Zhuhai Sichuang ST266F Ring Main Unit Protection Device
Developed primarily for ring main unit system applications, it features three-stage overcurrent protection, inverse-time overcurrent protection with multiple characteristic curves, two-stage zero-sequence overcurrent (ground) protection, multiple reclosing functions, overvoltage and undervoltage protection, and intelligent switch input capabilities. It also includes monitoring functions such as multi-electrical quantity measurement, remote control, and remote signaling.

The ST266F intelligent protection device utilizes a highly integrated microprocessor with on-chip bus architecture to process signals from voltage and current transformers, controlling the device's outputs through digital logic operations. The device employs a sealed enclosure with a maintenance-free design and excellent anti-interference performance, making it highly suitable for ring main unit systems operating in harsh environments with limited installation space.

1. The entire unit adopts low-power consumption design technology to ensure reliable and rapid activation of protection functions under any conditions.

2. The device features a simple and compact structure with flexible installation options, making it ideal for the confined installation conditions of ring main units.

3. Three-phase overcurrent protection, two-stage zero-sequence (ground) overcurrent protection, multiple IEC standard inverse-time curve options, and voltage protection functionality.

4. Equipped with circulation blocking function to prevent false tripping of switches due to transformer energization.

5. Instantaneous overcurrent protection utilizes a short data window algorithm to ensure rapid clearance of short-circuit faults and prevent upstream tripping.

6. Flexible and comprehensive configuration capabilities, with all protection functions freely enabled or disabled via control words.

7. Comprehensive measurement and control functions, including measurement of voltage, current, active power, reactive power, power factor, and other electrical parameters; dedicated remote control relay for remote operation; 7 natural switch input circuits with user-definable functionality.

8. Full Chinese LCD display interface with multi-level menu display, optional Chinese/English menus, pop-up event alarm design, and user-friendly human-machine interface.

9. Current measurement circuit with automatic dynamic gain adjustment ensures reliable operation in various extreme environments.

10. User-configurable 50Hz/60Hz system operation, with selectable zero-sequence current acquisition method (external input or internal calculation).

11. Wide operating temperature range with waterproof and dustproof design, ensuring reliable performance in various harsh environments.

12. The device records up to 60 events with non-volatile data storage, facilitating post-fault analysis.

13. Provides RS-485 communication interface with open communication protocol for users to implement SA functionality.