Surge Voltage Testing and Its Applications with Surge Testing Machines

I.Electric equipment’s reaction to lightning surge
Most people are familiar with the existence of a lightning surge voltage test. It is mainly used to evaluate the surge resistance of railway signal equipment connected to the power line. But do you know what the implications of a lightning surge would be for electronic devices? Here is a brief explanation of the effect a lightning surge can have on electronic equipment.

LISUN SG61000-5 fully automatic surge voltage test (also called lightning surge immunity test, combination wave generator, surge current generator/surge voltage generator, combined surge voltage and current generator) . 

SG61000-5_Surge Generator

1. Lightning surges occur in microseconds, and voltage and current amplitudes exceed normal values by more than two times. Due to the rapid charging of input filter capacitors, this peak current is far higher than the steady state input current. The power supply should restrict the surge level to which AC switches, rectifiers, fuses, and EMI filters can be exposed. The AC input voltage should not damage the power supply or cause a fuse to burn out due to repeated switching.

2. Voltage fluctuation. In the normal working situation, the surge testing machine will stop or start automatically. The use of electric equipment such as air conditioners, compressors, elevators, pumps or motors often results in an inexplicable reset. Motors often need to be replaced or rewound. Electrical equipment is prone to failure, reset or voltage problems, shortening its service life.

3. Damage to equipment. Voltage breakdown of semiconductor devices, destruction of the metallicized surface of components, destruction of the printed circuit board of printed circuits or contacts, destruction of three-terminal bi-directional thyristors/thyristors, andgate-tristors.

4. Interference with equipment use. Lockouts, thyristors or three-terminal bi-directional thyristors out of control, partial destruction of data files, error and failure of data processing programs, premature aging, pre-mature aging of components, dramatic reduction in the life of appliances, decreased output sound quality and picture quality.

II.Testing Method of Surge Voltage Test

The origin of a surge testing machine is the transient of power system switches and lightning; while the purpose of surge interference test is to establish a common benchmark to evaluate the performance of electrical and electronic equipment when subjected to surges (shocks). According to the general requirements of the IEC61000-4-5 surge interference test standard, the lightning surge generator simulates the 1.2/50us voltage waveform, 8/20us current waveform, and combined waveform (voltage waveform: 10/700us, current waveform: 5/320us). With the coupling network, the waveform is coupled to the circuit under test to achieve the test purpose.

III.Surge Voltage Test  Grades
The test grades of lightning surge tester are divided into Grade 1, 2, 3, 4 and X according to the severity of voltage, as shown in Table 1. Grade X is an open grade, and the corresponding voltage intensity is given for each grade.

The application scope of the severity grade depends on the environment (the environment exposed to the surge possibility) and the installation conditions. It is generally classified according to the following conditions:
Grade 1: Relatively well-protected environment, such as the control room of a factory or power station.
Grade 2: Environment with certain protection, such as factory without strong interference.
Grade 3: Normal electromagnetic interference environment, no special installation requirements for equipment, such as ordinary installed cable networks, industrial workplaces and substations.
Grade 4: Severely disturbed environment, such as civilian overhead lines and unprotected high-voltage substations.
Grade X: Special grade, determined by user and manufacturer consultation. Generally, which grade to choose for specific products is determined by product standards.

IV.Experimental results of Surge Voltage Test
Lightning surge tester testing is a destructive test, which is divided into the following situations according to the degree of damage to the test object:
1. The performance is normal within the limit values specified by the manufacturer, consignor or purchaser.
2. Function or performance temporarily lost or reduced, but can be restored automatically after the disturbance stops, without the intervention of the operator;
3. The function or performance is temporarily lost or reduced, but needs the intervention of the operator to be restored;
4. The hardware or software of the device is damaged or the data is lost, resulting in an irrecoverable loss of function or reduction of performance.