With the popularization of photovoltaic power generation, it has become an important step to convert solar energy into electric energy and send it to the power grid. So, how is photovoltaic power generation integrated into the power grid?

Basic principle of grid connection
Inverter conversion: Direct current is converted into alternating current through solar inverter, and it has the function of synchronizing frequency and voltage, ensuring that the output is compatible with the power grid
Synchronous grid connection: The inverter will detect the grid frequency (such as 50Hz or 60Hz) and voltage, and keep the converted AC parameters consistent with the grid
Grid connection: Connect the photovoltaic power generation system with the designated nodes of the power grid through intelligent grid-connected equipment
Architecture of grid-connected photovoltaic system
Centralized grid-connected system: It is suitable for large-scale ground photovoltaic power stations and transmits electric energy to the main power grid through high-voltage grid-connected points
Distributed grid-connected system: It is more common in industrial buildings and residential roofs, and directly transmits electric energy to nearby users or power grids through low-voltage power grids
Micro-grid system: An independent system including photovoltaic, energy storage and load, which can realize two-way energy interaction with the main grid
Policy support & Incentive mechanism
Feed-in Tariff (FIT): Provide fixed returns for photovoltaic power generation and encourage investors to join
Net Metering: Allows users to send surplus photovoltaic energy into the power grid, and can extract the same amount of energy from the power grid in the future, saving electricity bills
Renewable energy quota (RPS): Power grid companies are required to absorb a certain proportion of clean energy
Technical & equipment requirements for grid connection
Inverter standard: The inverter must meet the voltage, current and frequency requirements of the power grid, and support fault ride-through and reactive power compensation
Grid-connected protection equipment: Including island protection device to ensure automatic disconnection in case of power grid failure and avoid security risks
Metering equipment: Two-way ammeter shall be installed to accurately record the input and output power
Evaluation of power grid access points: Access points should be selected according to power grid capacity and stability to avoid power grid overload or instability

Challenges faced by grid connection
Power grid stability: A large number of distributed photovoltaic access will lead to voltage fluctuation and increase the difficulty of power grid regulation
Power fluctuation: Photovoltaic power generation is affected by the weather, and the power output may be unstable
Power grid capacity limitation: In some areas, the power grid has insufficient carrying capacity and it is difficult to absorb more photovoltaic power
Policy implementation: Some areas lack clear grid-connected policies or have low implementation efficiency
Future Outlook & Solutions
Smart grid technology: Through real-time monitoring and dynamic regulation, improve the compatibility of power grid with photovoltaic power generation
Energy storage system integration: Add battery energy storage equipment to photovoltaic system to balance power fluctuation
Optimization of photovoltaic consumption mechanism: Promote efficient consumption of photovoltaic power through market-oriented trading mechanism
Distributed energy management: Using block-chain technology and virtual power plant to optimize the coordination ability of distributed energy
Grid-connected photovoltaic power generation is not only a key link to achieve the goal of clean energy, but also an important direction of modern power grid development. In the future, with the progress of technology and the improvement of policies, photovoltaic grid connection will become more efficient and stable.