In recent years, with the huge photovoltaic stock market and rapid iterative system efficiency, falling system costs, and rapid technological progress, space has been created for technological transformation. Especially after the photovoltaic industry achieves grid parity, the hidden value of existing power stations is increasing. The technical transformation of photovoltaic power stations mainly through the deep integration of the Internet of Things, cloud computing, big data, artificial intelligence, new materials, new technologies and the photovoltaic power generation industry, transforming power stations with low performance indicators into new smart photovoltaic power stations, so as to realize the improvement of old power stations. Intelligent. However, there are many practical issues to be considered in achieving this step.
1.Wired communication construction is difficult
In the initial construction of PV power plants, power cables and communication cables (optical fibers) are generally laid and buried together. Some old power stations did not lay communication cables during construction, and secondary construction is required for intelligent transformation. When digging trenches and other operations, it is easy to damage the original power cables, resulting in casualties or property losses.
2.High construction cost
The construction cost of the transformation of photovoltaic power plants is also very high. According to statistics, a 30MW photovoltaic power station requires 6,300 meters of optical fiber cables and 3,000 meters of line trenches. Among them, there are also circuit presets, equipment debugging, etc., and the loss of labor and cost is huge.
3.Poor wireless communication
There are many wireless communication solutions, but there are not many cases applied in the field, which are mainly affected by the following aspects
Short transmission distance: The equipment on site has exceeded the wireless transmission distance, so the equipment room cannot receive equipment information.
Restricted transmission types: Some sites are located in remote locations and do not have 2G/4G signals, which hinders the transmission scheme using DTU.
Environmental interference: When the wireless transmission antenna is built into the combiner box, the combiner box, photovoltaic panels, etc. will block the wireless signal, resulting in the inability to transmit device information. There is a risk of lightning strikes when the antenna is placed at a high place. At the same time, problems such as harmonics generated by the inverter will also interfere with the wireless.
Increased cost: necessary to implement wireless transmission, antennas and communication modules. Therefore, the cost of the combiner box monitoring module with wireless function is about 100 higher than that of the ordinary one.
FR-DCMG-MMPL power line carrier communication products are mainly used in DC power transmission, distribution and other occasions, such as photovoltaic combiner boxes, DC cabinets, telecommunication equipment rooms and communication base stations. Collect node data through power line carrier, and then communicate with the host computer through RS485. Its main functions include real-time monitoring of each branch current, bus voltage, box temperature, lightning arrester status and DC circuit breaker status in the DC system. It can realize automatic alarm of abnormal state and so on.
Power line carrier communication module: through the power line carrier expansion module DC-DCMG-PLCx, the communication of up to 24 nodes can be realized
Monitoring function: Real-time monitoring of the generation current, voltage, temperature of the combiner box, lightning arrester status, DC circuit breaker status and DC arc fault status of each PV string in the combiner box.
Display content: For the detected voltage, current, temperature, power generation and other data, the bar graph interface can be displayed through the LCD, and the current and other data can be read out more intuitively.
Alarm function: All alarm functions are set to enable bits, which can be configured as required.
Chint 10MWPLC combiner box communication case
Gansu Hongyuan 5MW old power station technical renovation case