Photovoltaic power plant is a kind of photovoltaic power generation system that uses the sun's energy, using special materials such as crystalline silicon panels, inverters and other electronic components, connected to the grid and transmits electricity to the grid. Among them, photovoltaic power plants can be divided into centralized photovoltaic power plants and distributed photovoltaic power plants, then centralized photovoltaic power plants and distributed photovoltaic power plants what is the difference between the following to understand.
Distributed photovoltaic power plant features
Distributed basic principles: mainly based on the surface of the building, the nearest solution to the user's electricity problem, through the grid to achieve compensation for the difference in power supply and outgoing.
A, the advantages of distributed photovoltaic power plant.
1, photovoltaic power supply in the user side, power generation supply local load, as a load, can effectively reduce the reliance on the grid power supply, reduce line losses.
2, make full use of the building surface, can be photovoltaic cells at the same time as building materials, effectively reducing the footprint of the PV power plant.
3, effective interface with the smart grid and microgrid, flexible operation, under the appropriate conditions can be off draft grid independent operation.
Second, the disadvantages of distributed photovoltaic power plants.
1, the tidal direction in the distribution network will change in due course, the counter-current leads to additional losses, the relevant protection are required to re-adjust, transformer taps need to constantly change and other problems.
2, voltage and reactive power regulation difficulties, large-capacity photovoltaic access to the power factor control there are technical difficulties, short-circuit power will also increase.
3, the need for energy management system at the distribution network level, the same management of the load in the case of large-scale PV access. Provides new requirements for secondary equipment and communication, increasing the complexity of the system.
Features of centralized PV power plant
Concentrated basic principle: make full use of the abundant and relatively stable solar resources in desert areas to build large scale PV power plants, and access to high voltage transmission systems to supply long distance loads.
I. Advantages of centralized photovoltaic power station.
1, due to more flexible site selection, photovoltaic output stability increased, and take full advantage of solar radiation and the positive peaking characteristics of the electricity load, play a role in peak shaving.
2, operation is more flexible, compared to distributed PV can be more convenient reactive power and voltage control, to participate in the grid frequency regulation is also easier to achieve.
3, construction cycle is short, environmental adaptability, no water, coal transportation and other raw material security, low operating costs, easy to centralize management, by the small space constraints, can easily achieve expansion.
Second, centralized photovoltaic power plant disadvantages.
1, need to rely on long-distance transmission lines to feed electricity into the network, but also itself is a large source of interference in the grid, transmission line losses, voltage dips, reactive power compensation and other issues will come to the fore.
2, large-capacity photovoltaic power plant by the combination of multiple conversion devices to achieve, these devices need to work together for unified management, the current technology is not yet mature.
3, to ensure grid security, large-capacity centralized PV access requires new features such as LVRT, this technology is often in conflict with the island.
Centralized large grid-connected photovoltaic power station is the state use of desert, centralized proposal of large photovoltaic power station, power generation directly into the public grid, access to high-voltage transmission system to supply long-distance load. Distributed small grid-connected PV system, especially PV building integrated power generation system, is the mainstream of grid-connected PV power generation in developed countries due to the advantages of small investment, fast construction, small footprint, and strong policy support.
