Lightning surge tolerance test

2018-07-23 11:54:14 SUSHI GUANGBO TEST TECHNOLOGY CO.,LTD 已读
Lightning surge tolerance test
 
Overview
 
The international standard on which the surge immunity test is based is IEC61000-4-5:2005, and the corresponding national standard is GB/T17626.2:200X "Electromagnetic compatibility test and measurement technology surge (impact) immunity test".
 
Surge (impact) immunity test is to simulate the interference effect caused by lightning strikes, but it should be pointed out that the surge immunity test of the electromagnetic compatibility performance of the assessment equipment is different from the withstand voltage test of the high-voltage insulation capability of the assessment equipment. The former is only It is the effect of simulating indirect lightning strikes (direct lightning strikes are usually unacceptable).
 
Surge (impact) immunity test purpose
 
The purpose of this standard is to establish a common benchmark to evaluate the performance of electrical and electronic equipment in the event of a surge (impact). This standard specifies a consistent test method to assess the immunity of equipment or systems to specified phenomena.
 
Surge (impact) immunity test application
 
This standard applies to electrical and electronic equipment, but does not target a specific equipment or system, and has the status of a basic EMC electromagnetic compatibility publication.
 
Terms and definitions
 
(1) Surge (shock)
 
The transient wave of current voltage or power transmitted along the line is characterized by a rapid rise and then a slow decline.
 
(2) Combined wave signal generator
 
A signal generator capable of generating a 1.2/50μs open-circuit voltage waveform, an 8/20μs short-circuit current waveform, or a 10/700μs open-circuit voltage waveform, and a 5/320μs short-circuit current waveform.
 
(3) Coupling network
 
A circuit that transfers energy from one circuit to another.
 
(4) Decoupling network
 
A circuit used to prevent surges applied to affect other equipment or systems that are not tested.
 
(5) equivalent output impedance of the (surge generator)
 
The ratio of the open circuit voltage peak to the short circuit current peak value.
 
(6) Symmetry line
 
The differential mode to the common mode conversion loss is greater than 20dB of equilibrium alignment.
 
Test level and selection
 
The preferred test level ranges are shown in Table 1.
 
Table 1 Test level
 
grade
Open circuit test voltage (±10%) kV
1
0.5
2
1.0
3
2.0
4
4.0
1)
special
1) “ ́” can be a level above, below or between other levels. This level can be specified in the product standard.
The test level should be based on the installation conditions, and the installation categories are as follows:
 
Class 0: A well-protected electrical environment, often in a dedicated room.
 
All drop cables have overvoltage protection (first and second). Each electronic equipment unit is interconnected by a well-designed grounding system, and the grounding system is not affected by electrical equipment or lightning at all.
 
Electronic equipment has a dedicated power supply (see Table A1)
 
The surge voltage cannot exceed 25V.
 
Class 1: A partially protected electrical environment
 
All cables introduced into the room have overvoltage protection (first stage). Each device is well connected to each other by a ground network, and the ground network is not affected by electrical equipment or lightning.
 
Electronic devices have a power supply that is completely isolated from other devices.
 
Switching operation can generate interference voltages indoors.
 
The surge voltage cannot exceed 500V.
 
Category 2: The cable is well isolated, and even short traces are also isolated from the good electrical environment.
 
The equipment group is connected to the grounding system of the power equipment through a separate ground wire, and the grounding system almost encounters the interference voltage generated by the equipment group itself or lightning. The power supply of electronic equipment is mainly isolated by other transformers.
 
There are unprotected lines in this type of device group, but these lines are well isolated and limited in number.
 
The surge voltage cannot exceed 1kV.
 
Category 3: Electrical environment in which the power cable and signal cable are laid in parallel.
 
The equipment group is grounded to the ground through a common grounding system of the electrical equipment. The system almost always encounters interference voltages generated by the device group itself or by lightning.
 
In an electrical facility, currents caused by ground faults, switching operations, and lightning strikes can generate higher amplitude interference voltages in the grounded system. Protected electronic devices and less sensitive electrical devices are connected to the same power network. The interconnect cable can have a portion that is outdoors but close to the ground grid.
 
There are uninhibited inductive loads in the device group and there is usually no isolation for different field cables.
 
The surge voltage cannot exceed 2kV.
 
Category 4: Interconnect lines are laid along the power cable as outdoor cables and these cables are connected to the grounding system of the electrical equipment as an electrical environmental equipment group of electrical and electrical circuits that is susceptible to interference voltages generated by the equipment group itself or by lightning. .
 
In an electrical facility, thousands of amps of current generated by ground faults, switching operations, and lightning can generate higher amplitude interference voltages in the grounded system. Electronic and electrical devices may use the same power network. Interconnect cables are routed like outdoor cables or even connected to high voltage equipment.
 
A special case in this environment is that the electronic device is connected to a communication network in a densely populated area. At this time, outside the electronic device, there is no grounding network with a systematic structure, and the grounding system is composed only of pipes, cables, and the like.
 
The surge voltage cannot exceed 4kV.
 
Category 5: Electrical environment in which electronic equipment is connected to communication cables and overhead power lines in non-populated areas.
 
All of these cables and lines have overvoltage (first level) protection. There are no large-scale grounding systems (exposed devices) outside of electronic equipment. The interference voltage caused by ground fault (current up to 10Ka) and lightning (current up to 100Ka) is very high.
 
Test level 4 includes requirements for this category.
 
Class X: The special environment specified in the technical requirements of the product.
 
The relationship between surges (signal generators) and installation categories is as follows:
 
1 - 4 categories: 1.2/50μs (80/20μs)
 
Category 5: For power line ports and short-range signal circuits/line ports: 1.2/50μs (80/20μs)
 
1 - 5 categories: symmetric communication lines: 10/700μs (5/320μs)
 
The source impedance should be the same as noted in the relevant test configurations.
 
11. Power frequency magnetic field tolerance test
 
Stable continuous power frequency magnetic field immunity test level
 
1).1A/m ;
 
2).3A/m;
 
3).10A/m;
 
4).30A/m;
 
5).100A/m;
 
6).X/to be determined
 
Power frequency magnetic field immunity laboratory room climatic conditions
 
Temperature: 15 to 35 degrees
 
Relative humidity: 25%-75%
 
Atmospheric pressure: 86-106kPa.
 
Evaluation of the test results of power frequency magnetic field immunity
 
The power frequency magnetic field test results shall be classified according to the loss of function or performance degradation of the EUT. These classifications are related to the manufacturer's, the requirements specified by the tester, or the performance level agreed between the manufacturer and the user. The recommended classification is as follows:
 
A) normal performance within the limits specified by the manufacturer, applicant or user;
 
B) The function or performance is temporarily reduced or lost, but the device under test can resume its normal performance after the disturbance has ceased, without operator intervention;
 
C) The function or performance is temporarily reduced or lost, but requires operator intervention to recover normally;
 
D) The function of the hardware or software is damaged, or the data is lost, and the function that cannot return to the normal state by itself is reduced or lost. The manufacturer's specifications can specify which responses to the EUT can be ignored or acceptable.
 
In the absence of suitable GM, product or product standards, this classification may be developed by a professional standardization technical committee responsible for the corresponding product as a guide to clear functional guidelines or as a framework for performance specifications negotiated between the manufacturer and the purchaser.
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