Solar power generation has become an essential complement to traditional energy sources. Due to its significant role in environmental protection and economic growth, all developed countries are actively promoting the development of solar energy. Currently, small and medium-sized solar power systems have formed a mature industry. There are two main methods of solar power generation: photovoltaic (PV) power generation and solar thermal power generation. Among these, photovoltaic power generation stands out for its ease of maintenance and flexibility in power output, making it widely used as a medium or small-scale grid-connected power supply.
Photovoltaic power systems can be connected to the grid in two primary ways: centralized grid connection and distributed grid connection.
In centralized grid connection, the electricity generated is directly transmitted to the main power grid, and the distribution of power to users is managed by the grid itself. The power exchange between the system and the grid is one-way. This method is typically used for large-scale photovoltaic power plants, which are often located far from the load centers, such as desert-based solar farms.
On the other hand, decentralized or distributed grid connection allows the generated electricity to be directly supplied to local loads. Any surplus or deficit in power is managed through the main grid, enabling bidirectional power exchange. This approach is ideal for small-scale PV systems, particularly those installed in urban areas or integrated with buildings.
With the increasing support for household distributed photovoltaics, the installed capacity is expected to reach 60 GW by 2020, surpassing that of centralized PV plants. As more people begin to engage with solar energy, it's important to understand the correct wiring methods for grid-connected electricity meters.
Currently, photovoltaic grid-connected meters come in single-phase and three-phase types. When the inverter capacity of a PV system is 5 kW or less, a single-phase meter is sufficient. To ensure proper installation, it's crucial to understand the differences between single-phase and three-phase electricity.
Three-phase electricity refers to a system where three alternating currents are generated with equal amplitudes, frequencies, and a 120° phase difference. A three-phase generator supplies this type of power, and the circuit powered by it is known as a three-phase circuit. In China, the power system operates on a three-phase four-wire system, consisting of three phase lines (U, V, W) and a neutral line. The voltage between two phase lines is 380V (line voltage), while the voltage between a phase line and the neutral line is 220V (phase voltage). If the load is unbalanced, it can cause a zero-voltage offset, leading to some voltages being higher or lower than 220V.
Household electricity is typically single-phase, using either 220V or 380V. It involves one phase line (commonly called the live wire) and the neutral line. Most household appliances operate on single-phase power, whether they have two or three pins. Two-pin sockets are used for non-metallic appliances, while three-pin sockets include a ground wire for metal-cased devices.
Single-phase electricity is part of a three-phase system. Even when two live wires are used (e.g., 380V), it is still considered single-phase. Understanding this distinction is key to proper electrical installation.
For most residential PV systems below 5 kW, a single-phase inverter is used, requiring a bidirectional (single-phase) meter for grid connection. These meters are designed to measure both the electricity consumed and the surplus generated, allowing for net metering.
The typical appearance of a bidirectional meter includes six terminals: incoming lines at positions 1 and 3, outgoing lines at 4 and 6, and pulse output ports at 2 and 5. While these are not always used in practice, they are essential for testing and accuracy.
When installing a bidirectional meter, it’s important to connect the main power supply to terminal 1, the neutral line to terminal 4, and the outgoing line to the unidirectional meter’s terminal 1. Terminal 6 should be connected to terminal 3, and the load should be connected to terminals 2 and 4 of the unidirectional meter. Additionally, a user-side meter should be added to track the total power generated by the PV system.
Wiring diagrams vary depending on the system size and configuration. For example, a simple setup may involve one bidirectional meter and one unidirectional meter, while more complex systems may use multiple meters. Three-phase systems require careful attention to phase colors—typically yellow for phase A, green for phase B, and red for phase C.
Before installation, it's crucial to consult a professional electrician to ensure safety and compliance with local regulations. Additional components such as air Switches and leakage protection devices should also be included to safeguard the household electrical system. Proper planning and execution are essential to ensure a safe and efficient photovoltaic grid connection.
Industrial Aluminum PDU | Schuko Type F
Pdu Aluminum Power Strips For Computers,Pdu Aluminum Power Strips For Cruise Ships,Pdu Aluminum Power Strips For Outdoor,Pdu Aluminum Power Strips For Outdoor Use
Yang Guang Auli Electronic Appliances Co., Ltd. , https://www.ygpowerstrips.com