The neutral grounding system is a crucial facility in the power system for suppressing overvoltages, guiding fault currents, and ensuring the safety of personnel and equipment. Its operational status directly affects the reliability of the power grid and the effectiveness of the protection system. Because grounding devices are buried underground or exposed to complex environments for extended periods, they are susceptible to soil corrosion, mechanical stress, and current surges. Therefore, scientific and standardized maintenance is essential to maintain their stable performance.
Regular grounding parameter testing is fundamental to maintenance. The testing cycle should be determined according to regulations and the site environment, generally at least once a year for comprehensive measurement, focusing on grounding resistance, grounding electrode conductivity, and contact resistance at connection points. In special areas such as coastal areas with high salinity, chemical pollution, or high soil resistivity, the testing frequency should be appropriately increased to promptly detect performance degradation trends. Standardized instruments and methods should be used for testing to ensure data comparability and accuracy.
Visual and connection inspections are indispensable. Exposed grounding leads, terminal blocks, and welded joints should be inspected for oxidation, corrosion, loosening, or mechanical damage. Any problems found should be immediately addressed or the affected parts replaced. While underground components are not easily observed visually, the integrity of the grounding grid can be verified through potential distribution testing and spot checks during excavation. Special attention should be paid to the effectiveness of anti-corrosion measures at cross-material connections (such as copper-steel connections) to prevent poor contact caused by galvanic corrosion.
Corrosion and moisture protection are crucial for extending the lifespan of grounding devices. For steel grounding electrodes, the integrity of the galvanized layer or anti-corrosion coating should be checked, and recoating or replacement should be done as necessary. For copper grounding electrodes, the surface oxide layer should be checked to ensure it does not affect conductivity. Grounding leads entering indoor spaces or equipment foundations should be properly sealed and waterproofed to prevent moisture intrusion and deterioration of the connection points. In highly corrosive environments, cathodic protection or replacement with corrosion-resistant alloy materials may be considered.
Data recording and analysis should be integrated throughout the entire maintenance process. A grounding system ledger should be established, detailing all test data, changes in environmental conditions, maintenance measures, and information on materials used, creating a traceable historical curve. Trend analysis can predict potential grounding performance degradation points, guiding preventative maintenance and avoiding sudden failures.
After system upgrades or fault handling, relevant grounding parameters should be retested promptly to confirm that the changes have not adversely affected the overall grounding network. In the event of grid expansion, line extensions, or the addition of new distributed power sources, the grounding capacity and protection range must be recalculated, and weak points must be reinforced.
Generally speaking, the maintenance of neutral grounding systems should be based on periodic inspections, focusing on connection reliability and corrosion and moisture prevention, supplemented by the accumulation and analysis of data and experience, forming a closed-loop management system that combines prevention and remediation. Only by institutionalizing and refining maintenance work can we ensure that the grounding system plays its due role at critical moments, providing a solid guarantee for the safe and stable operation of the power grid.
