LPED, Singapore, 19th April 2013, NS Koh
Lightning and Surge Protection
with SPD
© ABB
11/16/2011 | Slide 1
Lightning & Surge Protection
Background Information
CP33 : 1996 Code of Practice for Lightning Protection
Scope:
Guidelines for protection of Persons and property from hazards
arising from exposure to lightning.
Protection of variety of building or structures, including those with
explosive or highly-flammable contents
Protection of persons both outdoors and indoors
Protection of sensitive electrical & electronic equipment and its
associated services from overvoltages due to a lightning strike
Exclude protection for large scale power or communication system
and special structures such as oil and gas platforms
© ABB Group
April 20, 2013 | Slide 2
Lightning & Surge Protection
SS 555 : 2010 - Protection against Lightning
National foreword
Review of CP 33 : 1996 resulted in the development of SS 555.
Part 1:
General Principles
Part 2:
Risk Management
Part 3:
Physical Damage to Structures and Life Hazard
Part 4:
Electrical & Electronic System within Structures
The four parts replace CP 33: 1996
This codes is a modified adoption of International Standard IEC
62305-1 to -4 : 2006 (Edition 1.0)
Modification to the IEC 62305-1 are given in Annex ZA
Annex ZB: Singapore‘s Lightning intensity information
© ABB Group
April 20, 2013 | Slide 3
Lightning & Surge Protection
SS 555 - 1
© ABB
Month DD, YYYY | Slide 4
Lightning & Surge Protection
SS 555 - 1
© ABB Group
April 20, 2013 | Slide 5
Lightning & Surge Protection
SS 555 - 1
© ABB Group
April 20, 2013 | Slide 6
Lightning & Surge Protection
SS 555 - 1
Lightning strokes:
99.98% are below 200kA
90% are below 50kA
© ABB Group
April 20, 2013 | Slide 7
Lightning & Surge Protection
What is a Transient Surge?
Transient surge
A sudden (shorter than a millisecond) rise in the flow of power
Voltage peak can reach 12x’s the nominal voltage
Can cause costly damage to electric/electronic equipment
© ABB Group
April 20, 2013 | Slide 8
Lightning & Surge Protection
What is a Transient Surge?
8000V during 140µs
460V during 10s
230V 50 Hz
Lightning surge
TOV
Switching surge
Rms Voltage: 230V
© ABB Group
April 20, 2013 | Slide 9
Transient over voltage
Temporary over voltage
Purpose of SPD
Enemy of SPD
Lightning & Surge Protection
Point of Strike of Lightning
© ABB Group
April 20, 2013 | Slide 10
Lightning & Surge Protection
Transient Surge
Transient surge
Industrial causes:
Switching on/off any elements that create a sudden variation of
load will also cause a sudden change in current flow and
generate transient surges (i.e. Circuit Breakers, Transformers,
Motors)
© ABB Group
April 20, 2013 | Slide 11
Lightning & Surge Protection
Transient Surge
Transient surge
External vs. Internal
About 20% of transients are generated from external sources (i.e.
lightning, power company grid switching)
Effects:
Catastrophic equipment failure
Immediate operation shutdown
Long term disruption of business
Expensive equipment repair and replacement
© ABB Group
April 20, 2013 | Slide 12
Lightning & Surge Protection
How Does SPD Work?
The
flowthe
issituation,
increasing
dangerously
In normal
thewill
system
is the
Luckily
protection
control
for
the
working
at withstand
the righ flow
flow
to equipments
the
level by the
equipments
© ABB Group
April 20, 2013 | Slide 13
Lightning & Surge Protection
Spark Gap Technology
Electronic
for triggering
Arc
Chamber
Triggering
needle
(Brass or
stainless)
Air Gap
Tungstène and copper
Exhaust
channel
Lightning & Surge Protection
Spark Gap Technology
When the surge
comes, the
electronic will
detect and
amplify it
At this stage, a
little spark is
generated at the
needle head
Little spark
commutes the air
gap, thus surge
energy is driven
to ground
Once the surge is
earthed, arc
enters in the arc
chamber. this is
self extinguishing
time
Hot gas exit
passing through
the exhaust
channel that
avoid any fire
risks
Lightning & Surge Protection
Follow on current Ifi
Rt1
Iscwithstand = 25 kA
In the specific case of spark gap or gas tube
technology be careful not to mix
Follow on current : Ifi of the SPD
with
Short circuit withstand:
Isc of electrical devices
Lightning & Surge Protection
Follow on current Ifi
Rt1
After the surge is driven to the ground,
The Spark Gap is a short circuit!
