© 2008 Eaton Corporation. All rights reserved.
This is a photographic template – yourphotograph should fit precisely within this rectangle.
© 2007 Eaton Corporation. All rights reserved. Last Updated 15/08/07
Surge Protection Devices for LV SystemsAustralasia
A technical overview
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Who are we, what do we do?Part of Eaton group. EPQS / Powerware.Was Total Power Systems, acquired by Invensys / Powerware.New product design to AS/NZS and IEC standards. Specialising in TVSS / SPD devices.26 man years of TVSS product development and delivery.Specialised secure power applications to Navy, Air force, Army, Data Centres.Specialised TVSS solutions to major commercial operations. Optus, NSW Health, QLD Health, Switchboard manufacturers, Mining industry. Australia, New Zealand, Vietnam, Sri Lanka, Africa, Europe.54 man years in electrical design and manufacture across 2 people and 5 multinational corporations.R&D lab Mascot limit 4kA/8kV 8/20us with access to R&D lab Chinaup to 120kA 10/350us. 8/20us. 1.2/50us waveforms.
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SPD Industry Myth
Lightning strikes can produce in upwards of 200 000 amps of surge current. Therefore 200 000 amps can flow into electrical distribution systems.
Fact!
A maximum of 20kV and 10kA gets induced into electrical distribution systems from a lightning event. Voltages and currents in excess of this will cause irreparable damage. Cable insulation would fail before the surge could even get into the building.
Source: ANSI/IEEE C62.41
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A surge is a random, short burst of excess electrical energy to a system. Also referred to as a transient, impulse or spike, these electrical disturbances can damage or even destroy sensitive microprocessor-based equipment. Its duration is in the micro and millisecond time frame.
What is a Surge?
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Why do I need surge protection?
Electrical equipment design moving to reduce costs and relying on
specified mains voltages being maintained to supply standards.
Most equipment is now designed in accordance with regulated surge
protection standards (especially Europe).
Utility suppliers can no longer guarantee absolutely error free power.
Trying to deal with excess energy at the final point of entry into your load
is the wrong place to deal with it.
Increases the longevity of your investment.
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Where do they come from?
InternalInternal
ExternalExternal
80% of transients are generated from internal sources such as load switching, motors starting up or even turning on air conditioning systems.
The other 20% of transients are generated from external sources such as lightning strikes and power company grid switching.
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There is a standard for everything. No need to re invent the wheel. Let the standards do the work for you.
Starts with EN LV directives, then flows to surge risk assessment standards, then to equipment standards, then to test standards, then to reporting standards.Some standards you may here about are:
ANSI/IEEE C62.41. Low voltage surge protection, waveform, test and current standards and limits.Test waveforms. Each Category / Class type has a different standardised test waveform.
10/350us is Class I8/20us is Class II short circuit.1.2/50us is Class II open circuit. 100khz Ring wave is Class III only.
Equipment standard will determine the correct waveform to be used.
Standards.
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Standards.
AS/NZS1768 Region-specific standards - Risk assessment.
IEC61643, UL1449 Equipment standards.
AS/NZS 3000:2007 Wiring rules. Appendix F.
They do overlap but don’t confuse them.
In Australia, New Zealand and most of Asia, AS/NZS1768, IEC61643-1 and ANSI/IEEE C62.41 are all you will ever need.
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Protection Zones (ANSI/IEEE)
Category E (70kA)
Elevated very high exposure & critical load
Category A (200A)
Long final sub circuits & power outlets
Category D (30kA)
High exposure such as elevated overhead lines
Category C (15kA)
Point-of-Entry / Service Entrance
Category B (3kA)
Major sub mains & short final sub circuits
There are two more categories, which simply extend the Category C
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Solutions
Protection zones – IEC61000 series European standards
Class I – Outdoor, “direct strike” Class I devices. Extreme to high risk zone.Class II – Indoor, induced strike Class II devices. High to medium risk zone.Class III – Final circuit, equipment, Class III devices. Medium to low risk zone.
ANSI/IEEE C62.41. U.S. StandardsCategory E – External elevated supply point. Extreme risk zone. Direct strike.Category D – External supply point. Extreme risk zone. Direct and induced surge.Category C – Point-of-entry High risk zone. Direct and induced surge.Category B – Sub-SWB or intermediate circuit. Medium risk zone. Induced surge.Category A – Final circuit, equipment. Low risk zone. Induced surge.
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Solutions
Protection technologiesEach Category / Class uses different types of technology in different
ways to manage the harmful energy levels .
Surge diverters – MOV, Spark gaps, Gas arrestors. Usually parallel
connected.
