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Applications of Surge Protection
Devices
Presented by
Telematic Ltd
Introduction
Thermionic Valve Technology - Disadvantages
<1000 µJ
Thermionic Valve Technology - Advantages
<10 µJ
Discrete Transistor Technology
<1 µJ
Integrated Circuitry
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Down
draughts of
cold air
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Updraughts of
warm air
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Negative charged
cloud base
Surface rain
Charge accumulation within cloud
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Progression of a stepped leader
 Economic
 $139 Million property damage in
USA
 $40 Million claims to Factory Mutual
 Personal
 Average 70 fatalities
Lightning’s annual cost (USA)
 Surges also cause:
 System down time
 Lost business opportunities
 System unreliability
Less obvious cost of strikes
Before
Day off?
After
Permanent retirement !
CAPACITIVE
INDUCTIVE
RESISTIVE
Coupling Mechanisms for Transients
Little or no damage occurs to
sub-systems within structure
200KA
High local
potential
Lightning Strike to Building
200KA
High local
potential
Remote ‘ground’
High
potential
across
insulation
Resistive Coupling into Cabled System
IEC 1000-4-5
European std for transients
FCC Part 68, Bellcore TR-NWT-001089
US Telecommunications
BS6651:1992 Appendix C
recommendations in UK
IEEE/C62.41:1991 , REA PE-60, UL1449
AC power SPD test standards
Standards for Surge Protection
Lightning
Static discharges
Switching transients
Power cable induction
Nuclear Electro Magnetic Pulse
Sources of Transients
Source
Field Density
Rise Time
Lightning
3V/m
@10km
600V/µs
Static discharge
20kV
at impact
2kV/ns
NEMP
50 kV/m
@500km
5kV/ns
Comparison of Transient Sources
SPDs act by:
 Diverting surge current to earth
 Clamping output voltage to a
safe level
 Does NOT prevent lightning but
protects against effects
Surge Protection Devices
IEC 1000-4-5
European std for transients
BS6651:1992 Appendix C
recommendations in UK
IEEE/C62.41:1991 , REA PE-60, UL1449
AC power SPD test standards
Standards for Surge Protection
I
PK
(10KA)
90%
50%
10%
8µs
20µs
8/20µs Short-circuit Current Pulse - IEC 60-1
t
V
PK
90%
50%
10%
1.2µs
50µs
1.2/50µs Open-circuit Voltage Pulse
t
V
PK
90%
50%
10%
10µs
700µs
10/700µs Open-circuit Voltage Pulse
t
• Why install SPDs?
– High likelihood of lightning induced
transients
– Combustible gases present
– Uncontrolled flashover may cause
ignition
SPDs in Zone 0 - IEC 60079-14
 Installation
 Must be installed in Zone 1
 Must be close to Zone 0
 Must withstand 10kA 8/20µs test to
IEC 60-1
Zone 0 Protection - IEC 60079-14
 Simple Apparatus
 Non-energy storing
 non-voltage producing
 Certified
 Gives greater confidence
IS Applications
 IEEE C62.41
 Gives recommendations only
 Splits installations into
Categories
 Lots of real-world data
IEEE C62.41 summary
Service Entrance
Category C3
Panelboard
Category B3
10kV(1.2,50µs)
6kV(1.2,50µs)
10kA(8/20µs)
3kA(8/20µs)
Branch Panel
Category A1
Impulse
Ringwave
6kV/500A 100kHz
IEEE C62.41-1991
6kV/500A 100kHz
Cat A
Cat C
Cat B
IEEE C62.41 Locations
IEC 1312 protection zones
 IEEE C37.90
 Standard Surge Withstand Capability (SWC)
Tests for Protective Relays and Relay Systems
 Applies to a system and not individual
components
 SPDs will help comply to the standard
IEEE C37.90 summary
 IEC 1000-4-5 (801-5)
 Testing and measurement techniques - Surge
immunity test
 Direct lightning is not considered in this
standard
 Highest test level specified is 4kV
IEC 1000-4-5 summary
 BS 6651
 Protection of structures against lightning
 Appendix C covers protection of electronic
equipment
 Gives advice on
 how to assess lightning risk for an installation
 the level of protection required
BS 6651 summary
+100MV
Lightning as a Capacitor
Incoming cables
Local Earth
Common mode surges
Voltage shift is
the same for
both cables
Incoming cables
Difference mode surges
Voltage
difference is
between cables
Air spark gap
Carbon spark gap
Gas-filled discharge tube
Primary Protection Elements
Spark Gap
1
2
2-electrode Gas Discharge Tube
1
Electronic
Apparatus
2
2-electrode GDT in 2-wire loop
1
Electronic
Apparatus
2
3-electrode gas discharge tube
Transient Voltage Surge Suppression
Diode
Metal Oxide Varistor
(MOV)
Secondary Protection Elements
Surge Suppression diode
1500W surge rating
Conventional diode
5W steady state rating
Surge Diodes
Metal oxide particles
Power absorption
throughout pellet volume
Multiple
current paths
Varistors (MOV)
V
V
MOV
I
Surge Diode
Secondary Element Characteristics
I
Device
Speed
Sensitivity Energy
Stability
Air Gap
Fast
Poor
High
Poor
GDT
Fast
Good
High
Good
Zener
V Fast
V Good
Low
Excellent
Transorb
V Fast
Good
Medium Excellent
Varistors
V Fast
Poor
High
Relays
V Slow
Good
Medium Good
Fuses
Slow
Fair
Medium Good
Poor
Comparison of Protection Components
1
2
Conventional Hybrid SPD
1
2
Incoming
surge
GDT
Diode
Multi-stage SPD Operation
Hybrid
1
2
Hybrid Device with Steering Diodes
1
2
Continuous Overvoltage Suppression
Incoming Surge
SPD
DC Power
Protection of Panel Equipment
Tx
Incoming surge
Surge
diversion
Protection of Transmitters
SPDs
RF
Telemetry
I/O
lines
Equipment
AC
SPD
PSTN
Telemetry Outstation
 SPD basics
 Let-through or limiting
voltage
 Working voltage
 Maximum leakage current
Terminology - SPD basics
Thermocouples
mV
RTDs
<2V
RS422
<12V
Loadcells
<30V
RS232
<25V
Switches
24V,110Vac
Process control loops (4/20mA)
24V/48V
Ultra-sonic level transducers
100V
Surge Protector Applications - Selected by Voltage
 Networks
Bandwidth
Crosstalk
Insertion loss
Terminology - Networks
Thermocouples
SD07X, TP48
RTDs
SD07X, TP48
RS422
SD16R
Loadcells
LC30
RS232
SD16X, SD32X
Switches
PC30/D,SD150X
Process control loops (4/20mA)
SD32X, TP48
Ultra-sonic level transducers
CA350
Surge Protector Applications - Typical solutions
Transmitter protection
Replaceable fuse module
or loop disconnect
Minimal series
resistance
4
1
Two lines plus
shield
2
5
3
6
Automatic grounding
via DIN-rail
SD series circuit
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
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

