In recent years, due to the reduction of the cost of photovoltaic power generation components and the promotion of government policy encouragement, distributed photovoltaic power generation projects have continued to increase. With the rapid development of distributed photovoltaic power generation, how to correctly dose the project’s power generation, on-grid power, and off-grid power is the key to affecting the grid-connected quality of photovoltaic power generation and the economic benefits of the project. We must pay more attention to this aspect and formulate Scientific plan, through effective measures to optimize management.

1 Distributed photovoltaic power generation project

Photovoltaic power generation is mainly through the photovoltaic effect, where the sun irradiates special materials, prompting some of its internal particles to absorb certain photons and move in a certain direction to generate electric potential energy, achieving the effect of converting light energy to electric potential energy to generate electricity. The general distributed photovoltaic power generation system mainly includes several parts such as solar panels, batteries, controllers, DC distribution boxes and AC distribution boxes. Distributed photovoltaic power generation is divided into grid-connected power generation and independent power generation. Grid-connected power generation uses standard interfaces to connect to the public grid, similar to a small power plant. An independent power generation system, which is different from a grid-connected power generation system, forms a circuit in a closed-circuit system. The photovoltaic array converts the received solar radiation energy into electrical energy to supply the load, and the energy is processed by the charge controller. It is stored in the battery in the form of chemical energy.

2 Key points of electric energy measurement for distributed photovoltaic power generation projects

2.1 Determine the electric energy measurement plan

Photovoltaic power measurement needs to determine the corresponding measurement method according to the actual form, and the power generation needs to be calculated separately. On the basis of relevant national regulations, complete the calculation of on-grid electricity price and grid electricity price, and at the same time classify electric energy dosing meters, including gateway metering and grid-connected metering. The scope of gateway metering includes the calculation of grid-connected and off-grid electricity between the public grid and users. Grid-connected power generation and electricity price subsidies can be measured by electric energy meters. If it is self-generation and self-use mode, it is for both grid-connected and self-generated electricity. The difference is measured.

2.2 Basic principles for setting measurement points

For distributed photovoltaic power generation projects, the core requirement is not to affect users and the economic benefits of the project, and to protect the rights and interests of users and power companies. First, when photovoltaic power is connected to the grid, it is necessary to scientifically set up a metering point at a reasonable location. Generally, the search ability, convenience and operability of the metering point location should be ensured, and it is suitable for measuring the size of electrical energy as the power consumption of each stage. The objects of electricity inventory can also be used to conduct electricity price compensation statistics. Second, the grid-connected distributed photovoltaic power generation should be set up at the trade stage gate metering point to effectively settle the trade between the upper and lower grids. Third, when applying the unified purchase operation mode, a unified method can be used to set the grid-connected metering point and the gateway metering point, and play the function of compensating for the difference in electricity price and calculating the electricity bill.

2.3 Determination of electric energy metering device

When determining the electric energy metering device of a distributed photovoltaic power generation project, it must be ensured that it has high reliability and accuracy, and can achieve the effect of timely communication. The metering device, configuration and technology set up at the metering point shall meet the relevant technical standards and procedures, and shall not be lower than the standards of the second-class electric energy metering device. For 110KV voltage connection, a special metering winding should be selected, and it is strictly forbidden to connect irrelevant equipment. In addition, the metering device should be equipped with a special cabinet. If a current transformer is installed, it needs to be divided into cabinets.