10kva-333kva Oil Immersed Single Phase Pole Mounted Transformer​

Q1: What is a Single-Phase Pole-Mounted Transformer?

A single-phase pole-mounted transformer is a compact electrical device installed on utility poles, with a rated capacity typically ranging from 10 kVA to 333 kVA (expandable to 3 kVA–500 kVA in special scenarios). Its primary function is to step down high-voltage distribution lines (e.g., 10 kV) to low-voltage outputs (e.g., 240V/120V), serving as a critical component in the final stage of power distribution networks for residential areas and small commercial establishments with low electricity demands.

Q2: What is the Typical Capacity Range of Pole-Mounted Single-Phase Transformers?

Common capacity ratings span 10 kVA to 333 kVA, with special cases extending from 3 kVA (minimum) to 500 kVA (maximum).

• Rural/remote areas: 25 kVA or 50 kVA units are commonly used due to lower load demands.
• Urban suburbs/commercial zones: Higher-capacity units (e.g., 100 kVA+) are preferred to meet increased electricity requirements.

Q3: Key Considerations for Installing Single-Phase Pole-Mounted Transformers?

1. Pole Selection: Use poles with adequate strength and stability. Mounting height must ensure a safety clearance of at least 3 metersfrom the ground to prevent human or object contact.
2. Secure Fixing: Employ specialized clamps to ensure firm fixationand prevent component loosening caused by operational vibrations.
3. Grounding Requirements: The grounding system must be reliable, with a grounding resistance ≤ 4 Ω, to safeguard against lightning strikes and ensure personal safety.
4. Environmental Conditions: Install away from obstacles to ensure good ventilation(for heat dissipation) andreserve sufficient space for maintenance.

Q4: Differences Between Single-Phase and Three-Phase Pole-Mounted Transformers?

Q5: How to Detect Faults in Single-Phase Pole-Mounted Transformers?

1. Abnormal Noises/Vibrations: Unusual humming, buzzing, or excessive vibration during operation.
2. Temperature & Oil Condition(for oil-immersed transformers): Overheating (exceeding rated temperature), oil leakage, or discolored oil.
3. Voltage Instability: Fluctuations in low-voltage output beyond acceptable limits.
4. Physical Damage: Burn marks, cracks, or electrical discharges (e.g., sparks during rain) on the enclosure or bushings.

Q6: Maintenance Schedule for Single-Phase Pole-Mounted Transformers?

• Routine Inspections: Every 6–12 months, including exterior cleaning, connection tightness checks, oil level verification (for oil-immersed units), and bushing insulation assessments.
• Critical Maintenance Tasks:

• Oil-Immersed Transformers: Annual to bi-annual dielectric oil tests (e.g., breakdown voltage, dielectric loss factor).
• Grounding System: Yearly inspection to ensure resistance ≤ 4 Ω.
• Heat Dissipation: Regularly clean radiator fins to prevent dust accumulation.

Q7: Causes of Transformer Overheating?

1. Overloading: Sustained operation beyond rated capacity, leading to increased winding losses.
2. Poor Heat Dissipation: Blocked radiator fins, excessive dust/oil accumulation, or inadequate ventilation.
3. Internal Faults: Winding short circuits, core insulation degradation (e.g., aging silicon steel sheets).
4. Oil-Immersed Specific Issues: Low oil level or deteriorated oil quality (reduced insulation and cooling performance).

Q8: How to Protect Transformers Against Lightning or Short Circuits?

1. Lightning Protection: Install zinc oxide surge arresters on the high-voltage side to limit overvoltage caused by lightning strikes.
2. Short Circuit Protection: Equip high-voltage fuses (e.g., CSP-type) or circuit breakers to quickly cutfault currents and prevent winding damage.
3. Enhanced Grounding: Ensure the grounding system complies with standards to minimize ground potential rise during faults.

Q9: What is the Lifespan of Pole-Mounted Transformers?

Under normal operating conditions, the typical lifespan is 20–30 years. Key factors affecting longevity include:

• Environmental Conditions: High humidity, coastal salt spray, or dusty environments accelerate insulation aging.
• Maintenance Quality: Frequent overloading or neglecting maintenance (e.g., delayed oil replacement) shortens service life.
• Manufacturing Standards: Premium materials and craftsmanship extend operational durability.