It means that your installation is in short circuit…
something has to open the short circuit!
Lightning & Surge Protection
Follow on current Ifi
Iscexpected of the installation = 25 kA
Rt1
Ifi
Iscexpected
The SPD cuts the short circuit current, and
“gives back the hand” to installation.
Ifi < Iscexpected
The SPD cannot cuts the short circuit current,
the MCB will trip or fuse will blow
Lightning & Surge Protection
Follow on current Ifi
Rt1
In both case, equipment has
been protected…but in the
second one, there is no more
protection and you have to
change the fuse or reset the
MCB!!!
Iscexpected of the installation = 25 kA
Lightning & Surge Protection
Varistor Technology
R
I (A)
Uoc
U (V)
A varistor is a
voltage limiting
component
Lightning & Surge Protection
Varistor Technology
Clamping
voltage
(depends of
the varistor)
1mA
Leakage
current
< 25ns
Normal
working of
the MOV
When a surge
occurs
T(µs)
Umov=fc(Imov)
Lightning & Surge Protection
Varistor Technology
- Constant Voltage
U (V)
- Free Current Flows
up to Destruction
destruction
Infinite Impedance
I (A)
Real Characteristic
U (V)
1mA
20kA
destruction
1A
Up
I (A)
Lightning & Surge Protection
Choice of technology according application
In the Main Distribution Board, we need:
High capacity in 10/350
Withstand voltage fluctuation on the electrical network
Spark Gap is ideal
In the Sub Distribution Board, we need:
Low surge capacity
Low Up (<1,5kV) under a low surge
A selection without the knowledge of the Isc expected
MOV is ideal
Lightning & Surge Protection
Type and Technology of SPD
2 major types of SPDs
4 major characteristics
Type 1 (10/350µs)
Iimp for Type 1
Type 2 (8/20µs)
Imax for Type 2
Uc: Maximum Operating voltage
2 major Technologies
Spark gap / Gas
Tube
Varistors (MOVs)
© ABB Group
April 20, 2013 | Slide 24
Ifi: Follow current of SPD must be
> Isc of installation (Spark gap
technology)
Lightning & Surge Protection
Terms and Definitions
TVSS : Transient voltage surge suppressor (US denomination).
No longer used in the new UL 1449 3rd edition, dated September 2009.
SPD : Surge Protective Devices (International denomination)
Surge Protective Device (SPD) : Device designed to limit transient overvoltages
=> Protection of the electrical installation
Type 1 SPD (15 & 25kA): SPD designed to divert surge current comparable to that of a direct
lightning strike: 10/350 wave - Class I test
=> Installed in the MDB : Industrial applications, ...
Type 2 SPD (15 up to 100kA): SPD designed to divert surge current due to switching operations :
8/20 wave - Class II test
=> Mainly installed in the SDB and/or for domestic/commercial applications
Iimp (impulse current): Maximum discharge current for Type 1 surge arresters
Imax : Maximum discharge current for Type 2 surge arresters
Uc : Maximum operating voltage
Up : Protection level (<1.5kV for Class 2 SPD – 230V / Conform to Category 1 equipment)
Ifi : Follow current. Short circuit of the installation that can be cut by the SPD (Only for spark gap/Gas
tube technology used in Type 1 SPD)
© ABB Group
April 20, 2013 | Slide 25
Lightning & Surge Protection
Class I / Type 1 SPD
Class 1 testing (10/350µs):
© ABB Group
April 20, 2013 | Slide 26
Lightning & Surge Protection
Class 2 / Type 2 SPD
Class 2 testing (8/20µs):
© ABB Group
April 20, 2013 | Slide 27
Lightning & Surge Protection
Surge Current Waveform
Comparing the 2 wave form
8/20µs
100%
10/350µs
90%
80%
60%
50%
40%
20%
10%
0%
0
T1
50
100
150
T2
Type 1 SPD (10/350µs wave form) :
200
250
300
350
time [µs]
10/350µs:
The first number corresponds to the time from 10% to 90% of its peak value
(10µs)
The second number corresponds to the time taken for the wave to descend to
50% of its peak value (350µs).
Type 2 SPD (8/20µs wave form) :
8/20µs:
The first number corresponds to the time from 10% to 90% of its peak value
(8µs).
The second number corresponds to the time taken for the wave to descend to
50% of its peak value (20µs).
