Surge Protective Devices
Chris Martin
Sales Manager
Surge Protection Devices
Where surges originate
80% - Internal Disturbances
• Load switching
• Variable frequency drives
• Lighting and air handlers
20% - External Disturbances
– Utility load switching
• Smart grid
– Lighting strikes
• Cloud to cloud
• Cloud to ground
• Cloud to man-made object
Isokeraunic Map
Surge damage
1.
Cause disruptions in computer
signals and processors
2.
Degrade component junctions
causing “random” delayed failure
3.
Cause instant damage to electrical
components
How SPDs work
• Cross Section of a MOV
20,000v
Eliminated Voltage
1,500v
Clamped Voltage
•
Clamped Voltage
Turn on Voltage
•
Turn on Voltage
SPD
150v
Source
Load
(depends on surge level)
(always the same)
UL 1449 2nd Edition 2005
• 2nd Edition 2005 Revision (effective 2/9/2007)
• Expanded OVERVOLTAGE Testing
(2 x nominal voltage)
• Added 7 hour intermediate fault current levels
10 amps
100 amps
500 amps
1000 amps
• SPD manufacturers pass this new requirement by
either adding fusing per MOV, thermal sensing
technology, or requiring an external OCPD for the
safe removal of the SPD
20 mm MOV Surge Current Rating Curve
10000
1
2
10
Surge Current
1000
10 2
10 3
10 4
100
10 56
10
Indef.
10
1
Impulse Duration (Microseconds)
10
100
20 microseconds
1000
10000
5000 microseconds
At 20 micro-seconds the MOV can protect up to 6500Amps (1 time) at 5000
micro-seconds that same MOV can only protect up to 30Amps
UL 1449 3rd Edition
• Creates SPD types (Type1, Type2, Type3, Type4)
–
Surge Arrestor, Lightning Arrestor, TVSS
• New Nominal Discharge Surge Current test, In Thermal
“stress” test
• Tested MCOV per mode. No longer a claimed value
• SVR 6kV, 500A replaced with VPR 6kV, 3kA
• Surge Arrestor incorporated into UL1449 as Type 1 device
SPD Types - UL 1449 3rd Ed.
Competitors Surge Arrestor
Needs a breaker to
pass UL testing
Type 1 SPD (LINE SIDE)
Permanently Connected SPD –
Installation between the secondary of
the service transformer and the LINE
side of the service disconnect over
current device, as well as the LOAD
side, including watt-hour meter
socket enclosures. (Not exceeding
1000V)
Secondary Surge
Arrestor
SPD Types (Continued)
Type 2 SPD (LOAD SIDE)
Permanently Connected SPD intended for installation on the LOAD side
of the service disconnect over current device, including SPDs located at
the branch panel.
SPD Types (Continued)
Type 3 SPD
Point of utilization SPDs, installed a minimum of 10 meters (30 feet)
from the electrical service panel, for example cord connected, direct
plug-in (DPI), receptacle type and SPDs installed at the utilization
equipment being protected.
SPD Types (Continued)
Type 4 SPD
Component SPDs, including discrete components as well as
component assemblies.
(Note: as proposed the 3rd Edition will allow Type 4 SPDs to be tested and
applied where Types 1 and 2 are allowed)
Measured Limiting Voltage (MLV)
• All SPD Types are to be tested to 6kV/3kA - 3 pulses per
mode with applied voltage. VPR is determined by
averaging results. (Per 34.9 and Table 34.1)
• SVR 6kV/500A
Good reading 400v or 500v
• VPR 6kV/3kA
Good reading 700v, 800v, 900v, or as
high as 1000v
• Higher surge current results in higher clamping voltages
Nominal Discharge Current Test (In)
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Type 1:
Choose 10kA or 20kA/Mode
Type 2:
Choose 3kA, 5kA, 10kA, or 20kA
Surge unit at chosen surge value
Apply chosen over voltage to unit within 1s for 1min
2008 NEC
•
COPS - Critical Operations Power Systems
– NEC guideline to increase protection and reliability of the power
infrastructure for critical facilities
•
What are Critical Facilities?
– Government agency (Federal, state, municipal)
– Facility engineering
– Facilities that if destroyed may disrupt:
• National security, the economy, public health, or safety
•
To include
– HVAC, fire alarm, security, communications, and signaling
2008 NEC
• NEC Section 708.20 (D)
• Surge Protective Devices must be used to comply
• SPDs must be used for each voltage at the facility
– Service Entrance
– Distribution panels
Improving SPD Installed
Performance
• How does lead length affect the installed
performance of a surge protective device?
• Does an internally mounted SPD outperform
an externally mounted SPD?
• Impact of upstream OCPDs
How are SPDs Tested?
• 6 inches outside of the enclosure
The surge is injected here
6 inches
Surge Protective
Device
Phase A
Phase B
Phase C
Clamping characteristics
are recorded
by an Oscilloscope
• Phase length + Neutral length affect the performance of the
SPD
Internally Mounted Lead Length
The surge must travel
through the phase
through the SPD
and through Neutral
Phase length
+ Neutral length
= SPD clamping
voltage
Lead Length
• Lead length affects the installed performance of a SPD
• 10’ sections of cable (commonly used sizes)
– 14 AWG
– 10 AWG
– 6 AWG
• Apply IEEE defined 20kV/10kA surge
• Measure the voltage drop
Wire size
• Voltage drop across 10 foot cable when exposed to a
20kV/10kA surge
– 14 AWG 2,650v
– 10 AWG 2,400v
– 6 AWG 2,350v
• What does this do to the installed performance of the
SPD?
