The general requirements for the selection of gapless metal oxide arrester manufacturers are as follows:

(1). The ambient conditions for the use of the arrester should be determined according to the temperature, altitude, wind speed, pollution and earthquake in the area of use, and according to the nominal voltage of the system, the highest voltage of the system, the rated frequency, the neutral grounding method, and the short-circuit current value. And conditions such as the duration of the ground fault determine the system operating conditions of the arrester.

(2) Determine the type of arrester according to the object to be protected.

(3) Determine the continuous operating voltage of the arrester according to the highest voltage acting on the arrester for a long time.

(4) Select the rated voltage of the arrester according to the amplitude and duration of the temporary overvoltage at the installation location of the arrester.

(5) Estimate the amplitude of the discharge current through the arrester, and select the nominal discharge current of the arrester.

(6) According to the rated lightning impulse withstand voltage and rated operating impulse withstand voltage of the protected equipment, and according to the requirements of insulation coordination, determine the lightning overvoltage protection level and operating overvoltage protection level of the arrester.

(7) Estimate the impulse current and energy passing through the arrester, select the test current amplitude of the arrester, the discharge endurance test level and energy absorption capacity of the cold-shrinkable cable terminal line.

(8) According to the maximum fault current where the arrester is installed, select the pressure release level of the arrester.

(9) According to the degree of environmental pollution where the arrester is installed, select the leakage distance of the arrester porcelain sleeve.

(10) Choose its mechanical strength according to the wire tension, wind speed and earthquake conditions of the arrester installation

(11) When the arrester does not meet the requirements of insulation coordination, remedial measures such as appropriately reducing its rated voltage or nominal discharge current level or increasing the insulation level of the protected equipment can be taken.