The composition of the battery energy storage system mainly includes the battery system, PCS converter system, box transformer system, station transformer system, energy management system and monitoring system (SCADA system), primary and secondary cables, etc. The following is a detailed introduction to these systems.
1. Battery system
We know that the current energy storage methods are mainly divided into three categories: physical energy storage (pumped water energy storage, compressed air energy storage, flywheel energy storage, etc.), chemical energy storage (lead-acid batteries, redox flow batteries, sodium-sulfur batteries, lithium In addition to pumping energy storage, chemical energy storage is the most widely used due to economic reasons and application scenarios. From the international and domestic markets, the application of lithium-ion in chemical energy storage More.
2. PCS converter system
The energy storage two-way converter is abbreviated as PCS. The energy storage converter can realize the AC-DC conversion between the battery and the grid, complete the two-way energy flow between the two, and realize the charge and discharge management of the battery system and the network load measurement through the control strategy. Power tracking, battery energy storage system charging and discharging power control, and control of grid voltage measurement in normal and island operation modes; it has the characteristics of high conversion efficiency, wide voltage input range, fast on-off and off-grid switching, convenient maintenance, etc., and complete protection functions, such as islanding protection, DC overvoltage protection, and low voltage ride through (optional), etc., to meet the requirements of the system on and off the grid.
3. Box change system
If a high-voltage (6kV, 10kV, 20kV, 35kV, etc.) grid-connected system is adopted, a box transformer must be used to complete the boost task. In order to minimize the electromagnetic interference and circulation effects between the two branches, the box transformer system uses a double split transformer. Other parameters There is no big difference between wind power and photovoltaics.
4. Station substation system
Provide AC power for the equipment in the substation, such as lighting, heating, maintenance, protection screens, energy storage motors in high voltage switch cabinets, switch energy storage, power supply for living and working facilities, etc., which require operating power. For example, a multi-energy complementary power station with wind power, photovoltaics, etc. can be shared with wind power or photovoltaics in a station-use substation system. At the same time, select the appropriate station variable capacity according to the power load.
5. Cable (primary and secondary)
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6. Battery management system(BMS), energy management system (EMS)
The battery management system(BMS) mainly manages the charge and discharge protection of the battery pack. When fully charged, it can ensure that the voltage difference between the individual cells is less than the set value, realize the equal charge of the individual cells of the battery pack, and effectively improve the charging effect in the series charging mode. At the same time, it detects the overvoltage, under-voltage, overcurrent, short circuit, and overtemperature status of every single battery in the battery pack to protect and extend the battery life. The BMS system is provided as a complete set of lithium-ion batteries.
The energy management system(EMS) mainly monitors the real-time operating status information of the power station, including system power curve, battery voltage and temperature information, cumulative processing power information, and other agreed-to monitor information. In addition, remote monitoring software can be established in the server to remotely control and download data, alarm in real-time, and transmit it to the designated mobile phone.
7. Monitoring system and related access system equipment
The basic functions of the battery energy storage monitoring system include measurement and monitoring functions, data processing functions, analysis and statistics functions, operation control functions, event alarm functions, protection management functions, man-machine interface functions, accident recall and historical inversion functions, historical data management functions, Telecontrol and forwarding functions, system maintenance functions.
The equipment connected to the system is an integral part of the entire monitoring system. Due to the differences in the construction of power grids in various places, the equipment required for the access system is different. However, according to the requirements of the national standard GB and the industrial standard DL, it is still Some common devices can be found.
The power quality indicators such as harmonics, voltage fluctuations, and flicker of the energy storage system connected to the public connection point need to be monitored, and power quality equipment needs to be monitored and fed back to the grid company.
The configuration and setting of the protection of the energy storage system should be compatible with the grid-side protection equipment, and coordinated with the grid-focused reclosing strategy. Safety automatic devices are required to form the "three fire lines" of the grid company.
The energy storage system should be equipped with an electric energy metering device, and located at the outlet side of the energy storage system or at the public connection point.
The above is the relevant introduction about the battery energy storage system. If you do not know enough about this information after reading the above content, you can contact us for more information and related solutions.
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