GWZC-9802 DEF Relay Introduction
The GWZC-9802 Directional Earth Fault Relay is engineered for reliable protection in6kV and 11kV transmission and distribution networks. Utilizing a 32-bit DSP processor and 512KB FRAM memory, it detects and isolates ground faults with high precision through directional impedance analysis. Key technical highlights include 0.2% measurement accuracy for zero-sequence parameters, 32-cycle COMTRADE waveform recording for post-fault analysis, and adaptive anti-maloperation logic to prevent false trips. It integrates seamlessly into automation systems via multiple protocols like Modbus and DNP3.0, with low power consumption (<5W) and EMC Class IV certification. Designed for substation switchgear, it enhances grid resilience by minimizing downtime and supporting remote monitoring, ideal for modern, unmanned facilities.
GWZC-9802 DEF Relay Functions and Characteristics
- Primary Functions (ANSI Codes):
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- 67N: Directional earth fault protection for selective isolation.
- 21: Distance protection to identify fault locations.
- 50/51: Instantaneous and time-delayed overcurrent backup. .
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- Communication Functions:
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- Protocols: IEC 61850 (Optional), Modbus, DNP3.0, Ethernet RS485.
- Interfaces: 2×RJ45 ports for high-speed data exchange (100Mbps), enabling seamless SCADA integration.
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- Processing and Memory: 32-bit DSP core with 512KB FRAM (ensures 10-year data retention for fault logs).
- Measurement Accuracy: Monitors |Z|, Φ, I0, V0 with 0.2% precision for reliable fault discrimination.
- Input/Output Flexibility: 7×CT/VT inputs and 10×programmable relays for customizable trip circuits.
- Logic Configuration: LOGIC>EDIT™ graphical editor for easy protection logic programming.
- Trip Circuit: 250V AC/DC rated with seal-in monitoring to prevent nuisance operations.
- Time Synchronization: IRIG-B/PPS support (±1μs accuracy) for coordinated event recording.
- Anti-Maloperation: Adaptive TV algorithm filters noise to avoid false triggering.
- Communication: Dual Ethernet and fiber interfaces for redundant connectivity.
- Data Recording: 32-cycle COMTRADE waveform capture for detailed fault analysis.
- Low Power Design: <5W operation (compatible with 24-220V DC/AC supplies).
- EMC Robustness: Class IV certification (IEC 60255-26) for electromagnetic compatibility.
- Environmental Tolerance: Operates from -40°C to +85°C, ensuring reliability in extreme conditions.
GWZC-9802 DEF Relay Working Principle
Core Principle: Identifies faulty lines by detecting zero-sequence current characteristics generated during single-phase ground faults.
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- Continuously monitors zero-sequence current (3I 0 ) and zero-sequence voltage (3U 0 ) in all branches of non-solidly grounded neutral systems (6-35kV).
- Characteristic Analysis
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- Amplitude Comparison: Faulty line’s zero-sequence current exceeds non-fault lines (Formula: I 0(fault) =∑I 0(non-fault) ).
- Direction Discrimination: Phase angle between zero-sequence current and voltage in faulty lines is inverse (180°±10°), while non-fault lines share the same phase.
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- Combines transient/steady-state waveform analysis (e.g., initial half-wave direction, harmonic components) to eliminate interference and locate faults.
