As a core component of power transmission systems, bus duct connectors require multiple mechanisms to ensure their structural integrity during short-circuit faults, preventing connection failure due to electrodynamic impacts, thermal expansion, or mechanical stress. Their design logic revolves around material selection, structural optimization, process control, and protective measures, forming a systematic protection system.
At the material selection level, the conductive components of bus duct connectors must possess high strength and high conductivity. Copper or copper alloys are the mainstream choice due to their excellent mechanical and conductive properties, capable of withstanding the enormous current surges generated during short circuits. Simultaneously, the insulating material must be a special material resistant to high temperatures and arcs, such as epoxy resin or silicone rubber. These materials will not melt or carbonize due to high temperatures during short circuits, thus maintaining insulation performance and preventing phase-to-phase short circuits. Furthermore, the shell material is typically made of aluminum alloy or steel, possessing sufficient mechanical strength, reducing external interference through electromagnetic shielding, and ensuring long-term stable operation in harsh environments due to its corrosion resistance.
Structural optimization is crucial for ensuring connector integrity. Bus duct connectors often employ a sandwich-style stacked structure, with alternating conductive busbars and insulating layers. This design not only enhances current-carrying capacity but also reduces the risk of localized overheating by uniformly distributing the electric field. At the connection points, the combination of double-locking bolts and anti-loosening washers ensures the mechanical stability of the inter-segment connection, maintaining stable contact resistance even under vibration or thermal expansion and contraction conditions. Some high-end products also incorporate spring-loaded contact finger technology, using elastic contact surfaces to compensate for installation errors, further reducing contact resistance and minimizing heat points.
Process control also significantly impacts connector performance. During production, the rolling process of the conductive busbars requires strict control of surface quality to avoid defects such as burrs and bumps. These defects can become the starting point of an electric arc during a short circuit, leading to insulation breakdown. Optimized welding processes, such as using argon arc welding or laser welding, can reduce impurities and porosity at the weld, improve weld strength, and prevent weld misalignment or cracking during short circuits. Furthermore, insulation layer forming processes, such as vacuum casting or heat-shrink tubing, ensure a tight fit between the insulation layer and the conductive busbar, eliminating gaps and preventing partial discharge.
Protective measures are the last line of defense against short-circuit faults. Bus duct connectors must undergo type testing to verify their short-circuit withstand capability, including peak withstand current and short-time withstand current tests, ensuring they can withstand short-circuit current for a specified time without permanent deformation or damage. In practical applications, matching protection levels is crucial. For example, connectors with IP65 and higher ratings effectively prevent dust and moisture intrusion, avoiding insulation failure due to environmental factors. For special scenarios, such as humid or corrosive environments, connectors should also employ nano-hydrophobic coatings or stainless steel shells to further enhance protection performance.
The standardization of installation processes directly affects the long-term stability of connectors. During installation, it is essential to ensure that the busbar trunking and shell are concentric, with deviations controlled within allowable limits to avoid localized overheating caused by uneven magnetic field distribution. During inter-segment connections, phase sequence verification and mechanical alignment must strictly adhere to operating procedures to prevent short circuits caused by incorrect phase sequence or poor contact. Furthermore, the inclusion of expansion joints compensates for thermal expansion, preventing stress concentration caused by temperature changes and protecting the connection structure from damage.
Operation and maintenance management is an extension of ensuring connector integrity. Regularly check the tightness of the fastening bolts at the connection points to ensure the torque value meets the requirements and prevent increased contact resistance due to loosening. Simultaneously, infrared thermography can monitor the connector temperature in real time, promptly detecting potential hot spots and preventing the fault from escalating. Aging or damaged connectors should be replaced promptly to prevent short circuits caused by deteriorated insulation performance.
