Pumped storage hydropower station is the most widely used and mature technology in large-scale energy storage, and the installed capacity of the power station can reach gigawatt level. At present, the pumped storage power station with the most mature development scale in the world.
Pumped storage hydropower station has mature and stable technology and high comprehensive benefits. It is often used for peak shaving and standby. Pumped storage hydropower station is the most widely used and mature technology in large-scale energy storage, and the installed capacity of the power station can reach gigawatt level.
According to the incomplete statistics of the energy storage Professional Committee of China Energy Research Association, at present, the pumped storage hydropower station with the most mature development and the largest installed capacity in the world is the pumped storage hydropower station. By 2019, the global energy storage capacity has reached 180 million KW, and the installed capacity of pumped storage hydropower stations has exceeded 170 million KW, accounting for 94% of the total global energy storage.
Pumped storage hydropower station uses the power at the low load of the power system to pump water to the high place for storage, and discharge water for power generation during the peak load period. When the load is low, the pumped storage hydropower station is the user; At peak load, it is a power plant.
The unit of Pumped Storage Hydropower Station has two basic functions: pumping and power generation. The unit operates as a hydraulic turbine during the peak load of the power system. The opening of the guide vane of the hydraulic turbine is adjusted through the governor system to convert the potential energy of water into the mechanical energy of unit rotation, and then the mechanical energy is converted into electrical energy through the generator;
When the load of the power system is low, it is used as a water pump to operate. The electric energy at the low point is used to pump water from the lower reservoir to the upper reservoir. Through the automatic adjustment of the governor system, the opening of the guide vane is automatically adjusted according to the pump head, and the electric energy is converted into the potential energy of water for storage.
Pumped storage hydropower station is mainly responsible for peak shaving, frequency modulation, emergency standby and black start of the power system, which can improve and balance the load of the power system, improve the power supply quality and economic benefits of the power system, and is the pillar to ensure the safe, economic and stable operation of the power grid. Pumped storage hydropower station is known as “stabilizer”, “regulator” and “balancer” in the safe operation of power grid.
The development trend of pumped storage hydropower stations in the world is high head, large capacity and high speed. High water head means that the unit is developing to a higher water head. Large capacity means that the capacity of a single unit is increasing. High speed means that the unit adopts a higher specific speed.
Structure and characteristics
The main buildings of Pumped Storage Hydropower Station generally include upper reservoir, lower reservoir, water conveyance system, powerhouse and other special buildings. Compared with conventional hydropower stations, the hydraulic structures of pumped storage hydropower stations have the following main characteristics:
There are two reservoirs. Compared with conventional hydropower stations with the same installed capacity, the reservoir capacity of pumped storage hydropower stations is usually small.
The reservoir water level changes greatly and rises and falls frequently. In order to undertake the task of peak shaving and valley filling in the power grid, the daily variation range of reservoir water level of Pumped Storage Hydropower Station is usually large, generally more than 10 ~ 20m, and some hydropower stations reach 30 ~ 40m, and the variation rate of reservoir water level is fast, generally up to 5 ~ 8m / h, or even 8 ~ 10m / h.
The requirements for anti-seepage of reservoir are high. If the pure pumped storage hydropower station loses a lot of water due to the leakage of the upper reservoir, the power generation of the power station will be reduced. Therefore, the requirements for anti-seepage of the reservoir are high. At the same time, in order to prevent the deterioration of hydrogeological conditions in the project area, seepage damage and concentrated leakage caused by water seepage, higher requirements are also put forward for the seepage prevention of the reservoir.
The water head is high. The water head of Pumped Storage Hydropower Station is generally high, mostly 200 ~ 800m. Jixi Pumped Storage Hydropower Station with a total installed capacity of 1.8 million kW is the first 650 meter head section project in China, and Dunhua Pumped Storage Hydropower Station with a total installed capacity of 1.4 million kW is the first 700 meter head section project in China. With the continuous development of the technical level of pumped storage hydropower stations, the number of high head and large capacity hydropower stations in China will be more and more.
The installation elevation of the unit is low. In order to overcome the influence of buoyancy and seepage on the powerhouse, large pumped storage hydropower stations built at home and abroad mostly adopt the form of underground powerhouse in recent years.
Post time: Apr-25-2022
