10kV high-voltage switchgear has a large number and a wide range of applications, and its insulation level plays an important role in the safe operation of power grid. If an insulation accident occurs in a 10kV high-voltage switchgear, the harm will be light, which will cause equipment damage, and heavy, which will cause a large-scale power outage and cause irreparable losses to the country. Therefore, it is necessary to study this problem seriously and solve it effectively.

Two suggestions

The design and manufacturing departments of 1.10kV high-voltage switchgear should strictly implement the relevant insulation standards and ensure the insulation gap and the quality of accessories.

Before the equipment is put into operation, the user of 2.10kV high-voltage switchgear must do a good job of AC withstand voltage test. If the test results do not conform to the relevant provisions of the Preventive Test Regulations, they should resolutely return the goods. The 10kV high-voltage switchgear in operation should be fully maintained and overhauled, and the operating environment should be improved as much as possible. Common defects and their causes

Matching accessories have poor insulation performance.

There are many manufacturers of 10kV high-voltage switchgear in China. In order to reduce the cost, some manufacturers use accessories with low insulation level, resulting in the reduction of pollution lightning voltage of the whole switchgear, which can not meet the rated standards. According to the Selection Principle of 6-10kV High Voltage Switchgear, combined with practical operation experience, the author thinks that the creepage ratio of the accessories of 10kV High Voltage Switchgear should not be lower than the following requirements: porcelain insulation 18mm/kV and organic insulation 20mm/kV.

Small air insulation gap

For a long time, some manufacturers of high-voltage switchgear did not strictly implement the relevant technical standards, so that the air insulation gaps between phases and between phases and ground of electrified bodies in some 10kV high-voltage switchgear in operation at present are mostly between 100-125 mm. As an electrical equipment with pure air insulation, the Technical Specification for Design of High Voltage Distribution Equipment clearly stipulates that the minimum gap of pure air insulation in 10kV system is 125 mm. From the results of AC withstand voltage test and accident analysis, it can be seen that the minimum air insulation gaps between phases and between phases and between phases and between phases and ground in the 10kV high-voltage switchgear are less than 125mm, and the capacity has an accident.

When using composite insulation, air gap should not be ignored.

Some 10kV high-voltage switch cabinets are equipped with partitions made of insulating materials to form a composite insulation mode of charged body-air gap-insulating partition-grounding body. From the actual situation, when using this kind of composite insulation, we can't ignore the air gap, and the air gap is at least 30mm, otherwise it will easily lead to insulation accidents.

Poor operation environment and low maintenance quality.

Generally speaking, the operating environment of 10kV high-voltage switchgear is poor, and it is often attacked by dust, smoke, steam, etc., so that the surface of insulation layer is corroded and conductive substances are generated to form insulation defects. There are also individual switchgear users who do not pay attention to the overhaul and maintenance of equipment, and cannot find and eliminate various insulation defects in time, which eventually leads to insulation accidents.