Siemens 3EK7 User Manual
3EK7 Medium Voltage
Silicone Insulated Surge Arresters
Answers for energy.
Setting new Standards
The 3EK7‘s mechanical features:
Glass-collared MOV,
Silicone rubber housing,
FRP rods and
Aluminium end fi ttings.
Three types of 3EK7 surge arresters are available:
3EK7…-. C .. surge arresters according to IEC 60099-4
with metric thread,
3EK7...-. A .. surge arresters according to IEEE Std C 62.11
with imperial thread.
For special applications:
3EK7...-. B .. surge arresters according to IEEE Std C 62.11
with metric thread.
The new 3EK7 surge arrester from Siemens offers superior
protection against power surges for the equipment in
electrical distribution systems with operating voltages
of up to 72.5 kV. Besides being highly resistant to
environmental pollution of all kinds, its performance in
dealing with earth faults and its excellent short-circuit
ratings are setting entirely new standards. The silicone
on the new 3EK7 surge arrester refuses to allow any
deposits of pollution or fi lms of moisture to form on it.
Thus, surface currents caused by pollution will virtually
not occur. The 3EK7 arrester is also very lightweight,
robust and durable, due to its special cage design.
2
3EK7 Design
3
M12 or
Nut, washer
Clamp
End fi tting
Silicone housing,
directly molded
Metal oxide varistor MOV
Glass coating
FRP rods
End fi tting
Nut, washer
M12 or
8
/
inch stainless steel stud
3
8
/
inch stainless steel stud
3EK7 a top quality product
The silicone rubber (SR) housing is
molded directly onto the MOV blocks
and the protection cage. It provides an
excellent sealing system against
moisture ingress and partial discharges.
In addition, the MOV blocks are
glass-collared to prevent aging.
Highest quality materials. SR is highly
hydrophobic and maintains this ability
to repel water and any deposits of
pollution throughout its entire service
life. This results in high tracking and
erosion resistance. Furthermore, the
SR housing is self-extinguishing and
fl ame-retardant. These advantages
provide maintenance free and reliable
service life for 3EK7 arresters.
Manufacturing plants are certifi ed
under ISO 9001 and ISO 14001.
3EK7 arresters have been type tested
by an independent test laboratory.
Secure and reliable design
The 3EK7 series is based on a cage
of pre-stressed fi ber-reinforced plastic
rods for high mechanical strength,
reducing the risk of internal components
being ejected. In the extremely rare
event of the resistors being overloaded,
arcing cannot result in a build-up of
critical internal pressure, since the
resistors are not enclosed in a sealed
mechanical shell. Thus, the arc can
escape through the silicone sheath,
leaving the mechanical support
structure of the enclosure unharmed.
The cage is lightweight design and yet
it offers excellent torsional, tensile and
cantilever strength: Maximum working
cantilever strength of 350 Nm.
SR is resistant to UV and ozone exposure
as well as to all common organic and
non-organic solvents and cleaning
agents. Therefore, the 3EK7 is suitable
for any environmental conditions of
industrial areas as well as in desert or
coastal regions.
3EK7 arresters are suitable for a
temperature range from –55° C to +50° C.
Application altitude up to
3600 m a.s.l.
Fast delivery
Flexibility in production and in our
global network of service and sales
facilities provide fast and prompt
supply e. g. shipment ex stocks within
six days after your order has been
received for the surge arresters marked
with asterisk (*) (Refer to table on
page 4 and 6).
3
3EK7 Arresters According to IEC 60099-4
Selection and Main Data
Voltage per unit U
1.25
1.2
1.15
1.1
1.05
1
0.95
0.9
0.85
0.8
0.1 1 10 100 1000
r
Preheating to 40° C
Preheating to 60° C and stressing
with rated energy
Time in seconds
Table 1: IEC power-frequency voltage versus time characteristic
Nominal discharge current I
Maximum continous operating voltage U
Rated voltage U
Long duration current impulse 150 A 325 A
High current pressure relief 20 kA 20 kA
Low current pressure relief 600 A 600 A
High-current impulse 65 kA 100 kA
Maximum permisible static service load 280 Nm 350 Nm
Maximum permisible service load (MPSL) 400 Nm 500 Nm
Energy absorption capability 2.2 kJ/kV U
r
n
c
5 kA 10 kA
48 kV 48 kV
60 kV 60 kV
r
3.5 kJ/kV U
Table 2: 3EK7 arrester main data
Highest
voltage
for
equipment
U
m
[kV]
2.75 30; 45; 60 3EK7 030-.C.. 3EK7 050-.C.. 3EK7 030-.C.. 3EK7 050-.C..
3.6 20; 40 3EK7 030-.C.. 3EK7 050-.C.. 3EK7 030-.C.. 3EK7 050-.C..
5.5 45; 60; 75 3EK7 050-.C.. 3EK7 090-.C.. 3EK7 060-.C.. 3EK7 090-.C..
7.2 40; 60 3EK7 060-.C.. 3EK7 090-.C.. 3EK7 090-.C.. 3EK7 090-.C..
8.25 60; 75; 95 3EK7 090-.C.. 3EK7 105-.C.. 3EK7 090-.C.. 3EK7 105-.C..
12 60; 75; 95
15.5 75 3EK7 120-.C.. - 3EK7 150-.C.. -
15.5 85; 110 3EK7 120-.C.. 3EK7 210-.C.. 3EK7 150-.C.. 3EK7 210-.C..