© ABB Group
April 20, 2013 | Slide 28
Lightning & Surge Protection
How Does SPD Work?
Voltage protection level = Up
Unetwork
SPD
UP
Equipment
Up=1,2kV
Lightning & Surge Protection
How Does SPD Work?
Surge Protective Devices (SPD)
Devices intended to limit transient voltages and divert
surge currents to the ground
Unprotected
© ABB Group
April 20, 2013 | Slide 30
SPD
Protected
installed
Lightning & Surge Protection
Impulse withstanding voltage of equipment
What do you want to protect?
Determination of the protection level: Up
According to insulation coordination for equipment within low
voltage system (IEC 60364-4)
© ABB Group
April 20, 2013 | Slide 31
Lightning & Surge Protection
Impulse withstanding voltage of equipment
Type 1 (10/350µs):
As installed in the MDB, generally have a Up
<2.5kV
Type 2 (8/20µs):
As installed in SDB to protect sensible
equipment, generally have a Up <1.5kV
© ABB Group
April 20, 2013 | Slide 32
Lightning & Surge Protection
SS 555: LPZ Lightning Protection Zone
S3: Service
connected to
Structure
S4: Near a
Service
© ABB Group
April 20, 2013 | Slide 33
S1: Structure
S2: Near a
Structure
Lightning & Surge Protection
SS 555: LPZ Lightning Protection Zone
LPZ OA
LPZ OB
LPZ 1
LPZ 2
LPZ 3
© ABB Group
April 20, 2013 | Slide 34
Lightning & Surge Protection
SS 555-1: Lightning Protection Zone
Type 1
Type 2 or 3
Type 2
90%
9%
1%
70kA / 40kA
40kA / 10kA
Surge risk
25kA / 15kA
The choice of surge arrester is made accordingly to several characteristics:
Maximum discharge capability : Iimp or Imax
Protection level : Up
Network earthing system
Operating voltage (Uc) according to the nominal voltage (Un)
© ABB Group
April 20, 2013 | Slide 35
Lightning & Surge Protection
Common Mode Protection
Problem
I surge
Up L/G
= 1200V
+
I surge
Up G/N
= 1200V
=
I surge
Up L/N
= 2400V
Up L/N too high to protect
equipment category I
Lightning & Surge Protection
Common + Differential Mode Protection
Solution 1: MOV
I surge
Differential
Mode
Up L/G
= 1200V
=
I surge
Up N/G
= 1200V
=
I surge
Up L/N
= 1200V
Up L/N is OK to protect
equipment category I
Lightning & Surge Protection
Common + Differential Mode Protection
Solution 2: MOV + GDT
I surge
Up L/N
= 1200V
+
Up N/G
I surge
= 1400V
=
Up L/G
= 1400V
Up L/G is OK to protect
equipment category I
I surge
Lightning & Surge Protection
End of Life Disconnector
Associated switching element
Lightning & Surge Protection
End of Life Disconnector
or
protection against short
circuit currents
Thermal Disconnection protection
(included in the lightning arrester)
Defined by the lightning arrester manufacturer
instructions.
Lightning & Surge Protection
End of Life Disconnector
If the varistor die slowly:
•
Normal ageing after several shocks
Thermal disconnection
If the SPD die in short circuit (6% for MOV techno.):
When the last current shock(Lightning) is too high for
the capability of the varistor
•
When the maximum operating voltage (Uc) is
overload for a too long time
•
When the the temporary over voltage (Ut) is reached
more than 5 seconds
•
MCB or Fuse
Lightning & Surge Protection
End of Life Disconnector
Comment in case of upstream RCD:
RCD is mandatory in TT network.
RCD can be used in TN-S, IT, TN-C-S
RCD is not required in TN-C network
If an RCD is needed, choose a S-type
Install SPD at the (before) incoming of RCD
Lightning & Surge Protection
SPD kA Selection
IEC 61643-12 Annex I: Low voltage surge protective Device
Annex I : Selection & Application
When an individual evaluation is not possible, It can be assumed that
50% of the total lightning current (I) enters the Earth terminal of the
installation & the other 50% is distributed among the services entering
the structure.
