Bushings, as important insulation and protection components in power and industrial systems, play a crucial role in safely leading out live conductors.Their operating condition directly affects the insulation level of equipment and system safety; any insulation deterioration or mechanical damage can lead to flashover, breakdown, or even system shutdown. Therefore, establishing a systematic and standardized maintenance mechanism is a necessary way to ensure the performance of bushings throughout their entire life cycle.
Maintenance work should begin with periodic inspections. Inspections should cover the bushing's appearance, insulation surface, connection points, and sealing condition, focusing on the presence of cracks, damage, dirt accumulation, discharge traces, and signs of leakage. Outdoor bushings are prone to surface contamination in polluted, salt spray, humid, or high-humidity environments; cleaning cycles should be established according to the environmental pollution level to prevent flashover. Inspections should also be combined with infrared thermography and partial discharge detection to promptly detect abnormal heating and partial discharge phenomena caused by poor contact or insulation aging, ensuring early detection and handling of potential hazards.
Cleaning is an important part of maintenance. For surface dirt, gently wipe with a dry, soft cloth or a special insulating cleaner to avoid damaging the glaze or composite insulation layer. Do not wash in rain, snow, or high humidity environments to prevent moisture from seeping into the insulation. For porcelain bushings, avoid scratching with hard objects to prevent damage to the glaze's smoothness and insulation performance. For silicone rubber or composite insulating bushings, strong acids, strong alkalis, and organic solvents are prohibited to prevent material swelling or cracking. During maintenance, pay attention to the integrity of the anti-flashover coating on bushings, and recoat as needed according to the manufacturer's requirements.
Sealing checks and maintenance are crucial for the bushing's moisture-proof and seepage-proof performance. Oil-filled bushings should have their oil level and color checked regularly. Any leaks or oil deterioration should be addressed promptly, and qualified insulating oil should be added. Gas-filled bushings require pressure and sealing checks to prevent gas leakage from reducing insulation strength. Sealing rings, gaskets, and other easily aging components at bushing connections to equipment housings or wall penetrations should be replaced regularly to ensure a tight, gapless interface.
The reliability of mechanical connections is equally important. Regularly check the tightness of the connections between the conductive rod and the busbar or lead-out wire, ensuring there is no loosening, oxidation, or overheating discoloration, and retighten to the specified torque. For operating conditions involving vibration or thermal expansion and contraction, check the effectiveness of supports, fixation, and buffering devices to prevent fatigue or cracking of the bushing structure due to repeated mechanical stress.
Necessary electrical tests must be performed during maintenance. These include insulation resistance measurement, dielectric loss factor (tanδ) testing, power frequency withstand voltage and impulse withstand voltage tests, etc., to determine if the insulation condition meets operational requirements. For older bushings or bushings operating in harsh environments, the testing cycle should be appropriately shortened, and bushings with abnormal test results should be promptly repaired or replaced.
Record keeping and data analysis are crucial components of closed-loop maintenance management. Detailed records should be kept of each inspection, cleaning, test, and maintenance activity to establish a bushing health record. Trend analysis should be used to understand performance change patterns, providing a basis for condition-based maintenance and replacement decisions.
Personnel qualifications and safety measures are essential for ensuring maintenance quality. Personnel engaged in bushing maintenance must undergo professional training, be familiar with equipment structure, testing methods, and safety procedures, and strictly adhere to procedures such as power outage, voltage testing, and grounding wire installation during operations. They must also use qualified insulation and protective equipment to prevent personal injury and equipment accidents.
In short, bushing maintenance is a systematic project integrating visual inspection, cleaning and anti-fouling, sealing and reinforcement, connection verification, and electrical testing. Only by systematizing and refining maintenance work, and continuously optimizing solutions based on environmental characteristics and operating conditions, can we ensure that bushings maintain excellent insulation and mechanical properties over the long term, providing a solid barrier for the safe and stable operation of power and industrial systems.
