 10). This results in an Inverted
Switch (Figure 9) or Inverted Fuse Switch (Figure 10)
that may not be desirable. In such a case, the configuration of Figures 15 or 16 can be furnished.
햶 For power company meter unit, width will be as
needed to comply with power company requirments.
Siemens Electrical Products and Systems
Specification Guide
햷
Bus position to match location in motor control or
switchgear.
58 in. (1473 mm) deep units required only when
Figure 9 or Figure 10 are not desired.
Note: For equipment that must be UL labeled, enclosures must be minimum 44 in. (1117 mm) deep
and 60 in. (1524 mm) deep versus 42 in. (1067
mm) deep and 58 in. (1473 mm) deep.
햸
CSI Section 16431
Power Switching Centers
UL and ANSI Units
Dimensions
Figures on this page depict the basic and standard units available. For most applications, 44 in. (1118 mm) deep front accessible
units will be adequate. The 60 (1524 mm) deep front and rear accessible units will be required for the following conditions:
쐍 Upfeed with the main bus at the top
쐍 Downfeed with the main bus at the bottom
쐍 Downfeed with Pothead cable terminations
쐍 Both current and potential transformers in a switch unit
햷
44 Inch (1118 mm) Deep Entrance and Feeder Units 5kV and 15kV
90 in.
(2886 mm)
44 in.
36 in. (1118 mm)
(914 mm)
Entrance Unit
No Switch
Downfeed햲
Entrance Unit
Unfused Switch
Downfeed햲
Tie Unit
Unfused Switch
햲
햳
햴
햵
햶
햷
Entrance Unit
Fused Switch
Upfeed햳 햴햶
16 in. (406 mm)
Transition Unit
No Switch
Feeder Unit
Unfused Switch
Downfeed햲
Metering Unit 햵
Feeder Unit
Fused Switch
Downfeed햳 햴햶
Entrance
Metering Unit
Invert for Upfeed.
Invert for Downfeed.
Inverted Unit only available with current limiting fuses. An Inverted Fused Switch may not be desirable.
For power company meter unit, width will be as needed to comply with power company requirements. Refer details to Siemens for review.
Unfused switch section available.
All sections designed for use with Eye Bolt Lugs. Consult Siemens for other termination requirements.
Note: For equipment that must be UL labeled, enclosures must be minimum 44 in. (1117 mm) deep and 60 in. (1524 mm) deep
versus non UL labeled equipment 42 in. (1067 mm) deep and 58 in. (1473 mm) deep.
5
Power Switching
Centers
CSI Section 16431
Siemens Electrical Products and Systems
Specification Guide
73
Power Switching Centers
Guide Form Specifications
General
These specifications describe metalenclosed load interrupter switchgear
assemblies consisting of fused and / or
unfused load interrupter switches and auxiliary devices as shown on drawing no.
_____________ and as described herein.
Ratings
The load interrupter switchgear will be
nominally rated (4.16kV nominal, 4.76kV
maximum, 60kV BIL) (13.8kV nominal,
15kV maximum, 95kV BIL). The equipment will be designed to withstand and
protect against the effects of a fault condition of ______MVA at ________kV.
Load interrupter switches shall be:
Manual operated “close” and “open” in
Units___________. Motor operated spring
charging mechanism with latch and electrical release for “close” and “open” in
Units_________. Switches shall be (600)
(1200) ampere continuous in Units ____
and (600), (1200) in Units ______.
Momentary and fault close rating shall be
(40,000) (61,000) amperes. Fused switch
continuous, fault close and interrupting
ratings shall be dependent upon the specified fuse characteristics. Main bus rating
shall be (600) (1200) amperes.
Power Switching
Centers
5
Enclosure Construction
The load interrupter switchgear shall be
(indoor) (outdoor) construction. Units shall
be of individual frames of bolted steel
construction. Full side sheets shall separate adjacent units. Each frame shall be
adequately braced and vented to function
properly under both normal operating and
short circuit conditions.
For non-UL, access to switch or switch /
fuse compartments will be through single
front door. The door shall be Kirk Key
interlocked with the switch mechanism
so that the switch must be in the open
position before the door can be opened.
