Product acceptance and preventive testing methods
Preventive testing should be conducted before the product is put into operation and every 12 months during use:
The preventive test method for gapless metal oxide surge arresters (overvoltage protectors) is:
1.1 DC 1mA reference voltage test: Apply DC voltage to both ends (relative to ground) of the lightning arrester (overvoltage protector), and read the voltage value when the current flowing through the lightning arrester (overvoltage protector) stabilizes at 1mA. This value should meet the specifications in the technical parameter table.
1.2 Leakage current test: Apply 0.75 times the DC reference voltage value of 1mA at both ends of the lightning arrester (overvoltage protector), and the current flowing through the lightning arrester (overvoltage protector) should not exceed 50 μ A.
1.3 Gap free metal oxide surge arresters (overvoltage protectors) cannot undergo power frequency discharge voltage tests.
Preventive testing method for metal oxide surge arresters (overvoltage protectors) with series gaps:
2.1 Power frequency discharge voltage test: Connect a 10A or above ammeter in series on the primary side of the test transformer. During the experiment, voltage should be uniformly applied from zero and the ammeter should be observed. When the ammeter experiences a sudden change, it indicates gap discharge, and the voltage value at this time is the power frequency discharge voltage value. After each discharge, the power supply should be cut off within 0.2 seconds. The interval between every two tests shall not be less than 10 seconds, and the number of measurements shall be 3. The average value of the three tests shall comply with the specified values in the technical parameter table.
2.2 Leakage current test: Apply a DC voltage to both ends of the lightning arrester (overvoltage protector), and the applied voltage value is the nominal system voltage of the lightning arrester (overvoltage protector). At this time, the current flowing through the lightning arrester (overvoltage protector) should not exceed 50 μ A.
2.3 Metal oxide surge arresters (overvoltage protectors) with series gaps cannot undergo a DC 1mA reference voltage test.
It is strictly prohibited to conduct insulation withstand tests on lightning arresters (overvoltage protectors). When conducting insulation withstand tests on other equipment in the system, the lightning arrester (overvoltage protector) must be disconnected from the equipment connection.
