LAR-24 - Lithium Battery Rectifier System
Electricity Distribution Networks and Transformer Substations
The motors of the "Load Switchgear" systems, which enable the energy connections to be directed within the "Transformer Substations" (TS), which is an important unit for the Electricity Distribution Networks, are fed 24V DC. "Battery Backed up-Rectifier" systems are positioned in TS fields as DC uninterruptible power supply so that the DC energy feeding the Load Switchgear Cells is not cut off during AC Energy routings.
VRLA type lead acid batteries are used in “Maintenance Free Battery Rectifier” (Turkish short name BAR-24) systems used in Transformer Substation sites. Due to their nature, VRLA batteries lose capacity very quickly when operated at high and low temperatures. As the Load Switchgear motors demand sudden high inrush currents, they become inoperable with the decrease in the capacity of the VRLA batteries. BAR-24 systems in the fields cannot measure the capacity loss of the battery and cannot report it in detail to the SCADA center, as they do not take precautions regarding VRLA battery management. In addition, due to the rapid capacity loss of VRLA batteries, frequent battery replacement service to BAR-24 systems in TS sites creates an additional operational cost.
LAR-24 systems are designed to eliminate all the problems experienced in BAR-24 systems, thanks to the wide operating temperature range of lithium batteries and their cycle life 5-6 times longer than VRLA batteries. LAR-24 systems include Lithium Battery Management Systems (BMS) and Intelligent Lithium Battery Charge systems (LiCh) developed by BATKON. Switchgear, SCADA and Backup systems are supplied with 24 VDC by LAR-24 with separate fuse protections. The charging rectifier in the system is in the "Switched Mode Power Supply" ( SMPS ) structure, > 90% efficiency, providing very high power factor, includes high-tech power electronics.
LAR-24 systems are designed not only as a battery power backup system, but also as “On-Net” remotely monitored/managed systems to support Internet of Things (IoT) and SCADA protocols. Thanks to the Ethernet TCP/IP interface on the system, it can be monitored/managed over the Internet/Intranet.
It has a visual interface in the form of a tablet screen, which can be navigated through the menus in the field with a finger swipe on the wide touch TFT LCD screen. In this way, field personnel can monitor the data of the device and make its settings simply by touching the screen. Thanks to its multi-page screen design, voltage, current and temperature information of all units in the LAR-24 system can be viewed in detail on the LCD screen.
In terms of backward compatibility with the old BAR-24 systems in the fields, LAR-24 systems also have “dry contact alarm” outputs. In this way, alarm conditions such as AC fuse status, Rectifier failure, Battery weak, Phase failure etc. can be transmitted to old SCADA systems with relay dry contacts. In addition, existing SCADA systems can be connected to protocols such as RS-485 MODBUS or Ethernet MODBUS /TCP, Ethernet MQTT. IEC 60870-5-104 over TCP/IP “Telecontrol Network Access” SCADA protocol and SNMP protocols can also be added to the system as needed.
Lithium Cell Balancing Method: "Passive Balancing" (180 mA balancing current)
Lithium Cell Protection Features: If any cell exceeds the "Over Voltage Protection" (OVP 3.65V adjustable) value at charging or If the voltage drops below the "Under Voltage Protection" (UVP 2.5V adjustable) voltage during discharge, the current is cut off.
It can transfer data to remote servers with TCP/IP protocols over RJ45 Ethernet. Data can be viewed with the browser via the embedded web server.
The system includes a 24 Ah / 25.6V Lithium Iron Phosphate (LFP) battery pack. LFP batteries are much longer lasting and durable than VRLA lead acid batteries at high operating temperatures (40 - 50 oC). In addition, the "voltage collapse" problem seen in VRLA batteries during sudden inrush currents drawn by the motors of the Breaker Cells is not seen in LFP batteries.