2024-12-12
Our photovoltaic power plants, wind farms or home solar systems may be equipped with off-grid systems when purchasing. Then, when the equipment needs to be connected to the power grid, an equipment "grid cabinet" must be installed. The grid-connected cabinet can deal with and monitor the electric energy of the system to make it meet the power grid's requirements in voltage, frequency, phase, and other matching parameters, as well as provide protection functions to prevent faults from causing damage to the power grid and power generation equipment.
For example, the customer configured 300kwh photovoltaic self-use, residual power does not go online energy storage system, need to install photovoltaic grid-connected cabinet. This prevents the current from flowing back into the grid and not being fined a huge amount by the grid. The anti-countercurrent photovoltaic grid-connected cabinet can solve the trouble for you, can monitor the photovoltaic power, voltage, current, and power consumption of the local load in real time. By detecting the direction and size of the current, it can detect the direction of current detection, countercurrent release detection, and timely control the power of the inverter or cut off the connection with the grid.
However, in the case of multi-motor parallel connection with load power supply, it is also necessary to install a grid-connected cabinet to realize synchronous detection, synchronous closing, automatic and other functions, so as to ensure that the output voltage, frequency, phase sequence, phase and other parameters of each unit are consistent, and to protect the generator combination grid equipment. The diesel generator with solar energy, wind energy, energy storage batteries needs to coordinate to work in some microgrid systems. In order for collaborative works with their mutual complementarities to have their power supply, one has to install grid cabinets for unified control and regulation. According to the loads demands and the state of all the power supplies, automated switching and allocation of powers to ensure stability and dependability in power supply should be affected.
In general, small-distributed power generation projects rely on voltage grade. Systems below 1kv can use a low-voltage grid-connected cabinet; those with system voltage grades between 1KV-35kV use medium-voltage grid-connected cabinets, while high-voltage power grids with 35kV and above need large centralized power stations. For instance, most large hydropower stations, thermal power plants, large photovoltaic power stations, and large wind farms are connected to the power grid by high voltage grid-connection.
Classified by functional characteristics
Ordinary grid-connected cabinet: It has basic grid-connected control, protection and metering functions, which can realize the connection, monitoring and protection of power generation equipment and the grid, and meet the general grid-connected needs.
Intelligent grid-connected cabinet: integrates advanced intelligent control technology and communication functions, can achieve remote monitoring, data analysis, fault diagnosis, automatic control and other functions, improve the intelligent level and efficiency of the grid-connected system.
Anti-island grid-connected cabinet: specially equipped with anti-island protection device, power grid failure or power failure, can quickly detect and cut off the connected line between the generating equipment and the power grid, prevent generating equipment from continuing to operate under the island state, and ensure the safety and stability of the power system.
So how to choose an appropriate grid-connected cabinet? Consider the following aspects :
Due to the different power generation systems, such as photovoltaic, wind, energy storage, etc., the requirements for the grid-connected cabinet are also different. For household roof PV, the power is usually in a few kilowatts to tens of kilowatts, you can choose low-voltage grid-connected cabinet; Large centralized photovoltaic power plants or wind farms with power above the megawatt level may require medium or high voltage grid-connected cabinets. If the power generation project has a subsequent expansion plan, a grid-connected cabinet with certain scalability should be selected, such as a grid-connected cabinet with a modular design, which is easy to add modules or equipment when needed, without replacing the whole grid-connected cabinet.
Grid Access according to Requirements : According to requirements set by the State Grid in China, if the capacity of photovoltaic power stations is less than 8000 watts, 220 volts of grid connection shall be preferred, while for that of over 8000W, up to 400 kWp, 380V of grid-connection transformer should be chosen. Also consider the output voltage to ensure that the rated voltage of the grid-connected cabinet matches the output voltage of the power generation system to avoid equipment damage or low power transmission efficiency due to voltage mismatch.
The basic functional completeness: with perfect protection functions, such as overcurrent, over-protection, under-voltage, short circuit, anti-island protection, etc., to ensure safe operation of power generation system and power grid; it should possess accurate power metering function at the same time, which is convenient for statistics of electricity generation and electricity bill settlement.
Intelligent control and monitoring requirements: A grid-connected cabinet with intelligent control and remote monitoring functions can be chosen for large-scale power generation projects or systems that need to be remotely monitored. It is connected to the monitoring system through a communication interface to realize real-time monitoring and remote control of the operating status of the grid-connected cabinet.
Choose brands that have high visibility and a good reputation in the market, mostly those with mature technology and a production process where product quality and stability are more guaranteed. Pay attention to the brand and quality of the electrical components in the grid-connected cabinet, such as the circuit breakers, contactors, relays, fuses, etc.; it is necessary to select high-quality products of famous brands so that the parts will be of reliable performance with a long service life.
Compatibility and installation maintenance: the grid-connected cabinet shall ensure that it is compatible with other equipment in the power generation system such as inverters, transformers, monitoring equipment, etc. for perfect dock and collaboration; according to the installation mode and space requirement of the grid-connected cabinet, choose the grid-connected cabinet with compact structure and easy installation to facilitate the field installation and commissioning. At the same time, it is necessary to choose a grid-connected cabinet that is easy to maintain, so as to reduce maintenance costs and workload in the later period.
According to the investment budget of the project, the model and configuration of the grid-connected cabinet should be reasonably selected to avoid excessive pursuit of high-end products and high costs. Under the premise of meeting the function and quality requirements, compare the prices of different manufacturers and different models of grid-connected cabinets, and choose cost-effective products.
AC Low-voltage Grid-connected Cabinet: It is a crucial piece of equipment in the distributed energy project and can be called an intelligent energy scheduler. The photovoltaic and energy storage output, the acceptance of the grid-all are elaborately matched by it.
It has a sturdy and durable cabinet structure, which can well bear up against a variety of terrible conditions in the environment to make the inside electrical components operate safely and stably. Simultaneously, due to accurate wiring and reasonable layout, installation and maintenance can be performed easily and conveniently.
Meanwhile, in functions, anti-island protection is one of the highlights. This function may monitor the system status in real time to take swift actions that are appropriate for ensuring safety in view of any anomalies in a power grid or the island phenomenon. The power quality optimization function effectively filters and regulates the photovoltaic and energy storage so that the output power meets the strict standards of the power grid, reduces the impact on the power grid, and improves the stability and reliability of the power grid.
In addition, our series of network cabinets are also equipped with an intelligent monitoring system. Baidirectional sensors and advanced communication technology allow the real-time operating status of equipment to be transmitted remotely so that users can learn about power generation conditions at any time and from anywhere, work parameters for the grid-connected cabinet, timely alarm when there is an exception, with fault information available in detail. This will be convenient for quick maintenance and the solution of problems.
According to different sizes of new energy projects, our AC low-voltage grid-connected cabinets can provide customized solutions. No matter if it is a small distributed photovoltaic, energy storage power station, or a large centralized photovoltaic, energy storage project, we can tailor the most suitable grid-connected cabinet configuration according to the actual needs of customers to ensure the best energy conversion efficiency and economic benefits.
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