&Nbsp&Nbsp&Nbsp&Nbsp; Live working safety equipment, each with its own insulation structure. These equipment and appliances are subject to overvoltage from both internal and external sources that are much higher than the normal rated working voltage, which may cause defects in the insulation structure and become latent faults. On the other hand, along with the operation process, the insulation itself will also experience heating and aging under natural conditions, resulting in a decrease. Preventive testing is a comprehensive system of insulation performance diagnosis and detection methods developed to prevent accidents caused by changes in the insulation performance of electrical equipment during operation, targeting these issues and possibilities

 &Nbsp&Nbsp; Testing cycle

According to the national "Preventive Testing Regulations for Electric Power Equipment", the testing cycle for each equipment in the distribution room is as follows:

1) Preventive testing for high-voltage electrical equipment: 10kV indoor electrical equipment is tested every two years

2) 10kV lightning arrester is tested once a year, and it is generally required for substations to be put into operation from April 1st to November 30th

3) 0.4kV lightning arrester shall be tested once a year

4) Power cable project: Insulation resistance once a year

5) Power Transformer Project: Winding insulation resistance and coefficient ratio should be compared every two years 6) Insulation tools (insulated shoes, insulated gloves, high-voltage test pens, high-voltage insulation rods, etc.) are tested every six months

7) Current transformer and voltage transformer projects: The insulation resistance and transformation ratio of the winding should be measured every two years 8) Oil switch project: Insulation resistance once a year 9) Relay protection device project: 10kV once every two years