Surge Filters – creating a a protection zone by limiting current through
inductors and using high frequency clipping via capacitors to improve
noise rejection. Usually series connected
Each technology has differing electrical attributes and no one
technology can be used in all situations.
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Protection Technologies
Silicon Avalanche Diode (SAD)Suits lower risk zones only
Gas Discharge Tube
Suit all zones but must not be connected across Line –Neutral or Earth in some circumstances. Has follow current.
Spark GapsSuits high risk zones
only
Metal Oxide Varistors (MOV)Suit all zones except direct strike.
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Surge Diverters
Surge Diverters are parallel connected devices that provide shunt diversion only and are typically used at the point-of-entry to a facility. These devices offer coarse protection, making them suitable as the primary defense against power surges.
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Surge Filters
Note: The inductor provides current limiting of surges to load
Surge Filters are series connected devices that provide fine protection. They are usually installed closer to the load to act as a second line of defense, providing further surge reduction, current limiting & noise filtering for sensitive electrical equipment.
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Cascading
• SPD’s are designed to work as part of a complete protection system.
• They are typically installed as PRIMARY and SECONDARY devices ( see standards recommendations ). This is known as Cascading and is an important concept in surge protection. No one device can do everything from point of entry to final sub circuit.
• You may have up to 3 levels of protection in a complete system. Ie. A Class I device at high risk point, Class II device at POE and Class III device on GPO.
• In most cases you will need at least 1 x Class II and 1 x Class III device. OR 1 x Class I and 1 x Class II device.
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Protection modes
• Protection modes refers to the way in which the SPD controls harmful energy.
• There are 4 modes: L-N, L-L, L-E, N-E.• L-N & L-L are referred to as Differential modes.• L-E, N-E are referred to as Common modes.• Choosing the right modes for your application depends on your electrical
system characteristics. Ie TT, TN, TN-C, TN-CS.• Most systems in Australia are TN type. Ie Neutral is derived from Earth at
the user point of entry. ( commonly called the M.E.N. link ). • Whatever modes you select the harmful energy must make its way
back to Earth SOMEWHERE. So make the control path easy for the energy to get to earth and dissipate.
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System Design
Installation issues.
1. Physical location.2. Electrical location.3. Safety disconnectors.4. Cable length and type.5. Earthing.
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Installation Issues
Physical location.
1. As close as possible to Main Switch or metering point – within Main SWB if possible.
2. Accessible for maintenance – extra isolation switch.3. Environmentally benign – no excess moisture or heat.4. Personal safety.
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Installation Issues
Electrical location.
1. Locate at a point close to the Main Isolating Switch, allowing close access to all phase and N/PE conductors.
2. If N/PE is remote from phase conductors, consider extending all conductors to an intermediate point.
3. Earthing point (for Main SWBs) must be located within a short distance.
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Installation Issues
Safety disconnector.1. Preferred to use HRC Gg/Gl fuses, not CBs. CBs break down in
instant high current waveforms. They can either nuisance trip or be partly damaged causing premature MTBF failure. Fuses are much better at conducting rapid transients. If you must use an MCB then be aware that the total circuit performance may not equal that of the SPD. It will still work, but its not as efficient.
2. For medium & high-current services (250-3000A), use the maximum fuse as recommended by manufacturer.
3. For low-current services (<250A), the fuse rating will limit surge capacity.
4. For very low-current services (<80A), it may be necessary to rely on line fuses.
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Installation Issues
Cable length and type.
Cable voltage drop is the biggest loss.
1kA/1m ~ 150V @ 8/20us >> Cat C (15kA)/1m ~ 2250V @ 8/20us
That’s a lot of stress on the cable BEFORE the SPD gets going. Make the SPD work for you.
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Installation Issues
Cable length and type continued.
1. Cable length (inductance) is the biggest issue.2. Multiple, small cables better than one large cable.3. Busbars are much preferred, where applicable.4. Keep total connection length below 0.5m on any cable and always
tie cables tightly together.5. Try to keep surge voltage drop to <1kV/cable.6. Do not loop extra cable!7. Keep input ,“ DIRTY “ power separated from output, “ CLEAN”
power. Do not bundle together.
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Installation Issues
Earthing.
1. Site earth must be as good as possible.2. Busbars should be used for runs >3m (remember 1kA/m = 1kV!)3. Use a ‘star’ (or ‘single-point’) earthing system in all cases -do not
daisy-chain earth systems.4. Always interconnect sub-SWB earths with adjacent building metal.
