Here is a detailed explanation of the advantages and disadvantages of centralized photovoltaic plants and distributed photovoltaic plants, including the roof PV systems, ground PV systems and floating PV systems
Photovoltaic plants are the power generation systems that use solar energy and special materials such as crystalline silicon panels and inverters and other electronic components. It is connected to the grid and the grid of photovoltaic power generation system. The photovoltaic plants can be divided into centralized photovoltaic plants and distributed photovoltaic plants. What are the differences between centralized photovoltaic plants and distributed photovoltaic plants? Let us see it now.
Characteristics of distributed photovoltaic plants
The basic principle of distributed PV plants: it is mainly based on the surface of the building. It can solve the problem of power consumption of users nearby through the grid to realize the compensation and delivery of power supply difference.
Advantages of distributed photovoltaic plants:
1. The photovoltaic power supply is on the user side, and the power generation supplies the local load, which is regarded as the load. It can effectively reduce the dependence on the power grid and reduce line loss.
2. Make full use of the surface of the building. The photovoltaic cells can be used as building materials at the same time. It effectively reduces the area of the photovoltaic plants.
3. Effective interface with smart power grid and micro-grid. The operation is flexible, and independent operation of off-draft power grid can be done under appropriate conditions.
The disadvantages of distributed PV plants:
1. The direction of power flow in the distribution network will change in time, and the inverse power flow will lead to extra losses. The relevant protection needs to be reset, and the transformer tap needs to be constantly changed, etc.
2. It is difficult to adjust voltage and reactive power. There are technical problems in the control of power factor after the access of large-scale photovoltaic. The short-circuit power will also increase.
3. The energy management system at the distribution grid level is required to carry out the same management of load in the case of large-scale photovoltaic access. New requirements for secondary equipment and communication increase the complexity of the system.
Characteristics of centralized PV plants:
The basic principle of centralized PV plants: It can make full use of abundant and relatively stable solar energy resources in desert areas to construct large-scale photovoltaic plants. It can connect these stations to high-voltage transmission systems to supply long-distance loads.
Advantages of centralized PV plants:
1. Due to the more flexible site selection, the stability of photovoltaic output is increased. The positive peak regulation characteristics of solar radiation and electricity load are fully used to play the role of peak cutting.
2. The operation mode is more flexible. Compared with distributed photovoltaic, reactive power and voltage control can be carried out more conveniently. It is also easier to participate in the power grid frequency regulation.
3. The construction cycle is short. A strong ability can adapt to the environment. The photovoltaic plants do not need water, coal transportation and other raw materials. It has a low operation cost. It is easy to centralize management and small space restrictions. It can easily achieve capacity expansion.
Disadvantages of centralized PV plants:
1. It is necessary to rely on long-distance transmission lines to send electricity to the network. It is also a large interference source of the power grid. Problems such as transmission line loss, voltage sag and reactive power compensation will be prominent.
2. Large capacity photovoltaic plants can be realized by the combination of multiple conversion devices. The collaborative work of these devices requires the same management, which is still not mature.
3. To ensure power grid security, large-capacity centralized photovoltaic access needs new functions such as LVRT, which often conflicts with isolated islands.
The centralized large-scale grid-connected photovoltaic plants is a kind of large-scale photovoltaic plant that is centralized and recommended by the state. The power generation is directly integrated into the public grid and it is connected to the high-voltage transmission system to supply long-distance load. The distributed small grid-connected photovoltaic system, especially the integrated photovoltaic building power generation system, is the mainstream of grid-connected photovoltaic power generation in developed countries due to its advantages of small investment, fast construction, small footprint and strong policy support.