3. BMS

the battery management system bms is composed of battery module management unit bmu and battery string management unit cmu which is connected to the bess controller bms system has the functions of high precision detection and reporting of analog signals, fault alarm, upload and storage, battery protection, parameter setting, passive equalization, battery module soc calibration and information interaction with other equipment main features of battery management system · carry out comprehensive detection of battery operation status, including voltage, current, temperature, etc ; · high accuracy of single battery voltage detection ± 5mv, ensuring the reliability of system data analysis; · multi point temperature monitoring to avoid battery thermal runaway and ensure system safety; · passive equalization mode, effectively delaying battery life; · modular design, strong scalability; · complete and reliable battery protection function; 3 1 bms specifications the technical specifications of bmu and cmu are shown in the table below bmu item specification operating voltage range (v / dc) 18 32 normal working current (a) 0 03 number of battery detection strings 16 temperature detection points 8(6 way battery package temperature + 2 way connection pole temperature) cell voltage measurement accuracy ±5 mv cell temperature measurement accuracy ±2℃ cell balancing current 2a max operating temperature range 30℃ 55℃ balancing method active equalization bms insulation voltage all internal cables to shell 3kvac, 1 minute, no arcing cmu item specification operating voltage range (v / dc) 18 36 normal working current (a) 0 1 string voltage measurement range 100 1500 v string voltage measurement accuracy 1%fsr string voltage measurement period 200ms string current measurement range ±300 a string current measurement accuracy 1%fsr string current measurement period 50ms temperature measurement range 40℃ 120℃ operating temperature range 30℃ 55℃ soc calculation accuracy 8% leakage current measurement range 20ma +20ma gpc item specification operating voltage range 400vac±10% operating temperature 30 +40℃ relative humidity 20% 90%rh (non condensing) thermal management method air cooling input insulation resistance ≥10mω, 1500vdc 3 2 bess controller gridpoint controller the gpc is the bess system core to realize the whole system comprehensive logical control, operation model switch control, dc incoming control, blocking, protection and data communication and exchange gridpoint controller item description power supply 400vac/24vdc communication protocol modbus tcp/ip communication port ethernet relay 24 stem node input / output dimension （wxdxh） 625x500x950mm weight 30kg communication connects layout of system all round signal collection \ state of charge and fault signal of each battery string; pcs fault signal; system emergency stop signal; ac & dc circuit breaker position signal; dc contactor position signal; air conditioning operation signal; gas fire extinguishing system alarm signal; \ total dc current and voltage, dc current and voltage of each battery string, grid access point active power, demand power, and container ambient temperature signal; intelligent communication \ pcs, bms, air conditioning, fire protection, third party platform comprehensive logical control \ monitor the dc voltage level difference between battery strings, and block the dc busbar connection to avoid circulating current due to large voltage difference; \ monitor battery temperature and container ambient temperature, automatically start fan and air conditioner in battery cabinet to meet the battery working environment requirements; \ adaptive adjustment of the charge/discharge power of the pcs; \ automatically disconnect the fault battery string, without affecting the charging and discharging of other racks; multiple protection includes \ overload protection in charging monitor the transformer load status at the grid access point busbar in charging, and adjust the charging power or stop charging when overloading; \ reverse power protection in discharging monitor the transformer load status at the grid access point busbar in discharging and adjust the discharging power or stop discharging when there’s reverse power human machine interaction \ 10 inch touch screen providing comprehensive monitoring of bess status, \ real time data query, alarm event query, \ parameter values setting, and operating strategy query multiple interfaces \ rs485 interface for connection to scada control servers or third party platforms support for modbus tcp/ip and iec8150 goose communication for rapid grid switching \ optional 4g and satellite ip communication gateway for critical communications backup