The National Grid: National grid provides services of connection system design, electricity meter device installation, acceptance and debugging of integration etc., without any charge, for owners of distributed Solar Power plants; Supoort the connection of distributed Solar Power plant to low-voltage grid, purchase surplus electricity in accordance with state policies; free of system reserve capacity fee to all distributed solar power plant projects. Project's access to the public power grid is also paid by the National Grid. Users only need to invest in their own photovoltaic equipment and a small number of cable lines for their own use.

Calculated by construction surface of the households, 150W electricity can be generated on 1 m². For a solar power plant of 3kw to 5kw, only about 20 m² surfaces are required. Sloping roof and flat roof are both suitable for installation.

PV battery components include monocrystalline silicon battery, polycrystalline silicon battery and amorphous silicon battery. Monocrystalline silicon battery component possesses the highest efficiency, which means more electricity can be generated on the same surface. It is the best choice for smaller installation area, but the price is the highest too. Polycrystalline silicon battery component is the second. It’s more suitable for bigger installation area, with relatively low price. Amorphous silicon battery has the lowest efficiency, which is not recommended.

Grid-connected PV inverter, as an interface device between PV battery components and the grid, converts DC energy of PV cell into AC energy and transmits it to the grid. It plays a vital role in the grid-connected PV power generation system.

There are two kinds of grid-connected inverter for household use. One is centralized grid-connected PV converter, minimum power 1kw, input voltage varing from 150V to 550V. The other thye is micro grid-connected PV converter, generally for AC 220V voltage, with power from 200W to 500W, input DC voltage varing from 12V to 28V. The usage of two converters is also different. The centralized grid-connected converter usually has bigger size and is suitable for wall mounting installation. The micro type is smaller and installed near to the battery components (i.e. on a bracket under the battery). Both of the above can be used in household distributed gird-connected PV system.

After the installation of battery boards, thhe connection of series and parallel should better be done after the sunset to avoid high voltage electric shock. At same time, lightning protection grounding work should be completed. In addition, pay attention to the wind resistance bracket. The northern users should pay attention to snow resistance level.