Views: 0 Author: Site Editor Publish Time: 2026-06-02 Origin: Site
For a 50MVA power transformer, OFAF is the standard cooling choice: oil pumped + fans forced air; higher cooling capacity than ONAN/ONAF, supports full load + short-time overload, common in 30–300MVA transformers.
Core System Layout (50MVA)
Main Tank: 50MVA winding/core, hot oil at top, cold oil at bottom.
Oil Pumps: 2–3 × submersible pumps (1 duty + 1–2 standby) at tank bottom; force hot oil to radiators.
Radiator Banks: 4–6 units (finned tube, aluminum alloy); mounted on tank side/separate frame.
Cooling Fans: 8–12 × axial fans (1.5–3kW each); blow air over radiator fins.
Control Panel: Auto-start pumps/fans at set oil temp (e.g., 55°C); fault alarm/standby auto-switch.
Piping & Valves: Steel pipes, isolating valves, strainers, drains, vents.
How It Works (50MVA)
Heat Generation: Winding/core heat oil to ~75°C at full load.
Forced Oil Circulation: Submersible pumps suck hot oil from tank bottom, push it through radiator banks at high flow.
Forced Air Cooling: Axial fans blow 3–5 m/s air over radiator fins, transfer oil heat to ambient.
Cold Oil Return: Cooled oil (~45–50°C) flows back to tank, absorbs heat again.
Auto Control: Pumps/fans start at 55°C oil temp; modulate speed or stage on/off with load/temp; standby units auto-start on fault.
Why OFAF for 50MVA
Higher Cooling Capacity: 30–50% better than ONAF; supports 110–120% overload for 2h.
Compact Footprint: Smaller radiator area vs ONAF; saves substation space.
Stable Under Heavy Load: Maintains temp stability at 50MVA full load, high ambient (40°C).
Proven Reliability: Standard for 30–300MVA utility transformers.
