According to the enterprise standard plan of the State Grid Corporation of China, through the research and analysis of distributed power and its impact on the power grid, combined with the characteristics of various distributed power sources in my country, the voltage level of 35kV and below, the structure of the power grid, and the power supply requirements for power grid operation, my country The compilation principles of distributed power grid-connected technical standards are as follows:
(1) Technical standards comply with existing relevant laws, regulations, standards and guidelines, etc., taking into account the requirements of power grid operation and distributed power development. Relevant laws and regulations include the Renewable Energy Law of the People’s Republic of China (Revised), the Electricity Law of the People’s Republic of China, and the Regulations on the Administration of Power Grid Dispatching (1993) (State Council Decree No. 115).
(2) The starting point and basic principle of technical standards are to ensure the safe, stable and high-quality operation of power grids and distributed power sources, and at the same time, try to make the clauses operational to a certain extent, which is easy to understand, quote and implement.
(3) The technical standard takes into account the existing power grid structure and configuration, as well as the technical level of distributed power generation, and develops distributed power generation without requiring a lot of investment to change the existing power system structure. At the same time, technically, distributed power sources can also achieve safe and stable operation without affecting the power quality of the power grid through appropriate design and technical means, and can support the operation of the power grid through the communication of the power grid dispatching agency and appropriate control to meet the specified technical requirements.
(4) The technical standard is applicable to the distributed power supply with the voltage level of 35kV and below connected to the power grid.
For very small power sources with a capacity of only a few kilowatts (kW), the impact and support on the grid is very limited, considering cost and various factors. In terms of voltage/reactive power adjustment, active power adjustment, voltage, current and frequency effects, communication functions, etc., the specified requirements can be appropriately relaxed. The technical standard divides the power supply within the scope of application into two categories: 10 (6) kV~35kV voltage level grid-connected and 380V voltage level grid-connected, and put forward different technical requirements in terms of access system principles, power quality, power control and voltage regulation, start-stop, frequency operation range, safety, voltage protection, communication and information, and electric energy measurement.
(5) The power supply referred to in the technical standards refers to the newly built and expanded distributed power supply integrated into the power grid of 35kV and below. Since the self-provided power supply and the non-self-provided power supply are quite different in terms of access capacity and voltage level, it is difficult to define uniformly, so the technical standards are mainly compiled for the non-self-provided power supply, and the self-provided power supply can be implemented by reference.