Feeder Arc Protection Relay Product Introduction
The GWZC-9505 Feeder Arc Flash Protection Relay is an advanced solution for enhancing safety in medium voltage electrical systems. It combines highspeed light detection with overcurrent supervision to ensure rapid and selective tripping during arc flash events. The relay offers configurable protection logic, comprehensive event recording, and seamless integration with modern communication protocols.
Feeder Arc Protection Relay Technical Features
1. 32bit DSP processor with 128MB flash memory.
2. Measures light intensity, phase current, and ground current.
3. Configurable I/O: 8 digital inputs, 6 relay outputs, and 2 arc sensor inputs.
4. Programmable protection logic with AND/OR conditions for flexible operation.
5. Trip circuit supervision with healthy contact monitoring.
6. IRIGB time synchronization support for accurate event timestamping.
7. TV fuse failure detection with blocking function to prevent maloperation.
8. Dual communication ports: RS485 and Ethernet for versatile connectivity.
9. 128cycle fault recording in COMTRADE format for detailed analysis.
10. Low power consumption (<5W typical).
11. EMC compliance: IEC 6025526 Class A.
12. Operating temperature range: 40°C to +85°C.
Working Principle of Feeder Arc Protection Relay
Arc protection employs the “dual-criterion” or “primary-auxiliary criterion” principle, simultaneously detecting both arc light and current surge. A trip signal is issued only when both conditions (or at least the primary condition) are met. This significantly enhances reliability and prevents misoperation caused by single signals (such as flashes from switching operations or external strong light).
1. Primary Criterion – Arc Light Detection:
- Sensors: Point-type arc light sensors or fiber-optic arc light sensors are used.
- Point-type sensors: Installed at critical points inside the switchgear (e.g., circuit breaker compartment, cable compartment, busbar compartment) to directly detect visible light intensity in specific areas.
- Fiber-optic sensors: Fiber optics are wound around busbars or critical connection points to form a “detection network,” making them sensitive to arc light within specific areas.
- Principle: Sensors convert detected light signals into electrical signals and transmit them to the main control unit. When the light intensity exceeds the set threshold (adjustable), the arc light criterion is satisfied.
2. Auxiliary Criterion – Current Detection:
- Sensors: Conventional current transformers (CTs) are used.
- Principle: Monitors the current of the protected circuit. When an arc fault occurs, it is usually accompanied by a sudden current increase (though not necessarily large). The main control unit detects whether the current exceeds the set threshold (e.g., 1.2 times the rated current or higher), and the current criterion is satisfied.
3. Logic Judgment and Execution:
The main control unit of the feeder arc protection relay comprehensively evaluates signals from multiple sensors for logical judgment.
- “AND” Logic (Recommended): A trip command is issued only when both arc light and current surge are detected simultaneously. This is the most commonly used mode and prevents misoperation.
- “OR” Logic: A trip is triggered if either arc light or current surge is detected. Used in applications requiring extremely high speed, but anti-misoperation measures must be implemented.
The trip signal is sent to the circuit breaker of the feeder, causing it to open within an extremely short time (typically <10 ms; adding the breaker opening time, the total fault clearance time can be controlled within 50–100 ms), thereby interrupting the fault current.
