Battery Management System
The LIGHTNING system is controlled by an internal Energy Management System (EMS) that is composed of electronics power and control systems to manage and optimize the overall assets on different levels. The modular architecture allows for scaling storage systems through a hierarchy of three levels:
- System Level information is concentrated, processed, and communicated for all lower-level assets and the HMI
- Secondary level at the battery racks / group of racks for all local peripherals such as power switches, fan speed, and control of LEDs and panel switches
- Battery cell level that incorporates the voltage and temperature measurement electronics and voltage balancing circuit between cells.
Key algorithms are based on the State of Charge (SoC), State of Health (SoH), and the implementation of behavior models of storage technologies including State of Function (SoF), as a virtualization layer for system operation. Lower system level control is through the Battery Management Systems (BESS) and/or Ultracapacitor Management Systems (UCMS).
A BESS or UCMS is an electronic system managing the rechargeable batteries or ultracapacitors, respectively. The BESS or UMCS monitors the current state, authenticates, and balances the batteries/ultracapacitors, calculates and report data, and controls the internal environmental conditions. The BESS or UMCS provide management, safety control and algorithms to improve the performance, safety, and life of energy storage assets.
Ultra Capacitor Management System
LIGHTNING uses a COTS Supervisory Control and Data Acquisition (SCADA) tool adapted and programmed for the Human Machine Interface. The COTS SCADA is compliant with applicable industry standards such as Open Software Foundation (OSF), is written in C++, and runs on a Linux operating system. The SCADA architecture will include the following features:
- Operator Interface (Touchscreen, Keyboard, and USB port)
- Database & Display Editor
- Alarm Management
- Enhanced Tagging
- Areas of Responsibility
- Command Interpreter
- Sequence of Events
- Historic Data Collection
- Reporting
- Trending
- Cybersecurity
Automatic Transfer Switch
LIGHTNING is equipped with an Automatic Transfer Switch cabinet that is equipped with a lightning protection device, a power grid load switch, a bypass load switch, a PCS circuit breaker and a load circuit breaker, and the below figure is a topology diagram of its constituent structure. The ATS module (cabinet) is composed by fast switch, high-precision detection, logical control and external communication.
ATS is used to achieve automatic switching between on-grid and off-grid. The signal detection board inside STS module will collect power grid’s data in real time and transfer these data to controlling board. When the voltage in power grid’s side fails, the controlling board will monitor it for half cycle. After confirming power off in power grid side, the ATS module will cut off the fast switch and initiate on/off-grid switching command to PCS’s monitoring system. When the power grid recovers, the ATS module will detect the power grid’s status (such as phase angle) and adjust the PCS’s output. When PCS output is the same as power grid, the ATS will turn on the fast switch inside it. This process requires 20 ms.
