Surge- and Pulse Immunity Testing

Lightning- and surge- or NEMP- protection components are subject to various international standards. To prove conformity HUBER+SUHNER AG has set up a pulse-test laboratory with various pulse generators. All tests are based on the direct injection principle, i.e. the surge is directly loaded between centre conductor and outer conductor of the coaxial D.U.T. By means of an extremely fast oscilloscope the residual pulse can be analysed at the output of the device under test.

This document shall help to get along with the various international EMC standards that are relevant to coaxial (N)EMP and surge protectors and give you an update about the test equipment which is available in the HUBER+SUHNER pulse-test lab:

Electrostatic Discharge Immunity Test (ESD)
- IEC 61000-4-2
Direct Lightning
- IEC 62305-1 waveform 10/350 µs
Surge Tests
- IEC 61000-4-5 , waveforms (1.2/50 µs; 8/20 µs)
High Altitude Electromagnetic Pulse (HEMP / NEMP)
- Mil-Std-188-125-1; Mil-Std-188-125-2, Mil-Std-464
- IEC 61000-2-9, IEC-77
- VG-96903-78, VG-96903-80, VG-95371-10

This document is not containing all aspects of pulse testing, it shall only help the reader to find his way through this subject and give hints where further information can be found.

ESD Tests acc. to IEC 61000-4-2

ESD stands for electrostatic discharge. The sudden electric current that flows between two objects at different electrical potentials can cause equipment or components to fail, create system downtime or lead to catastrophic failure depending of the place of the application. The theory distinguishes between three ESD test models: the MM or machine to machine model, the CDM or charged device model and the human body model ( HBM). In our lab we can apply the HBM.

The human body model or HBM testing:
This ESD test simulates an electrical discharge of a human body onto an electronic component or equipment. Through the triboelectric effect a human body can build up residual charge in dry atmosphere when moving on in specific cloth on specific ground (i.e. carpet).

ESD waveform; Test Voltage 2, 4, 6 or 8 kV

Direct Lightning pulse acc. to IEC 62305-1 (current pulse 10/350 µs)

This test simulates direct lightning strikes (current waveform 10/350 µs) into outdoor installations (antennas, cables, coaxial components etc.). This test is used to find the current handling limits of the lightning protectors and to optimize our products during the design phase. The maximum current our generator can perform is 25kA (10/350 µs)

Current waveform 10/350 µs
Front time: T₁ = 10µs
Time to half value: T₂ = 350µs

Surge pulse acc. to IEC 61643-21 (current pulse 8/20 µs)

This current pulse generator is capable to produce current pulse shapes in shorted circuits. It is used to simulate induced lightning currents. It can generate maximum currents up to 112kA (8/20 µs) and is used to find the overstress current and to define the respective fault mode.

Current waveform 8/20 µs
Front time: T₁ = 8 µs
Time to half value: T₂ = 20µs

Surge tests acc. to IEC 61000-4-5, combination waveform (Voltage: 1.2/50 µs; Current: 8/20 µs)

Surge tests on our protectors are generally non-destructive tests. They are applied to prove the efficiency of our protectors or to benchmark various products. This generator can perform voltage amplitudes up to 24 kV and current amplitudes up to 12 kA.

Combination wave generator 1.2/50 µs - 8/20 µs

Voltage waveform 1.2/50 µs
Front time: T₁ = 1.2 µs
Time to half value: T₂ = 50 µs

HEMP/NEMP Surge tests acc. to IEC 61000-2-9 and VG 96903-80, LF80 and VG 96903-78, LF 78; waveform (Voltage: 5/200 ns)

This generator simulates the High Altitude Nuclear Electromagnetic Pulse HEMP/ NEMP which is specified in various non classified standards as a double exponential transient with a few nanoseconds rise time. The maximum output voltage amplitude is defined with >10 kV and its maximum current amplitude is 1 kA.

E(t)=E₀k(e^-αt-e^-βt)

Voltage waveform 5/200 ns
Front time: T₁ = 5 ns
Time to half value: T₂ = 200 ns

Surge pulse acc. to ITU-T K.20 (voltage pulse 10/700 µs)

This pulse generator simulates high energy transient pulses occurring on long unshielded telecommunication-, signal- and control lines due to lightning (capacitive coupling).

Voltage waveform 10/700 µs
Front time: T₁ = 10 µs
Time to half value: T₂ = 700 µs

Damped sine-waves acc. to IEC 61000-4-12 (100 kHz ring wave)

This generator supplies damped oscillatory waves which occur at equipment terminals as a consequence of switching events in power and control lines and due to lightning strikes.

Damped sine-waves acc. to MIL-STD-461 (10MHz, 30MHz, 70MHz ring wave)

This generator supplies damped oscillatory waves which occur at equipment terminals as a consequence of switching events in power and control lines and due to lightning strikes. CS10 is specified for testing Naval equipment, subsystems interface pins and terminals of power leads, control leads and signal leads. CS11 is specified for testing Naval equipment and subsystems having interconnection and interconnecting control, signal or power cables.

