1.1 Scope of application :
Test and pre-test for 10kV and above arrestors after overhauling.
1.2 Instruments used in the test :
2500V megohmmeter for 35KV and below;5000V megohmmeter for 35KV and above;Low pressure is measured with 500V megohmmeter.
1.3 Measurement steps :
1.3.1 Disconnect the power supply of the test product, remove or disconnect all external connections, and discharge the test product to earth.The discharge should be carried out with insulating rods and other tools, and the discharge wires should not be touched by hand.
1.3.2 Wipe the dirt on the external insulation surface of the test product with a dry, clean and soft cloth, and wash it with appropriate detergent if necessary.
1.3.3 Mega-ohmmeter terminal "E" is connected to the test grounding terminal, "L" is connected to the high voltage terminal, "G" is connected to the shielding terminal.Shielded wires and insulated shielding rods shall be used for connection.Stable the megohmmeter horizontally. When the speed of the megohmmeter is still rotating at a low speed, connect the terminals "L" and "E" with the wire instantaneously, and the pointer should point to zero.Open circuit, megohmmeter speed up to the rated speed of the pointer should refer to "∞".Then make the megohmmeter stop rotating, connect the ground end of the megohmmeter with the ground wire of the tested product, connect the high voltage end of the megohmmeter with the shielding connecting wire, the other end of the connecting wire is suspended (not to meet the test product), drive the megohmmeter again or connect the power supply, the indication of the megohmmeter should be no obvious difference.Then the megohmmeter stops rotating and connects the shielded connecting wire to the measuring site of the test product.
1.3.4 Drive megohm to express the rated speed, or switch on the power of megohm meter, and read the insulation resistance value after the pointer is stabilized (or 60S).
1.3.5 After reading the insulation resistance, first disconnect the wire connected to the high voltage end of the test product, and then stop the megohmmeter.
1.3.6 After the megohmmeter is disconnected, short discharge and ground the test product.