Surge (shock) immunity test is to simulate
the interference effect caused by lightning strike, but it should be pointed
out that the surge immunity test to assess the EMC performance of equipment is
different from the voltage test to assess the high voltage insulation
capability of the equipment. The former merely simulates the effects of
indirect lightning strikes (devices usually cannot bear direct lightning). The
international standard for surge (shock) immunity test is IEC61000-4-5:2005.
The corresponding national standard is GB/T17626.2:200X《Electromagnetic
Compatibility Test and Measurement Technology Surge (Shock) Immunity Test》
The purpose of this standard is to
establish a common benchmark for evaluating the performance of electrical and
electronic equipment in the event of surge (shock). This standard provides a
consistent test method for evaluating the immunity of equipment or systems to
Open Circuit Test Voltage（10%）
2. Test Configuration
1) Test Equipment
－Equipment under test（EUT）；
－Cable（Specified type and length）；
－Coupling decoupling network；
－Combined wave signal generator；
－Coupling network / protection device；
－When the test frequency is high (such as gas discharge tube
coupling) and the shielding cable is tested, the metal grounding reference
plate is required. Only the typical installation of EUT needs metal grounding
reference plane and it is necessary to connect to the ground reference plane in
2) Test Configuration of EUT Power
The surge of 1.2 / 50s is added to the EUT
power supply through the capacitance-coupled network (see figs. 7, 8, 9 and
10). In order to avoid the adverse effects on the non-tested equipment supplied
by the same power supply and to provide sufficient decoupling impedance for the
surge wave, so as to add required surge to the tested cable, the decoupling
network is needed.
If there is no other provision, the length
of the power line between EUT and coupling / decoupling network should not
exceed 2m. Only ports directly connected to AC and DC power systems are
considered power ports.
3. Test Procedure
1) Laboratory reference condition
In order to minimize the impact of environmental parameters on the test
results, the test should be conducted under the climatic and electromagnetic
environmental baseline conditions specified in 8.1.1 and 8.1.2.
2) Climatic Conditions
Unless otherwise specified in general
standards, industry standards and product standards, the laboratory climate
conditions shall be within the scope of the normal operation of the instruments
specified by the respective manufacturers of the EUT and the test instruments.
Tests should not be conducted if the
relative humidity is so high that condensation occurs on EUT and test
3) Electromagnetic Environment
Electromagnetic environment of laboratory
should not affect the test results.
4) Conducting Surge Tests in the Laboratory
The signal generator and the coupling /
decoupling network should be calibrated before the test. Performance checks are
usually limited for the presence of surge pulses and their voltages and / or
The test shall be conducted in accordance
with the test program, which shall specify the test configuration and shall
include the following elements:
— Test grade (voltage)；
— Surge number;
Unless specified in the relevant product standards, the number of surge pulses
applied on the DC power source and the interconnection line shall be five times
positive and five times negative, and five positive and five negative pulses
shall be applied to the AC power supply port at 0 °/ 90 °/ 180 °/ 270 °phase
— Time interval between continuous
pulses: 1min or shorter；
— Typical working condition of EUT
— Position of the surge applied
The power port (DC or AC) may be an input
or output port.
Note 1: a. It is recommended that the surge be applied to the output ports that
can easily carry the surge into the EUT (e.g. switching load with high power
loss). For example, when secondary circuits (isolated from AC power ports) do
not suffer directly from transient high voltage (e.g., reliably grounded,
capacitance-filtered DC secondary circuits, the ripple of peak value is less
than 10% of that produced by tributary element), the DC input/output of low
voltage (equal or less than 60V) cannot carry out surge test.
b. In the case of several identical lines, only a certain number of lines
should be selected for typical measurements.
c. If the repeat rate of surge in the test is shorter than 1/min and as a
result the EUT goes wrong, and if the 1/min repetition rate is used to test the
EUT and the EUT works normally, the 1/min repetition rate is usually used for
Note 2: If the product is suitable, the
product committee may choose different phase angles, or increase/decrease the
number of surges per phase.
Note 3: a. For common surge protection
devices, although their peak voltage and peak power can withstand large
currents, their average power is low. Therefore, the interval between the two
surges depends on the EUT built-in protection device.
b. When line-ground testing is carried out, if there are no other regulations,
the test should be carried out in turn.
c. The test procedure shall take into
account the nonlinear current-voltage characteristics of the equipment under
test, so that the test voltage can only be incrementally increased from a low
grade to the test level specified in the product standard or test plan / report
and cannot exceed it. All lower grades (including selected test grades) shall
meet the requirements.
d. For the second stage protection test,
the output voltage of the signal generator should be increased to the lowest
voltage breakdown value of the first stage protection. If no actual working
signal source is provided to the EUT, it can be simulated.
e. For acceptance tests, equipment that has
not previously been surge should be used, otherwise protective devices should
be replaced prior to testing.
4. Evaluation of test results
The test results shall be classified
according to the loss of function or deterioration of the performance of the
tested equipment, and the relevant performance level shall be determined by the
manufacturer or the demand party of the equipment, or by the agreement of the
manufacturer and the buyer of the product. It is proposed to classify according
to the following requirements:
a) The performance is normal within the limits specified by the
manufacturer, the client or the purchaser.
b) Temporary loss or reduction of
function or performance, but self-recovery after cessation of harassment
without the need of intervention by the operator;
c) Function or performance is temporarily
lost or reduced, but operator intervention is needed to recover.
d) Unrecoverable loss of function or
reduction of performance due to equipment hardware or software damage or data