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RCD’S in a Surge Circuit
RCD’s are designed to detect current flow between active conductors and earth. When a SPD shunts to earth an RCD will most likely trip. Most L-N shunts should have no impact as long as MEN link is close.
SPD’s should be installed UPSTREAM of any RCD.
Latest wiring rules add another level of complexity to the solution.
There is no avoiding the physics.
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Installation Issues
Why we must try hard(er)
All SPD systems have appreciable losses.
“Weak links” concentrate energy loss.
…because lightning doesn’t care.
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Selecting a TVSS product
Specify what you really need. Avoid ‘cut and pasting’other manufacturer’s specifications. Let the SPD
equipment standard do the work for you.
What to look for.
“Must have” features.
“Nice to have” features.
Coordinating with upstream and downstream infrastructure.
… BUT DON’T OVERDO IT!
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Selecting a SPD product
What to look for (questions to ask customers).
Specify a standard. It does the hard work for you. Don’t invent your own. IEC61643-1, AS/NZS 1768, ANSI/IEEE C62.41 are more than you will ever need.Service voltage and type – 1 or 3-phase, 240/415V, local M.E.N.What are we protecting? – Specific equipment or the entire building?Proposed location of SPD – At M.E.N. point or sub-SWB/equipment?Maintenance requirements – Repair or replacement shouldn’t require site to be blacked-out.Likelihood of damage – if SPD is affected by service faults.
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Selecting a SPD product
“Must-have” features (questions to ask customers).
Look for Vpl, MCOV, Inom, Imax, SCW specs. Make sure they are quoted in each mode of operation. Lowest, fastest and largest does not always mean the best. There are traps.There is a benchmark for each specification.Service rating determines maximum surge current. Small services (63-80A) are incapable of Isurge > 40kA without the supply fuse(s) rupturing. Do not overspecify.Common-mode protection is only required for applications remote from the M.E.N. point.
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Selecting a SPD product
“Nice to have” features (questions to ask customers).
Alarms – few people monitor them (except telcos etc.)Displays – More for show than ‘go’. A clear and concise “Fault”indication is better than taking bets on longevity.IP ratings – if a customer asks for IP65, ask why – pointing out that SPD equipment should never be ‘stand alone’.User-replaceable modules – “users” should never work on live equipment. When damaged, TVSS equipment should be replaced in it’s entirety, not 1 phase at a time.SPD certifications – IEC61643-1 should be adequate!
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Selecting a SPD product
Coordinating with upstream and downstreaminfrastructure (questions to ask customers).
If sizing primary protection, what secondary protection (if any) is intended? Conversely with secondary (sub-SWB) protection.Service fusing level and fault rating affect SPD capability.Position, position, position – is the device being protected close to it’s protection? If not, use an auxiliary protector at the load.For filters, what is the load? If the load has high current distortion, consider using shunt SPD instead.Filters draw current! Allow for 5% filter current (I.e. 63A filter = 3.15A >> 66.15A supply current OR 59.5A load current.
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SPD product certificationWho cares? (You should. Check for standards compliance and test
evidence in specs. IEC standards reflect more closely our low voltage
system than UL standards)
Be careful about performance claims. Not all claims are valid or even
meaningful.
Why is UL1449 irrelevant in Australia ?
Understanding some of the characteristics:
MCOV, TOV, VPL, Inom, Imax, SCW
Standardised specifications in IEC 61643-1. This standard covers all
aspects of safety, test waveform compliance, performance reporting
rules etc.
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Load protection guarantee claims
It’s almost impossible to GUARANTEE a failsafe outcome. There are
limits to all semiconductor technologies. Such guarantee’s are really
about RISK REDUCTION. They also have lots of limiting conditions.
And for good reason.
Common installation faults. Devices with multiple ports ( power, data,
phone, video etc ) all rely on common earth point VIA the SPD. If even
one port is not DIRECTLY connected to the SPD then it will almost
certainly fail. RTBM.
Learn to scale your risk. 100kA at a 10A GPO ???
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Good installations vs poor installations
Actually, there are no “really good”installations…
… but we can try to make them as ‘good’ as possible.
© 2008 Eaton Corporation. All rights reserved.
This is a photographic template – yourphotograph should fit precisely within this rectangle.