Lead Length Impact
4000v
3000v
Voltage
Seen
At load
2000v
1000v
1'
SPD
2'
3'
4'
5' Lead length 7'
8'
9'
10'
LOAD
The Low Impedance Cable
Inside View of one end of the Low Z Cable
Ground Cable
Termination 30"
Neutral Cable Termination
30"
Three colored leads
Top
Insulation
Layer
Top Braid
Layer (Ground)
Ground Coupler
Ground Split Ring
Middle
Insulation
Layer
Internal Braid
Layer (Neutral)
Neutral Coupler
Neutral Split Ring
HPI Voltage Drop
• Voltage drop across 10 foot cable when exposed to a
20kV/10kA surge
– 10 AWG 560v
– 6 AWG
560v
Lead Length Impact
83% improvement
4000v
3000v
#14 AWG
Voltage
Seen
At load
1000v
HPI Cable
1'
SPD
2'
3'
4'
5' Lead length 7'
8'
2000v
9'
10'
LOAD
Breaker Impact
• Does a breaker upstream of an SPD limit the effectiveness of the
SPD?
• Breakers have surge trip and surge failure values: The SCCR value
is based on 60Hz current, not surge current!
• Type 2 SPDs must be installed behind a breaker!
Trip kA
CB Pulse Performance
Fail kA
160
140
Pulse kA
120
These values are based on testing
performed by Current Technology’s
Surge generator on commercially
available off the shelf breakers.
100
80
60
40
20
0
15
30
40
CB Rating
60
100
The ISM
Integrated Suppression Module
ISM Design
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300kA Model
Utilizes TPMOV technology
Bus Bar construction
N-G filter (removable)
Improved L-N Filter
100% surge rated
Reduced weight
Individually monitored MOVs
Advanced monitoring
The TPMOV
DRC contacts
DRC switch
50mm MOV
Thermal spring
Barrier
Barrier spring
Select3 (SL3)
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THE SERVICE ENTRANCE
SURGE PROTECTOR OF CHOICE
Listed by UL to UL1449 3rd Edition
as a Type 1 SPD
50kA, 100kA, 150kA, 200kA, 250kA,
300kA per mode
TPMOV/Selenium Hybrid
– Option for enhanced selenium
Test reports for single and repetitive
surge testing
Surge rated disconnect with line side
barrier
DTS-2 internal test port option
6 levels of monitoring
20 year warranty
TransGuard3 (TG3)
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Listed by UL to UL1449 3rd Edition
as a Type 1 SPD
50kA, 100kA, 150kA, 200kA, 250kA,
300kA per mode
TPMOV Technology
RoHS compliant
Test reports for single and repetitive
surge testing
Surge rated disconnect with line side
barrier
DTS-2 internal test port option
6 levels of monitoring
15 year warranty
Panel Extension (PX3)
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Listed by UL to UL1449 3rd Edition
as a Type 1 SPD
50kA, 100kA, 150kA, 200kA per
mode
9 inch height for 50kA-100kA units
TPMOV Technology
RoHS compliant
Test reports for single and repetitive
surge testing
DTS-2 internal test port option
6 levels of monitoring
15 year warranty
DTS-2 Tester
The ONLY proactive test kit for SPDs on the market
• Updated test card for both MOV and TPMOV
based products with or without selenium
• Validates “health” of surge components
• Compares installed clamping performance to
original factory values
• Detects and provides early warning for stressed
components
• Can be used to evaluation competitive products
performance
• Part of any startup or commissioning
• Validates integrity of upstream Xo bond
M1 Standard Monitoring
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LED indication per phase
Audible alarm
Alarm silence switch
2 sets of dry relay contacts
Tri-colored LED that reports on % protection
– Green = 75% or greater
– Orange = 75% - 40%
– Red = 40% or less
– Extinguished = Loss of protection
M2 Monitoring Option
• All M1 monitoring options
• Surge counter
M3 Option
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New Mastermind
Includes all M1 monitoring features
Time/Date stamp
Duration and Magnitude
User settable thresholds
Tracks
– Sags, swells surges, dropouts,
outages, THD, frequency, Volts
RMS, % protection
Local character display
ModBus remote communications
M4E Option
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New Mastermind
Includes all M1 monitoring features
Time/Date stamp
Duration and Magnitude
User settable thresholds
Tracks
– Sags, swells surges, dropouts,
outages, THD, frequency, Volts
RMS, % protection
Local character display
ModBus and Ethernet remote communications
Web based interface
M6E Option
M5 Option
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Adds Large Graphics Display
Includes all M1 monitoring features
Time/Date stamp
Duration and Magnitude
User settable thresholds
Tracks
– Sags, swells surges, dropouts,
outages, THD, frequency, Volts
RMS, % protection
Local character display
ModBus remote communications
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Adds Large Graphics Display
Includes all M1 monitoring features
Time/Date stamp
Duration and Magnitude
User settable thresholds
Tracks
– Sags, swells surges, dropouts,
outages, THD, frequency, Volts
RMS, % protection
Local character display
ModBus and Ethernet remote communications
Web based interface
Review
• Specs need to be Updated to include new requirements
outlined in UL1449 3rd Edition
• Externally mounted SPDs offer a safer installed alternative
without affecting performance
• External OCPDs can have an affect on the installed
performance of the SPD
• Ask for documentation. Single surge, repetitive surge, and
tested MCOV value
Questions?