Analysis of Advantages and Disadvantages of Centralized Photovoltaic and Distributed Photovoltaic

Photovoltaic power station refers to a photovoltaic power generation system that uses solar energy and uses special materials such as crystalline silicon panels, inverters and other electronic components to connect to the grid and transmit power to the grid. Among them, photovoltaic power stations can be divided into centralized photovoltaic power stations and distributed photovoltaic power stations. So what is the difference between centralized photovoltaic power stations and distributed photovoltaic power stations? Let’s understand together.

Characteristics of distributed photovoltaic power plants

The basic principle of distribution: mainly based on the surface of the building, solve the user’s electricity consumption problem nearby, and realize the compensation and delivery of the power supply difference through grid connection.

The photovoltaic power supply is on the user side, and the power generated is supplied to the local load, which can be regarded as a load, which can effectively reduce the dependence on the grid power supply and reduce line loss.

By making full use of the building surface, photovoltaic cells can be used as building materials at the same time, effectively reducing the footprint of photovoltaic power plants.

Effective interface with smart grid and micro grid, flexible operation, and independent operation of the grid under appropriate conditions.

The direction of the power flow in the distribution network will change in time, and the reverse flow will cause additional losses. The relevant protections need to be re-adjusted, and the transformer taps need to be constantly changed.

Difficulties in voltage and reactive power regulation. There are technical difficulties in the control of power factor after the connection of large-capacity photovoltaics, and the short-circuit power will also increase.

The energy management system at the distribution network level is required to perform the same load management in the case of large-scale photovoltaic access. New requirements are placed on secondary equipment and communications, increasing system complexity.

Centralized basic principles: make full use of the abundant and relatively stable solar energy resources in desert areas to build large-scale photovoltaic power plants, and connect to high-voltage transmission systems to supply long-distance loads.

• Due to the more flexible site selection, the stability of photovoltaic output has increased, and the positive peak-shaving characteristics of solar radiation and electric loads have been fully utilized to play the role of peak-shaving.
• The operation mode is relatively flexible. Compared with distributed photovoltaics, it is more convenient to carry out reactive power and voltage control, and it is easier to realize the frequency regulation of the power grid.
• Short construction period, strong environmental adaptability, no need for water source, coal transportation and other raw material guarantees, low operating costs, easy centralized management, small space constraints, and easy expansion.

• It needs to rely on long-distance transmission lines to send power into the grid. At the same time, it is also a large source of interference to the power grid. Issues such as loss of transmission lines, voltage drop, and reactive power compensation will become prominent.
• Large-capacity photovoltaic power plants are realized by combining multiple conversion devices. The coordinated work of these devices requires unified management, and the technology in this area is not yet mature.
• In order to ensure the safety of the power grid, large-capacity centralized photovoltaic access needs new functions such as LVRT. This technology often conflicts with isolated islands.

The centralized large-scale grid-connected photovoltaic power station is the use of deserts by the country to centrally propose large-scale photovoltaic power stations, the power generation is directly integrated into the public grid, and connected to the high-voltage transmission system to supply long-distance loads. Distributed small-scale grid-connected photovoltaic systems, especially building-integrated photovoltaic power generation systems, are the mainstream of grid-connected photovoltaic power generation in developed countries due to their advantages such as small investment, fast construction, small footprint, and strong policy support.