Transformer Oil Cooler Used in Photovoltaic Power Plants
1, Core application scenarios of photovoltaic power plants
Box type transformer
Photovoltaic string → inverter → box transformer boosting (0.27/0.315kV → 10/35kV) is the main application scenario of oil coolers in photovoltaic power plants, with a single capacity of 1000-3000kVA.
Mostly located in the photovoltaic field area, dispersed, outdoors, unmanned, with high requirements for the environmental adaptability, reliability, and low maintenance of the cooler.
Gathering station main transformer
After the output of multiple box transformers is collected, it is boosted to 110/220kV and connected to the grid through the main transformer, with a large capacity (10-100MVA level) and large load fluctuations, requiring efficient and adjustable heat dissipation.
SVG/reactive power compensation matching transformer
The SVG device of the photovoltaic power station is equipped with a transformer that needs to cope with harmonic and dynamic loads, and the cooler needs to adapt to high-frequency load changes.
2, Special requirements for oil coolers in photovoltaic power plants
1. Environmental adaptation
High altitude (≥ 3000m): The air is thin and the air cooling efficiency decreases. It is necessary to increase the heat dissipation area or choose oil-water composite cooling, and adjust the heat dissipation parameters.
High and low temperatures: -40 ℃~+60 ℃ temperature difference, heat tracing/antifreeze design is required in high cold areas, and heat dissipation is strengthened in high temperature areas.
Wind and sand/salt spray: Northwest and coastal photovoltaic power stations require anti-corrosion coatings (epoxy zinc rich+fluorocarbon paint), anti clogging filters, and sealing structures.
Strong sunlight: Outdoor exposure, the cooler shell needs to be UV resistant and insulated to avoid abnormal oil temperature rise.
2. Adaptation of operating characteristics
Large load fluctuation: The photovoltaic output changes dramatically with the illumination, and the cooler needs to respond quickly, supporting variable frequency fans/intelligent temperature control.
Unmanned operation: requires high reliability, minimal maintenance, integrated oil temperature/oil level/pressure/leakage monitoring, and supports remote alarm.
Low noise: Some photovoltaic power plants are located near residential areas and require low-noise fans and noise reduction structures.
3. Safety and Energy Efficiency
Fire and explosion prevention: Photovoltaic power plants are mostly located in deserts/mountainous areas, and the cooling system requires flame-retardant materials, oil leakage collection, and fire-resistant spacing design.
Energy saving: Adopting variable frequency fan and intelligent temperature control, the air volume is automatically adjusted according to the oil temperature, reducing the power consumption of the plant.
4, Key Technology and Configuration Suggestions
Intelligent temperature control system
Integrate PT100 oil temperature sensor, start the fan in stages (such as starting one at 40 ℃ and all at 50 ℃), support remote setting and monitoring.
Corrosion prevention and protection
Shell: Q235B+epoxy zinc rich primer+fluorocarbon topcoat, anti-corrosion grade ≥ C4.
Protection level: IP54/IP55, waterproof, dustproof, and animal proof.
Antifreeze and heat tracing
High cold regions: bundle with tropical zone, oil temperature low limit protection to prevent oil condensation and freeze-thaw.
Monitoring and early warning
Integrate oil level, pressure, leakage, and fan fault monitoring, connect to the SCADA system of the photovoltaic power station, and achieve remote operation and maintenance.
5, Application Development Trends
Lightweight integration: Integrated design with the transformer box, reducing land occupation and improving transportation and installation efficiency.
Full lifecycle operation and maintenance: Predictive maintenance, predicting cooler failures through data analysis, reducing downtime.
Green and low-carbon: air cooling replaces water cooling to reduce water consumption; Efficient heat exchange materials, improving energy efficiency, and adapting to dual carbon targets.
