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What is the key technology of energy storage system?
- Sep 21, 2018 -

What is energy storage system?

Energy Storage System (ESS) is a system that can store and supply electricity. It has the functions of smooth transition, peak shaving and valley filling, frequency modulation and voltage regulation. It can make the solar and wind power output smoothly and reduce the impact of randomness, intermittentness and fluctuation on the grid and users; through valley-time charging, peak-time discharging can reduce the user's electricity expenses; when the power grid is cut off, it can run on an island to ensure uninterrupted power supply to users.

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Because battery energy storage has the advantages of relatively mature technology, large capacity, safety and reliability, low noise, strong environmental adaptability and easy installation, battery is commonly used in energy storage system to store electric energy. At present, energy storage system is mainly composed of energy storage unit, monitoring and scheduling management unit, and energy storage unit includes energy storage battery pack (BA). Battery Management System (BMS), Energy Storage Converter (PCS), etc. Monitoring and Dispatching Management Unit (MSU) includes Central Control System (MGCC), Energy Management System (EMS), etc.

What is the key technology of energy storage system?

The technology of the energy storage system mainly includes the control of the energy storage converter, the management of the energy storage battery, and the reasonable scheduling of the system energy by the monitoring and dispatching management unit.

1. Converter Control Strategy

The energy storage converter, also called the power conversion system (PCS), is the power-regulating execution device in the energy storage unit. Under the deployment of the monitoring and dispatching system, effective and safe storage and discharge management is implemented.

2. Battery management system

Battery management system (BMS) is installed in energy storage battery pack. It is responsible for collecting voltage, temperature, current, capacity and other information of energy storage battery pack, real-time state monitoring and fault analysis. At the same time, it communicates with PCS, monitoring and dispatching system online through CAN bus to realize optimal charging and discharging management and control of battery. Each cluster of batteries is equipped with a battery management system, which can effectively and efficiently use each cluster of energy storage batteries and the overall reasonable allocation of the purpose.

BMS should have the functions of battery voltage balance, battery protection, thermal management, battery performance analysis and diagnosis. BMS requires real-time measurement of battery module voltage, charging and discharging current, temperature and cell terminal voltage, as well as calculation of battery internal resistance and other parameters. Through analysis of the diagnosis model, the diagnosis of the current or residual capacity (SOC) of single battery, the diagnosis of the health status of single battery (SOH) and battery pack status are obtained. Evaluation and estimation of the continuous discharge time in the current state of discharge.

3. Monitoring and dispatch management system

The monitoring and dispatch management system is the energy dispatching and management center of the energy storage unit, including the central control system (MGCC) and the energy management system (EMS), which is responsible for collecting all battery management system data, energy storage converter data and power distribution cabinet data. , issuing control commands to each part, controlling the operation of the entire energy storage system, and arranging the operation of the energy storage converter reasonably; the system can automatically operate according to the preset charging and discharging time, power and operation mode, and can also accept the operator's instant. The instruction runs.

Among them, the energy management system is the brain of the energy storage system, which mainly realizes the reasonable scheduling of energy. According to the characteristics of the peak and valley of the power grid, it realizes the economic operation of the microgrid, and has functions such as operation optimization, load forecasting, power generation prediction, micro-source scheduling, and power flow control.