17.5 75 3EK7 150-.C.. - 3EK7 180-.C.. -
17.5 95 3EK7 150-.C.. 3EK7 220-.C.. 3EK7 180-.C.. 3EK7 220-.C..
24 95 3EK7 210-.C.. - 3EK7 240-.C.. -
24 125; 145 3EK7 210-.C.. 3EK7 300-.C.. 3EK7 240-.C.. 3EK7 300-.C..
25 125; 145 3EK7 210-.C.. 3EK7 315-.C.. 3EK7 250-.C.. 3EK7 315-.C..
27 95 3EK7 210-.C.. - - -
27 125 3EK7 210-.C.. - 3EK7 270-.C.. -
27 150 3EK7 210-.C.. 3EK7 360-.C.. 3EK7 270-.C.. 3EK7 360-.C..
30 160 3EK7 240-.C.. 3EK7 390-.C.. 3EK7 300-.C.. 3EK7 390-.C..
36 145 3EK7 300-.C.. - 3EK7 360-.C.. -
36 170 3EK7 300-.C.. 3EK7 450-.C.. 3EK7 360-.C.. 3EK7 450-.C..
38 125 3EK7 300-.C.. - - -
38 150 3EK7 300-.C.. - 3EK7 390-.C.. -
38 200 3EK7 300-.C.. 3EK7 480-.C.. 3EK7 390-.C.. 3EK7 480-.C..
40.5 190 3EK7 315-.C.. 3EK7 510-.C.. 3EK7 420-.C.. 3EK7 510-.C..
48.3 150 3EK7 390-.C.. - - -
48.3 200 3EK7 390-.C.. - 3EK7 480-.C.. -
48.3 250 3EK7 390-.C.. 3EK7 600-.C.. 3EK7 480-.C.. 3EK7 600-.C..
52 250 3EK7 420-.C.. - 3EK7 540-.C.. -
72.5 325 3EK7 570-.C.. - - -
Rated
lightning
impulse
withstand
voltage
[kV]
Solidly earthed
neutral system
3EK7 090-.C..
or
3EK7 105-.C..
Isolated neutral
system
3EK7 150-.C.. 3EK7 120-.C.. 3EK7 150-.C..
Impedance earthed
neutral system
Resonant earthed
neutral system
Table 3: Typical 3EK7 arresters for system voltages according to IEC 60099-4
4
Rated
voltage U
[kV] [kV]
10.5* 8.4 3EK7 105 -2CB4 24.4
12* 9.6 3EK7 120 -2CC4 27.8
15* 12 3EK7 150 -2CC4 34.7
21* 16.8 3EK7 210 -2CD4 48.6
31.5 25.2 3EK7 315 -2CH4 72.9
r
Continuous
operating
r
voltage U
3 2.4 3EK7 030 -2CB4 7.0
6 4.8 3EK7 060 -2CB4 14.0
9* 7.2 3EK7 090 -2CB4 20.9
18 14.4 3EK7 180 -2CD4 41.7
24 19.2 3EK7 240 -2CE4 55.5
27 21.6 3EK7 270 -2CF4 62.6
30 24 3EK7 300 -2CF4 69.3
33 26.4 3EK7 330 -2CH4 76.4
36 28.8 3EK7 360 -2CH4 83.3
39 31.2 3EK7 390 -2CH4 90.5
42 33.6 3EK7 420 -2CH4 97.4
45 36 3EK7 450 -2CH4 104
48 38.5 3EK7 480 -2CK4 111
51 41 3EK7 510 -2CK4 118
54 43.2 3EK7 540 -2CK4 125
57 45.6 3EK7 570 -2CK4 132
60 48 3EK7 600 -2CK4 139
c
Arrester
part number
1 kA
8/20 µs
[kV cr]
Table 4: 3EK7 nominal discharge current 5 kA
Rated
voltage U
[kV] [kV]
10.5* 8.4 3EK7 105 -4CB4 22.8
12* 9.6 3EK7 120 -4CC4 25.9
15* 12 3EK7 150 -4CC4 32.3
18* 14.4 3EK7 180 -4CD4 38.8
21* 16.8 3EK7 210 -4CD4 45.3
22* 17.6 3EK7 220 -4CE4 47.5
24* 19.2 3EK7 240 -4CE4 51.7
30* 24 3EK7 300 -4CF4 64.6
31.5 25.2 3EK7 315 -4CH4 67.9
36* 28.8 3EK7 360 -4CH4 77.6
50.5* 40.5 3EK7 505 -4CK4 107
Continuous
operating
r
voltage U
3 2.4 3EK7 030 -4CB4 6.6
5 4 3EK7 050 -4CB4 10.8
6 4.8 3EK7 060 -4CB4 13.0
9* 7.2 3EK7 090 -4CB4 19.4
25 20 3EK7 250 -4CE4 53.9
27 21.6 3EK7 270 -4CF4 58.2
33 26.4 3EK7 330 -4CH4 71.1
39 31.2 3EK7 390 -4CH4 84.2
42 33.6 3EK7 420 -4CH4 90.7
45 36 3EK7 450 -4CH4 97.2
48 38.5 3EK7 480 -4CK4 104
51 41 3EK7 510 -4CK4 110
54 43.2 3EK7 540 -4CK4 117
57 45.6 3EK7 570 -4CK4 123
60 48 3EK7 600 -4CK4 130
c
Arrester
part number
1 kA
8/20 µs
[kV cr]
Table 5: 3EK7 nominal discharge current 10 kA
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