The composition of the energy storage system mainly includes battery system, PCS converter system, box transformer system (if any), station transformer system (if any), energy management system and monitoring system (SCADA system), primary and secondary cables, etc.
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 ion battery) and electromagnetic energy storage. Due to economic and application scenarios, chemical energy storage is the most widely used except for pumped energy storage. From the perspective of international and domestic markets, lithium-ion applications in chemical energy storage more.
The energy storage bidirectional converter is referred to as PCS. The energy storage converter can realize the AC/DC conversion between the battery and the power grid, complete the bidirectional energy flow between the two, and through the control strategy, the charge and discharge management of the battery system, the power tracking of the network measurement load, the charge and discharge power control of the battery energy storage system, and the control of the network measurement voltage in the normal and island operation modes are realized;
It has the characteristics of high conversion efficiency, wide voltage input range, fast on-grid switching and easy maintenance, etc. At the same time, it has perfect protection functions, such as islanding protection, DC overvoltage protection and low voltage ride-through (optional), etc., meeting system integration and off-grid requirements.
If a high-voltage (6kV, 10kV, 20kV, 35kV, etc.) grid-connected system is used, a box-type transformer must be used to complete the step-up task. In order to minimize the electromagnetic interference between the two branches and the influence of circulating current, the box-type transformer system adopts a double-split transformer. Other parameters are not much different from wind power and photovoltaics.
Provide AC power for equipment in substations, such as lighting, HVAC, maintenance, protection screens, energy storage motors in high-voltage switch cabinets, switch energy storage, power supply for living and working facilities, etc., which need to operate the power supply. If it forms a multi-energy complementary power station with wind power and photovoltaics, it can share a set of station transformer systems with wind power or photovoltaics. At the same time, according to the electricity load, select the appropriate station variable capacity.
AC ZR-YJV22 or ZR-YJV23 flame retardant XLPE insulated power cable has the characteristics of high mechanical strength, good environmental stress resistance, excellent electrical performance and chemical corrosion resistance, light weight, simple structure and convenient use. This product is suitable for transmission and distribution lines with AC rated voltage of 35kV and below.
ZR-RWP control cable is a low-smoke halogen-free flame-retardant cable, which is characterized by the fact that the cable not only has flame-retardant properties, but also has low smoke and harmlessness (less toxicity and corrosiveness). Places with special requirements for density and toxicity index.
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 single cells is less than the set value, realize the equal charging of the single cells of the battery pack, and effectively improve the charging effect in the series charging mode. At the same time, it detects the overvoltage, undervoltage and overcurrent, short circuit, and overtemperature status of each single cell in the battery pack to protect and prolong the battery life.
BMS systems are supplied complete with 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, accumulated processing power information and other agreed monitoring information. Remote monitoring software can be established in the server, which can remotely control and download data, and can alarm in real time and transmit it to the designated mobile phone.