'Strongly urged to' PV-inverter capacity ratio 'as soon as possible to relax, no one I have to emphasize.' January 29, in the China Photovoltaic Industry Association, co-sponsored by the photovoltaic 2018 Third PV Power Station Design and Equipment selection seminar, the National Development and Reform Commission researcher Wang Si Cheng shouted so.
The so-called tolerance ratio (also known as the power ratio), is the PV inverter connected PV modules and the rated power of the inverter capacity ratio has been the components and the inverter ratio than the standard are 1: However, judging from practical application and international practice, this standard is apparently out-of-date, and the optimal system-to-system ratio is often greater than 1: 1.
"GB50797-2012: Design Specification for Photovoltaic Power Station" states that the sum of the nominal power of the PV modules installed in a PV power station is called the installed capacity and the unit of measure is the peak wattage (Wp); the inverter The configuration capacity should be matched with the installed capacity of PV array. The maximum DC input power allowed by the inverter should not be less than the actual maximum DC output power of its corresponding PV array.
Internationally, the AC capacity of a PV power system is defined as the rated output of the PV system or the capacity is the maximum power agreed in the contract, usually in MW. It is also common to regard the sum of the PV module power as the rated power of the PV system. Obviously, Domestic standards are still in the queue of "common." In terms of power ratio, international PV power plants are often designed with high PV-to-PVR for low cost of electricity.
In fact, moderately increasing the PV-to-PVR ratio is an important technological innovation in PV system design. It is generally accepted by the photovoltaic industry after 2012, especially the United States FirstSolar. The power plant capacity ratio is generally 1.4: 1.0.
'In the United States, I visited a PV plant with a capacity ratio of 1.4: 1.0. During the morning, the power was running at full power. During the normal time, it would not be overloaded. After the inverter reached the rated power, it would switch to limited power operation , Will not affect the safety. 'Wang Shicheng introduced to.
If the system based on the principle of averaging the lowest cost of electricity to determine the merits of the system, the optimal system of photovoltaic inverter ratio are greater than 1: 1. In other words, to a certain extent, to enhance PV module capacity (also known as components Over-allocated), will help to improve the overall efficiency of the system.In fact, many power plants in order to improve the operating efficiency of the inverter and plant revenue, have adopted the method of component over-allocation.
In addition, Wang Si-cheng also pointed out that the PV-inverter compatibility ratio is not as high as possible, involving radiation resources, environmental temperature, components and DC equipment costs, land costs, electricity prices, 'rate of light' and many other Factors, or to optimize the design based on the principle of "the lowest cost of electricity LCOE".
'Recently, the investigation of expansion, but the expansion can greatly enhance the system yield, reduce costs, why not be allowed?' Wang Shicheng stressed at the meeting, 'called for the amendment of national standard GB50797 as soon as possible to eliminate obstacles hindering technological innovation and technological progress '
