Basler BE1-11g Generator Protection System

87N neutral point differential: dedicated to detecting grounding faults in the Y-side winding. In impedance grounding systems, the ground fault current may be much lower than the phase differential sensitivity threshold, and 87N provides critical supplementary protection.

5. Directional overcurrent protection (67) and polarization method

The directional overcurrent component of BE1-11g supports multiple polarization modes to adapt to different fault types and system conditions:

Positive sequence polarization: used for three-phase fault direction discrimination, with "memory voltage" function, can maintain direction discrimination ability for up to 20 cycles when the three-phase fault voltage drops below 12V in the near area.

Negative sequence polarization: used for asymmetric faults, comparing the impedance angle and maximum torque angle (MTA) of negative sequence current and negative sequence voltage.

Zero sequence voltage polarization: provides four combination methods (V0/IN, V0/IG, VX/IN, VX/IG) to adapt to different grounding methods and VT wiring.

Zero sequence current polarization: relies only on IG input and is not affected by PT disconnection.

Engineering Tip: The reliable operation of directional overcurrent components depends on the minimum voltage, current threshold, and sequence component ratio threshold (such as I2 ≥ 9% I1). If the applied amount is insufficient during testing, the direction judgment logic will be skipped.

BEST logicPlus Programmable Logic System

BE1-11g has reached new heights in logic programming flexibility. BEST logic Plus is a programmable logic tool based on graphical drag and drop operations, designed with the concept of "rewiring in software" - users can define protection and control logic by dragging and dropping function blocks and connecting input/output pins.

Logical object classification:

Input objects: physical inputs (IN1-IN10), fixed logical values (0/1), status inputs (target reset, alarm reset, etc.).

Output objects: Physical output relays (OUT1 – OUT8/OUTA), Off Page outputs used for cross page connections.

Components: Basic logic gates (AND, OR, NAND, NOR, XOR, NOT), rising/falling edge flip flops, latches (set priority/reset priority), logic counters (8), and pickup/dropout timers.

Component: All protection function blocks (24, 27, 40Z, 50, 51, 87, etc.) are provided in the form of independent logic blocks, and the "Trip" and "Pickup" outputs of each block can be connected to the logic diagram.

Logical hierarchy: BEST logicPlus provides 4 logical pages (Logic Pages 1-4), which achieve cross page signal transmission through "Off Page Input/Output". This layered design keeps complex logic diagrams clear.

Logic verification: The built-in "Offline Logic Simulator" in BESTCOMSPlus allows users to change the state (0/1) by double clicking on a logical node without connecting to an actual device, verifying the correctness of logical paths. This greatly reduces the risk and time cost of on-site debugging.

Communication architecture and time synchronization

BE1-11g provides multi-level communication and time synchronization capabilities, enabling seamless integration into digital substations.

1. Communication port

USB (front panel): B-type USB 2.0 interface, used for local connection to BESTCOMSPlus, the driver automatically loads during software installation.

RS-485 (rear panel): Supports Modbus RTU or DNP3 protocols, with a maximum baud rate of 115200.

Ethernet (optional): Supports 10/100BASE-T (RJ45) or 100BASE-FX (fiber ST interface). Supports Modbus TCP, DNP3 over TCP/IP, and optional IEC 61850 protocol stack (KEMA certified Class A). Simultaneously supporting embedded web servers (BEST netPlus), real-time data, fault reports, and event sequences can be viewed through a browser.

2. Time synchronization

BE1-11g supports three types of time synchronization sources and can be set according to priority:

IRIG-B (demodulation format, Format B006): accuracy better than 1 cycle, used for on-site hard wired synchronization.

NTP (Network Time Protocol): Synchronizes with network time servers via Ethernet and is suitable for wide area systems.

DNP: Implement master station timing through DNP protocol.

Backup battery: The device is equipped with CR2032/BR2032 button batteries, which can maintain clock operation for more than 5 years after the control power supply loses power. Capacitors provide a short-term holding time of approximately 24 hours.

Debugging and Testing Methodology

The BE1-11g manual provides systematic testing guidelines, covering three levels: acceptance testing, commissioning testing, and periodic testing.

1. General testing principles

The manual emphasizes that since BE1-11g is a microcomputer protection device, its characteristics are defined by software, and therefore it is not recommended to perform a complete accuracy check on each protection component unless specific applications require it. Acceptance testing should focus on verifying the following:

Correct physical connection of input/output circuits

Connectivity of communication ports (USB, Ethernet)