When analyzing the energy storage process, the part of the object or space range drawn out in order to determine the research object is called the energy storage system. It includes energy and matter input and output, energy conversion and storage equipment. Energy storage systems often involve a variety of energy, a variety of equipment, a variety of substances, multiple processes, is a complex energy system that changes over time, and requires a number of indicators to describe its performance. Commonly used evaluation indicators include energy storage density, energy storage power, energy storage efficiency, energy storage price, and environmental impact.


The composition of the energy storage system mainly includes the battery system, PCS converter system, box change system (if any), station change system (if any), energy management system and monitoring system (SCADA system), primary and secondary cables.

1, battery system We know that the current energy storage methods are mainly divided into three categories: Physical energy storage (pumped energy storage, compressed air energy storage, flywheel energy storage, etc.), chemical energy storage (lead-acid battery, REDOX flow battery, sodium sulfur battery, lithium-ion battery) and electromagnetic energy storage three categories, due to economic and application scenarios, in addition to pumped energy storage, chemical energy storage is the most widely used, from the international and domestic market, chemical energy storage lithium ion applications.

2. The energy storage bidirectional converter of the PCS converter system is referred to as PCS. The energy storage converter can realize the AC/DC conversion between the battery and the power grid, complete the two-way energy flow between the two, and realize the charge and discharge management of the battery system, the power tracking of the network load, the charge and discharge power control of the battery energy storage system, and the control of the voltage measurement under the normal and island operation mode through the control strategy. It has the characteristics of high conversion efficiency, wide voltage input range, fast and off-grid switching and easy maintenance, and has perfect protection functions, such as island protection, DC overvoltage protection and low voltage crossing (optional), etc., to meet the requirements of system and off-grid.

3, box transformer system (if any) such as the use of high voltage (6kV, 10kV, 20kV, 35kV, etc.) grid-connected system, must use the box transformer to complete the booster task, in order to minimize the electromagnetic interference and circulation impact between the two branches, the box transformer system uses double split transformers, other parameters follow the wind and photovoltaic no big difference.

4, station substation system (if any) to provide AC power for the equipment in the substation, such as lighting, HVAC, maintenance, protection screen, high voltage switch cabinet energy storage motor, switch energy storage, living and working facilities power supply, need to operate the power supply. For example, a multi-energy complementary power station composed of wind power and photovoltaic can share a set of station transformer system with wind power or photovoltaic. At the same time, according to the power load, select the appropriate station variable capacity.


5, cable (primary and secondary) AC ZR-YJV22 or ZR-YJV23 flame retardant crosslinked polyethylene insulated power cable has high mechanical strength, good environmental stress resistance, excellent electrical performance and chemical corrosion resistance and other characteristics, light weight, simple structure, easy to use. This product is suitable for transmission and distribution lines with rated AC voltage of 35kV and below.

ZR-RVVP control cable low smoke halogen-free flame retardant cable is characterized by the cable not only has flame retardant performance, but also has low smoke and harmlessness (less toxicity and corrosion), suitable for cable flame retardant, smoke density, toxicity index has special requirements.

6, battery management system BMS, energy management system EMS Battery management system BMS, mainly for the battery pack charge and discharge protection management. When fully charged, it can ensure that the voltage difference between each single battery is less than the set value, and realize the uniform charging of each single battery pack, and effectively improve the charging effect under the series charging mode. At the same time, the state of overvoltage, undervoltage, overcurrent, short circuit and overtemperature of each single battery in the battery pack is detected to protect and extend the service life of the battery. The BMS system is supplied with the lithium-ion battery kit.

The energy management system EMS mainly monitors the real-time operating status information of the power station, including the system power curve, battery voltage and temperature information, accumulated processing power information and other agreed monitoring information. And you can establish remote monitoring software in the server to remotely control and download data, real-time alarm, and transmission to the specified mobile phone.

7, monitoring system, related access system equipment battery energy storage monitoring system basic functions include: measurement and monitoring function, data processing function, analysis and statistics function, operation control function, event alarm function, protection and management function, man-machine interface function, accident recall and historical inversion function, historical data management function, remote and forwarding function, system maintenance function.

Related access system equipment is an integral part of the entire monitoring system, due to the different conditions of local power grid construction, the formation of the access system required equipment is not the same, but according to the GB, DL and other requirements, you can still find some common equipment.

Power quality indicators such as harmonics, voltage fluctuations and flickers of the energy storage system at the public connection point need to be monitored, monitored by power quality equipment, and fed back to the power grid company.

The configuration and setting of energy storage system protection should be compatible with the protection equipment on the power grid side, and cooperate with the power grid focus closing strategy, and need safety automatic devices to form the "three fire lines" of the power grid company.

The energy storage system should be equipped with an energy metering device, and located at the outlet side of the energy storage system or at the public connection point.

The energy storage system is connected to the power grid and the equipment required to meet the dispatching requirements of the power grid, that is, the power dispatching data network and secondary security equipment.

Summary: The composition of the energy storage system varies according to the characteristics of the project, such as combined with photovoltaic or wind power, there is no need to set up a separate station system; If the low voltage grid connection is used, the box change system is not involved.