Generator with three damped sine-waves:

10 MHz max. 3000 V

30 MHz max. 3000 V

70 MHz max. 1500 V

*HUBER+SUHNER disclaims any liability resulting from incorrect installation and use, including any damages resulting from the use of tools and accessories other than the ones recommended herein.

This EMP Protector Tool Box is subdivided in four parts:

EMP Protector SELECTION Program
GDT SELECTION Program
HEMP Calculation Program
Connector RF Power Chart

To jump to another program part press

In addition you can find "Technical Notes":

"Surge- and Pulse Immunity Testing" and the available hardware in our pulse laboratory.
Screening effectiveness and transfer impedance". This paper helps to define the optimal design, material and plating for (N) EMP protectors which must fit into NEMP proof shelters.
"Electrochemical corrosion prevention"
"RF power and DC current ratios of various interfaces"
"Protection against electromagnetic fields"
"Lightning vs. HEMP residual pulse"

A button called "Helpful Information" unveils further useful documents such as:

"Maintenance" (Recommendations and available test instruments)
NATO registered protectors.

In the following sections you can find out more about the EMP Protector Tool Box.

EMP SELECTION

The EMP SELECTION Program is a tool which helps you to find the best suitable surge-, lightning- or EMP protector for the given input parameters. Just answer five questions:

What DC voltage must pass through the EMP protector (0 - 60V)?
What is the system impedance: 50 Ω, 75 Ω, 100 Ω?
Is passive intermodulation (PIM) specified: YES, NO?
Define the lower and the upper frequency band limits.
Define the CW power of up to four transmission channels on the feeder line. Note that this is optional information.

The program now selects one or more protector families out of a list of nine which fit to the given input data. The selected families are highlighted while the rest is faded-out. To narrow the potential candidates down the list gives typical information about:

Residual energy and residual voltage acc. to IEC 61000-4-5
Typical PIM level if applicable
Recommended Gas discharge tube based on a system VSWR 1.22 : 1

As additional information you can read the peak voltage on the center conductor based on the CW RF-power with zero modulation given as input. To make sure that a Gas discharge tube will not ignite due to the RF-power the program also calculates the peak voltage with a security factor of 1.5.

You can hide the inactive (faded) protector families by clicking on the "Hide inactive" button. Vice versa you can make all again visible with the "Show inactive" button.
By clicking on a product in the list of the selected protector families you open a page which describes this specific protector family in more details.
To select a specific product out of this family you have the possibility to jump to the specific page in the lightning protector catalogue by clicking the button "See product in catalogue"

Note: Not all available products are listed in the catalogue. For special requirements call your closest Huber+Suhner sales engineer or our product manager in the headquarter in Switzerland!

GDT SELECTION

The GDT SELECTION Program is a tool which helps you to select the best suitable Gas Discharge Tube for the given input parameters.

Just answer five questions:

RF CW power in Watts (max. 100kW) or dBm (max. 80dBm)?
DC supply voltage (0-60V ) ?
VSWR of the Antenna feeder line ?
Impedance of the Feeder line?

The program selects the correct GDT out of nine possible Gas Discharge Tubes (U_Z(stat) : 90 V to 2500 V) which fits the specific application. In addition it lists the Peak voltage and the Peak voltage with a security factor of 1.5 with zero modulation.
Note: See how the peak voltage will change by changing the System VSWR.

HEMP CALCULATION

The HEMP CALCULATION Program simulates the worst case coupled transient voltage and current of High altitude nuclear pulses (H)EMP into Monopole and Dipole antennas. The program is working with seven unclassified electromagnetic pulse standards.

As input the program asks for:

Antenna Length
Antenna Diameter
Antenna Design
Threat parameters (unclassified (H)EMP pulse standard)
"Transient voltage" or "Transient current" calculation?

The program calculates and plots the selected transient pulse response (voltage/current and energy). By clicking the "HEMP scenario" button a text describing the theory is opened.

CONNECTOR RF POWER

The Connector and RF Power window opens a graph which shows the admissible RF (CW) power vs. frequency of the nine most common interfaces used for lightning/EMP protectors. The graph is calculated at 25 °C /sea level, VSWR 1.0 with zero modulation.

GDT Type	U_{z (stat)}		min. V
9071.99.0548	90 V	+/-20%	72
9071.99.0547	230 V	+/-15%	196
9071.99.0549	350 V	+/-15%	298
9071.99.0550	470 V	+/-15%	400
9071.99.0551	600 V	+/-15%	510
9071.99.0052*	900 V	+/-15%	765
9071.99.0053*	1200 V	+/-15%	1020
9071.99.0054*	1500 V	+/-15%	1275
9071.99.0055*	2500 V	+/-20%	2000
* Non standard values on request

Input: