Distributed photovoltaic power station characteristics, distributed power station basic principles: mainly based on the surface of buildings, including village and town residential housing rooftop solar power station and industrial and commercial enterprises rooftop photovoltaic power station, near to solve the user's electricity problems and resource utilization problems, through the grid to achieve the compensation of the difference in power supply and outward transmission, as well as enterprises and residents of self-use electricity.
I. Advantages.
1, photovoltaic power supply is on the user side, and the power generated is supplied to the local load and treated as a load, which can effectively reduce the dependence on the national grid power supply and reduce the line loss.
2, make full use of the building surface, can use the PV cells as building materials at the same time, effectively reducing the footprint of the PV power plant, creating economic benefits for users.
3、Effective interface with smart grid and microgrid, flexible operation, can be off draft grid independent operation under appropriate conditions, reduce the cost of electricity for users.
Second, the disadvantages.
1, the direction of the tide in the distribution network will change in due course, the counter-current leads to additional losses, the relevant protection all need to be re-adjusted, transformer taps need to be constantly changed, and other problems. At present, with the development of technology, the probability of this situation is becoming less and less.
2, voltage and reactive power regulation difficulties, large-capacity photovoltaic access after the power factor control there are technical-type difficulties, short-circuit power will also increase. At present, with the development of technology progress, the probability of this situation is less and less.
3, the need for energy management systems at the distribution network level, the same management of the load in the case of large-scale photovoltaic access. Provides new requirements for secondary equipment and communication, increasing the complexity of the system. At present, as the development of technology progresses, the management of distributed PV electrical energy is becoming more and more perfect, and the defects are becoming less and less obvious.
The characteristics of centralized photovoltaic power plant, centralized photovoltaic basic principles: make full use of desert areas, barren mountains, collapsed mines rich and relatively stable solar energy resources to build large photovoltaic power plants and water photovoltaic power plants, access to high-voltage transmission system to supply long-distance loads.
I. Advantages.
1, more flexible site selection, better lighting conditions, increased stability of photovoltaic power generation, and take full advantage of the positive peaking characteristics of solar radiation and electricity load, to play a role in peak shaving.
2, operation mode is more flexible, compared to distributed photovoltaic power plant can be more convenient reactive power and voltage control, to participate in the grid frequency regulation is also easier to achieve.
3, short construction period, strong environmental adaptability, high utilization rate of natural conditions, no need for water (conditions of water power generation), coal (conditions of thermal power generation) transportation and other raw material security, low operating costs, easy to centralize management, less restricted by space, can easily realize capacity expansion.
Second, the disadvantages.
1, centralized photovoltaic power plants need to rely on long-distance transmission lines to feed electricity into the grid, but also itself is a larger 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 work together requires the same management, this aspect of technology is not yet mature. At present, the accumulation of domestic photovoltaic technology experience and development, basically overcome the power station management problems.
3, in order to ensure grid security, large-capacity centralized PV access needs to have new features such as LVRT, which puts forward higher requirements for the construction and operation of centralized power plants, of course, is also a reasonable and intelligent use of electricity to play a role in promoting.