© 2007 Eaton Corporation. All rights reserved. Last Updated 15/08/07
SPD Product Range
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Eaton SPD Products
Dataline & Rack Mount Dataline & Rack Mount ProtectionProtection
DIN Rail & Panel DIN Rail & Panel Mount Surge Mount Surge
ProtectionProtection
Portable Portable Surge FiltersSurge Filters
Premium 3 Phase Premium 3 Phase Diverters & FiltersDiverters & Filters
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Three Phase Surge DiverterMSDiKey Features:
Surge current rating = 60kA/ph Inom & 200kA/ph Imax
Point-of-entry protection
LED Bar graph display on each phase
Enclosed in IP24 painted steel cabinet
Protection fail alarm relay
Surge Category:
Category E, D & C locations
Class II device
Application:
Main protection for industrial plants, commercial buildings and process control systems
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QuickmovTM Surge DiverterQuickmovTM
Key Features:
Fits any QuicklagTM load centre
Surge current rating = 30kA Inom & 60kA Imax
In-built HRC fuse, with the added safety of integrated thermal protection.
Surge Category:
Category C & B locations
Class II device
Application:
Industrial sites, commercial sites, factories, schools and process control systems
SPD50NGi Key Features:
Compact N-E protection solution
Surge current rating –50kA Inom & 70kA Imax
Class II device
Compatible with most switchboards
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Din Rail Surge DivertersSPDi din rail seriesKey Features:
SPDV60 – 1 Pole 30kA Inom, 60kA Imax
SPD120i – 1 Phase 50kA Inom, 100kA Imax
SPD3i – 3 Phase 20kA/Ph Inom, 40kA/Ph Imax
Alarm contacts as standard
Surge Category:
Category C & B locations
Class II device
Application:
Industrial sites, commercial sites, telecommunication, medical and process control systems
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3 Phase Premium Power FilterPPFiKey Features:
Gear tray versions available
Imax rating up to 240kA
EN certified EMI/RFI Filter
Can be customised to specification
Enclosed in IP24 painted steel cabinet
Panel-mounted mimic display andalarm relay outputs
Surge Category:
Category D, C & B locations
Class II device
Application:
Multi-storey buildings, hospitals, IT datacentres and airport facilities.
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1 & 3 Ph 40-63A Surge FilterMSFiKey Features:
Surge rating Inom = 60kA and Imax = 160kA
Enclosed in IP24 paint steel housing
Available in 40 or 63 Amp ratings
Protection fail alarm relay
Front panel status indicators
Surge Category:
Category D, C & B locations
Class II device
Application:
Telecommunication systems, process & control systems, small commercial offices & industrial sites
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Compact Surge FiltersCSFiKey Features:
3-25Amp 240V AC
Surge rating Inom = 10kA and Imax = 25kA
Can be used as stand alone solution for units and small offices
Protection Fail Alarm Relay
Surge Category:
Category B & some C locations
Class II device
Application:
PLC’s, computer systems, servers, mission critical circuits
DSFiKey Features:
5-32Amp 240V AC
Surge rating Inom = 15kA and Imax = 40kA
Dual stage filter
Can be used as stand alone solution in lightly exposed sites
IP20 painted steel housing
Surge Category:
Category B & some C locations
Class II device
Application:
UPS systems, rectifiers, AV circuits in clubs & hotels
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Portable Surge FiltersPOD & POD+Key Features:
60kA surge protection rating
Handles more than 1 Million surges *(AS1768 Cat A ring wave 200 Amps)
6 or 8 extra wide socket spacing
Ideal for data, AV, phone line and Cable TV protection
Surge Category:
Category A locations(unprotected or lightly protected sites)
Class III device
Application:
Home, office, entertainment systems, laboratories, computer systems
SSFiKey Features:
Surge rating Inom = 10kA and Imax = 25kA
Surge suppression and filtering in a single package
Small footprint, modular design
Enclosed in IP50 painted metal housing
Surge Category:
Category A locations
Class III device
Application:
Industrial printers, servers, plug-in UPS and POS systems
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Data and Rack Mount ProtectionRack MountKey Features:
Unique mounting system
Rigid steel case
22.5kA Surge Rating
Category A, Class III device
PWSF8R-U
Data & NetworkKey Features:
Protects all CAT5 network devices
Protects all 8 wires of a CAT5 cable
Simple to install
Does not effect network traffic
Category A. Class III devices
ERAK16EC5EMTJPOE60V
ECAT6PPC
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MSDi
SPFi
Category C Category C (15kA)(15kA)
SPDi
Quickmov
Category C / Class II products
MSFi
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Category B / Class II products
MSFi
DSFi
CSFiCategory BCategory B
(3kA)(3kA)SPFi
SPDi
Quickmov
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Category A / Class III products
POD
SF8RU
EMTJPOE60VERAK16EC5
Category ACategory A
(200A)(200A)
SSFi
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If you need assistance or advice on design or specifications:
Mike Hale. 9693 [email protected]
Ryan Nguyen. 9693 [email protected]