Energy storage is an important part of the six links in the power production process, namely, "extraction, generation, transmission, distribution, utilization and storage". Energy storage system can realize energy transfer and promote the application of new energy; it can establish micro-grid and provide power for the areas without electricity; it can adjust peak frequency and improve the stability of power system operation. Energy storage system is of great strategic significance to the construction of smart grid.
The ways of electric energy storage are: battery-type energy storage, inductor-type energy storage, capacitor-type energy storage and other types of energy storage.
Battery Energy Storage System (BESS) is a system that utilizes lithium batteries/lead batteries as energy storage carriers to store electricity for a certain period of time and supply electricity for a certain period of time, and the electricity provided has the functions of smooth transition, peak shaving and valley filling, frequency and voltage regulation, and so on.
Inductor-type energy storage: the use of itself is an energy storage original, its stored electrical energy and its own inductance and the current flowing through it itself is proportional to the square: E=L*I*I/2. Because the inductor at room temperature has a resistance, the resistance to consume energy, so a lot of energy storage technology to use superconductors. Inductive energy storage is still immature and has fewer applications;
Capacitor type energy storage: itself is also a kind of energy storage original, its stored power and its own capacitance and terminal voltage is proportional to the square: E = C*U*U/2. Capacitor energy storage is easy to maintain, do not need superconductor. Supercapacitors are produced by utilizing the characteristics of capacitor-type energy storage to provide instantaneous high power, and are suitable for lasers, flash lamps, and other applications.
In addition, there are other types of energy storage: for example, mechanical energy storage.
Containing energy storage, photovoltaic, hydropower, etc., the energy storage system is the core component of the microgrid, often used in conjunction with photovoltaic, wind power and so on.
Because battery energy storage has the advantages of relatively mature technology, large capacity, safety and reliability, low noise, strong environmental adaptability, easy to install, etc., so the energy storage system is commonly used to store electricity, the current energy storage system is mainly composed of energy storage unit and monitoring and scheduling management unit: the energy storage unit contains the energy storage battery pack (BA), the battery management system (BMS), the energy storage converter (PCS), etc.; monitoring and scheduling management unit includes the central control system (MGM). Monitoring and scheduling management unit includes central control system (MGCC), energy management system (EMS) and so on.
Currently more commonly used application modes are: energy-based energy storage system, power-based energy storage system, grid-level energy storage system commercial energy storage system, home energy storage system and so on.
Energy storage system technology
The technology of the energy storage system mainly consists of the energy storage bidirectional inverter, the management of the energy storage battery, as well as monitoring and scheduling management unit of the system energy reasonable scheduling.
1. Battery Management System
Battery management system (BMS) is installed in the energy storage battery pack and is responsible for the collection of voltage, temperature, current, capacity and other information, real-time status monitoring and fault analysis of the energy storage battery pack, and at the same time, it communicates with the PCS, monitoring and scheduling system through the CAN bus, so as to realize optimized charging and discharging management and control of the battery. Each cluster of batteries in the system is equipped with a set of battery management system (BMS), which can achieve the purpose of effective and efficient use of each cluster of energy storage batteries and overall rational deployment.
BMS has the functions of battery voltage equalization, battery pack protection, thermal management, analysis and diagnosis of battery performance. It is required to be able to measure real-time battery module voltage, charging and discharging current, temperature and single cell terminal voltage, and calculate the internal resistance of the battery and other parameters, and through the analysis and diagnosis model, it can arrive at the diagnosis of the current capacity or remaining capacity of a single cell (SOC), the diagnosis of the state of health of a single cell (SOH), the assessment of the state of the battery pack, and the estimation of the time of continuous discharging under the current state at the time of discharging.
2. Monitoring and Scheduling Management System
The monitoring and scheduling management system is the energy scheduling and management center of the energy storage unit, including the central control system (MGCC) and energy management system (EMS), which is responsible for collecting all the data of the battery management system, the data of the energy storage converter and the data of the power distribution cabinet, sending out control commands to each part, controlling the operation of the whole energy storage system, and reasonably arranging the work of the storage converter; the system can run automatically in accordance with preset charging and discharging times, power and operation modes. The system can either run automatically according to the preset charging and discharging time, power and operation mode, or accept the operator's instant instruction.
Among them, the energy management system is the neural control system of the energy storage system, in order to achieve reasonable scheduling of energy, according to the characteristics of the grid peaks and valleys, to achieve the economic operation
of the micro-grid, with operation optimization, load forecasting, power generation prediction, micro-source scheduling, trend control and other functions.
Battery energy storage system is the trend of the development of the new energy industry in the next five years, the domestic and international market size is predicted to reach trillions of dollars, at present the construction of domestic and foreign energy storage power plant in full swing, Guanlong Power with nearly 20 years of photovoltaic power supply products R & D and service level, with a wealth of photovoltaic power plant and energy storage power plant development, design, construction, operation and maintenance of a series of integrated capabilities. It is an enterprise specializing in R&D, production and sales of PV inverters, PV controllers and energy storage inverters as well as investment, development, construction and service of PV power stations and energy storage power stations. In terms of energy storage has walked in the forefront of the industry, I believe it will occupy a place in the energy storage market.
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