Author: Site Editor Publish Time: 2022-06-23 Origin: Site
What is energy storage? Energy storage is an important part of the power production process, which consists of six major components: "extraction - generation - transmission - distribution - use - storage". Energy storage systems can achieve energy transfer and promote the application of new energy sources; they can establish micro-grids to provide power to areas without electricity; they can regulate peaks and frequencies and improve the operational stability of power systems. Energy storage systems are of great strategic importance to the construction of smart grids.
Battery Energy Storage System (BESS) is a system that uses lithium/lead batteries as energy storage carriers, storing electricity for a certain period of time and supplying electricity for a certain period of time, and providing electricity with functions such as smooth transition, peak shaving, frequency regulation and voltage adjustment.
As battery storage has the advantages of relatively mature technology, large capacity, safety and reliability, low noise, strong environmental adaptability, easy installation, etc., so the energy storage system often uses batteries to store electrical energy, and the current energy storage system mainly consists of energy storage unit and monitoring and scheduling management unit: energy storage unit contains energy storage battery pack (BA), battery management system (BMS), energy storage converter (PCS), etc.; monitoring and scheduling Management units include central control systems (MGCC), energy management systems (EMS), etc.
At present, the 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, household energy storage system, etc.
The technology of the energy storage system consists mainly of the management of the energy storage bi-directional inverters, the management of the energy storage batteries, and the monitoring and dispatch management unit for the rational dispatch of the system energy.
The battery management system (BMS) is installed in the energy storage battery pack and is responsible for the collection of voltage, temperature, current and capacity information, real-time status monitoring and fault analysis of the energy storage battery pack, as well as on-line communication with the PCS, monitoring and dispatching system through the CAN bus to achieve optimal charge and discharge management and control of the battery. The system is equipped with a set of battery management system for each battery cluster, which can achieve the purpose of effective and efficient use of each cluster of energy storage batteries and overall reasonable deployment.
The BMS has functions such as battery voltage equalisation, battery pack protection, thermal management and analysis and diagnosis of battery performance. It requires real-time measurement of battery module voltage, charging and discharging current, temperature and terminal voltage of individual batteries, as well as calculation of the internal resistance of the batteries and other parameters. Through the analysis and diagnosis model, the diagnosis of the current or remaining capacity (SOC) of individual batteries, the diagnosis of the state of health (SOH) of individual batteries, the assessment of the state of the battery pack and the estimation of the sustainable discharge time in the current state during discharge.
The monitoring and scheduling management system is the energy scheduling and management centre of the energy storage unit, including the central control system (MGCC) and the energy management system (EMS), which is responsible for collecting all the battery management system data, energy storage converter data and distribution cabinet data, issuing control commands to each part, controlling the operation of the whole energy storage system and reasonably arranging the work of the energy storage converter; the system can either operate automatically according to the preset charging and discharging The system can operate automatically according to the preset charging and discharging time, power and operation mode, or it can accept the operator's instant command to operate.
The energy management system is the neural control system of the energy storage system. It is designed to realise the rational scheduling of energy and the economic operation of the micro-grid according to the peak and valley level characteristics of the grid, with functions such as operation optimisation, load forecasting, power generation forecasting, micro-source scheduling and tidal control.
