3 10 4
3 10 4
3 10 4
Lightning Impulse
n Chopped Lightning Impulse
n Switching Impulse
n Fast Transient
3.10/4 Type IP L, M, G
HIGH-VOLTAGE
IMPULSE TEST
SYSTEMS
12
facts IN BRIEF
APPLICATION
The impulse voltage test systems are applied to test the ability
of equipment for the power grid to withstand transient voltage
peaks, such as those resulting from lightning strokes or switching.
Main applications for lightning impulse voltages are:
Routine tests for power transformers and bushings
(full and chopped impulses)
Routine tests on surge arresters
Sample tests or type tests for medium or high
voltage cables
Type tests on GIS
For higher rated voltage levels also tests with switching impulse
voltage have to be made. Furthermore, the impulse voltage test
systems are also able to generate fast transient impulses. All test
procedures are in accordance with the relevant IEC and IEEE
standards.
Power supply
Test
Object
15
5
7
8
12345
10
U (t)
14
13
11
Power connections
Communication/measurement
Control unit
Charging unit
HV circuit
Impulse generator
Chopping gap
Overshoot compensation
Connection Point
Control system
Operator device
10
Industrial computer
11
12
Ethernet/PROFIBUS
13
LAN, Internet
Measuring system
14
15
GIS testing:
Special inductors for generation of oscillating
lightning and switching impulses
Overshoot compensation
HIGHVOLT impulse generators have a low inductive design. In
comparison with a traditional impulse test system with a separate divider and chopping gap, the circuit inductance is further
reduced due to the compact design of the Connection Point.
Impulse tests with peak voltages higher than UP=2000kV require longer dielectric distances between the components of
the test circuit. The effective parasite inductance of the entire
test circuit is not negligible under the assumption that the connections between the test circuit components have a specific
inductivity of L=1H/m. An overshoot with a value of more than
= 5% can appear, depending on the load of the test object.
An additional overshoot compensation, which is integrated into
the chopping gap, reduces the overshoot and allows the test of
high capacitive load by maintaining the allowed overshoot and
the permitted front time T1. The overshoot is explained in IEC
60060-1.
200kV/div 2s/div
Ch1
Ch2
1600
1400
1200
1000
800
600
400
200
0
-2
CH1:1000MS/s
1800
10
12
14
16
18
in %
1.66
7.5
With compensation
1.52
4.2
Without compensation
1.74
8.5
With compensation
1.52
5.0
HIGHVOLT Prftechnik Dresden GmbH 2014/09 3.10/4.pdf Subject to change without prior notice
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