In recent years, the PV industry of our country has developed rapidly, and the installed capacity of PV in 2018 exceeds 43 GW. As a highly intelligent unit of photovoltaic system, inverter is the core equipment of photovoltaic power generation system. In today's wave of high-speed development of science and technology, the industry with a very rapid rate of iteration. Today's solar inverter are not only more powerful and smarter, they are also constantly pushing the limits of individual power. Recently many domestic photovoltaic projects 70/80KW and larger power series inverter gradually become the mainstream. Similarly, in medium-high voltage grid-connected PV power plants, the group of series inverter also gradually replace the trend of centralized inverter. Taking the SUNTREE series 70/80K of Jingfuyuan as an example, this paper briefly introduces several advantages of group series inverter compared with centralized inverter in photovoltaic power plant project.

MPPT way more. SUNTREE 70/80K adopts 4-way MPPT design, which can adapt to the complex terrain of component installation. In the later period of operation, the efficiency of the whole system will not be affected because of partial occlusion or component failure.

Saving DC bus box cost. SUNTREE 70/80K adopts 12-channel input design and fuse protection, and integrates DC bus box functions -LRB-bus, lightning protection, switch, anti-reverse connection, etc.) , which can connect each group string directly to DCe dc input of inverter, no additional DC bus is required. The system design is simplified and the system cost is saved, at the same time the failure risk is reduced. With waterproof cooling fan, and the machine is completely isolated from the internal circuit board, the body reached IP65 protection level, can meet the outdoor installation conditions, direct wall-mounted installation. No complex inverters (fire, air conditioning, lighting, etc.) are required.

High output voltage, lower cost. With 480VAC and 540Vac-based, compared with the general centralized inverter output voltage 315VAC, in the AC output cable part can save costs. Because the higher the voltage, the smaller the current, and the lower the loss at the same power, the higher the output voltage is, the less current the AC cable can carry, meaning that smaller cables can be used. Similarly, the high voltage level, for the boost transformer can also save winding, thus achieving the goal of cost reduction.

Fault location accurate * * . If a local component fails in a power station, it will first respond to the corresponding inverter. Through the monitoring platform, we can directly see the abnormal current and voltage on each MPPT circuit, to quickly locate the fault location. Convenient maintenance, completely eliminate the large-scale downtime caused by economic losses.