What does the capacity matching ratio of a photovoltaic power station mean?
The capacity matching ratio of a photovoltaic power station refers to the ratio between the nominal power of the photovoltaic modules and the rated active power of the inverter in the system. Currently, an over-matching design is commonly used, as it can improve the overall utilization efficiency of the photovoltaic system, reduce the cost per kilowatt-hour (kWh), and increase profitability.
According to different principles, the capacity matching ratio can be divided into two categories:
Compensatory Over-matching: This increases the system’s capacity matching ratio with the principle that the system will not experience power limitation, ensuring the inverter can reach full load output when sunlight is optimal.
Active Over-matching: This increases the system's capacity matching ratio with the principle of minimizing the system's Levelized Cost of Electricity (LCOE). While this may lead to inverter power limitation and some energy loss, the overall investment and output result in the lowest cost per kWh.
Due to the instability of photovoltaic power generation and its susceptibility to environmental factors, simply matching the installed capacity of the photovoltaic modules to the inverter on a 1:1 ratio would lead to waste of inverter capacity. Therefore, to improve the photovoltaic system’s power generation efficiency while ensuring stable system operation, the optimal capacity matching ratio should be greater than 1:1.
Increasing the capacity matching ratio can enhance the utilization of inverters and transformers, reduce the engineering cost of inverters and transformers, and lower the investment cost of common infrastructure like booster stations and transmission lines, further reducing costs and lowering the cost of electricity generation. On the other hand, a higher matching ratio can smooth the photovoltaic power output, thus improving grid compatibility.