What is energy storage? It is an important part of the six major links in the power production process of “collection-generating-transmission-distribution-use-storage”. The energy storage system can realize energy transfer and promote the application of new energy; it can establish a micro grid to provide electricity for areas without electricity; it can adjust peak frequency and frequency to improve the operation stability of the power system. Energy storage system has great strategic significance for the construction of smart grid. The battery energy storage system is a system that uses lithium batteries and lead batteries as energy storage carriers to store electrical energy within a certain period of time and supply electrical energy within a certain period of time. The technology of the battery energy storage system mainly includes the management of the energy storage bidirectional inverter, the energy storage battery, and the reasonable scheduling of the system energy by the monitoring and dispatching management unit.
1. Battery management of battery energy storage system
The battery management system (BMS) is installed in the energy storage battery pack, and is responsible for the collection of information such as voltage, temperature, current, and capacity of the energy storage battery pack, real-time status monitoring and fault analysis, and at the same time through the bus and PCS, monitoring and dispatching systems. On-line communication to realize optimal charge and discharge management control of the battery. Each cluster of battery packs in the system is equipped with a battery management system, which can achieve the purpose of effectively and efficiently using each cluster of energy storage batteries and the overall rational allocation.
The battery management of battery energy storage system has functions such as battery voltage equalization, battery pack protection, thermal management, and analysis and diagnosis of battery performance. It is required to be able to measure the battery module voltage, charge and discharge current, temperature, and the terminal voltage of the single battery in real time, and calculate the internal resistance of the battery and other parameters, and obtain the diagnosis of the current capacity or remaining capacity of the single battery by analyzing the diagnosis model. Diagnostics of battery state of health, battery pack state assessment, and estimation of how long it will last in the current state while discharging.
2. Monitoring and dispatching management of battery energy storage systems
The monitoring and dispatching management system is the energy dispatching and management center of the energy storage unit, including the central control system and the energy management system. It is responsible for collecting all battery management system data, energy storage converter data and power distribution cabinet data, and issuing control to each part. command, control the operation of the entire energy storage system, and reasonably arrange the work of the energy storage converter; the system can run automatically according to the preset charging and discharging time, power and operation mode, or can accept the operator’s immediate command to run. Among them, the energy management system is the neural control system of the energy storage system. In order to realize the reasonable dispatch of energy, according to the peak-to-valley characteristics of the power grid, the economic operation of the micro-grid is realized, and it has the functions of operation optimization, load forecasting, power generation forecasting, micro-source dispatching, and power flow control.
The battery energy storage system is the development trend of the new energy industry in the future. The international market size is predicted to reach several trillions. At present, the construction of international energy storage power stations is in full swing. With years of research and development and service level of photovoltaic power supply products, Sicon Chat Union Electric Co., Ltd. (SCU) has a series of integrated capabilities in the development, design, construction, operation and maintenance of photovoltaic power plants and energy storage power plants. It is an enterprise specializing in R&D, production, sales and investment, development, construction and service of energy storage power stations. It has been at the forefront of the industry in terms of energy storage, and it is believed that it will occupy a place in the energy storage market.