Hybrid SPD
Shield termination point
Automatic grounding
Series fusing
Line disconnect
All in 7mm width
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
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
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Single component protection
No shield termination point
Manual grounding per terminal
Additional series fusing
Additional line disconnect
12-15mm width/loop
plus fuse terminal
plus knife-edge terminal
SD vs terminal protectors
3-wire transmitter protection
Oil storage tanks
Control
computer
Load cells
Weigh bridge
LC30
Junction box
Surge Protection of Weighing System
LC30
4-Wire Field Cable
Supply
LC30
Signal /
Sense
Compensated
Load Cell
4-wire Bridge / 4-wire Line
Summation
box
To
indicator
Bond
Effective system earth
Surge protection device
Metal Weighbridge Bonding
VP08 - video protection
Monitoring area
Field Installation
VP08 installation
Clipit 100
CA90/CA350 Aerial protector
SPDs
RF
Telemetry
I/O
lines
Equipment
AC
SPD
PSTN
Telemetry Outstation
SPDs
RF
Telemetry
I/O
lines
Equipment
PSTN
RTU Protection
1c. SPD on subdistribution
boards
feeding critical
areas
1a. SPD on Main
Electrical
Distribution
Board
SPD
Main
Computer
Data
SPD
Cable
3. SPD on interbuilding Data
Cables
SPD
Telephone
Exchange
SPD
Telephone
Cable
Mains Power
2. SPD on External
Telephone Lines
Cable
Building Protection
Damage caused by surge on
communications link cable
Local AC
supply
Local AC
supply
Remote earth
Communications links between buildings
Outside
FL
NP
NP
Building 1
Building 2
Protection for Inter-building Network Link
Industrial area
within building
Office area
1
NP
High transient
overvoltage
generated by heavy
machinery,
welding equipment
& power cables
2
NP
Network running through Different Building Areas
 Signal level
 Bandwidth or bits/s
 Connector type
 In line resistance
Network characteristics
 Thin ethernet
 NP08/B
 Thick ethernet
 NP08/N
 Token Ring
 NP08/2R
Typical LAN Applications