Conversely, the door must be closed and
locked and the key returned to the switch
before the switch can be closed. Also
included is a provision for padlocking. An
inner plexiglass barrier in front of each
switch is to be provided to prevent inadvertent access to the switch when changing fuses.
For UL Listed, access to switch and / or
fuse compartments will be through separate doors. The doors shall be mechanically interlocked with the air interrupter
switch to prevent closing the switch with
the door open and to prevent opening the
door with switch closed. Kirk Key type
interlock is an optional feature. Also
included is a provision for padlocking.
74
Protective hinged screen steel barriers,
retained with captive thumb screws, shall
be provided to prevent inadvertent access
to the switch when changing fuses.
Where access to the rear is required, easily removable panels with handles shall
be provided.
An ample size safety window shall be
provided in the door of each switch unit
to allow observance of the position of the
switch blades.
Where meters and instruments are provided, they shall be isolated from any
high voltage equipment by a grounded
steel barrier.
All external surfaces shall be cleaned,
treated, and painted with a corrosionresistant paint. Color will be ANSI No. 61
light gray.
Danger and / or Warning labels shall be
attached to the switchgear in accordance
with industry standard and OSHA requirements.
Load interrupter switchgear assemblies
shall be tested at the factory in accordance with NEMA and ANSI standards
prior to shipment.
The equipment will be shipped in sections as required to meet manufacturing
and shipping restrictions. The sections
will be constructed to permit lifting,
rolling, or jacking in the field.
Load Interrupter Switches
Load interrupter switches shall be threepole, gang-operated stored energy type
quick-make, quick-break operation.
Incoming and feeder switches are to be
arranged with hinged end of the switch
blade “dead” in the open position. Fuses,
when specified, will be located on hinged
side of the switch. Switch handles shall
be non-removable and located on front of
the unit.
The interrupter switch is to have separate
main and arcing contacts to provide maximum endurance for fault close and load
interrupting duty. The arcing contacts
shall be spring loaded so that on opening
they break after the main contacts, and
on closing make after the main contacts.
Arc interruption is to take place in an
interruption chute.
Fuses
Fuses can be either current limiting or
expulsion type. Current limiting is preferred because let-through current is limited and no expulsion of gases occur on
interruption. Depending on choice, specify one of the following:
Siemens Electrical Products and Systems
Specification Guide
Specifications
Current Limiting Fuses: Fuses shall be
of the fast replaceable current limiting
type which will operate without explosive
noise, expulsion of gas vapor, or foreign
matter from the tube. The fuses shall be
coordinated to meet the short circuit rating and continuous current ratings specified. Each fuse shall have an indicator to
show if it has blown. Fuse contact shall
be retained by a high-pressure locking
device to prevent slip-out or blow-out
during operation.
Expulsion Fuses: Fuses shall be the
expulsion type. The gases emitted on
interruption shall be controlled and
silenced by chambers designed for that
purpose. They shall have an rms symmetrical interrupting rating of________
amperes at the operating voltage ____.
Each fuse shall have an indicator to show
it has blown. Fuses shall be furnished in a
disconnect type mounting for ease in
removal. Fuses shall be renewed using
replacement fuse units, Fuses shall be
S&C type SM or Westinghouse type
RBA.
Main and Ground Bus
For non-UL, the main and ground bus will
be bare tin-plated aluminum with a continuous and momentary rating as specified above. The main bus will be mounted on stand-off insulators. The ground
bus shall have a short circuit rating equal
to that of the integrated assembly and
shall extend the full length of the
switchgear line-up.
For UL Listed, the three-phase copper
bare main bus shall have continuous rating of 600, 1200, or 2000 amperes and
shall be braced to withstand the full
effect of a short circuit within the ratings
of the interrupter switch and / or fuses
applied to the equipment. All bus bar
joints shall be plated silver on copper bus.
Supports for the main bus shall be porcelain above 5kV.
Each unit shall also contain a copper
ground bus, accessible for connection to
ground. Both ground bus and main bus
shall have provisions for extension in
either direction for future additions.
Where bus bars are insulated for reliability
or to allow closer spacing, insulation shall
be extruded sleeving. Where joints are
made, they shall be sealed with molded
covers, or a void-free filler covered with
suitable layers of insulation tape and
mechanic protective tape.
Optional Features
Furnish optional features per page 69 for
basic list of options.
CSI Section 16431