The 10kV high-voltage switchgear has a large number and wide application range, and its insulation level is very important for the safe operation of the power grid. If an insulation accident occurs in a 10kV high-voltage switchgear, the damage will cause equipment damage, and the large-scale power outage will cause irreparable damage to the country. Therefore, the issue must be carefully studied and effectively resolved.
1 Common Defects and Causes 1.1 Air insulation gap has been small for a long time, some high-voltage switchgear manufacturers, do not strictly implement the relevant technical standards, so that some of the currently operating 10kV high-voltage switchgear cabinets in the phase and phase, phase and ground The air insulation gap is between 100 and 125 mm. As a pure air-insulated electrical equipment, the "Technical Regulations for the Design of High-Voltage Power Distribution Devices" clearly states that the minimum clearance of pure air insulation for a 10kV system is 125mm. From the results of the AC withstand voltage test, combined with the accident analysis, it can be seen that the minimum air insulation gap between the phase and the phase, phase and ground of the charged body in the 10kV high voltage switch cabinet is less than 125mm, and the capacity is accidental.
1.2 Insulation performance of supporting accessories is poor. There are many manufacturers of 10kV high-voltage switchgear in China. In order to reduce the cost, some manufacturers use the accessory with lower insulation level, which causes the pollution flash voltage of the whole switchgear to be reduced, which does not meet the requirements of the rated standard.
According to the "6 ~ 10kV high-voltage switchgear selection principle", combined with the actual operating experience, the author believes that the 10kV high-voltage switchgear equipped with accessories along the surface insulation creepage ratio, should not be lower than the following requirements: porcelain insulation 18mm / kV, Organic insulation is 20mm/kV.
1.3 When using composite insulation, the inside of the 10kV high-voltage switchgear with air gap should not be neglected , and the partition made of insulating material should be added to form the composite insulation mode of the charged body-air gap-insulation partition-grounding body. .
From the actual situation, when using this composite insulation, the air gap cannot be ignored, and the air gap is at least 30 mm, otherwise it is easy to cause insulation accidents.
1.4 Poor operating environment and low maintenance quality Generally speaking, the operating environment of 10kV high-voltage switchgear is poor, often affected by such as dust, smoke, steam, etc., causing the surface of the insulation layer to corrode and generate conductive materials, which constitute insulation defects. There are also individual switchgear units, which do not pay attention to the maintenance and maintenance of equipment, and can not find and eliminate various insulation defects in time, resulting in insulation accidents.
2 Two points suggestion 2.1 The design and manufacturing department of the 10kV high-voltage switchgear should strictly implement the relevant insulation standards, and close the insulation gap and the quality of the parts.
2.2 The unit of use of 10kV high-voltage switchgear must do the AC withstand voltage test before the equipment is put into operation. If the test result does not meet the relevant provisions of the Preventive Test Procedure, it should be resolutely processed for return; 10kV for operation High-voltage switchgear should be fully maintained and repaired, and the operating environment should be improved as much as possible.
1 Common Defects and Causes 1.1 Air insulation gap has been small for a long time, some high-voltage switchgear manufacturers, do not strictly implement the relevant technical standards, so that some of the currently operating 10kV high-voltage switchgear cabinets in the phase and phase, phase and ground The air insulation gap is between 100 and 125 mm. As a pure air-insulated electrical equipment, the "Technical Regulations for the Design of High-Voltage Power Distribution Devices" clearly states that the minimum clearance of pure air insulation for a 10kV system is 125mm. From the results of the AC withstand voltage test, combined with the accident analysis, it can be seen that the minimum air insulation gap between the phase and the phase, phase and ground of the charged body in the 10kV high voltage switch cabinet is less than 125mm, and the capacity is accidental.
1.2 Insulation performance of supporting accessories is poor. There are many manufacturers of 10kV high-voltage switchgear in China. In order to reduce the cost, some manufacturers use the accessory with lower insulation level, which causes the pollution flash voltage of the whole switchgear to be reduced, which does not meet the requirements of the rated standard.
According to the "6 ~ 10kV high-voltage switchgear selection principle", combined with the actual operating experience, the author believes that the 10kV high-voltage switchgear equipped with accessories along the surface insulation creepage ratio, should not be lower than the following requirements: porcelain insulation 18mm / kV, Organic insulation is 20mm/kV.
1.3 When using composite insulation, the inside of the 10kV high-voltage switchgear with air gap should not be neglected , and the partition made of insulating material should be added to form the composite insulation mode of the charged body-air gap-insulation partition-grounding body. .
From the actual situation, when using this composite insulation, the air gap cannot be ignored, and the air gap is at least 30 mm, otherwise it is easy to cause insulation accidents.
1.4 Poor operating environment and low maintenance quality Generally speaking, the operating environment of 10kV high-voltage switchgear is poor, often affected by such as dust, smoke, steam, etc., causing the surface of the insulation layer to corrode and generate conductive materials, which constitute insulation defects. There are also individual switchgear units, which do not pay attention to the maintenance and maintenance of equipment, and can not find and eliminate various insulation defects in time, resulting in insulation accidents.
2 Two points suggestion 2.1 The design and manufacturing department of the 10kV high-voltage switchgear should strictly implement the relevant insulation standards, and close the insulation gap and the quality of the parts.
2.2 The unit of use of 10kV high-voltage switchgear must do the AC withstand voltage test before the equipment is put into operation. If the test result does not meet the relevant provisions of the Preventive Test Procedure, it should be resolutely processed for return; 10kV for operation High-voltage switchgear should be fully maintained and repaired, and the operating environment should be improved as much as possible.
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