RS232
 SD16X, SD16
 DP16/D, DP16

RS423
 SD16R, SD16X
 PC16/D, PC16

RS422 / RS485
 SD16/R, SD16X
 NP16/S
Typical industrial network Applications
Allen Bradley data highway plus
PC16/D, SD32R
Foundation Fieldbus
SD32R, SD55R
HART
SD32X, SD32
Honeywell DE
SD32X, DP30/D
Interbus
SD32R, NP16/S
Modbus
SD32R, NP16/S
Profibus
SD32R, NP16/S
WorldFIP
SD32R, NP16/S
Common industrial bus systems
Bus Powered Systems
NP08/N - Thick ethernet
Thick Ethernet installation
NP08/B - Thin ethernet
Thin Ethernet installation
Allen Bradley Data Highway Plus
Category 5 installation
250
Voltage
200
150
100
50
0
PSTN ringing voltage
 UK jack and socket - office
 DP200/4/I
 Krone strip - exchange
 PX200/10
 Telemetry outstation
 DP200/D
 mSAPN
Typical PSTN Applications
 Krone strip - exchange
 DP16/PX
 Telemetry outstation
 SD16X
 DP16/D
 mSA16
Typical Private Wire Applications
Earth terminal
DP200/4/I
PSTN
connection
DP200/4/I installation
DP200/D installation
MOV surge clamping
Power cables transient sources
Lightning
Load switching
Welding equipment
Elevators/lifts
Applicable standards
IEEE Std. 587-1980 (obsolete)
ANSI/IEEE C62.41 1991
IEC 801-4, -5
AC Power Line Protection
SPD
L
N
SPD
G
Protected
Load
Spur vs Series Connection
Fuse protected
network
L
N
G
Delta Network of Varistors
Fuses not
shown for
clarity
L1
L2
L3
N
G
Star-connected Varistors
SPD
L
N
SPD
G
Fusing AC Power SPDs
 MA05/D, MA10/D
 PLC power supply
 Instrument PSU
 MA05/SC, MA10/SC
 Fire/burglar alarm panel
 Computer PSU
 MA05/I, MA10/I
 Fax Machine
 Computer
MA05, MA10 applications
Divert current as soon as possible
Use dedicated low impedance connection
Make sure other systems are bonded to it,
once!
Convert series-mode current into commonmode voltage
Grounding for Lightning Protection - Principles
Lightning strike to Aeroplane
 Mains Protective Earth
 Essential for personnel safety
 Carries leakage currents
 Surge Protective Earth
 Must be able to carry huge currents
 Low voltage drop
 Instrument or Computer Earth
 Needs to be kept from ‘dirty’ earth
Different types of Earth
Telecomms
Instrumentation
Computers
Star-connected System Earths
Inductance
+
Resistance
Cable impedance
Recommended earthing philosophy
Incoming Surge
SPD
DC Power
To
distribution
ground
Common Grounding System
Incoming Surge
SPD
DC Power
To
distribution
ground
Preferred Grounding System
Incoming Surge
SPD
DC Power
To
distribution
ground
Disastrous Grounding System
Safe Area
Hazardous Area
SPD
SPD
TX
SPDs with IS Barriers
IS Barrier
SPDs with Zener Barriers
Hazardous Area
SPD
Safe Area
SPD
Galvanic Isolator
TX
SPDs with Galvanic Isolation
Protect equipment;Exposed to lightning surges & other transients
With difficult or remote access for maintenance
Critical to plant operation & control
Conclusion



SRF Range

High current surge protection and filtering (50 - 120kA)

Recommend MA230, MA103 or MA2003
MT Range

Two terminal device containing 5 MOVs (40 - 120kA)

Recommend MA230, MA103 or MA2003
MPM Range

Box containing three MT units (50kA L-N)

Recommend MA230, MA103 or MA2003
Critec AC power products




LAN-TYPE-1E

Token Ring protector

Recommend NP08/2R
LAN-TW280

TwinAx protector

Recommend NP16/T
LAN-BNC

Thin Ethernet

Recommend NP08/B
LAN-N

Thick Ethernet

Recommend NP08/N
Critec LAN protectors



LSAC Range

4A AC data SPD

Recommend MA05 or SD150X (higher surge rating)
LSCP and LSSC Range

High frequency coaxial SPDs

Recommend CA90 or CA350
LSJK and LSEK Range

Includes GDT, MOV and surge diode

Recommend SD series
Critec data protectors