1.2.2 Lightning surges
The largest voltage peaks the low-voltage consumer
network are caused lightning discharges.2.
switching operations involving large inductive loads
such motors.
Induced surge voltages
Induced voltage peaks building installations and en-
ergy data supply cables can also reach many times
the nominal operating voltage and cause the immedi-
ate failure the systems. rule, switching surges amount to
twice three times the operating voltage.g. Permanent
surges caused impermissible conditions the
mains network are not considered transient surges. These de-
pend the exact cause and/or impact point the
lightning discharge.2.
1.1 Transient surges
Transient surges are voltage increases lasting for a
matter microseconds but whose magnitude sev-
eral times that the mains voltage. The damage/loss then categorised
according four different types damage (L1-L4).
1. Lightning
surges can sometimes reach 100 times the nominal
voltage value and transport high energy content.3 Sources and causes damage
according standards
For the purposes the risk analysis according to
IEC/EN 62305-2, lightning strikes are assigned one
of four possible “sources damage” (S1-S4).2.TBS
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1.3 Effects surges
Energy-rich lightning currents often cause the instant-
aneous destruction unprotected systems.
When direct strike hits the external lightning protec-
tion system low-voltage exposed cable, this usu-
ally causes without internal lightning and surge pro-
tection damage the insulation and total outage of
the connected consumers.
Circuit board destroyed surge
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15
Chapter General introduction
.
Lightning surges can sometimes
reach 100 times the nominal
voltage value and contain high
energy content. light-
ning strike can lead three possible sources dam-
age (D1-D3).
Switching surges
Switching surges can arise from various sources, e. the
case small surges, the other hand, failures often
occur only after time delay they accelerate the
aging process the components the affected
devices, causing them insidious damage.2.2. number of
different protection measures are required
