How To Select The Step-Up Transformer For Photovoltaic Power Station?
04-17 2025 | By:
How to select a step-up transformer for a photovoltaic power station?
The selection of a step-up transformer for a photovoltaic power station needs to consider multiple factors, including capacity, voltage, number of phases, connection group, etc.
Capacity selection
The capacity of the step-up transformer should be determined based on the maximum output power of the photovoltaic array, which is generally 1 to 1.25 times the photovoltaic peak power. For example, if the designed installed capacity of a photovoltaic power station is 1MWp (megawatt peak), then the corresponding step-up transformer capacity should be between 1MVA and 1.25MVA. In addition, the total load power should not exceed about 80% of the rated capacity of the selected transformer
How to select a step-up transformer for a photovoltaic power station?
Voltage selection
The voltage level of the transformer should be determined based on the needs of the line power supply and power-consuming equipment. Usually, the primary coil voltage is 10kV, 35kV or 110kV, and the secondary coil voltage is selected according to the needs of the electrical equipment. It is best to choose a low-voltage three-phase four-wire power supply.
Phase selection
The number of phases of the transformer is selected according to the needs of the power supply and load. Usually a three-phase transformer is used because the three-phase transformer is superior to the single-phase transformer in terms of efficiency and stability.
Connection group selection
The Dyn11 connection method is recommended. This connection method helps to suppress high-order harmonics and enhance the ability to withstand unbalanced loads.
Type selection
The step-up transformer can be an oil-immersed transformer or dry-type transformer. Considering factors such as environmental adaptability and maintenance costs, it is recommended to use a box-type substation with a higher protection level in coastal areas or places with strong winds and sand.
Specific model selection
The specific model selection should be determined by communicating with the transformer manufacturer based on the project’s technical parameters, drawings, etc. Dry-type transformers are more commonly used in photovoltaic power generation due to their low loss, low noise, and good energy-saving effects.
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