What Are the Experimental Requirements for the Leakage Current of the Surge Protector?

1. The value of surge protector discharge current protection equipment

In addition to the discharge current, the lightning protection capability also depends on the test waveform. The outdoor incoming cabinet uses a Class 1 surge protector, and the lightning current waveform is (10/350μs). According to the highest protection standard (explosive environment), the total lightning The current is only 200KA. The biggest risk to the power distribution system is that each line flows through 25KA. For the base station, even if it is designed according to Category 2, the discharge current of each line is 20KA, which meets the protection requirements. The largest 100kA, 200kA, 400kA (8/20μs) products on the market use varistors and diodes that can only be used as Class 2 surge protectors and cannot pass the Class 1 test, which means they cannot be used for outdoor incoming lines The protection of the cabinet, and the maximum discharge current claimed by such products is 100kA, 200kA, 400kA (8/20μs), which is realized by multiple discharge devices in parallel. action and burn. Furthermore, the meaning of the maximum surge protection capability is that it will be damaged after one hit, which cannot be used as the main parameter in the standard.

2. Experimental requirements for leakage current of surge protectors

The leakage current test is an important item in the detection of industrial surge protectors. According to the technical specifications, the test requirements are listed as follows:

(1) The test is only applicable to SPDs with metal oxide varistor (MOV) as the voltage limiting element and no other series-parallel elements.

(2) The leakage current value of the SPD can be measured with a lightning protection component tester or a leakage current test meter.

(3) First, disconnect the backup protection device and confirm that the power supply is disconnected, then directly measure the corresponding module with the instrument, or remove the pluggable SPD from the line for measurement.

(4) Qualification judgment basis: When measuring 1ma for the first time, the measured value of the leakage current of the SPD composed of a single MOV should not exceed the nominal maximum value of the manufacturer; if the leakage current is not declared by the manufacturer, the measured value should not be greater than 20μA. For a surge protector with multiple MOVs connected in parallel, the measured leakage current should not exceed the maximum nominal value of the manufacturer. If the manufacturer declares the leakage current, the measured value should not be greater than 20μA multiplied by the number of MOV valves. When the number of valves cannot be determined, the measured value of the surge protector should not be greater than 20μA.

(5) When the subsequent measurement is 1ma, the measured value of the leakage current of the surge protector composed of a single MOV and multiple MOVs should not be greater than 1 times the first measured value.