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IT Infrared detection image of overheating part of 110kV トランスブッシング
The locking nut is loosened due to the vibration of the body and the conductor during operation. It was found that the pressure between the terminal cap and the contactor rod was insufficient. After re-tightening, the DC resistance test was qualified. Because there may be no local overheating spots, there may be no abnormal chromatography.
The maintenance content:
1, After the power outage, measure the DC resistance of the medium voltage side.
2, Inspect the medium voltage side bushing: check whether there is oil leakage on the outer surface of the bushing, and whether the contactor rod terminal and the bushing terminal bolt have blackening and burning signs
3, Close the butterfly valve on the side of the gas relay and remove the B-phase bushing terminal cap: according to the structural diagram, first remove the terminal (1), loosen the bolt (2), then loosen the bolt (6), remove the sealing washer (7), and unscrew the terminal cap.
4, Use the utility knife to gently scrape off the overheating traces of the conductor rod, and clean the thread overheating spots inside the cap with a toothbrush.
5, Using 502 glue to align and fix the new sealing gasket in the terminal cap to avoid sliding or blocking the screw hole when tightening the terminal cap general hat. After fastening, check the deviation of the screw hole and adjust until it is completely suitable.
6, Use tools to tighten the terminal cap and lock nut in the reverse direction. Diagonal uniform fastening terminal cap bolts.
7, Measure DC resistance, qualified
Quality Management of Maintenance Procedures
1, Before the maintenance, all participating team is organized to study the work plan, refine the operational details, clarify the work risk, carry out the safety training and examination of the workers, and ensure that all tasks are performed safely and in an orderly manner.
2, On-site implementation of five transformer maintenance rules, keep hidden engineering photos.
3, Maintenance process and technical requirements
3.1, Demolition and installation of the wiring board should be correct, can not be shaken by force, to avoid damage to the conductive rod.
3.2, When the general hat is spun out, it is necessary to slowly and uniformly speed to avoid excessive shaking. When the general hat is spun out to the visible position pin, a staff member takes the two ends of the position pin with both hands.
3.3, The disassembled parts should be sealed with plastic cloth and special for special use.
3.4, After the cap is spun out, the positioning pin is fixed with insulating tape, and the conductive rod is continuously wound and wrapped to prevent the impurities from polluting the transformer oil through the gap when dealing with the hot spot of the conductive rod.
3.5, Installation of the general hat pay attention to the protection of the sealing surface and the sealing groove, to prevent man-made causes damage to the sealing surface, all after the disassembly of the gasket must be replaced, before the installation of the sealing surface clean, installation process should always pay attention to the gasket deviation, displacement, gasket compression amount of 1 / 3.
3.6, bolt uniform diagonal fastening, according to the requirements of the torque check.
3.7, After the replacement is completed, the DC resistance test is carried out, and the test results should be qualified.
In terms of overheating faults, dry-type bushings have the following significant advantages over OIP bushings:
1. Lower risk of failure
Dry-type bushing doesn’t use insulating oil, completely avoiding the problems of oil decomposition, carbonization and gas production caused by overheating, and avoid the risk of insulation breakdown or explosion caused by oil dielectric degradation.
2. Superior Heat Dissipation
Dry-type bushing, especially #RIFbushing efficiently transfers heat to the air through epoxy resin/glass fiber, the heat dissipation path is short, and the temperature rise distribution is uniform ( the surface temperature difference is usually ≤ 5K ).
3.Easy fault diagnosis
Dry bushings’ overheating fault is mostly concentrated in the external connection part ( such as the terminal cap bolt), which can be quickly located by infrared temperature measurement or visual inspection.
4. Simplified maintenance
Dry bushings only require treatment of the conductor surface (such as polishing oxidation layers, replacing the bolt), with typical repairs completed in 2-4 hours.
5. Superior Thermal Resistance
Dry bushings’ epoxy resin withstands short-term overheating up to 180°C with no moisture absorption, maintaining >90% mechanical strength at high temperatures.
6. No Cascading Seal Failures
Dry bushings’ gaskets serve only dust/weather protection purposes – seal failure doesn’t compromise insulation performance.
Typical cases
• #OIP bushing of the same voltage: similar faults require oil discharge to replace the gasket, and the processing cost is increased by more than 3 times.
• A dry bushing of 110 kV: the looseness of the terminal cap bolt causes the contact resistance to rise to 200 μΩ (normal value of 50 μΩ). The infrared temperature measurement finds a heating spot at 80 °C, which needs to be repaired only by fastening the bolt and applying conductive paste.
The dry bushing has the advantages of safety, maintainability and economy in overheating fault- The Ideal Choice for Smart Substations.
While oil-impregnated paper bushings retain advantages in #UHV applications due to mature manufacturing processes, dry-type bushings outperform comprehensively in modern power systems.
As a leading supplier focusing on #DryBushings for many years, Hewei Power uses high-quality epoxy resin and reinforced fiber glass for our dry-type bushing, it has excellent heat resistance, anti-aging and maintenance-free advantages, especially suitable for long-term stable operation under high load and harsh environments.
For High-Reliability, Low-Maintenance Bushing Solutions, please contact Hewei Power today! Our custom-engineered bushings deliver:
- Unmatched Safety – Eliminate oil-related failure risks
- Reduced OPEX – 60% lower maintenance vs conventional designs
- Smart Grid Ready – Perfect for digital substation integration
Your #PowerSystem Deserves the Best – Engineering Excellence ∙ Tailored Solutions ∙ Future-Ready Performance!
www.heweipower.com Mobile/Whatsapp/Wechat: +86 15031254260
