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Medium-voltage Vacuum Circuit Breaker are key equipment in power systems, and their maintenance should follow the principle of "combining condition monitoring with regular overhauls." Based on standards such as DL/T 596-2021 and mainstream manufacturer specifications, the core points are as follows.
Graded Maintenance Cycles
Daily Inspection: Daily verification of external condition, unusual sounds, position status, and temperature at connection points.
Routine Maintenance (6–12 months): Removal of dirt, securing of components, application of lubricant to moving parts, and adjustment of supplementary contacts.
Periodic Testing (1–3 years): Dielectric strength, loop resistance, voltage endurance, and operational behavior tests.
Overhaul (5-6 years or 10,000 operations): Disassembly, inspection, and replacement of arc-extinguishing chambers and vulnerable parts.
Core Items and Standards
Circuit resistance: ≤1.2 times factory value; no overheating at connection points.
Insulation Test: Main circuit insulation ≥1000MΩ measured with a 2500V megohmmeter; 10kV withstand voltage 42kV/1min.
Vacuum interrupter: Vacuum level is indirectly determined by power frequency withstand voltage; no cracks or discoloration on appearance.
Mechanical characteristics: Three-phase asynchrony ≤2ms; closing bounce ≤2ms.
Operating voltage: Reliably operates at 30%-65% of rated voltage; does not operate below 30%.
Operation and Safety
Strictly adhere to the power outage, voltage testing, grounding, and lockout (LOTO) procedures. Work only after releasing the stored energy. Data must be retained for each maintenance operation, and a full lifecycle log must be established.
Replacement Criteria
If vacuum level fails circuit resistance consistently exceeds limits, mechanical characteristics exceed tolerances, or short-circuit current is interrupted, the interrupter or major overhaul should be performed promptly.
Following the above quantitative procedures can effectively improve the reliability of VCB operation and prevent power accidents.
If you are interested in the VTZ-12 1250A Vacuum Circuit Breaker , please contact us.
Our address
Nanpo Village, Chencang Avenue Jintai District Baoji City, Shaanxi Province, China.
Phone Number
+86 18091765882(WhatsApp/facebook/telegram)
