With the support of dual carbon-related policies, with the explosive growth of distributed photovoltaic with the characteristics of randomness, intermittency, periodicity and volatility, the grid-connected access of a large number of distributed power sources under the new power system has a certain impact on the operation of the power grid and the power quality of the distribution network.
In order to ensure the safe and stable operation of the power grid and improve the quality of power supply, from the policy point of view, there are requirements for active and reactive power control systems in the technical regulations for photovoltaic power stations to access the power system.
The National Energy Administration's latest "Regulations on the Management of Grid-connected Electricity Operation" also emphasizes the importance of the system, and puts forward the assessment requirements for the active and reactive power control system.
Source**: National Standard Full-text Disclosure System, National Energy Administration.
In terms of function, AGC **C ensures that the electricity generated by the photovoltaic power plant has a stable frequency and voltage, and minimizes the impact on the power grid in the process of grid access, so as to ensure the safe and stable operation of the power grid and reduce the network loss.
AGC system refers to automatic power generation control system, which controls the output of photovoltaic inverters to meet the changing power demand of users, so that the power grid is in a safe operating state. **C refers to the automatic voltage reactive power control system, which automatically adjusts the voltage and reactive power of the power grid, improves the voltage quality of the power grid, reduces the loss of the power grid, and realizes the stable and economic operation of the power grid.
How is AGC **C regulated in different scenarios?Take the CET-7320 intelligent policy controller as an example to take you to learn more.
Scenario 1: A grid-connected distributed PV station needs to implement active and reactive voltage control (AGC**C) functions
For example, in Shandong Power Grid, all distributed photovoltaic with a grid-connected voltage level of 10kV and above are adjustable and controllable, and the distributed photovoltaic projects that have been completed are required to carry out AGC transformation. After investigation, the actual installed capacity of distributed photovoltaic is 22MW, the grid record capacity is 25MW, 2 500kW and 2 600kW inverters, only 1 CET-7320 intelligent policy controller needs to be installed at the grid-connected point.
The instruction value that dispatching is distributed to each inverter after dismantling and calculating, the distribution mode is calculated according to the power proportion of each inverter when dispatching instruction is issued, the system sends control instruction to each inverter according to the calculated value and then monitors the completion of each inverter instruction, finds that there is inverter does not complete the instruction after the program redistributes, decomposes the target value that does not execute to other inverters that can be successfully executed to ensure the normal completion of scheduling instruction value.
Scenario 2: Photovoltaic and energy storage control projects of distributed photovoltaic systems in industrial and building parks
In the optical storage and charging integration project of a company in Tianjin, 200kW photovoltaic was built on the roof, and a set of 100KW 200kWh energy storage containers was built in 40kW photovoltaic carport. The project deploys one CET-7320 intelligent policy controller at the grid-connected point to collect the underlying equipment data in real time, monitor the photovoltaic power generation, load electricity consumption and energy storage remaining electricity, and formulate the optimal charging and discharging strategy for energy storage based on seasonal, working day and time-of-use electricity prices to ensure maximum economy.
According to the characteristics of photovoltaic power generation and the demand for electricity, the automatic charging and discharging control strategy of energy storage is customized to ensure that photovoltaic green power maximizes self-consumption, and at the same time, economic benefits can be obtained through the peak-to-valley electricity price difference.
Scenario 3: Projects in the distribution network system that need to realize on-site PV consumption and source-grid-load-storage control
At present, there are 5 220V photovoltaic users and 10 380V photovoltaic users, and the photovoltaic users are still increasing.
The CET-7320 intelligent policy controller is installed at the JP cabinet to realize the data collection and transmission of smart meters, intelligent grid-connected switches, photovoltaic inverters, SVGs and other equipment in the station area, and configure intelligent control strategies in a targeted manner to realize the intelligent control of the output power of the photovoltaic inverter, the intelligent control of the switching operation of the intelligent grid-connected switch, and the flexible control of reactive power compensation equipment such as SVG, and realize the accurate regulation and control of distributed photovoltaic power generation grid-connected through multi-point monitoring and centralized control.
Through various interactive forms such as source complementation, source-grid coordination, grid-load interaction, grid-storage interaction, and source-load interaction, we can promote the active consumption of new energy and improve the power dynamic balance ability of the power system more economically, efficiently and safely.
Due to the randomness and volatility of photovoltaic power generation, it is difficult to ensure that all photovoltaic green power is self-absorbed.
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