Maintenance details of high and low voltage tubular busbars
1、 Key points of daily inspection
Appearance inspection: Conduct at least one appearance inspection daily to check for any abnormal phenomena such as damage, cracks, bulges, or discoloration on the insulation outer layer of the tubular busbar. These signs may indicate damage or moisture to the internal insulation layer, affecting the insulation performance and normal operation of the busbar. For example, if tiny cracks are found in the insulation sheath, moisture may seep in, causing a decrease in insulation resistance and triggering a short circuit fault. At the same time, check the connection parts of the busbar, including bolt connections and welding points, to ensure that there is no looseness, deformation, or corrosion. Loose connections can increase contact resistance, causing severe heating in that area, which may pose a fire hazard in the long run; Corrosion can affect the mechanical strength and conductivity of the connection.
Temperature monitoring: Use infrared thermometers to regularly measure the temperature of various parts of the busbar, with a focus on connection points, bends, and areas with high loads. During normal operation, the temperature of each part of the busbar should be relatively stable and meet the design standards. Generally speaking, the conductor temperature of high-voltage tubular busbars should not exceed the allowable value (such as 90 ℃) when operating at full load. If an abnormal temperature rise is detected in a certain part, exceeding the normal range by 5 ℃ or more, the cause should be analyzed in a timely manner and measures should be taken. It may be caused by factors such as overload operation, poor contact, or deterioration of heat dissipation conditions. For example, when the current carried by the busbar exceeds the rated value for a long time, it will generate excessive heat due to Joule's law, causing the temperature to rise.
Sound recognition: Listen carefully to the sound of the bus running in a quiet environment. Under normal circumstances, the busbar should only have a slight electromagnetic buzzing sound. If there is any abnormal sound, such as sharp whistling, crackling discharge sound, or intermittent impact sound, it indicates that there is a potential problem with the busbar. Sharp whistling may be caused by resonance between the vibration frequency of the busbar and surrounding components; The discharge sound implies the possibility of partial discharge, which will gradually erode the insulation material; The impact sound may be caused by loose busbar fasteners colliding with other objects.
2、 Cleaning and maintenance methods
Regular dust removal: Every certain period (usually 3-6 months, depending on the degree of environmental dust), use a dry and clean soft bristle brush or compressed air spray gun to comprehensively remove dust from the surface of the tubular busbar. For difficult to reach corners and gaps, a small vacuum cleaner with a fine nozzle can be used for cleaning. Excessive accumulation of dust can affect the heat dissipation effect of the busbar, reduce its current carrying capacity, and may also adsorb moisture and other corrosive substances in the air, accelerating the corrosion process of the busbar. For example, in some industrial plants with high levels of dust, if the dust on the busbar is not cleaned in a timely manner, a thick layer of dirt may form after a period of time, seriously affecting the normal operation of the busbar.
Stain treatment: When the surface of the busbar is contaminated with oil or other stains, a suitable cleaning agent should be used to wipe and clean it in a timely manner. When choosing a cleaning agent, be careful not to cause damage to the insulation material of the busbar. Neutral and non corrosive specialized electrical equipment cleaning agents can generally be used. First, use a clean cloth dipped in an appropriate amount of cleaning agent to gently wipe the stained area, then use another clean and damp cloth to remove residual cleaning agent, and finally dry with a dry cloth to ensure that the surface of the busbar is dry and free of moisture residue. Because residual moisture not only leads to a decrease in insulation performance, but may also freeze in low-temperature environments, causing damage to the busbar structure.
3、 Insulation performance testing
Insulation resistance test: Regularly (recommended at least once a year) use an insulation resistance tester to measure the insulation resistance of the tubular busbar. When measuring, the correct wiring should be carried out according to the instrument operation manual, and the insulation resistance values of each phase to ground and phase to phase should be measured separately. Generally speaking, the insulation resistance of high-voltage tubular busbars should not be less than 1M Ω per kV, and the insulation resistance of low-voltage tubular busbars should not be less than 0.5M Ω. If the measured value is lower than this standard, it indicates that the insulation performance of the busbar has declined and further investigation is needed to determine whether there are insulation aging, moisture and other problems. For example, if it is found that the insulation resistance of a certain phase is significantly low, it may be due to local damage to the insulation layer of that phase or long-term exposure to a humid environment. At this point, it can be tested after drying treatment. If it still fails, it is necessary to consider replacing some or all of the insulation components.
Dielectric loss tangent (tan δ) test: For important locations or high and low voltage tubular busbars with long operating years, dielectric loss tangent tests should also be conducted regularly. This test can more sensitively reflect the aging, deterioration degree, and moisture condition of insulation materials. Normally, newly installed or in good condition busbars have a small and stable tan δ value within a certain range. As the usage time increases and various factors affect it, the tan δ value will gradually increase. Once it is found that the tan δ value exceeds the upper limit of the normal range by a certain proportion (such as 10% -15%), it is necessary to conduct a thorough analysis of the cause and take corresponding measures, such as strengthening monitoring, improving the operating environment, or arranging maintenance plans.
4、 Strengthening protective measures
Anti corrosion treatment: Take targeted anti-corrosion measures according to the environmental conditions of the busbar. For busbars installed outdoors or in humid environments, a layer of anti-corrosion coating can be applied on the surface, such as a combination of epoxy zinc rich primer and weather resistant topcoat. This coating can effectively block the direct contact between oxygen, moisture, and other corrosive media in the air and the busbar metal substrate, playing a role in delaying corrosion. At the same time, the integrity of the coating should be checked regularly, and any damage such as peeling or flaking should be repaired in a timely manner. In addition, for some special industries (such as chemical enterprises), it is necessary to consider using higher-level anti-corrosion measures, such as stainless steel busbars or adding corrosion inhibitors, to ensure the long-term reliable operation of busbars.
Anti vibration reinforcement: For high and low voltage tubular busbars near possible vibration sources, anti vibration measures should be strengthened. Firstly, ensure that the installation of the busbar is firm and reliable, and that all supporting structures and fasteners meet the design requirements and can withstand the corresponding dynamic loads. Secondly, vibration reduction devices such as rubber isolation pads or spring dampers can be installed at key parts of the busbar (such as the middle position of the span). These devices can absorb and dissipate vibration energy from the outside, reducing the risk of fatigue damage and loose connections caused by frequent vibration of the busbar. In addition, it is necessary to regularly check the working status of the vibration damping device, check for aging, deformation, or failure, and replace damaged parts in a timely manner to maintain good vibration damping effect.