The current in individual conductor:
Iv = Ii/m
Ii : surge current in service
m: number of conductor
© ABB
Month DD, YYYY | Slide 43
Lightning & Surge Protection
SPD kA Selection
Iv = Ii/m
Ii : surge current in service
m: number of conductor
© ABB
Month DD, YYYY | Slide 44
Lightning & Surge Protection
SPD kA Selection
The current in individual conductor:
200KA
Iv = Ii/m = 100/4 = 25KA
Ii : surge current in service
m: number of conductor (L1,L2,L3,N)
4 x 25KA
100KA
100KA
© ABB
Month DD, YYYY | Slide 45
Lightning & Surge Protection
SPD Connection Cable
As short
as
possible
Lightning & Surge Protection
Impedance of Cable
1m of cable
For a usual surge, we consider :
1m = 1 H = 1000V
Minimum bonding cable size for SPD :
5mm2 for T1 SPD, 3mm2 for T2 SPD
Lightning & Surge Protection
Impedance of Cable
RCBs
MCBs
SPD
UPS
Computers
Videos
Lights
Plugs
Lightning & Surge Protection
Impedance of Cable
1m=1 H
L1=65cm
RCBs
1m=1000V
MCBs
UPS
Computers
Videos
Lights
Plugs
L2=35cm
SPD
L3=65cm
Lightning & Surge Protection
Impedance of Cable
1m=1 H
VL1=65cm
ba=650V
RCBs
1m=1000V
MCBs
Vdc=350V
L2=35cm
UPS
Computers
Videos
Lights
Plugs
Ved=1SPD
200V
V
fe=650V
L3=65cm
Vfa=2850V
Lightning & Surge Protection
Impedance of Cable
RCBs
MCBs
SPD
UPS
Computers
Videos
Lights
Plugs
Lightning & Surge Protection
Impedance of Cable
RCBs
L1=10 cm
MCBs
L2=10 cm
SPD
L3=10 cm
UPS
Computers
Videos
Lights
Plugs
Lightning & Surge Protection
Impedance of Cable
RCBs
a
Vab=100V
b
MCBs
c
Vcd=100V d
SPD
Vde=1200V
e
Vef=100V f
UPS
Computers
Videos
Lights
Plugs
Vfa=1500V
IEC 62305-4 / SS 555-4
Oscillation phenomena
L
Equipment:
(Uw
impulse withstand
voltage of the equipment)
• The surge current passing through the SPD induces additional voltage into
the loop on the protected side
•If Up/f < Uw / 2 or L < 10m
protection distance Lpo may be disregarded
Additionnal SPD is not required
© ABB Group
April 20, 2013 | Slide 54
IEC 62305-4 / SS 555-4
Oscillation phenomena
L > lpo
Up/f
Equipment
to protect
Ures can double
Ures > Uw
Need of
additional
SPD
© ABB Group
April 20, 2013 | Slide 55
Lightning protection fundamentals
SPD for Solar panel or PV Application
Solar solution: OVR PV range
OVR PV 40 600 P & P TS
Ucpv: 670V d.c.
Iscwpv:100A
Imax: 40kA
Pluggable + auxiliary contact option
OVR PV 40 1000P & P TS
Ucpv: 1000V d.c.
Iscwp: 100A
Imax: 40kA
Pluggable + auxiliary contact option
© ABB Group
April 20, 2013 | Slide 56
Surge Protective Devices
Pluggable SPD
Type 2 pluggable SPD
Ex: OVR T2 3N 70 275 s P TS
Pluggable for easy replacement
Enable to change the cartridge without uninstalling the
SPD
© ABB Group
April 20, 2013 | Slide 57
Surge Protective Devices
SPD Safety Reserve
Type 2 SPD with Safety Reserve
Ex: OVR T2 3N 70 275 s P TS
Safety Reserve for Backup Protection
2 Varistors in the same cartridge for each Phase,
one varistor EOL the other take over for protection
Provide backup before replacement
© ABB Group
April 20, 2013 | Slide 58
SPD
SPDDisconnected
on
Reserve
Operational
Replacement
Replace
soon
Mandatory
Surge Protective Devices
SPD End of Life Auxiliary Contact
Type 2 SPD with end of life Auxiliary Contact
Ex: OVR T2 3N 70 275 s P TS
Auxiliary contact for alarm connection
Enables monitoring of surge arresters remotely
Dry contact: 1 NO / 1 NC
Remote
indication
STATUS
Dry contact for
remote control
© ABB Group
April 20, 2013 | Slide 59
Lightning protection fundamentals
Protection of sensitive
equipments
T2 SPDs in SDB
Protection of the
installation
SDB
T1 SPDs in MDB
MDB
© ABB Group
April 20, 2013 | Slide 60