Several trends of electrical energy:
(1) When the power generated by the inverter is not enough for their own use, the power grid and the inverter supply power to the household load together;
(2) The power generated by the inverter is enough for its own load, and there is also surplus: at this time, part of the power generated by the inverter is supplied to its own load, and part of it is transmitted out through cables:
For (2), this situation does not usually occur and should be avoided, which is why grid companies limit grid-connected capacity under one transformer. For example, some areas clearly require photovoltaic grid-connected capacity cannot exceed 30% of transformer capacity, which is to avoid photovoltaic capacity is too large, resulting in power generation can not be absorbed locally, but have to cross the upper level of power grid resulting in power loss and resource waste.
Some people may ask, is the electricity from the inverter intelligent, how can it choose to run to the neighbor load or go in other directions? Although inverters, meters and even transformers have been made smart by networking, where the electricity goes depends largely on the load.
If the power grid is a big reservoir, a transformer in a village can be a water tower, and our household load can be a faucet. When we install a photovoltaic system in our home, it's like installing a little water tower.
When their own small water tower (photovoltaic inverter) water surplus, and coincides with the neighbor also in the water. When a neighbour turns on a tap (a household appliance), water (electricity) flows to the nearest neighbour, and any shortfall is made up by a large tower (the grid). In this way, the extra water (or electricity) will in turn be consumed by nearby users.
When their own small water tower (photovoltaic system) capacity is too large, even more than the village that water tower (transformer), the village water tower will become redundant, resulting in a waste of resources.
