The maintenance costs of mining transformers vary depending on their capacity, type, and the severity of the fault, with routine inspection fees ranging from 800 yuan to 5,000 yuan per unit, and major overhaul or core component replacement costs potentially exceeding 10,000 yuan. Below is a detailed cost analysis:

　　Routine Inspection Costs:

　　Based on transformer capacity, the inspection fee for transformers with a capacity of ≤500kVA is approximately 800 yuan per unit. For capacities between 500kVA and 800kVA, the fee is around 1,500 yuan per unit. For capacities between 800kVA and 3,200kVA, the fee ranges from 2,000 to 2,700 yuan per unit, and for capacities exceeding 6,300kVA, the fee can reach 5,000 yuan per unit.

　　For mining dry-type transformers requiring preventive tests (such as insulation tests and voltage ratio tests), the test fee is 800 yuan per unit for capacities ≤500kVA, 1,500 yuan per unit for capacities ≤800kVA, and 2,000 yuan per unit for capacities ≤3,200kVA.

　　Major Overhaul and Component Replacement Costs:

　　If a transformer fault involves the replacement of core components (such as windings or iron cores) or requires a comprehensive overhaul, the costs will be significantly higher than those for routine inspections. For example, replacing high-voltage windings or iron cores can cost several thousand to ten thousand yuan, depending on the component model and material.

　　Mining flameproof dry-type transformers typically have 20%-30% higher maintenance costs than ordinary dry-type transformers due to their complex structure and stringent protection requirements. For instance, the selling price of a KBSG-315KVA mining flameproof dry-type transformer is approximately 55,000 yuan per unit, and the cost of a major overhaul may approach 30%-50% of the price of a new unit.

　　Factors Influencing Maintenance Costs:

　　Fault Type: Simple faults (such as poor contact or local overheating) incur lower maintenance costs, typically ranging from several hundred to a thousand yuan. Severe faults (such as winding short circuits or insulation breakdown) require component replacement or factory repair, with costs potentially reaching several thousand to ten thousand yuan.

　　Maintenance Method: On-site maintenance costs are lower than factory repair costs, but factory repair offers more professional equipment and technical support, making it suitable for handling complex faults.

　　Regional Differences: Maintenance costs in first-tier cities and areas with concentrated mineral resources may be higher than in other regions, primarily due to higher labor and logistics costs.