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 fittings.

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 films 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.

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3EK7 Design

M12 or 3/8 inch stainless steel stud

Nut, washer

Clamp

End fitting

Silicone housing, directly molded

Metal oxide varistor MOV

Glass coating

FRP rods

End fitting

Nut, washer

M12 or 3/8 inch stainless steel stud

3EK7 a top quality product	Secure and reliable design	Fast delivery

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 flame-retardant. These advantages provide maintenance free and reliable service life for 3EK7 arresters. Manufacturing plants are certified under ISO 9001 and ISO 14001.

3EK7 arresters have been type tested by an independent test laboratory.

The 3EK7 series is based on a cage

of pre-stressed fiber-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.

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).

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3EK7 Arresters According to IEC 60099-4 Selection and Main Data

Voltage per unit Ur

1.25

1.2

Preheating to 40° C

Preheating to 60° C and stressing

1.15

with rated energy

1.1

1.05

1

0.95

0.9

0.85

0.8

0.1

1

10

100

1000 Time in seconds

Table 1: IEC power-frequency voltage versus time characteristic

Nominal discharge current In

5 kA

10 kA

Maximum continous operating voltage Uc

48 kV

48 kV

Rated voltage Ur

60 kV

60 kV

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 Ur

3.5 kJ/kV Ur

Table 2: 3EK7 arrester main data

Highest

Rated

Solidly earthed

Isolated neutral

Impedance earthed

Resonant earthed

voltage

lightning

neutral system

system

neutral system

neutral system

for

impulse

equipment

withstand

Um

voltage

[kV]

[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..

3EK7 090-.C..

12

60; 75; 95

or

3EK7 150-.C..

3EK7 120-.C..

3EK7 150-.C..

3EK7 105-.C..

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..

-

-

-

Table 3: Typical 3EK7 arresters for system voltages according to IEC 60099-4

Rated	Continuous	Arrester
	operating
voltage Ur		part number
	voltage Uc
				1 kA
				8/20 µs
[kV]	[kV]			[kV cr]
3		3EK7 030 -2CB4		7.0
	2.4
6	4.8	3EK7 060 -2CB4		14.0
9*	7.2	3EK7 090 -2CB4		20.9
10.5*	8.4	3EK7 105 -2CB4		24.4
12*	9.6	3EK7 120 -2CC4		27.8
15*	12	3EK7 150 -2CC4		34.7
18	14.4	3EK7 180 -2CD4		41.7
21*	16.8	3EK7 210 -2CD4		48.6
24	19.2	3EK7 240 -2CE4		55.5
27	21.6	3EK7 270 -2CF4		62.6
30	24	3EK7 300 -2CF4		69.3
31.5	25.2	3EK7 315 -2CH4		72.9
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

Table 4: 3EK7 nominal discharge current 5 kA

Rated	Continuous	Arrester
	operating
voltage Ur		part number
	voltage Uc
				1 kA
				8/20 µs
[kV]	[kV]			[kV cr]
3		3EK7 030 -4CB4		6.6
	2.4
5	4	3EK7 050 -4CB4		10.8
6	4.8	3EK7 060 -4CB4		13.0
9*	7.2	3EK7 090 -4CB4		19.4
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
25	20	3EK7 250 -4CE4		53.9
27	21.6	3EK7 270 -4CF4		58.2
30*	24	3EK7 300 -4CF4		64.6
31.5	25.2	3EK7 315 -4CH4		67.9
33	26.4	3EK7 330 -4CH4		71.1
36*	28.8	3EK7 360 -4CH4		77.6
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
50.5*	40.5	3EK7 505 -4CK4		107
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

Table 5: 3EK7 nominal discharge current 10 kA

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