Energy storage system can provide a fast energy buffer for the micro-grid, so that the voltage and frequency of the micro-grid to maintain stability, so energy storage technology in the micro-grid play the role of increasingly prominent. Micro-grid energy storage devices in various forms, flexible installation location, under reasonable control can be stable operation of the micro-grid to provide some support. Energy Storage Systems And the frequency stability of the microgrid is studied. First of all, the energy storage power controller in the use of phase-locked loop technology to sample the required phase angle value and the active / reactive power decoupling, there is not accurate phase angle and power calculation more complex problems. In this paper, Energy Storage Systems the use of phase-locked loop technology to solve these problems. On this basis, a single energy storage power control strategy based on frequency tracking is established. The simulation results show that the single energy storage control strategy adopted in this paper can effectively suppress the frequency fluctuation of the system, and improve the frequency stability of the system more obviously than the traditional single energy storage control strategy. Then, Energy Storage Systems as more and more new energy power generation into the micro-grid, sometimes using a single energy storage technology has been unable to meet the micro-grid power supply quality and stability requirements. At this point we need to use hybrid energy storage technology to solve the problem. This article uses a hybrid capacitor system consisting of a super capacitor and a battery.
Energy storage system is the most widely used pumping and storage of compressed air storage and other traditional energy storage methods are also experiencing continuous improvement and innovation.
The existing energy storage system is divided into five categories: mechanical energy storage, Energy Storage Systems electrical energy storage, electrochemical energy storage, thermal storage and chemical energy storage. At present, the highest proportion of the world is pumping capacity, the total installed capacity of the scale reached 127GW, accounting for 99% of the total storage capacity, Energy Storage Systems followed by compressed air storage, the total installed capacity of 440MW, ranked third is the sodium sulfur battery , The total capacity of the scale of 316MW.
Global existing energy storage systems
1, mechanical energy storage
Mechanical energy storage mainly includes pump storage, compressed air storage and flywheel energy storage.
(1) Pumping and storage: the use of surplus power as a liquid energy medium of water from the low-lying reservoirs to the high-lying reservoirs when the grid is low, Energy Storage Systems and the water in the high-lying reservoirs at the peak of the power grid flows back to the reservoir to promote the turbine generator Power generation, efficiency is generally about 75%, commonly known as 4 out of 3, with the ability to adjust the day for the peak and standby.
(2) compressed air storage (CAES): compressed air storage is the use of power system load when the remaining capacity, driven by the motor air compressor, the air into the storage chamber as a sealed large-capacity underground cave, when the system When the power generation is insufficient, Energy Storage Systems the compressed air is mixed with the oil or natural gas through the heat exchanger and introduced into the gas turbine for power generation. More foreign research, technology is mature, China began later, as if Lu Qiang academicians on this research more, what the cold power generation and the like.
Compressed air storage also has a peaking function, suitable for large-scale wind field, because the wind energy generated by the mechanical work can directly drive the compressor rotation, reducing the middle of the conversion into electricity links, thereby improving efficiency.
(3) flywheel energy storage: the use of high-speed rotation of the flywheel to the energy in the form of energy storage. When the energy is needed, the flywheel decelerates and releases the stored energy. Flywheel energy storage of which the individual technology has a basic (but the gap between foreign and above 10 years), the difficulty lies in the development of different functions according to different applications of new products, so flywheel energy storage is a high-tech products but the original innovation Sex is not enough, which makes it more difficult to obtain the support of the country's research funding.