The photovoltaic grid-connected cabinet is a power distribution device that connects the photovoltaic power station and the power grid, and its main role is to serve as the boundary between the photovoltaic power station and the power grid. For low-voltage grid-connected photovoltaic power stations, photovoltaic grid-connected cabinets can also be home decoration reference metering and some protection functions. The photovoltaic grid-connected cabinet, as the total outlet of the photovoltaic power station, must exist in the photovoltaic system.

Compared with the ground centralized photovoltaic power station, the scale of the distributed photovoltaic power station is relatively small, but it is more scattered, and the grid-connected voltage level is generally 380V, in the case of this low-voltage grid-connected station, it is generally less involved in the secondary microcomputer protection, and the microcomputer protection used in the distributed photovoltaic power station is usually the anti-islanding protection device, which is installed in the grid-connected cabinet. For this reason, the use of distributed grid-connected cabinets is widely used in distributed photovoltaic power stations.

It can be seen that the composition of the photovoltaic grid-connected cabinet is composed of anti-island protection device, low-voltage circuit breaker, air switch, lightning arrester, temperature and humidity heater, stainless steel box and other equipment. The selection of the circuit breaker is based on the actual current flowing through the circuit breaker, which is generally about 1.2 times of the rated current.

The above is conventional, according to the different projects, the equipment in the distributed grid-connected cabinet is also different, and some projects need to install watt-hour meters or other equipment in the grid-connected cabinet, depending on the project. Friends often ask where the photovoltaic anti-islanding protection device is installed, which is actually very simple. The main functions of anti-islanding protection device are high-frequency protection, low-frequency protection, high-voltage protection, low-voltage protection, reverse power protection, etc. The anti-islanding protection device will jump off the grid-connected circuit breaker when a fault is detected.

Therefore, it is most suitable to install the anti-islanding protection device in the grid-connected cabinet. It should be noted that the anti-islanding protection device is a kind of microcomputer protection, and it needs to be debugged and experimented when used. The minimum protection value is set by the on-site electrical commissioning personnel in accordance with the protection value given by the relevant departments, if the value is not set, then the protection device is useless.

Characteristics of photovoltaic grid-connected cabinet

1. Advanced: The company's self-developed power quality management products (APF, SVG) can be selected, which can be targeted for on-site power problems (harmonics, power factors, etc.) to ensure that the acceptance is passed;

2. Worry-free: high degree of automation, can automatically run stably for a long time according to the voltage situation without human intervention (voltage detection option);

3. Flexible: the number of AC (inverter) input channels can be designed into multiple channels according to the actual situation;

4. Safety: It has a variety of protection functions such as voltage tripping, pressure closing, lightning protector protection, island protection, etc., and the electric energy meter is equipped with a seal device;

5. Reliable: The main circuit adopts all-copper design, which greatly reduces potential fault points, and the visual breakpoint design of the power grid (high-current knife switch);

6. Intelligent: It can collect voltage, current, frequency, active power, reactive power, and use ModBus-RTU communication protocol to achieve local/remote data monitoring through RS485 communication interface.