A photovoltaic power station is a power station that converts solar radiation energy into electrical energy through a square array of solar cells. Photovoltaic power stations can be divided into independent photovoltaic power stations and grid-connected photovoltaic power stations according to the operation mode.
A solar photovoltaic power station that is connected to the public power grid and jointly undertakes the power supply task is called a grid-connected photovoltaic power station. It is an important development direction for solar photovoltaic power generation to enter the stage of large-scale commercial power generation and become an integral part of the power industry. It is the mainstream trend of the development of solar photovoltaic power generation technology in the world today. The grid-connected system is generally composed of photovoltaic arrays, photovoltaic controllers and grid-connected inverters, as shown in Figure 1.
Compared with other new power generation technologies (wind power generation and biomass power generation, etc.), solar photovoltaic power generation is a new energy power generation technology with the ideal characteristics of sustainable development (the most abundant resources and the cleanest power generation process). Its main advantages are as follows:
1) Solar energy resources are inexhaustible and inexhaustible. The solar energy shining on the earth is 6,000 times larger than the energy currently consumed by human beings. Moreover, solar energy is widely distributed on the earth, and photovoltaic power generation systems can be used only in places with sunlight, which are not limited by factors such as region and altitude.
2) Solar energy resources are available everywhere and can supply electricity nearby. Without long-distance transmission, the power loss of long-distance transmission lines is avoided, and the transmission cost is saved. This also creates conditions for the large-scale application of household solar power generation systems in the western region where power transmission is inconvenient.
3) The energy conversion process of solar photovoltaic power generation is simple, it is a direct conversion from photons to electrons, there is no intermediate process (such as thermal energy conversion into mechanical energy, mechanical energy into electromagnetic energy) and mechanical activities, and there is no mechanical wear. According to thermodynamic analysis, photovoltaic power generation has a high theoretical power generation efficiency, which can reach more than 80%, and has great potential for technological development.
4) Solar photovoltaic power generation itself does not burn fuel, does not emit any substances including greenhouse gases and other waste gases, does not pollute the air, does not generate noise, is environmentally friendly, is not affected by energy crisis or fuel market changes, and is truly green Environmentally friendly new renewable energy.
5) The solar photovoltaic power generation process does not require cooling water and can be installed in the desolate desert without water. The photovoltaic power generation system can also be easily integrated with buildings to form a photovoltaic building integrated power generation system, which does not require exclusive land occupation and can save precious land resources.
6) The solar photovoltaic power generation has no mechanical transmission parts, and the operation and maintenance are simple and reliable. A photovoltaic power generation system can generate electricity only with solar cell components, and with the widespread adoption of automatic control technology, it can basically achieve unattended operation and low maintenance costs.
7) The solar photovoltaic power generation system is reliable, stable and has a long operating life. Crystalline silicon solar cells have a life span of 20 to 35 years.
8) The solar cell module is simple in structure, small in size and light in weight, which is convenient for transportation and installation. The photovoltaic power generation system has a short establishment period, and the capacity can be large or small according to the electricity load, which is convenient and flexible, and can be easily combined and expanded.