surge protective devices

Surge Protective Devices

Chris Martin Sales Manager

Surge Protection Devices

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

Where surges originate

Isokeraunic Map

1. Cause disruptions in computer signals and processors

2. Degrade component junctions causing “random” delayed failure

3. Cause instant damage to electrical components

Surge damage

How SPDs work

• Cross Section of a MOV

• Clamped Voltage (depends on surge level)

• Turn on Voltage (always the same)

SourceLoad

SPDTurn on Voltage

Clamped Voltage

150v

1,500v

20,000v

Eliminated Voltage

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 levels10 amps100 amps500 amps1000 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

Su

rge

Cu

rren

t

Impulse Duration (Microseconds)

12

10

10 2

10 3

10 4

10 5

10 6

Indef.

20 microseconds 5000 microseconds

20 mm MOV Surge Current Rating Curve20 mm MOV Surge Current Rating Curve

1

10

100

1000

10000

10 100 1000 10000

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.

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

Competitors Surge Arrestor

Needs a breaker to pass UL testing

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.


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.


Type 4 SPDComponent 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

• 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

Nominal Discharge Current Test (In)

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

Surge Protective Device

Phase A Phase B Phase C

6 inches

The surge is injected here

Clamping characteristics are recorded

by an Oscilloscope

• Phase length + Neutral length affect the performance of the SPD

The surge must travel through the phase

through the SPDand through Neutral

Phase length + Neutral length = SPD clamping

voltage

Internally Mounted Lead Length

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

SPD LOAD

Lead length

VoltageSeen

At load

1' 2' 3' 4' 5' 7' 8' 9' 10'

1000v

2000v

3000v

4000v

The Low Impedance Cable

Ground Cable Termination 30"

Neutral Cable Termination 30"

Top Insulation

LayerTop Braid

Layer (Ground)

Ground Coupler

Ground Split Ring

Internal Braid Layer (Neutral)

Neutral Coupler

Neutral Split Ring

Three colored leads

Middle Insulation

Layer

Inside View of one end of the Low Z Cable

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

SPD LOAD

Lead length

VoltageSeen

At load

1' 2' 3' 4' 5' 7' 8' 9' 10'

1000v

2000v

3000v

4000v

HPI Cable

#14 AWG

83% improvement

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!CB Pulse Performance

0

20

40

60

80

100

120

140

160

15 30 40 60 100

CB Rating

Puls

e k

A

Trip kA

Fail kA

These values are based on testing

performed by Current Technology’s

Surge generator on commercially

available off the shelf breakers.

The ISMIntegrated Suppression Module

ISM Design

• Utilizes TPMOV technology

• Bus Bar construction

• N-G filter (removable)

• Improved L-N Filter

• 100% surge rated

• Reduced weight

• Individually monitored MOVs

• Advanced monitoring

300kA Model

The TPMOV

Thermal spring

Barrier

50mm MOV

DRC switch

DRC contacts

Barrier spring

Select3 (SL3)

• 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

THE SERVICE ENTRANCE SURGE PROTECTOR OF CHOICE

TransGuard3 (TG3)


• 50kA, 100kA, 150kA, 200kA, 250kA, 300kA per mode

• TPMOV Technology

• RoHS compliant


• Surge rated disconnect with line side barrier




Panel Extension (PX3)


• 50kA, 100kA, 150kA, 200kA per mode

• 9 inch height for 50kA-100kA units

• TPMOV Technology

• RoHS compliant





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

• 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

• 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

• New Mastermind• Includes all M1 monitoring features• Time/Date stamp • Duration and Magnitude• User settable thresholds• Tracks


• Local character display• ModBus and Ethernet remote communications• Web based interface

M5 Option

• Adds Large Graphics Display• Includes all M1 monitoring features• Time/Date stamp • Duration and Magnitude• User settable thresholds• Tracks


• Local character display• ModBus remote communications

M6E Option

• Adds Large Graphics Display• Includes all M1 monitoring features• Time/Date stamp • Duration and Magnitude• User settable thresholds• Tracks


• 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?

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