As of the end of September 2021, the installed capacity of wind and photovoltaic power in China reached 297 million kilowatts and 278 million kilowatts respectively, accounting for a total of 25.1% of the total installed capacity of the power system, an increase of about 4 percentage points compared to the same period last year; Meanwhile, the proportion of wind and photovoltaic power generation in the first three quarters was 11.8%, an increase of about 1.8 percentage points year-on-year.



According to the Opinions of the Central Committee of the Communist Party of China and the State Council on Fully Implementing the New Development Concept and Doing a Good Job in Carbon Peaking and Carbon Neutrality, by 2025, the proportion of non fossil energy consumption will reach about 20%; By 2030, the proportion of non fossil energy consumption will reach around 25%; By 2060, the proportion of non fossil energy consumption will reach over 80%.



With the steady advancement of the new power system dominated by new energy, the power structure in the power system has undergone profound changes. Wind power and photovoltaic power have squeezed the space of conventional thermal and hydroelectric units, while thermal power units are still the main frequency regulation resources in the current power system, undertaking the most important frequency regulation work. At the same time, due to the characteristics of volatility, intermittency, and randomness, photovoltaic and wind power systems are facing an urgent need for frequency regulation resources. The frequency of China's power system is 50Hz, and exceeding the frequency limit will have a significant impact on the safe operation of the power system, and even cause the collapse of the power system. Generally speaking, the allowable range of frequency deviation is ± 0.2~0.5Hz.



Frequency adjustment in the power system is treated differently based on the period and amplitude of load changes, and is generally divided into three categories. The first type of frequency adjustment has a very small amplitude, a short period, generally less than 10 seconds, and belongs to the category of small variation components; The second type of frequency adjustment has a large fluctuation range, with a period of approximately 10 seconds to 2-3 minutes, which belongs to the impact of load changes; The third type is the long-term component, which has a period of approximately 2-3 minutes to 10-20 minutes and is mainly caused by changes in load caused by factors such as production, daily life, and meteorology.



Primary frequency regulation is mainly aimed at the short-term rapid fluctuations of the first type of load, belonging to differential control. When the frequency of the power grid exceeds the limit and the change value exceeds the dead zone value set by primary frequency regulation, it automatically provides active support to ensure the frequency stability of the power system.



The primary frequency regulation capability of energy storage, wind power, photovoltaic and other power sources is a mandatory requirement for new energy dominated power systems. Multiple regulations and specifications have put forward specific requirements for the primary frequency regulation capability of energy storage and other power sources. For example, according to the "Technical Specification for Grid Source Coordination in Power Systems" (DL/T1870-2018), wind farms and photovoltaic power stations should have primary frequency regulation function, which can be achieved by retaining active power reserves or configuring energy storage equipment, and using active power control systems or installing independent devices to achieve primary frequency regulation function; According to the national standard "Guidelines for Safety and Stability of Power Systems" (GB38755-2019), wind power, photovoltaic power, and energy storage connected to the grid with voltage levels of 35kV and above should have primary frequency regulation function; The recently released national standard "Technical Regulations and Test Guidelines for Primary Frequency Regulation of Grid Connected Power Sources" (GB/T40595-2021) further refines the requirements for primary frequency regulation of various types of power sources. For energy storage stations with voltage levels of 35kV and above that are connected to the grid, the dead zone for primary frequency regulation should be set between ± 0.03Hz and ± 0.05Hz. Power variation should not be limited in principle, and if necessary, it should be limited to no less than 20% of the rated active power. The primary frequency regulation adjustment rate should be between 0.5% and 3%, and they should have primary frequency regulation capability in charging or discharging states.



Integrated projects such as thermal power side supporting energy storage, centralized energy storage, and wind solar energy storage are currently the main forms of energy storage participating in primary frequency regulation. Energy storage has the advantages of short charging and discharging response time, fast regulation speed, and high regulation accuracy. It is an excellent frequency regulation resource that can effectively promote the consumption of new energy and provide support for the power grid. Generally speaking, according to the primary frequency regulation requirements of the power system, combined with the operating status of various units in wind power, photovoltaic or energy storage stations, the primary frequency regulation response output of each unit is optimized through the coordination of primary frequency regulation controllers, fast coordination controllers, and other equipment, in order to meet the primary frequency regulation requirements of the power system.