At this stage, high-voltage switchgear is widely used. The total number of switchgear is large, but common failures will cause consequences. And switch cabinets are often abnormal, which will affect all bus ducts or adjacent switch cabinets. Cause regional power outages or larger-scale power outages. Chi Yanjun will introduce the reasons and preventive measures for charging and discharging of high-voltage switchgear in detail.
High-voltage switchgear charging and discharging reasons:
1. The installation steps are not scientific. When assembling the high-voltage switchgear, the gap between the outer skirt of the voltage transformer and the insulating plate also gives resource advantages to the partial discharge of the high-voltage switchgear; the sealing performance of the heat-shrinkable protective cover of the cable room is not compliant. Gauge, insulator and edge of small box will also generate floating potential difference to charge and discharge. The screws are fixed irregularly, and there are too many nuts after tightening; the sealing of the heat shrinkable box is not tight, and it is very easy to charge and discharge after opening the mouth; the voltage transformer box in the tentacle box is arranged once, and the included angle is too small. At the same time, in the harsh environment of the high-voltage chamber, the insulation materials are prone to physical transformation, which has a negative impact on electrical performance. This unreasonable installation procedure can also lead to partial discharge in the high-voltage switchgear.
2. The insulation structure is unscientific. Unreasonable insulation structure is a frequent problem in the transportation and production process of high-voltage switchgear. The most common is that the insulation structure contains residues, burrs, bubbles, and dirt. This unreasonable insulation structure will also lead to uneven distribution of the electrostatic field in the internal structure of the high-voltage switchgear insulator, and partial discharges are prone to occur in areas with weak insulation. In the early stage of partial discharge, the insulating structure of the switchgear is generally not permeable, but partial discharge will still cause partial damage to the insulating material. If the partial discharge situation cannot be alleviated in time and further developed, it will lead to a sudden decrease in the insulation properties of electrical equipment, resulting in the penetration of the insulation structure of electrical equipment.
3. The actual operating standards are complicated. Although the high-voltage switchgear is equipped with an electric heater, if the switchgear is in a harsh environment, with frequent precipitation, high relative air humidity, and the power switch is exposed to a humid environment for a long time, the performance of the insulating material of the internal structure will gradually deteriorate. The generation of conductive chemicals or corrosion will increase the probability of stains shining, and it is easy to cause insulation safety accidents.
Strategies for charging and discharging high-voltage switchgear:
1. Standard material types and installation. When installing, producing and processing busbars and processing grounding copper bars, the relevant standards should be strictly implemented. Improve the appearance of the electric stage, increase the angle of the electric stage, make the electrostatic field evenly distributed, and improve the breakdown field strength of the gap. In order to prevent the over-concentration of part of the electrostatic field, when connecting the busbar, part of the external fixing screws should not exceed 3 teeth, and the overlapping part of the busbar should ensure that the overlapping surface is leveled. When choosing to shield the circuit breaker box, it is better to shield the circuit breaker box of the design scheme to achieve uniform distribution of the electrostatic field and avoid excessive concentration of the electrostatic field. In order to ensure the safety protection level of environmental pollution, it is best to choose a waterproof casing with a dual-screen design.
2. Manipulate insulation defects. The stability of power distribution equipment is determined by the insulating construction performance of electrical equipment. In order to maximize the insulation characteristics of electrical equipment and control insulation shortcomings, the insulation board in the high-voltage switchgear should be treated with pollution. Moisture-proof paint should be applied to improve the hydrophobicity of the insulation board. When selecting the insulating waterproof casing of the busbar, you should try to choose the insulating waterproof casing produced by the standard manufacturer. Goods with good quality and credibility. When checking the outer packaging, it is necessary to pay attention to whether it is magnetic density or not. No magnetic density. .The evenly folded busbar insulation waterproof casing can further improve the stability of the busbar and effectively improve the insulation characteristics of the switchgear. Corrosion resistance.
3. Improve operating standards. In order to prevent common failures in the operation of high-voltage switchgear caused by the natural environment, power engineering enterprises should improve the software environment of high-voltage switchgear. In order to discharge the heat of the switchgear immediately at high temperature, fans should be installed in the front, back, left and right sides of the car cabinet in the hand or open hot holes to improve the air. Circulation, convenient high-voltage switch cabinets are naturally ventilated and heat-dissipated to ensure dryness of the cabinets; in rainy seasons, the drainage pipelines must be worked well first, and electric heaters must be assembled in the busbar compartment. The heating dehumidifier is installed in the cable room and the power supply. In the switch room, adjust the temperature and humidity reasonably to ensure that the temperature and humidity around the high-voltage switchgear are within the standard range; in addition, the switchgear should be cleaned to ensure the reliable operation of the high-voltage switchgear.
4. Improve condition maintenance. The traditional maintenance mode is to use several maintenance elite teams and carry out maintenance operations on several maintenance actual operation surfaces, which not only leads to waste of resources, but also leads to huge property losses. At this stage, with the increase in rated voltage, along with the expansion of the power grid and the increase in electricity consumption, if the maintenance is powered off, the maintenance cost will be further increased. Therefore, environmental maintenance must be carried out on high-voltage electrical equipment. Situation maintenance can monitor the status of electrical equipment in the system in real time, and can accurately detect potential safety hazards in electrical equipment as soon as possible, and take immediate measures without large-scale power outages, which greatly saves maintenance costs and improves the purpose of maintenance work.
Post time: Aug-04-2022