Standard Maintenance Cycles
Routine Inspections & Maintenance: Conduct on-site inspections at least once a month; increase the frequency of special inspections following periods of high temperatures, heavy pollution, or extreme weather to promptly detect visible defects.
Minor/Routine Maintenance:Performed every 1–2 years under normal operating conditions; includes basic maintenance tasks such as contact inspection, lubrication of drive components, tightening of fasteners, and infrared thermography.
Systematic Major Overhaul: The standard overhaul cycle for 35kV outdoor disconnect switches is 6–9 years, while for units rated at 110kV and above, it can be extended to approximately 10 years. For newly commissioned equipment, the first comprehensive overhaul is recommended one year after entry into service.
Cycle Adjustments for Special Conditions
In coastal areas with high salt spray, regions with heavy industrial pollution, or high-altitude areas with intense UV radiation, the minor maintenance cycle is shortened to once a year, and the major overhaul cycle is advanced to 5–7 years to prevent the premature onset of issues like corrosion and pollution flashover.
For disconnect switches subject to frequent operation or long-term full-load operation, a specialized condition assessment is conducted every three years, with maintenance scheduled in advance based on the assessment results.
Following extreme events such as short-circuit faults, severe typhoons, or earthquakes, specialized maintenance is arranged immediately-regardless of fixed schedules-to check for hidden damage.
Condition-Based Maintenance vs. Fixed Cycles
Major power grids are increasingly adopting condition-based maintenance models, moving away from strict adherence to fixed time intervals:
Equipment health is dynamically determined using data from infrared thermography, contact resistance testing, and mechanical characteristic checks; targeted maintenance is scheduled only when indicators exceed limits, significantly reducing unnecessary power outage operations.
For older disconnect switch models in service for over 15 years, in-depth specialized inspections are required every two years-even if test data remains within limits-to prevent sudden failures caused by component aging.