The basic principle of distributed photovoltaic power station: mainly based on the building surface, solve the power consumption problem of nearby users, and realize the compensation and delivery of power supply difference through grid connection.

Advantages:

1. The photovoltaic power supply is at the user side, and the power generation is supplied to the local load, which is regarded as the load, which can effectively reduce the dependence on the power supply of the power grid and reduce the line loss.

2. By making full use of the building surface, photovoltaic cells can be used as building materials at the same time, effectively reducing the floor space of photovoltaic power stations.

3. Effective interface with smart grid and microgrid, flexible operation, and independent operation of power grid under appropriate conditions.

Disadvantages:

1, the power flow direction of the distribution network will change in time, and the reverse power flow will cause additional losses, the related protection needs to be reset, and the transformer tap needs to be constantly replaced.

2. It is difficult to adjust voltage and reactive power. After large-capacity photovoltaic access, there are technical problems in power factor control, and short-circuit power will also increase.

3. Under the condition of large-scale photovoltaic access, the energy management system at the distribution network level needs the same load management. New requirements are put forward for secondary equipment and communication, which increases the complexity of the system.

The basic principle of centralized photovoltaic power station: make full use of the abundant and relatively stable solar energy resources in desert areas, build large-scale photovoltaic power stations, connect to high-voltage transmission systems, and supply power for long-distance loads.

Advantages:

1. Because the site selection is more flexible, the stability of photovoltaic output is improved, and the positive peak regulation characteristics of solar radiation and power load are fully utilized to play the role of peak clipping and valley filling.

2. The operation mode is more flexible, it is more convenient to control reactive power and voltage than distributed photovoltaic, and it is easier to participate in power grid frequency modulation.

3. The construction period is short, the environmental adaptability is strong, raw materials such as water source and coal transportation are not needed, the operation cost is low, centralized management is convenient, space limitation is small, and expansion is easy to realize.

Disadvantages:

1, which needs to rely on long-distance transmission lines to send electricity to the network, is also a major interference source of the power grid, and problems such as transmission line loss, voltage drop and reactive power compensation will be highlighted.

2. A large-capacity photovoltaic power station is realized by combining multiple conversion devices, and the cooperative work of these devices needs the same management. At present, this technology is still immature.

3. In order to ensure the safety of power grid, large-capacity centralized photovoltaic access needs new functions such as LVRT, and this technology often conflicts with isolated islands.