Xi'an Yuanzheng YZ450 Integrated Microcomputer Protection Device

The YZ450 Integrated Microcomputer Protection Device is primarily developed for ring main unit (RMU) system applications. It features three-stage overcurrent protection, inverse-time overcurrent protection with multiple characteristic curves, two-stage zero-sequence overcurrent (grounding) protection, multiple reclosing functions, overvoltage and undervoltage protection, and intelligent switch input functionality. It also includes monitoring capabilities such as multi-parameter electrical measurement, remote control, and remote signaling.

● The device employs ultra-low power consumption design technology, ensuring reliable and rapid activation of protection functions under any conditions. Its structure is simple and compact, allowing for flexible and convenient installation, making it highly suitable for the confined installation conditions of ring main units.

● It offers three-stage overcurrent protection, two-stage zero-sequence (grounding) current protection, multiple IEC standard inverse-time curve options, and voltage protection functionality.

● Equipped with inrush current blocking to prevent false tripping of switches during transformer energization.

● Instantaneous overcurrent protection utilizes a fast algorithm with a short data window, ensuring rapid clearance of short-circuit faults and preventing unintended tripping.

● The protection configuration is flexible and comprehensive, with all protection functions freely enabled or disabled via control words.

● It includes comprehensive measurement and control functions, capable of measuring electrical parameters such as voltage (Ua, Ub, Uc), current (Ia, Ib, Ic, I0), second harmonic (Iax, Ibx, Icx), active power, reactive power, apparent power, and power factor. It features 4 switch output circuits with dedicated remote control relays for remote operation, and 8 intelligent switch input circuits with user-definable functions.

● The device uses a full Chinese LCD display interface with multi-level menu options, selectable Chinese/English menus, and pop-up event alarm windows, providing an extremely user-friendly human-machine interface.

● Designed with an automatic dynamic gain current measurement circuit, the device offers a very wide measurement range, accommodating current transformers with secondary ratings of either 1A or 5A.

● The system frequency (50Hz or 60Hz) can be user-defined, and the zero-sequence current acquisition method is selectable (external input or internal calculation).

● It operates reliably across an extremely wide temperature range and features waterproof and dustproof design, ensuring performance in various extreme environments.

● The device records up to 60 historical events, with data retention during power loss for easy fault analysis.

● It provides an RS485 communication interface and offers an open communication protocol to users.