The key points to note for the microgrid access technology of solar panels mainly include the following aspects:
First, planning and design before access
Analysis of Power Grid Conditions
Grid owner: Determine whether the grid to be connected is a public grid or a private grid, and understand the operation rules and technical requirements of the grid.
Access distance and capacity: Based on the scale of the photovoltaic power station, assess the distance from the access point to the grid access point to ensure that the transmission loss is within a reasonable range. At the same time, consider whether the access capacity of the photovoltaic power station meets the requirements of the power grid to avoid overload.
Voltage level: Select an appropriate grid-connected voltage level. Generally, distributed photovoltaic power generation projects can be connected to the system through dedicated lines or T-connection. The initial selection should be made based on the installed capacity. The final grid-connected voltage level should be determined through technical and economic comparison and argumentation according to the grid conditions. If both the high and low voltage levels are ready for connection, the lower voltage level should be given priority for connection.
System design and equipment selection
Inverter selection: Choose an inverter with efficient power conversion capabilities, good grid adaptability, safety and stability, as well as intelligent management functions. The inverter needs to be capable of converting the direct current generated by the photovoltaic system into alternating current, enabling it to be connected to the power grid or supply power to the loads in the microgrid.
Energy storage system configuration: According to the power generation characteristics and load requirements of the photovoltaic power station, the energy storage system should be rationally configured. Energy storage systems can balance the disparity between the power generation of solar photovoltaic systems and the load demand, enhancing the stability of the power grid and the quality of power supply. The current mainstream energy storage technologies include lithium batteries, lead-acid batteries, flow batteries, etc.
Microgrid controller: Selecting a microgrid controller with intelligent control functions can achieve coordinated control of photovoltaic power stations, energy storage systems, loads, etc., thereby enhancing the operational efficiency and reliability of the microgrid.
Second, technical requirements for the access process
The setting of the merging point
Definition of the grid connection point: For distributed power sources with a step-up substation, the grid connection point is the busbar or node on the high-voltage side of the distributed power source’s step-up substation. For distributed power sources without a step-up substation, the grid connection point is the output summary point of the distributed power source.
Grid connection equipment configuration: At the grid connection point, set up grid connection breaking equipment that is easy to operate, can be interlocked, and has a clear disconnection point. Ensure that the connection to the power grid can be quickly disconnected in emergency situations to guarantee the safety of the power grid and photovoltaic power stations.
Relay protection and automation configuration
Relay protection configuration: According to the access capacity of the photovoltaic power station and the requirements of the power grid, appropriate relay protection devices should be configured. Ensure that when faults occur in photovoltaic power stations or the power grid, the faults can be quickly and accurately removed to guarantee the stable operation of the power grid.
Automated configuration: Achieve remote monitoring and automatic control of photovoltaic power stations, enhancing operational efficiency and management level. The operation status of photovoltaic power stations is monitored in real time through the monitoring system, and abnormal situations are detected and handled promptly.
Electric energy metering and communication
Electric energy metering: Before a photovoltaic power station is connected to the grid, the metering points for the electricity fed to the grid and the electricity consumed by the grid should be clearly defined, and electric energy metering devices that meet the requirements should be installed. Ensure the accurate measurement and settlement of electric energy.
Communication system: Establish a stable and reliable communication system to achieve information exchange between photovoltaic power stations and the power grid. Select the appropriate communication protocol to ensure the real-time performance and reliability of data transmission.
Third, operation and maintenance after connection
Operation monitoring and optimization
Real-time monitoring: The operation status of photovoltaic power stations is monitored in real time through the monitoring system, including parameters such as power generation, voltage, current, and power factor. Timely detect and handle abnormal situations to ensure the safe and stable operation of photovoltaic power stations.
Operation optimization: Optimize the operation strategy based on the power generation characteristics and load demands of the photovoltaic power station. For instance, by adjusting the working mode of the inverter and the charging and discharging strategies of the energy storage system, the power generation efficiency of the photovoltaic power station and the stability of the power grid can be enhanced.
Regular maintenance and inspection
Equipment maintenance: Regularly maintain the equipment of photovoltaic power stations, including solar panels, inverters, energy storage systems, grid-connected equipment, etc. Check the operating status of the equipment, promptly identify and handle potential problems, and extend the service life of the equipment.
Safety inspection: Regularly conduct safety inspections on photovoltaic power stations to ensure the safe operation of the equipment. Check whether the grounding device, lightning protection device, etc. are in good condition and effective to prevent safety accidents caused by equipment failure or natural disasters.
Training and emergency drills
Personnel training: Provide training for the operation and maintenance personnel of photovoltaic power stations to enhance their professional skills and emergency response capabilities. Ensure prompt and accurate response and handling in emergency situations.
Emergency drills: Regularly organize emergency drills to test the emergency response capabilities and the ability to handle unexpected incidents of photovoltaic power stations. Through drills, identify existing problems and deficiencies, and promptly improve emergency plans and handling procedures.
Fourth, other precautions
Comply with relevant standards and norms
During the process of connecting photovoltaic power stations to microgrids, strict compliance with relevant national standards and norms should be ensured. For example, power quality standards, relay protection configuration standards, communication system standards, etc. Ensure the safe, stable and reliable operation of photovoltaic power stations.
Communicate and coordinate with the power grid company
Before a photovoltaic power station is connected to a microgrid, sufficient communication and coordination should be carried out with the power grid company. Understand the operation rules and technical requirements of the power grid, and clarify the specific requirements in aspects such as the setting of connection points, relay protection configuration, and electric energy metering. Ensure the smooth connection and stable operation of photovoltaic power stations.
Pay attention to the development of new technologies
With the continuous development of technology, the technology for photovoltaic power stations to be connected to microgrids is also constantly advancing. Attention should be paid to the development trends of new technologies, and new technologies should be actively introduced and applied to improve the power generation efficiency of photovoltaic power stations and the stability of the power grid.
In summary, the key points to note for the microgrid connection technology of solar panels involve multiple aspects such as planning and design before connection, technical requirements during the connection process, operation and maintenance after connection, and other precautions. Only by comprehensively considering these factors can the safe, stable and reliable connection of photovoltaic power stations to the microgrid be ensured.
